Search

Abstract Herein, we reported the adsorption and desorption of Pb(II) on l -lysine modified montmorillonite (L-Mt) with molecular dynamics simulation. l -lysine (Lys) modified montmorillonite (L-Mt) was prepared, characterized by various analytical techniques, and the simulation studies were performed to evaluate the interlayer structure and interaction properties of l -lysine and L-Mt. The results of X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) spectrum suggested that Lys+ was intercalated into the interlayer of Na-montmorillonite (Na Mt) successfully. The batch adsorption experiments were implemented to study the adsorption capacity of Pb(II) on L-Mt in water. The maximum adsorption capacity of Pb(II) on the L-Mt (up to 43.3 mmol/100 g) were considerably higher than that on Na Mt (up to 15.3 mmol/100 g), at room temperature. The adsorption isotherms of both, L-Mt and Na Mt can fit the Langmuir isotherm. The adsorption experiments showed that Pb(II) removal efficiency of L-Mt is better than Na Mt in acidic solution. The simulation results revealed the micro-mechanism of Lys+ inserted into the interlayer gallery of Na Mt. It can be deduced that lysine interacted with montmorillonite surface mainly through the protonated side-chain amino group rather than through the protonated main-chain amino group or deprotonated carboxyl group. These consequences are expected to elucidate the adsorption mechanisms occurring at the water/clay minerals interface at atom level, providing significant insight into the adsorption and retention of Pb(II) on L-Mt composite, and lead to relevant engineering applications while treating heavy metals of wastewater. Graphical abstract Unlabelled Image Highlights • l -lysine modified montmorillonite (L-Mt) has higher adsorption capacity for Pb(II) than Na Mt. Their maximum adsorption capacity is 43.3 mmol/100 g and 15.3 mmol/100 g, respectively. • L-Mt is more efficient on the retention of Pb(II) than Na Mt. When pH 3.0, the desorption ratio of Pb(II) is 16.08% and 58.31%, respectively. • The microstructure and interaction between lysine and Na Mt has been revealed by molecular dynamic simulation. [ABSTRACT FROM AUTHOR]

In this study, we reported a novel type-I heterojunction between red phosphorus and graphitic carbon nitride under vacuum condition, which is a novel synthesis process. For preparing the red phosphorus composites, the vacuum condition is appropriate to prevent it from self-ignition. The prepared materials were analyzed with different analytic techniques for the confirmation of their heterojunctions and structure formation. The introduction of red phosphorus into graphitic carbon nitride, reduce the structural defects and increase the charge separation ability. After medication, the synthesized composite shows an enhanced photocatalytic activity against acute toxicity category-III non-color (MTSM, Metsulfuron methyl) and color (RhB), organic pollutants. The photocatalytic degradation mechanism (Mott-Schottky and VB-XPS) study reveal that red phosphorus /graphitic carbon nitride possess type-I heterojunction with enhanced catalytic behavior, due to the effective transformation of photo-generated electrons from CB of GCN to CB of RP with the help of heterojunctions and due to unmoved photo holes on VBs. Synthesized composites also maintained their performance after reused them in three cyclic form. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Efficient Fe-ZrO 2 /g-C 3 N 4 photocatalyst successfully prepared. • FZ-GCN is efficient for the degradation of acarbose (ACB) and rhodamine (RhB). • Prepared catalyst have more degradation ability under visible light. • Acarbose (ACB) degradation products was studied. Abstract Fe-ZrO 2 imbedded g-C 3 N 4 was successfully prepaid by solvo-thermal method for the photo-degradation of anti-diabetic drug, acarbose (ACB). The synthesized material were characterized with the help of FT-IR-Spectroscopy, X-ray diffraction, UV–vis-Spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, HPLC-MS and scanning electron microscopy. These characterization results indicated that the target materials was well prepared and photo-catalytically active. The target catalyst (Fe-ZrO 2 /g-C 3 N 4) showed very high photo-degradation rate against acarbose (ACB) and rhodamine (RhB). Presence of heterojunction between FZ and GCN increased the surface area and light absorbance capability. HPLC-MS scrutiny indicated that photo-degradation process, under visible light, split the ACB into lot of intermediates and finally degraded completely. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-DP was first applied in the detection of organophophonates. • Fe-DP had highly selectivity and sensitivity for trace determination of DTPMP. • The micro-mechanism of fluorescence quenching was revealed. Diethylenetriamine pentamethylene phosphonic acid (DTPMP) is one of the most commonly used amino organic phosphonates. The existing methods for DTPMP detection are complicated, time-consuming, and cannot detect trace DTPMP in the natural environment. In the present work, the Fe-based 3,5-dimethyl pyrazole fluorescent sensor (Fe-DP) was constructed. The addition of Fe3+ to DP solution can greatly decrease the fluorescent intensity of DP, while the addition of different concentrations of DTPMP will restore the fluorescence intensity of DP to different degrees, to achieve quantitative detection of DTPMP, and the detection limit (LOD) of DTPMP was lower as 0.105 μΜ. The Fe-DP fluorescent sensor exhibited excellent anti-interference ability and good stability. Moreover, the fluorescence quenching mechanism of DP by Fe3+ was revealed by UV absorption spectrum and Multiwfn wavefunction analysis based on density function theory (DFT). The results revealed that the excitation of DP belonged to local excitation, in which the electrons were donated primarily by the N atom with double bond and redistributed within the pyrazole ring. The fluorescence quenching of adding Fe3+ was not caused by resonance energy transfer or charge transfer, which did not belong to dynamic quenching, but due to the ground state complex formed by the coordination of Fe3+ and the double bond N atom on the DP pyrazole ring. [ABSTRACT FROM AUTHOR]

Using condensation heat from cold storage refrigeration systems to provide heat for domestic hot water preparation and industrial hot water supply promotes energy conservation. However, few studies have investigated cold storage condensation heat recovery using phase change materials (PCMs). In this study, a cold storage condensation heat recovery system that uses PCMs has been designed and analysed. According to the principle of energy cascade recycling, different operation modes could be effectively switched to recycle condensation heat. Furthermore, a novel and suitable phase change composite material is developed for cold storage condensation heat recovery, which has a relatively large latent heat, high thermal conductivity, and an appropriate phase change temperature (i.e. 80 °C). With carnauba wax (CW) as the PCM and expanded graphite (EG) as the additive, a composite was developed with an optimal mass ratio of CW:EG = 10:1. The thermal and physical properties and the interior structure of the composite were then investigated using a scanning electron microscope (SEM), thermal constants analyser (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting and solidification processes and accelerated thermal cycling were also conducted. It was found that at the optimal mass ratio of 10:1, the temperatures of the CW/EG composite in the melting and solidification processes were 81.98 °C and 80.43 °C, respectively, while the corresponding latent heats were 150.9 J/g and 142.6 J/g, respectively. During both processes, CW could retain its original worm-like structure after being completely adsorbed by EG. Compared to only CW, the melting and solidification time of the CW/EG composite were reduced by 81.7% and 55.3%, respectively, while its thermal conductivity was 16.4 times higher. After 1000 runs of accelerated thermal cycling, the endothermic/exothermic phase change temperatures of CW and the CW/EG composite increased by only 0.42%/0.42% and 0.23%/0.27%, respectively, while their endothermic/exothermic latent heats decreased by 4.96%/4.78% and 2.05%/3.44%, respectively. These results indicate that both CW and the CW/EG composite have excellent thermal reliability, while the CW/EG composite exhibits a slightly better performance. Finally, the experiments show that the CW/EG composite has desirable thermal and physical properties such as high thermal conductivity and reliability; Hence, it has good potential as a material for facilitating condensation heat recovery from cold storage refrigeration systems. [ABSTRACT FROM AUTHOR]

A simple co-precipitation method was used to synthesize ibandronate nano-functionalized hydroxyapatite (IB-HAP) and used for the removal of Pb2+/Cu2+ and chlortetracycline. The effects of the amount of modifier IB added, the initial concentration and the pH value of the solution on the adsorption effect of heavy metal ions were investigated. When the P atom in IB accounts for 5% of the total phosphorus, the adsorption capacity of IB-HAP was 1565.3 mg/g (Pb2+) and 246.71 mg/g (Cu2+), respectively. By adding heavy metal ions and chlortetracycline (CTC) in different addition sequences, the co-adsorption effect of various pollutants on IB-HAP was studied. According to microstructure analysis and simulation, the adsorption mechanism was studied from a microscopic point of view. It is the first time that modifiers and pollutants were used as central molecules to study the interaction sites and interaction strengths with surrounding molecules in a wholly covered state by Hirshfeld surface analysis. Finally, the desorption experiments showed that IB-HAP had strong regeneration and sustainability. These results showed that IB-HAP was a potential adsorbent, and this study also provided new guidelines and valuable methods for analyzing the mechanism of co-adsorption of heavy metal ions and antibiotics. [Display omitted] • IB-HAP was synthesized, and its single adsorption capacity was 1565.3(Pb2+) and 246.71(Cu2+) mg/g, respectively. • Different addition sequences would affect the co-adsorption effect of Cu2+/Pb2+ and chlortetracycline. • The interactions in completely surrounded states were firstly studied by Hirshfeld surface analyses. • Hydrogen bond and coordination interaction were the main force for the adsorption process. • IB-HAP had strong regeneration and sustainability. [ABSTRACT FROM AUTHOR]

Our previous studies have shown that the modification of hydroxyapatite with organic phosphonates can greatly improve the adsorption effect of hydroxyapatite on heavy metal ion pollutants. Hydroxyethylydene-1,1-diphosphonate (HEDP) is a widely used multi-purpose chemical agent with the advantage of lower-cost, but the preparation and application of hydroxyapatite composites doped by HEDP have not been reported. Therefore, in the present work, calcium nitrate and diammonium hydrogen phosphate were used as the calcium source and inorganic phosphorus source, respectively. 5%, 10%, 20% and 25% HEDP was added as an organophosphine source in the process of preparing hydroxyapatite （HAP）to obtain inorganic-organic phosphorus hybrid HAP composite materials with different HEDP doping amounts, respectively. XRD characterization showed that when HEDP doping was 20% of total phosphorus, the crystallinity of the resulting composite material was greatly reduced and became amorphous HAP, and the maximum adsorption capacity of the obtained amorphous HAP was 1893.7 mg/g, 239.3 mg/g, 285.4 mg/g, and 339.7 mg/g for Pb2+, Cu2+, Zn2+ and Cd2+, respectively, which was 8.47, 4.25, 3.29, 3.41 times that of the commercial HAP, respectively. Furthermore, Hirshfeld surface analysis specially including fingerprint plot was applied to investigate the interaction between HEDP and HAP, and reduced density gradient (RDG) method was carried out to explore the interaction mechanism of HEDP doping amorphous HAP composite and heavy metal ions. Because of the low price of HEDP, the simple and low-consumption preparation method and the excellent removal effect to various heavy metal pollutants, the inorganic-organic phosphorus hybrid amorphous HEDP-HAP composite material will have broad application prospects in the field of heavy metal pollution control. [Display omitted] • Inorganic-organic phosphorus hybrid amorphous HEDP-HAP was synthesized. • The adsorption capacity of HAP-H-2.0 was much higher than that of HAP. • Hirshfeld surface analysis combined fingerprint plot were applied. • RDG was firstly used to reveal the interaction mechanism among different fragments. [ABSTRACT FROM AUTHOR]

Highlights: [•] Crystal morphology of ANPyO in vacuum and solvent was predicted by attachment energy. [•] Crystal shape becomes very close to a flake in trifluoroacetic acid solvent. [•] Interaction energies include hydrogen bond, Coulomb and Van der Waals forces. [•] Analysis of solvent self-diffusion coefficient shows stirring affects crystal habit. [ABSTRACT FROM AUTHOR]

Abstract: Molecular dynamics (MD) simulations were employed to investigate the interactions between polyether polyamino methylene phosphonate (PAPEMP) with different degrees of polymerization (n=1–7) and (010), (020) crystal surfaces of anhydrite. An aqueous environment was added through the introduction of water in the simulation cell. The results showed that PAPEMP molecules attach to the surfaces rather than remain in the bulk water and the interactions of the same PAPEMP molecule with the two surfaces show small differences; under the same mass of PAPEMP (n=1–7), the order of the binding energy E m of PAPEMP is as follows: PAPEMP (n=3)>PAPEMP (n=2)>PAPEMP (n=1)>PAPEMP (n=4)>PAPEMP (n=6)>PAPEMP (n=5)>PAPEMP (n=7). The number of the functional groups and the stereo-hindrance effect are two main factors influencing the interactions between PAPEMP and anhydrite. When n≤3, the former is the main factor; while n>3, the latter is the main factor. The binding energies are mainly provided by the ionic bond and the non-bonding interaction. The structures of the polymers are deformed during the combining processes. Simulation results provide theoretical guidance to judge the performance of scale inhibitors, and synthesize new highly effective scale inhibitor. [Copyright &y& Elsevier]

• Cu-MOF-74 was first applied in the detection of organophophonates. • Cu-MOF-74 had highly selectivity and sensitivity for rapid determination of ATMP. • The fluorescence intensity of Cu-MOF-74 increased 24.2 times by adding 90 μΜ ATMP. • The mechanism of action between Cu-MOF-74 and ATMP was firstly revealed. Due to the lack of rapid and efficient detection methods for the determination of trace organic phosphonate concentrations in the natural aqueous system, little is known about their impact on the ecosystem. Amino trimethylene phosphonic acid (ATMP) is an organic phosphonate that has been widely used in many fields. In the present work, the copper-based organic framework material (Cu-MOF-74) for the specific detection of amino trimethylene phosphonic acid (ATMP) in aqueous solution was prepared by hydrothermal synthesis using 2,5-dihydroxyterephthalic acid (DHTP) as raw material and copper nitrate trihydrate as metal source. The synthesized material can be used as a "turn-on" fluorescent sensor for the specific sensing of ATMP, the fluorescence intensity of Cu-MOF-74 can be enhanced 24.2 times by ATMP (90 μΜ), the emission wavelength of the fluorescence emission spectrum of the system was blue-shifted, and the detection limit (LOD) of ATMP was 0.844 μΜ. Moreover, the mechanism of ATMP greatly increasing the fluorescence intensity of Cu-MOF-74 was investigated by experimental and theoretical calculations of quantum chemistry. The experimental results showed that ATMP was involved in the coordination of open metal sites in Cu-MOF-74. Multiwfn wavefunction analysis results demonstrated that the charge transfer from the benzene ring and hydroxyl groups of the ligand to the metal (LMCT) occurred during the electron excitation of Cu-MOF-74, but after adding ATMP, the coordination of ATMP with copper led to the interruption and reduction of the energy transfer and electron transfer from ligand DHTP to Cu2+, and the fluorescence intensity of Cu-MOF-74 was improved. The Cu-MOF-74 fluorescent probe exhibited excellent anti-interference ability, high selectivity, good fluorescence intensity stability in the short term, so it can be used as a reliable fluorescent probe for the highly specific detection of low concentration ATMP, the revealed microscopic mechanism of Cu-MOF-74 fluorescent probe to ATMP from the atomic level can provide a theoretical basis for the research of new fluorescence detectors. [ABSTRACT FROM AUTHOR]

Amino trimethylposphonate(ATMP) functionalized HAP were synthesized with different ATMP addition (0, 5%, 10%, 15%) and the adsorption performance towards Pb2+ and Cd2+ were studied in an aqueous solution. Under the optimum condition, HAP with ATMP addition of 10% (10AT-HAP) displayed the most efficient adsorption performance with the adsorption capacity of 1458.79 mg/g and 321.26 mg/g towards Pb2+ and Cd2+, respectively, which improved 76% and 92% than that of the artificially prepared HAP in the laboratory, respectively. For both heavy metal ions, the adsorption mechanism also included ion exchange and surface complexation, in which the surface complexation played a predominant role. In addition, XRD showed that a new crystal phase was formed after Pb2+ adsorption, while no new phase appeared after Cd2+ adsorption, indicating that the adsorption mechanism of Pb2+ involved dissolution-precipitation. The fitting results of adsorption isotherm and kinetics showed that the adsorption of Pb2+ and Cd2+ on HAP and 10AT-HAP were well fitted by the Langmuir isotherm model and Pseudo-second model. Moreover, Multiwfn wavefunction program based on density functional theory (DFT) was applied to deeply probe and vividly visualize the interaction sites, interaction types, interaction strength and the essence of interactions between HAP and ATMP or ATMP-HAP composite and heavy metal ions. [Display omitted] • The adsorption capacity of 10AT-HAP on Pb2+ and Cd2+ reached 1458.79 and 321.26 mg/g. • The adsorption mechanisms were revealed by experiment and Multiwfn program. • ATMP formed ternary complex with HAP and heavy metal ions. • The oxygen atoms of the phosphate groups of ATMP played a major complexation role. [ABSTRACT FROM AUTHOR]

Two gemini surfactants propylbis (dodecyldimethyl) ammonium chloride (12−3−12) and propylbis (octadecyldimethyl) ammonium chloride (18–3-18) with different chain lengths were used to modify Ca- montmorillonite (Ca-Mt). XRD results showed that the arrangement of surfactants was mainly paraffin-type and with additional minor lateral-bilayer in the interlayer space of montmorillonite. Batch adsorption tests indicated that the modified organo-montmorillonite (G 12 -Mt and G 18 -Mt) had better removal effect on three benzotriazole emerging contaminants (ECs) than that of original Ca-Mt, and the sequence of adsorption capacity was 1-Hydroxybenzotriazole (OHBTA) > benzotriazole (BTA) >5-methylbenzotriazole (TTA). Molecular dynamics simulation was carried out to reveal the arrangement, conformation and behavior of Gemini surfactants in the interlayer of Mt. at atomic level. The results suggested that one of the two long alkyl chains was erected in a paraffin-type arrangement, the other long alkyl chain accompanying with the positively charged N head groups & the propyl spacer were parallel to the Mt. (001) plane and was fixed near the top and bottom surfaces with the arrangement of lateral-bilayer, which was agreement with the XRD data. BTA molecules located at the aggregate organic phase formed by the alkyl chain, while Cl− ions preferred to appear in the middle area of the interlayer of montmorillonite. Meanwhile, Multiwfn wavefunction program was applied to quantitatively analysis the molecular surface area in different electrostatic potential (ESP) intervals, the ESP minimum & maximum values on the three ECs molecular vdW surface, integrating with color-filled ESP planar maps and VMD program to insight the electrostatic interaction and magnitude order between Gemini surfactants modified Ca-Mt and three pollutants. The adsorption mechanisms of Gemini surfactants modified Mt. to three benzotriazole emerging contaminants involved electrostatic interaction and hydrophobic partitioning effect. [Display omitted] • ESP distribution was used to quantitatively assess the electrostatic interaction. • MD simulation was used to reveal the dynamics of interlayer species. • The adsorption effects of different gemini surfactants modified Mts were compared. • The adsorption micromechanisms were uncovered. [ABSTRACT FROM AUTHOR]

• Surface grafted HEDP-HAP composite was applied to the removal of Pb2+ and Cu2+. • The maximum uptake amount of Pb2+ and Cu2+ was 1521 mg/g and 168.9 mg/g, respectively. • Quantitative molecular surface analysis was applied to predict the active sites. • Becke surface analysis was implemented to reveal the H-bond between HEDP2− and HAP. • IGM and VMD were performed to visualize the interaction among different fragments. A simple hydrothermal method was employed to prepare the surface grafted 1-hydroxyethylidene-1,1-diphosphonic acid-hydroxyapatite (HEDP-HAP) composites, which were termed as 0.2HEDP-HAP, 0.5HEDP-HAP and 1HEDP-HAP respectively, according to the HEDP content. Adsorption experiments showed that the maximum adsorption capacity of 0.5HEDP-HAP for Cu2+ reached 168.9 mg/g, which was 4.19 times that of HAP, while the maximum adsorption capacity of 1HEDP-HAP for Pb2+ was as high as 1521 mg/g, which was approximately 10 times that of HAP. For the first time, the interaction mechanism of HEDP with HAP, or HEDP-HAP composite with the two heavy metal ions was illustrated by the combination of quantum chemistry (QC) calculation, quantitative analysis of molecular surface, Becke surface analysis and Independent Gradient Model (IGM) method. The active reaction sites, the types, relative strength and essence of the interactions were revealed based on the visual analysis of interactions. The results demonstrated that the phosphonic acid group (PO 3 H−) of HEDP2- can form hydrogen bonds with the phosphate group (PO 4 3-) and the hydroxyl group (OH) of HAP. The oxygen atom of PO 3 H- provided lone pair electrons to form chelate with Ca2+ of HAP, which resulted in the strong affinity of HEDP with HAP. Moreover, the significant improvements of uptake of surface grafted HEDP-HAP for Cu2+ and Pb2+ were due to the formation of the ternary surface complexes. [ABSTRACT FROM AUTHOR]

• AL-HAP was synthesized and used to remove heavy metals from wastewater firstly. • AL-HAP had a huge improvement on the adsorption capacity to Pb2+, Cu2+ and Cd2+. • DFT, HOMO, ESP and IGM were firstly applied to explore the properties of AL-HAP. • AL and metal ions form a ternary complex with HAP to improve removal of metal ions. • There were ionic bond, hydrogen bonds and van der Waals interactions. In this paper, a new nanobiomaterial, alendronate hydroxyapatite (AL-HAP), was synthesized by the conventional co-precipitation method with alendronate (AL) as dopant, and applied in the removal of heavy metal contaminants for the first time. The characterization results showed that the crystallinity of the AL-HAP nanocomposite biomaterials after doping has been greatly deteriorated, and the pore volume and pore size increased. When the doping amount of AL was 10 %, the maximum adsorption capacity of AL-HAP for Pb2+, Cd2+ and Cu2+ can reach 1431.8, 469 and 226.6 mg/g, respectively, which was much higher than that reported in other literature. Meanwhile, the adsorption mechanism of AL-HAP for heavy metal ions was discussed from both the views of experimental and Multiwfn program theoretical calculation based on density functional theory (DFT). Quantitative molecular surface analysis was carried out for the first time to study the minimum points and the positions of electrostatic potential (ESP) and average local ionization energy(ALIE), as well as the exact values, giving more accurate and reliable analysis conclusions for the reaction sites and binding mode. In addition, the independent gradient model (IGM) method was also firstly applied to investigate the interactions between AL and HAP or AL-HAP nanocomposite with metal ions. AL-HAP is a potential adsorption material for heavy metal wastewater treatment and soil remediation because of its advantages such as convenient synthesis, excellent adsorption performance and no secondary pollution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Environmentally friendly D-Mt composite is prepared. • The adsorption of AMP and AMX by D-Mt-1.4 under different conditions was studied. • DFT was applied to quantitatively analyze the molecular surface of AMP and AMX. • Multiwfn program was applied to quantitatively analyze the molecule surface. The quaternary ammonium surfactant-dodecyl benzyl ammonium chloride (DDBAC) was applied to modify Ca-montmorillonite (Ca-Mt) to obtain organo D-Mt that was used as the adsorbent for micropollutants-ampicillin (AMP) and amoxicillin (AMX). The XRD characterization indicated that DDBAC intercalated the interlayer space of Ca-Mt. When the amount of modifier was 1.4 CEC, the basal spacing enlarged from 1.53 nm to 2.97 nm, and the arrangement of modifier molecules were sloped in the interlayer of Ca-Mt along the longest axis. The saturated adsorption capacity of D-Mt-1.4 for AMP and AMX was 30.86 mg/g and 13.29 mg/g, respectively, while the saturated adsorption capacity of Ca-Mt for two contaminants was only 0.36 mg/g and 0.16 mg/g, respectively. The adsorption of the two pollutants was more consistent with Freundlich adsorption isotherm second-order kinetic model, and the thermodynamic study suggested that adsorption was more likely to occur at higher temperatures, which means that the adsorption of two pollutants was a spontaneous endothermic process. Moreover, Multiwfn wavefunction program based on Density Functional Theory (DFT) was applied to reveal the microadsorption mechanism of D-Mt to two pollutant molecules. This work confirmed that Ca-Mt functionalized by DDBAC was promising adsorbents for micro-contaminants of antibiotics and the insight of the adsorption mechanism from the atomic level, providing theoretical guidance for architecting high performance adsorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel ampholytic surfactant was firstly used to modify acidified Na-Mt. • Cationic panthenol modified Na-AMt had a higher adsorption capacity to two pollutants. • The arrangement of different components in the interlayer of Mt was revealed. • The bonding characteristics and dynamic behavior of different species were explored. • The electrostatic interaction and hydrophobic partitioning were demonstrated. A novel ampholytic surfactant (cationic panthenol, CP) modified montmorillonite (CPMMt) was firstly prepared and investigated its removal effect and mechanism for a class of emerging pollutants such as benzothiazole (BTH) and 2-hydroxybenzothiazole (2-OH-BTH) in water. Batch experiments were conducted to probe the effects of various conditions on the adsorption. The results showed CPMMt-1.0 had greater adsorption performance for BTH and 2-OH-BTH than Na-AMt (acidified Na-Mt), and the maximum equilibrium adsorption capacities of CPMMt-1.0 for BTH and 2-OH-BTH were three times that of Na-AMt. Zeta potential analysis, the effect experiments of solution pH combined with Multiwfn wave function program were carried out to inspect the electrostatic interaction. Furthermore, molecular dynamics simulation was applied to investigate the dynamics behavior of cationic panthenol (CP) and BTH or 2-OH-BTH in the interlamellar of montmorillonite. The results demonstrated that CP molecules presented a lateral bilayer structure, which was in good agreement with XRD experimental data, and the interaction between BTH and the surface of montmorillonite was stronger than that of 2-OH-BTH, which implies that the CPMMt-1.0 had better adsorption performance for BTH than 2-OH-BTH, which was consistent with the experimental results. The adsorption mechanism involved electrostatic interaction and hydrophobic partitioning. [ABSTRACT FROM AUTHOR]

Benzyldimethylhexadecylammonium chloride (HDBAC) modified montmorillonite was synthesized and the compounds were used for the adsorption of diclofenac sodium (DCF) and ibuprofen (IBU). The adsorption effect was the best when the best dosage of the HDBAC was 1.6 CEC (cation exchange capacity). The adsorption capacity (q e) of H-Mt-1.6 for DCF and IBU was 125.55 mg/g and 81.64 mg/g, respectively. The q e of Ca-Mt for DCF and IBU was 54.02 mg/g and 13.14 mg/g, respectively. H-Mt-1.6 had higher adsorption effect than Ca-Mt. The adsorption process of H-Mt-1.6 on DCF followed the Langmuir adsorption model and the adsorption process of IBU followed the Freundlich adsorption model. The equilibrium could be reached after 120 min. The adsorption process of H-Mt-1.6 on DCF and IBU followed a pseudo-second-order kinetic model. The adsorption on DCF was endothermic, while adsorption on IBU was exothermic. [Display omitted] [ABSTRACT FROM AUTHOR]

• Montmorillonite was modified with green and environment-friendly Histidine salt. • His-Mt is proved to be a high-efficiency adsorbent for removal of heavy metal ions. • Maximum adsorption capacity for Pb(II) and Cu(II) with His-Mt is 107.73 mg/g and 30.72 mg/g. • Ion exchange is main mechanism by Na-Mt by forming Pb(CO 3) 2 or Cu(OH) 2. A novel nanocomposite of sodium montmorillonite with L-Histidine (His-Mt), was prepared to remove Pb(II) and Cu(II) from aqueous media. The resulting nanocomposites were characterized by XRD, FT-IR, BET, SEM, TG/DTG, XPS techniques. All characterizations confirmed the anchoring of L-Histidine to Na-Mt, and the packing sequence of His in the interlayer gallery may form a monolayer structure. The His salt obtained a skewed orientation compared to the silicate surface. The single/ co-adsorption of Cu(II) and Pb(II) by pure and modified i.e. Na-Mt and His-Mt were carried out by batch adsorption experiments. The maximum adsorption capacity (q max) of Pb(II) and Cu(II) by Na-Mt and modified His-Mt was 89.08 mg/g, 23.93 mg/g, and 107.73 mg/g, 30.72 mg/g, correspondingly. The pseudo-second-order model (kinetic model) and Langmuir model (isotherm model) well-matched with the adsorption process. The data analysis showed it was an endothermic, favorable and spontaneous process, Cu(II) and Pb(II) showed competitive adsorption in the co-adsorption system. Na-Mt adsorbed M(II) ions by ion exchange mechanism, while M(II) formed complexes with histidine and were adsorbed in the interlayer region or the surface of His-Mt. [ABSTRACT FROM AUTHOR]

• A green and environment-friendly modifier was used to prepare Met-Mt. • The mechanism of adsorption by Met-Mt was studied by ESP and ALIE analysis. • Met-Mt exhibits excellent performance for removal of Pb2+. A novel and platelike nanomaterial of methionine-montmorillonite composite was successfully prepared and applied to the adsorption of lead ions in aqueous. The application of a series of characterization methods, such as XRD, FT-IR, BET, TG/DTG, SEM revealed the morphology, structure and physicochemical properties of the nanocomposites and confirmed the anchoring effect of methionine on Na-Mt. Furthermore, it has been demonstrated that the filling arrangement of methionine in the interlayer channel can be oriented along the y-axis or the z-axis or inclined to the silicate surface to form a single layer structure. Under optimized experimental conditions, Met-Mt-0.8 composites were verified to be the most effective adsorbent for Pb2+ ion along with a maximum adsorption capacity of 117.79 mg/g, significantly higher than that of Na-Mt (101.11 mg/g). Gaussian program and Multiwfn program were united to take a sight on the microscopic adsorption mechanism of Met-Mt and Pb2+, concluding that methionine formed a complex with lead ions and facilitated them to lock in the montmorillonite layer. Moreover, methionine is ligated with Pb2+ by oxygen atom on C-OH in the carboxyl group. [ABSTRACT FROM AUTHOR]

Sodium lignosulfonate (Na-LS) was used to modified montmorillonite to form lignosulfonate-montmorillonite (LS-MMT). The as-prepared samples were characterized by various equipment to analyze the surface morphology and structure of the pure and reformed samples. The adsorption capability (q e , mg/g) of LS-MMT or Ca/Na-MMT for Pb(II) and Cu(II) at different reaction intervals, the concentration of metal ions, temperature, and pH were studied by batch adsorption experiments. The results revealed that LS-MMT displayed a higher adsorption capacity than Ca/Na-MMT. The pH of solutions had a great influence on the q e of the two adsorbents, and the q e was slightly enhanced with temperature increasing. The isotherm and kinetic experiments studies indicated that the adsorption of heavy metal on LS-MMT or Ca/Na-MMT fit well with the Langmuir model and pseudo-second-order kinetic model. The competitive adsorption showed that LS-MMT had a stronger affinity for Pb(II) than Cu(II), which was different from Ca/Na-MMT. Additionally, the desorption experiment showed that LS-MMT had a stronger ability to lock heavy metal ions than Ca/Na-MMT in an acidic environment with pH ranging from 3 to 5. Unlabelled Image • Lignin is a non-toxic natural polymer comprising many functional groups, i.e. carboxy, phenol, hydroxyl and methoxy groups. • The results revealed that LS-MMT displayed a higher adsorption capacity than Ca/Na-MMT. • The isotherm and kinetic experiments fit well with the Langmuir model and pseudo-second-order kinetic model. • The competitive adsorption showed that LS-MMT had a stronger affinity to Pb(II) than Cu(II). • LS-MMT had a stronger ability to lock heavy metal ions in an acidic environment with a pH range from 3 to 5. [ABSTRACT FROM AUTHOR]

Abstract A novel Gemini surfactant, Propyl bis (hexadecyl dimethyl ammonium) chloride (16-3-16), was utilized to modify Ca-montmorillonite (Ca-Mt) to obtain organo-montmorillonite (G-Mt). The structure and morphology of G-Mt were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS), Thermogravimetric analysis (TGA), N 2 adsorption/desorption isotherms (BET) and Zeta potential. G-Mt was used to adsorb a class of emerging contaminants (ECS) such as 1-Hydroxybenzotriazole (HOBT), 1H-Benzotriazole (BTA) and 5-Methyl-1H-benzotriazole (TTA) from wastewater. Molecular dynamic (MD) simulations were performed to reveal the arrangement of 16-3-16 in the interlayer gallery of Ca-Mt. Furthermore, the adsorption properties of G-Mt were observed under different experimental conditions. The results showed that the saturation loading of 16-3-16 on Ca-Mt was 1.0 CEC and the maximum adsorption capacities at equilibrium were 25.93 mg/g, 18.31 mg/g and 16.24 mg/g for HOBT, BTA, and TTA, respectively. However, the adsorption capacities of three contaminants on Ca-Mt were only 2.37 mg/g, 1.28 mg/g, and 1.06 mg/g. The optimum removal of HOBT, BTA and TTA occurred at pH 4, 9, 9 respectively. The adsorption processes of three contaminants fitted well with the Langmuir isotherm model and the pseudo-second-order model. Thermodynamic results indicated that the adsorption processes of HOBT, BTA, and TTA on G-Mt were spontaneous and endothermic. These researches are expected to provide a sixpenny and efficient method to treat emerging contaminants in wastewater. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Synthesis of Sup-Bi 2 O 3 /Bi 2 MoO 6 under optimized reaction conditions i.e. time, pH and concentration. • The photocatalytic activity of the synthesized Sup-Bi 2 O 3 /Bi 2 MoO 6 is better in polar solutions. • Sup-Bi 2 O 3 /Bi 2 MoO 6 composite presents zero gap heterojunction. • Tetracycline (TC), ciprofloxacin (CPFX), Rhodamine B (RhB), and Methylene blue (MB) degraded successfully. Abstract In this article, Bi 2 O 3 /Bi 2 MoO 6 composites were synthesized hydrothermally under optimized conditions, by adjusting pH, the concentration of polyvinylpyrrolidone (PVP (K30)) and reaction time. During the synthesis process, flower-root shaped zero-gap Bi 2 O 3 /Bi 2 MoO 6 heterojunctions were successfully synthesized. The adopted samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), Photoluminescence (PL), and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity was measured under visible-light-irradiation (λ > 420 nm) by degrading tetracycline (TC), ciprofloxacin (CPFX) (antibiotics) and rhodamine B (RhB), methylene blue (MB) (dangerous dyes). The degradation results indicated that photocatalyst sample synthesized at pH 9.0, PVP (K30) 0.05 mol/L and 80 min reaction time (Sup-Bi 2 O 3 /Bi 2 MoO 6) demonstrated highly efficient performance. The Sup-Bi 2 O 3 /Bi 2 MoO 6 showed the highest apparent rate constant (K app) that's 50% more than the samples prepared at ordinary conditions. Photocatalytic degradation order was i.e. RhB > TC > CPFX > MB, which depends on the polarity of the degrading medium. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor based on nitrogen doped graphene (NGE) and palygorskite (Pal) for the simultaneous detection of hydroquinone (HQ) and catechol (CT) has been proposed. Pal is particularly pointed out for its appreciable specific surface area and reactive-OH groups on its surface. Acid treatment Pal demonstrated better physico-chemical properties, which are propitious to electrochemical sensor construction. The introduction of NGE not only improved the poor conductivity of Pal but also served as an excellent adherent matrix. The modified electrode demonstrated the enhanced redox peak currents of HQ and CT with good discrimination. Under optimized conditions, the linear ranges for HQ and CT were 2–50 μM and 1–50 μM, with detection limit (LOD) of 0.8 μM and 0.13 μM, respectively. The result designates that the Pal/NGE composite promises to be a new eco-friendly modified material for sensor fabrication. [ABSTRACT FROM AUTHOR]

A novel metal free, graphitic carbon nitride self-type heterojunction was successfully created. A self-type heterojunction between two different kind of graphitic carbon nitride with a promote charge separation ability, one was prepared by solvothermal using the dicyandiamide as precursor and other was prepared by direct heating from melamine precursor. This synthesis process is facile, economical and environment friendly. The confirmation of synthesis and heterojunction formation was based on the X-ray-Diffraction, Transmission electron microscopy, Scanning electron microscopy, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and photocurrent. The potential difference in heterojunction between different types of g-C 3 N 4 is the main acting power for the proficient separation and transformation of photo generated charges. Degradation results indicated that, the removal of antibiotic from effluents, graphitic carbon nitride heterojunction (GCN-DM) pointedly enhanced the visible light catalytic activity over solo graphitic carbon nitride (GCN-D, GCN-M). The improved photocatalytic behaviour of heterojunction may be due to charge separation and transfer ability with prolong lifetime of photo-generated charge carrier. The results also indicated that the optical and surface area properties also play a significance role in enhancement of photo-catalytical ability of target photo-catalyst. [ABSTRACT FROM AUTHOR]

In order to understand the mechanism of the effect of solvent on the crystal morphology of explosives, and be convenient for the choice of crystallization solvent, the attachment energy (AE) model was performed to predict the growth morphology and the main crystal faces of 1,3,3-trinitroazetidine (TNAZ) in vacuum. The molecular dynamics simulation was applied to investigate the interactions of TNAZ crystal faces and ethanol solvent, and the growth habit of TNAZ in ethanol solvent was predicted using the modified AE model. The results indicate that the morphology of TNAZ crystal in vacuum is dominated by the six faces of [0 2 1], [1 1 2], [0 0 2], [1 0 2], [1 1 1] and [0 2 0], and the crystal shape is similar to polyhedron. In ethanol solvent, The binding strength of ethanol with TNAZ faces changes in the order of [0 2 1] > [1 1 2] > [0 0 2] > [1 0 2] > [1 1 1] > [0 2 0], which causes that [1 1 1] and [0 2 0] faces disappear and the crystal morphology becomes more regular. The radial distribution function analysis shows that the interactions between solvent and crystal faces mainly consist of coulomb interaction, van der Waals force and hydrogen bonds. [ABSTRACT FROM AUTHOR]

[Display omitted] • "Pre-embedded seed then growth" ensures the stability of the adsorbent structure. • Co-doping of dual-functional components exhibits effective synergistic adsorption. • Theoretical calculations of ligand exchange and hydrogen bonding mechanisms. • Adsorbents that degrade after adsorbing phosphates have fertilizer effect. • Proposing a closed-loop design from waste utilization to treatment and final reuse. Recovering and reusing of phosphorus (P) in wastewater is the optimal solution to address mineral shortages and eutrophication. Here, the layered double hydroxides (LDHs) grown on wood-derived aerogels (WAs) were prepared after screening the powdered precursors and named La/MgFe-LDH(LS)@WAs. The intricate pore structure and surface morphology of the WAs formed a fibrous network with ultra-low density, good strength and elasticity, allowing for uniform loading. The sample exhibited excellent adsorption capacity of 139.5 mg P/g at pH 4.0, and over 100.0 mg P/g within a wide pH range (3.0–8.0). Thomas and Yoon-Nelson models could effectively describe the dynamic adsorption process. Microscopic morphology and textural characteristics of the samples were characterized and molecular dynamics (MD) simulations and theoretical calculations based on density functional theory (DFT) were used to study the interaction mechanisms. The coordination bonds and weak interactions between the active component LS and La(OH) 3 with phosphates were characterized using interaction region indicator (IRI) and independent gradient model based on Hirshfeld molecular density partitioning (IGMH) methods. The atomic δg index mapped to the molecular structure vividly illustrated the maximum contribution of hydroxyl hydrogen to phosphate deprotonation oxygen in inter-fragment interactions on LS. Combining the formation of Me-O-P bonds characterized by X-ray photoelectron spectroscopy (XPS), the mechanism involves weak interactions (hydrogen bond) and chemical adsorption via ligand exchange. High removal efficiency was demonstrated in real wastewater. A method for waste reuse was also proposed. Plant cultivation experiments showed that La/MgFe-LDH(LS)@WAs could sustain wheat growth with slowly degrade and maintain high phosphate availability. The composite shows potential for water restoration, waste treatment, and value-added conversion in the production of controlled-release fertilizers. [ABSTRACT FROM AUTHOR]

In a water solution and with a low reaction temperature of 85 °C, the green preparation of lanthanum-modulated MOF-808 (Zr) was realized, the obtained La-MOF-808 have smaller grain size, larger specific surface area, higher pore volume and larger average pore diameter. When the molar ratio of La: Zr=1:1, 1L-MOF-808 had the best fluoride ion removal performance, and its maximum adsorption capacity for F- reached 101.4 mg/g, which was higher than that of the unmodulated MOF-808 and some other reported fluorine adsorbents. Meanwhile, the regeneration experiment demonstrated that even after five cycles, 1L-MOF-808 retained 73.8 % of its initial adsorption capacity, highlighting its commendable reusability. In addition, when 1L-MOF-808 was applied to actual fluorine-containing wastewater, with the fluoride ion concentration of 25.3 mg/L and an adsorbent dosage of 0.6 g/L, 1L-MOF-808 exhibited excellent resistance to anionic interference (SO 4 2-, Cl-), the concentration of fluoride ions in effluent was lower than 10 mg/L, meeting the stipulations of fluoride ion discharge outlined in GB39371–2020. Further adsorption mechanism investigation revealed that 1L-MOF-808's affinity for F- was attributed to electrostatic interaction and ligand exchange. Overall, the as-synthesized 1L-MOF-808 not only presents an environmentally friendly approach to producing MOF materials without organic solvents but also develops a new strategy for the design of high-performance adsorbent for effectively removing fluoride ions from wastewater. [Display omitted] • La-modulated MOF-808(Zr) was prepared for the first time and used to remove F-. • The adsorption mechanism involved electrostatic interaction and ligand exchange. • The maximum adsorption of 1LMOF-808 for F- was 101.4 mg/g. • La modulating provided additional active sites and improved the adsorption effect. [ABSTRACT FROM AUTHOR]

• A redesigned and novel two-chamber electrodeposition-electrodialysis combination craft was adopted. • The efficient recovery of Ni2+ and the synchronous removal of HPO 3 2- from spent bath was achieved in simple and rapid one-step purification. • The influence of current density, operation time, pH, dilution multiple, flow rate, and electrolyte concentration on craft performance were investigated. With the continuous promotion and application of electroless nickel plating technology, the environmental pollution caused by heavy metals nickel and phosphorus in the spent bath becomes more serious. It is challenging to develop a method for the treatment of a spent electroless nickel plating bath with the high-efficiency recovery of Ni2+ and synchronous removal of HPO 3 2-, no secondary pollution, and low energy consumption. Herein, a means that absolutely incorporates the ascendancy of two single treatment methods, called a combination of electrodialysis and electrodeposition, was used to treat the spent electroless nickel plating bath. The effects of current density, operation time, pH value of the spent bath, dilution multiple, flow rate, and electrolyte (Na 2 SO 4) concentration on the recovery, removal rate, and energy consumption were investigated. Then, the reusability of the ion-exchange membrane was studied. The experimental results indicated that the recovery of Ni2+ was 82.34%, the removal of HPO 3 2- was 51.61%, the energy consumption of this method was only 18.28 Wh/kg, and the stability of the anion exchange membrane was desirable. Overall, the study of this combined process provides a basis for the one-step treatment of spent electroless nickel plating bath by a comprehensive method and an idea for engineering the application of handling spent bath. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designed a fluorescent probe to detect 1-hydroxyethane-1,1-diphosphonic acid. • Explored the optimum conditions for detection. • Researched the fluorescence quenching mechanism in detail. Organic phosphonates are widely used as scale inhibitors and metal ion chelators in industrial water treatment. 1-hydroxyethane-1,1-diphosphonic acid (HEDP) is one of the application of extensive organic phosphonates. However, due to physical and chemical properties, the detection process is extremely complicated. In this work, a fluorescent probe was prepared to detect HEDP which used salicylic acid (SA) and ferric ion (Fe3+) as sources for the first time. As far as optical properties were concerned, Fe3+-salicylic acid complex (Fe-SA) designed as fluorescent probe was significantly different from SA. The detection limit of HEDP was 2.7 μM (0.56 mg/L) under the optimal experimental conditions. The fluorescence quenching of SA can be attributed to static quenching.. [ABSTRACT FROM AUTHOR]

This work reports the synthesis of a novel 3D porous graphene (PG) from maleic acid (HO 2 CCH=CHCO 2 H) used as a carbon source through a simple one-step carbonization process. The sodium carbonate (Na 2 CO 3) was used as the skeletal substrate for 3D PG preparation and we observed that the ideal mass ratio of maleic acid (MA) to Na 2 CO 3 is 1:4, which gives the highest yield and net carbon content for 3D PG preparation. The Na 2 CO 3 decomposition temperature is greater than 550 °C which causes the release of CO 2 and hence ultimately it produced 3D porous graphene (PG). The prepared 3D PG was characterized by X-Ray Diffraction (XRD), Raman Spectra, Transmission Electron Microscope (HRTEM), Scanning Electron Microscope (SEM), X-Ray Photoelectron Spectroscopy (XPS), and Brunauer Emmett Teller (BET) Surface area. The synthesized 3D architectural frameworks of graphene offered well-defined pores with a large surface area amounting to 567.56 cm2g-1. However, with increasing temperature above 700 °C, there is a decrease in surface area which can be attributed to the heat shrinkage and sintering or collapse of smaller diameter pores. Also at higher temperatures, Na 2 CO 3 decomposes quickly which impart less effect on the morphology of synthesized graphene. In addition, electrochemical and adsorptive properties were also studied and a comparison is made with 3D rGO synthesized separately. The unique porous structure of 3D PG showed an excellent adsorption capacity of 433.3 (mg g-1) towards emerging pharmaceutical compound Atenolol and it further increases up to 642.4 (mg g-1) towards organic dye Rhodamine B, which is much higher than the 3D reduced graphene oxide rGO obtained by the chemical reduction process. Similarly, the as-synthesized 3D PG depicted enhanced oxidation and reduction properties as compared to 3D rGO as is evident from sharp anodic and cathodic peaks for the 3D PG prepared at 700 °C. [ABSTRACT FROM AUTHOR]

In this work, a novel adsorbent, 3D hierarchical CS@PANI@ZnAl-LDH composite, has been successfully fabricated through the hydrothermal synthesis of the carbon sphere, oxidative polymerization of polyaniline, and in-site growth of ZnAl-layered double hydroxides, simultaneously applied for the naproxen removal from aqueous solutions. The dynamics and isotherms fit better with the pseudo-second-order and Langmuir model, demonstrating the chemisorption, monolayer, and endothermic process. In addition, the high uptake capacities of CS@PANI@ZnAl-LDH for naproxen was 545.5 mg/g at 298 K when the pH was 5.0, outperforming most previously reported materials. Moreover, after five adsorption-desorption cycles, the spent CS@PANI@ZnAl-LDH maintains high removal efficiency and structural composition, revealing excellent recyclability and stability. Furthermore, Fourier transformed infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses indicate electrostatic interactions, π-π interactions, and hydrogen bonding between CS@APNI@ZnAl-LDH and naproxen. Quantitative analyses, Localized orbit locator (LOL)-π isosurface, and Independent Gradient Model further verify the adsorption mechanisms mentioned above, indicating the synergistic effects between PANI and ZnAl-LDH improve the elimination ability for naproxen. Significantly, Hirshfeld surface analyses reveal that naproxen behaves as the H-bond acceptor, and the ZnAl-LDH acts as the H-bond donor. This work provided a feasible way to design purification materials for wastewater treatment. [Display omitted] • 3D hierarchical CS@PANI@ZnAl-LDH composite was synthesized and characterized. • The maximum adsorption capacity of CS@PANI@ZnAl-LDH was 545.54 mg/g for naproxen. • Experimental analyses and theoretical calculations reveal the adsorption mechanisms. • Hirshfeld surface analyses explain the donor-acceptor relationship in hydrogen bonds. • Naproxen behaves as the H-bond acceptor and the ZnAl-LDH acts as the H-bond donor. [ABSTRACT FROM AUTHOR]

• A novel ratiometric imprinted fluorescence sensor N -CDs@Eu-MOF@MIP was constructed. • Eu-MOF were introduced and enhanced the response sensitivity. • The dual emission strategy endowed sensors remarkable fluorescence color changes. • The fluorescence sensor selectively recognized malathion. • Smartphone-assisted platform offered a promising tool for visual inspection. Sensitive and rapid detection of pesticide residues in food is essential for human safety. A ratiometric imprinted fluorescence sensor N -CDs@Eu-MOF@MIP (BR@MIP) was constructed to sensitively detect malathion (Mal). Europium-based metal organic frameworks (Eu-MOF) were used as supporters to improve the sensitivity of the BR@MIP. N -doped carbon dots (N -CDs) were used as fluorescent source to produce fluorescent signal. A linear relationship between the concentration of Mal and the fluorescence response of the sensor was found in the Mal concentration range of 1–10 μM with a limit of detection (LOD) of 0.05 μM. Furthermore, the sensor was successfully applied for the detection of Mal in lettuce, tap water, and soil samples, with recoveries in the range of 93.0 % − 99.3 %. Additionally, smartphone-based sensors were used to detect Mal in simulated real samples. Thus, the construction of ratiometric imprinted fluorescence sensor has provided a good strategy for the detection of Mal. [ABSTRACT FROM AUTHOR]

[Display omitted] • A II-type BiVO 4 /BiOBr heterojunction was prepared by anion exchange method. • The mechanism of II-scheme photocatalysis was explained. • Photocatalysis and PMS activation synergistically promote the degradation of enrofloxacin. • The presence of PMS induces a transformation of the primary active species. • O 2 − and 1O 2 are the prominent radicals for ENR degradation. Compared with the pure photocatalytic degradation system, although the sulfate radicals ( S O 4 · -) generated in the peroxymonosulfate-assisted photocatalytic (PMS-photo) system redound to improve degradation activity. However, the degradation mechanism of the PMS-photo system still needs to be improved. For example, the relationship between superoxide radical (O 2 −) generation and PMS has been overlooked. Herein, the BiVO 4 /BiOBr photocatalyst was prepared via anion exchange method. Subsequently, the in-situ growth of BiVO 4 on the surface of BiOBr nanosheet was confirmed though various characterization techniques. The degradation performance of the PMS-photo system was investigated, in which the 10 wt% BiVO 4 /BiOBr (BVB) composite exhibited the highest efficiency in degrading enrofloxacin (ENR, 95 %, 90 min) and tetracycline (TC, 94 %, 20 min) under visible light. Moreover, the structure of the intermediate product and the corresponding toxicity were determined by liquid chromatography-mass spectrometry (LC-MS) and Toxicity Estimation Software (T.E.S.T). Photoelectrochemical and fluorescence detection were employed to reveal that 10 wt% BVB has the fastest photogenerated carrier generation, separation and transmission efficiency. In addition, results from radicals quenching experiments, electron paramagnetic resonance (EPR), energy band structure analysis and DFT calculation were combined to substantiate the formation of II-type heterojunction between BiVO 4 and BiOBr. More importantly, based on the above results, it was confirmed that the active species in the pure photocatalytic system were holes (h+) and electrons (e−). Due to the introduction of PMS, O 2 − and singlet oxygen (1O 2) were generated, thereby achieving efficient degradation of pollutants. This result revealed the effect of peroxymonosulfate on the generation of O 2 −, presented a new perspective on the synergy of PMS with photocatalysis and offered a novel avenue for enhancing the performance of underperforming photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A facile dual physico-chemical activation strategy is proposed. • The synthesized NPHPC possesses high specific surface area, pore volume, specific capacitance and excellent hydrophilicity. • The NPHPC delivered a splendid desalination capacity and good cycling stability. The preparation of heteroatom-doped hierarchical porous carbons (HPCs) possessing both high-performance and cost-effective is advantageous for the advancement of capacitive deionization (CDI). Biomass, which is abundant and inexpensive, has been widely utilized as a precursor for carbon electrodes. However, the simple pyrolysis of a single biomass typically leads to insufficient porosity with narrow surface area, along with poor wettability and conductivity, thereby resulting in limited desalination performance. Therefore, we employ ammonium dihydrogen phosphate (NH 4 H 2 PO 4) and potassium carbonate (K 2 CO 3) as chemical and physical activators, respectively, to co-activate lotus petiole (LP) for the preparation of N/P co-doped hierarchical porous carbon (NPHPC). In comparison with conventional single K 2 CO 3 activation, NPHPC prepared through dual physico-chemical activation exhibits exceptional specific surface area (S BET , 2170.00 m2/g), excellent pore volume (V pore , 1.16 cm3/g), outstanding mesoporosity (V meso /V pore , 72.41 %), superior hydrophilic performance (contact angle: 39°), high specific capacitance (221.86F/g), moderate N-doping (3.1 %) and P-doping (0.4 %). When assembled for desalination, the synthesized materials demonstrate a fabulous electroadsorption capacity of 21.85 mg/g together with notable cycling stability, highlighting their excellent application prospects. In summary, this work presents innovative ideas in proposing a facile synthesis of high-performance heteroatom-doped HPCs for CDI desalination. [ABSTRACT FROM AUTHOR]

Highly efficient multifunctional adsorbent successfully realizes the removal of Cr ions from wastewater. The adsorbent is easily separated from the water to avoid secondary pollution. [Display omitted] • A novel 3D multifunctional composite magnetic adsorbent material has been successfully synthesized and applied for the removal of Cr(VI) from solution. • The composite adsorbent enables efficient capture and reduction of Cr(VI) under full light exclusion conditions. • The exceptional recyclability mitigates the issue of secondary contamination from the adsorbent. Designing a magnetic adsorbent material that is both reducible and has strong adsorption properties is significant in reducing Cr(VI) ion pollution. Herein, a 3D multifunctional composite adsorbent for Cr(VI) ions was obtained by using Fe 3 O 4 surface-arrayed magnesium iron layered double hydroxides (Mg/Fe-LDH) micro sheets as a substrate with in situ growth of Cu 2 O nanoparticles (Cu 2 O NPs) on their surfaces. Under dark conditions, adsorption capacity of the Cu 2 O@LDH@Fe 3 O 4 for Cr(VI) was up to 218.82 mg·g−1, surpassing that of Cu 2 O, Mg/Fe-LDH@Fe 3 O 4 , and Mg/Fe-LDH by factors of 1.39, 4.41, and 8.32 respectively. Surprisingly, the removal of Cr(VI) was as high as 76.16 % by the Cu 2 O@LDH@Fe 3 O 4 (C initial = 200 mg/L, pH = 3). Kinetic, isotherm, and thermodynamic results reveal that the removal of Cr(VI) by the Cu 2 O@LDH@Fe 3 O 4 is consistent with the pseudo-second-order kinetic model of spontaneous monomolecular layer chemisorption. Density functional theory (DFT) calculations show that HCrO 4 - has a lower energy band gap and is more easily reduced by Cu 2 O. Therefore, the reason for the adsorbent having more removal effect under acidic conditions was revealed. The XPS and FT-IR experimental mechanism analysis results indicated that Cr(VI) is immobilized on the Cu 2 O@LDH@Fe 3 O 4 surface through electrostatic interactions, followed by reduction to Cr(III) by Cu 2 O NPs, which is subsequently adsorbed on the surface of the Cu 2 O@LDH@Fe 3 O 4. This novel adsorbent structure and unique Cr(VI) removal mechanism provide new ideas for the design of future adsorbents. [ABSTRACT FROM AUTHOR]

Abstract: The interaction of organic phosphonates with mineral surfaces is of interest owing to their use as scale inhibitors. Molecular dynamic (MD) simulations have been employed to study the adsorption of four phosphonic acids, i.e. amino tris(methylene phosphonic acid) (ATMP), ethylene-diamine tetra(methylenephosphonic acid) (EDTMP), hexamethylene-diamine tetra(methylenephosphonic acid) (HDTMP), and diethylene-triamine penta(methylenephosphonic acid) (DTPMP) onto the stepped calcite (011) surface. It has been found that the phosphonate molecules can energetically interact well with the (011) face on the stepped dihedral nook. Furthermore, the strength of adsorption is DTPMP>HDTMP>EDTMP>ATMP based on the binding energy including vdw and electrostatic interaction, in agreement with the pHCM experiment. The results indicate that the phosphonic group number and the length of the backbone methylene chain play an important role in inhibitor effectiveness. [Copyright &y& Elsevier]

The release of benzothiazoles into the environment has been reported to affect the ecological environment and human health, so it makes significant sense to remove benzothiazoles from aquatic environment. They are poorly eliminated by conventional wastewater treatment. A few studies have shown that benzothiazoles are difficult to bioaccumulate or sorb to particles, therefore, it is very meaningful to study their efficient adsorption. In this work, the novel combined modified montmorillonite with hydroxyl iron pillared and cationic panthenol intercalation (Fe-CPMMt) was firstly prepared and evaluated its removal effect for emerging contaminant-benzothiazole. The batch adsorption experiments showed that the maximum adsorption capacity of Fe-CPMMt for benzothiazole was 69.72 mg/g, while that of the original acidified sodium montmorillonite, alone hydroxyl iron pillared montmorillonite (Fe-AMt), alone cationic panthenol intercalated montmorillonite were 11.39 mg/g, 43.68 mg/g and 38.18 mg/g, respectively. The adsorption process for benzothiazole on Fe-CPMMt-1.0 conformed well to Langmuir isotherm adsorption model and the pseudo-second-order kinetic model, and was spontaneous and endothermic. Moreover, combining with the Zeta potential values of Fe-AMt and Fe-CPMMt-1.0, and with the help of Multiwfn wave function program based on density functional theory, the electrostatic attraction and coordination between Fe-AMt and benzothiazole, while the electrostatic interaction, hydrophobic partitioning, complexation, p-π/π, OH/π and CH/π interactions were verified between Fe-CPMMt and benzothiazole pollutant. The work confirmed that the novel combined modified montmorillonite with hydroxyl iron pillared and cationic panthenol intercalation has a better adsorption effect on benzothiazole. Combined with the insight into the adsorption mechanism from the atomic level, it might provide novel information for exploring a new more efficient inorganic-organic combined modified montmorillonite adsorbent for removing stubborn organic contaminants in water. [Display omitted] [ABSTRACT FROM AUTHOR]

Many studies have proved that montmorillonite (Mt) has good adsorption properties for some antibiotic pharmaceuticals, but the detailed research on the microscopic sorption mechanism is very limited from the atomic level. In the present work, Mt was chosen as an adsorbent for common emerging contaminant-ciprofloxacin (CIP) to investigate the essence of the interaction between Mt and different CIP species at different pH. X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) characterization after adsorption under different pH were utilized to explore the difference of adsorption mechanism with the changed pH. Especially outstanding, for the first time, Molecular dynamics simulation (MD) was carried out to investigate the arrangement and dynamic behavior of cationic CIP in the interlayer of Mt, Multiwfn wave function analysis program was performed to quantitatively analyze the molecular surface electrostatic potential (ESP) distribution of different CIP species to evaluate the electrostatic interaction. Furthermore, for the first time, Hirshfeld surface analysis and independent gradient model (IGM) analysis were applied to probe and visualize the interaction sits between Mt and CIP zwitterion(CIP+/−) or CIP anion (CIP-), which can reveal the adsorption mechanism of Mt for CIP+/− and CIP- from the atomic level microscopic perspective. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag/CN-sr was synthesized by a fantastic chemical reduction via US method. • US inhibits the reagglomeration of g-C 3 N 4 and creates a micron-scale environment. • US promotes the uniform distribution and size reduction of Ag nanoclusters (Ag-nc). • For the first time, the degradation path of RhB was analyzed at the atomic level. Noble metals loading was found to be a promising strategy to improve the photocatalytic performance of g-C 3 N 4. In this, we synthesized Ag/g-C 3 N 4 composite (Ag/CN-sr) by an improved chemical reduction via ultrasonic spray technology. This process avoided the agglomeration of g-C 3 N 4 nanosheets and created a micron-scale reaction condition, which promoted the uniform distribution and size reduction of Ag nanoclusters. The results indicated that the apparent reaction rate constant for RhB degradation was 0.0322 min−1, which was about 3 and 7 times higher than that of Ag/CN composite prepared by the conventional chemical reduction method (Ag/CN-cr) and bare g-C 3 N 4 nanosheets, respectively. Furthermore, the degradation pathway of RhB was proposed by LC-MS and Multiwfn wave function analysis. For the first time, the frontier molecular orbital (FMO) analysis, orbital-weighted dual descriptor (OW DD) analysis and Atoms-In-Molecules (AIM) topological analysis were combined to study the degradation path of RhB from the atomic point of view. The theoretical analysis results were in good agreement with the LC-MS results. [ABSTRACT FROM AUTHOR]

In recent years, metal-organic framework derivatives have been regarded as materials with great potential for water treatment applications. In this study, we employed a polyvinylpyrrolidone (PVP)-assisted copper-cobalt bimetallic zeolitic imidazole framework (ZIF) as a template to rationally design nanosheet-like mixed metal oxide embedded nitrogen-doped carbon (CuCoO-PC). CuCoO-PC exhibited excellent degradation potential towards metronidazole (MNZ) and achieved almost complete degradation within 7 min through the activation of peroxymonosulfate (PMS). Importantly, the introduction of copper into CuCoO-PC established strong interactions between copper and cobalt, accelerating the activation performance of PMS. Furthermore, PVP, rich in nitrogen atoms, formed strong coordination interactions with ZIF precursors, which effectively protected the morphological stability of ZIF at high temperature, preventing collapse and aggregation. Meanwhile, the formation of nitrogen-doped carbon networks provides a pathway for the generation of non-radical. The study found that CuCoO-PC continuously activated PMS, generating various reactive oxygen species (ROS), among which SO 4 •- and 1O 2 played decisive roles. By calculating the HOMO, LUMO, and Fukui functions, we identified the reactive sites of MNZ and proposed possible degradation pathways. CuCoO-PC demonstrated excellent catalytic performance, reduced toxicity of intermediate products, and good reusability, all of which highlight its enormous potential in practical applications. [Display omitted] • CuCoO-PC composites are prepared using PVP to enrich the nitrogen content. • CuCoO-PC/PMS system exhibits prominent catalytic performance for MNZ removal. • SO 4 •- and 1O 2 was the main active substance involved in the MNZ degradation. • CuCoO-PC was stable and effective in multiple cycles of MNZ degradation efficiency. • The most reactive site on MNZ molecule was predicted by DFT calculation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green activation-self-activation strategy was proposed to prepare GO-inbuilt ENHPCs. • The splendid SAC of 17.86 mg/g and rapid ASAR of 0.99 mg/g/min for Ni2+ were gained. • The potential for eliminating NaCl, MgCl 2 , CaCl 2 and Ni2+ wastewater was evaluated. • Micro-mesoporous structure and copious active sites accelerated ion removal. Capacitive deionization (CDI) is considered a polar-promising technology to remove heavy-metal ions from wastewater. Herein, a green activation-self-activation strategy was exploited to build graphene (GO)-inbuilt mesopore-dominated N-doped hierarchical porous carbons (ENHPCs) using sodium lignosulfonate (SLS) as carbon sources/self-activators. Different from SLS self-activation and K 2 C 2 O 4 -SLS activation-self-activation, ENHPC LKG gained via GO-mediated K 2 C 2 O 4 -SLS activation-self-activation showed suitable mesopore-dominated micro-mesoporous structures with high surface area of 1795.5 m2/g, large mesoporous volume of 0.87 m3/g, 3.65 % N-doping and excellent conductivity. Its unique hierarchical porous structure and abundant active sites facilitated the ion rapid insertion and extraction. When utilized to capture low-concentration nickel (Ni2+) ions, ENHPC LKG delivered splendid salt removal capacity of 17.86 mg/g, rapid average salt removal rate of 0.99 mg/g/min and standout cycle stability. Meanwhile, ENHPC LKG was further extended to remove NaCl, MgCl 2 , CaCl 2 and Ni-containing wastewater, showing superior CDI property. Moreover, the recycled ENHPC LKG (10th) taken to eliminate indomethacin (IDM) depicted a splendid adsorption capacity. This work proved the significant applicant potential of the novel and green ENHPC LKG for disposing of Ni2+ ions via CDI technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • The prepared Tb-MOF emits stable Tb characteristic fluorescence at 545 nm in water. • The prepared Tb-MOF can be easily recycled after the OTC detection. • Based on the fluorescence detection of OTC by Tb-MOF, a test paper that can be easily carried, monitored in real time and has a clear color change was prepared. • Tb-MOF performed excellent in detecting the concentration of OTC in actual water samples. Oxytetracycline hydrochloride (OTC) is a commonly used over-the-counter antibiotic, valued for its potent antibacterial properties. However, the inappropriate and excessive use of OTC can result in the accumulation of the drug in both the environment and human body, causing significant harm to ecosystems and human health. Therefore, the development of a fast and sensitive method for detecting OTC is of great significance. Lanthanide metal–organic frameworks (LnMOFs) can effectively excite lanthanide metals to emit long-lifetime, narrow and stable fluorescence based on the antenna effect, but their application in fluorescence sensing is rarely reported. In this work, a strongly fluorescent material Tb-MOF was synthesized by a facile solvothermal method using 1,2,4,5-phenylenetetracarboxylic acid (H 4 btec) and 1,10-phenanthroline (1,10-phen) as organic ligands and lanthanide metal Tb as the luminescent center. Tb-MOF is a stable material in water and shows excellent linearity with OTC in the concentration range of 0 ∼ 70 μM, with low detection limit (0.12 μM) and luminescence color transition from bright green to dark green during the detection process. X-ray diffraction, UV–vis absorption and fluorescence lifetime analyses revealed that the fluorescence quenching of Tb-MOF by OTC is caused by the inner filter effect in static quenching. Test strips for OTC detection were successfully prepared using Tb-MOF. These strips are not only low cost and easy to prepare but can also be used as portable sensing devices that can be easily distinguished by the naked eye during OTC testing. This study not only presents a fluorescent probe for the detection of OTC in water but also offers a practical method for converting fluorescent luminescent materials into functional devices for OTC detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Composition of dual-emitting fluorescent probes was achieved by utilizing Eu and Tb as bimetallic centers. • First proposed dual-emission ratio sensor constructed with diaminoterephthalic acid. • Emission color conversion by adjusting the doping ratio of Eu and Tb. • The probe enables ratiometric sensing of furacilin and has excellent sensitivity and low detection limits. Lanthanide metal–organic frameworks (LnMOFs) have substantial potential in luminescence due to their unique antenna effect. Nevertheless, the single emission is susceptible to pseudo-signals caused by external environmental conditions, which significantly threaten the accurate measurement of the concentration. In this case, we prepared a dual-emission fluorescent probe {Eu x Tb 1-x (NH 2 -BDC) 3 (DMF) 4 ·2DMF} ∞ (NH 2 -BDC = Diaminoterephthalic acid, DMF = N , N -dimethylformamide). The stable dual-emission signal provides a superior signal output for detecting nitrofurazone (NFZ), which is detected by the probe with excellent fluorescence for 0–10 μM NFZ. In the investigation of the detection mechanism, it is speculated that NFZ incorporates with probe to generate a novel complex. Furthermore, The UV absorption curves of the novel complexes and NFZ overlap extensively with those of the probe. The addition of NFZ attenuates the characteristic luminescence of Eu and Tb by competing for the absorption of the excitation light of the probe. The probe has exhibits rapid response, excellent sensitivity, visual detection and a meagre detection limit (LOD = 0.013 μ M) for the detection of NFZ. This work not only broadens the application of LnMOFs in the field of ratiometric detection but also provides a favorable fluorescent probe for the quantitative detection of NFZ. [ABSTRACT FROM AUTHOR]

Rapid and real-time detection of 2, 4, 6-trinitrophenol (TNP) is of great importance for the living environment and human health. Herein, we constructed an innovative ratiometric fluorescence imprinted sensor with fast response and high selectivity based on magnesium and nitrogen co-doped carbon dots (Mg, N-CDs) and chromium telluride quantum dots (r-CdTe) self-assembled in zirconium-based metal organic frameworks (UiO-66) combined with imprinted polymers for the detection of TNP. In the protocol, the introduction of UiO-66 with large specific surface area and porosity using as carrier material significantly enhanced the mass transfer rate, which improved the sensitivity of the Mg, N-CDs/r-CdTe@UiO-66@MIP (LHU@MIP). And the Mg, N-CDs with high quantum yields and r-CdTe were selected as fluorescence emitting elements to yield fluorescence signal, achieving signal amplification. The dual-channel strategy enabled the sensor to not only display a fast fluorescence response, but also generate a dual-response signal under the action of internal filtering effect (IFE). Combining these advantages, the LHU@MIP had a wide linear range (1–100 μM), good detection sensitivity (0.56 μM), and a distinct color change (from blue to pink). Meanwhile, for accurate on-site analysis, we designed a portable smart sensing platform with a color recognizer application. The smartphone enabled visual sensing of TNP by capturing fluorescent images and converting them into digital values. More importantly, the platform was successfully utilized for the analysis of TNP in the simulated actual samples with considerable results. Therefore, the developed platform was characterized by low cost, portability, ideal specificity, and provided a strategy for on-site monitoring of TNP. [Display omitted] • A fluorescence imprinted sensor based on LHU@MIP for TNP was designed. • Porous UiO-66 was introduced to enhance the mass transfer rate and sensitivity. • Smartphone-assisted platforms offer promising tool for visual detection of TNP. • The platform was applied to the simulated real-sample with satisfactory results. [ABSTRACT FROM AUTHOR]

Biologically treated coking wastewater (BTCW) frequently contains many kinds of refractory and toxic organic pollutants, which is far from meeting the discharge standard of GB16171–2012. In the present work, the peroxymonosulfate (PMS) activation processes via Cu-doped LaFeO 3 (LFC) prepared with Bis (hexamethylene triaminepenta(methylenephosphonic acid) (BHMTMP) as the complexing agent was first utilized to degrade BTCW. The degradation reaction rate constant (k obs) of LaFe 0.5 Cu 0.5 O 3 (LFC5)/PMS for COD Cr and NH 3 -N was 3.65 times and 3.63 times for LFO (LaFeO 3)/PMS. Moreover, the k obs of LFC5/PMS system prepared using BHMTMP as the complexing agent surpassed that of the LFCC/PMS system prepared with citric acid (CA) as the complexing agent, and the former was 2.3 times and 1.8 times greater than that of the latter for the removal of COD Cr and NH 3 -N, respectively. The leaching of Cu and Fe of LFC5 was much less than that of LFCC, the strong chelation performance of BHMTMP with various metal ions can greatly reduce the leaching of metal ions and improve the stability of the catalyst. Hydroxyl radicals, sulfate radicals, and singlet oxygen were generated in the LFC5/PMS system, with singlet oxygen playing a dominant role. HPLC, UV absorption spectra, and 3D-EEM fluorescence spectra were used to analyze pollutant components in BTCW before and after degradation, demonstrating the effective removal of certain residual contaminants. In addition, the degradation process of BTCW was modeled using a 3-factor-3-level Response Surface Methodology (RSM) model. RSM model fitted the true experimental results well. This research offers a new approach for the comprehensive treatment of BTCW to meet standard discharge requirements and promote a more cost-effective operating process. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ternary core-shell CS@PANI@LDH composite was synthesized and characterized. • The maximum adsorption capacity of CS@PANI@LDH was 618.16 mg/g for DCF. • Multiwfn, Chimera, VMD, and IGM were combined to reveal the adsorption mechanism. • Deduced binding mechanism was electrostatic, hydrogen bonding, and π–π interaction. The efficient removal of Diclofenac sodium (DCF), a nonsteroidal anti-inflammatory drug, has attracted more and more attention. In this work, ternary core-shell CS@PANI@LDH composite was synthesized via the in-situ growth of Mg/Al layered double hydroxide plates onto polyaniline-wrapped carbon sphere and applied for DCF removal. Various influence factors like concentration, pH, time, temperature, and background electrolytes were systematically investigated. The maximum adsorption capacity was 618.16 mg/g. Besides, after 5 regeneration cycles, CS@PANI@LDH still retained high adsorption capacity. The adsorption mechanism was investigated by Fourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) characterization analyses. Simultaneously, the Multiwfn program combined the Chimera program was applied to calculate and visualize the localized orbit locator (LOL) of π electrons in DCF− molecule, which explored the π electronic structure and conjugation characteristics of DCF− molecule. Moreover, the Independent Gradient Model (IGM) analysis based on pro-molecular density revealed the interaction sites and interaction strength between DCF and LDH. The adsorption mechanism could be explained through electrostatic interaction and hydrogen bonding between LDH and DCF, π-π interaction between DCF and PANI. It was the synergistic effects of different interactions that improved the adsorption of DCF by CS@PANI@LDH composite. [ABSTRACT FROM AUTHOR]

• MD simulations reveal the interaction essence of deprotonated HEDP and HAP in presence of water. • The uptake of Cu2+ by single nano-hydroxyapatite and HEDP-HAP-0.5 hybrid system was 40.32 and 171.8 mg/g, respectively. • The adsorption mechanisms of HEDP-HAP hybrid system on Cu2+ involve the formation of surface complexes and ion exchange. The adsorption capacities of different ratios of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and nano-hydroxyapatite (HAP) hybrid systems on Cu2+ were probed. The FTIR, XRD, SEM and EDS analyses showed that HEDP with Cu2+ adsorbed on the surface of HAP and a new crystal phase appeared. The content of adsorbed Cu2+ were 4.4% and 21.8% on the surface of single HAP and HEDP-HAP-0.5 hybrid system, respectively, and later was 4.94 times that of the former. Conversely, the Ca/P (mol) ratio decreased from 1.40 to 0.61, indicating more Ca2+ were replaced by Cu2+. Meanwhile, molecular dynamics (MD) simulations results showed that HEDP and water molecules both formed ordered adsorption layer with similar concentration profiles, but the former preferred to gather on the HAP surface than the latter. The electrovalence bonds between the phosphonic acid functional groups of HEDP and Ca2＋ of HAP surface played the dominant role in their adsorption. The adsorption results showed that the maximum adsorption capacity of single hydroxyapatite for Cu2+ was 40.32 mg/g, while the maximum adsorption capacities reached 99.11, 171.8 and 147.27 mg/g for HEDP-HAP-0.2, HEDP-HAP-0.5 and HEDP-HAP-1.0 hybrid systems, respectively. The study illustrated that the adsorption process accorded with the pseudo-second-order kinetic and Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

The carboxymethyl-chitosan-montmorillonite (CMC-MMT) organic-inorganic hybrid material was applied to adsorb Pb(II) and Congo red (CR) anionic dye from aqueous solution. Molecular dynamics(MD) simulation was carried out to reveal the mechanism of CMC hybrid MMT. The results suggested that CMC has been adsorbed on the interlayer space and surface of MMT, hydrogen bonds had been formed between hydroxyl & carboxyl groups of CMC with the surface of MMT, Van der Waals interaction was also existed, while amino groups of CMC hadn't obvious interaction with the surface of MMT. Batch experiments were executed to investigate the adsorption effect of CMC-MMT was compared with Na-MMT and CMC. The results showed that CMC-MMT exhibited the higher adsorption capacity than Na-MMT and CMC, The OH and COOH or NH 2 groups of CMC chains may serve as electrostatic interaction active sites and coordination sites, which improved the adsorption performance of CMC-MMT on Pb(II)，and the insertion of CMC enlarged the inter-layer space of MMT, resulting in more surface active sites in the CMC-MMT hybrid composite, which increased the adsorption of organic pollutant CR. The kinetic and isotherm studies indicated that the pseudo-second-order and the Langmuir model well described the adsorption equilibrium of Pb(II) and CR on CMC-MMT. Unlabelled Image • Molecular dynamics (MD) simulation was carried out to reveal the mechanism of carboxymethyl chitosan (CMC) hybrid montmorillonite (MMT). • The hydroxyl groups of CMC molecules interacted most strongly with MMT by hydrogen bond and van der Waals forces, the carboxyl groups had a weak hydrogen bond with the surface of MMT, and the effect of the amino groups was not obvious. • CMC-MMT organic-inorganic hybrid composite exhibited the higher adsorption capacity on Pb(II) and Congo Red (CR) than Na-MMT and CMC alone. • The insertion of CMC enlarged the inter-layer space of MMT, resulting in more surface active sites in the CMC-MMT hybrid composite, which increased the adsorption of organic pollutant CR. • The OH and COOH or NH2 groups of CMC chains may serve as electrostatic interaction active sites and coordination sites, which improved the adsorption performance of CMC-MMT on Pb(II) [ABSTRACT FROM AUTHOR]

• Protonated graphite carbon nitride and acid activated montmorillonite (g-C 3 N 4 /Mt). • Batch experiments carried out at various conditions i.e. adsorbate concentration, pH, temperature, and contact time. • 2%-g-C3N4/Mt showed enhanced adsorption capacity for PO 4 3− and Pb(II), 5.06 mg/g and 182.7 mg/g respectively. • The adsorption process for both contaminants showed well-fitting with the pseudo-second-order kinetic model. • The thermodynamic study suggested that the adsorption of Pb(II) was a spontaneous and endothermic process. A novel protonated graphite carbon nitride and acid-activated montmorillonite (g-C 3 N 4 /Mt) composite was prepared and evaluated its removal efficiency for PO 4 3− and Pb(II) from aqueous media. The as-prepared composite was characterized by XRD, FT-IR, TG, XPS, SEM, BET and Zeta potential. Batch experiments were carried out under various conditions such as the amount of adsorbent, initial adsorbate concentration (C o), solution pH, temperature, and contact time. 2.0%-g-C 3 N 4 /Mt presented maximum adsorption capacity for PO 4 3− and Pb(II) as compared to single g-C 3 N 4 , Mt or other synthesized composites. The removal efficiency of the as-prepared composite (2.0%-g-C 3 N 4 /Mt) was significantly elevated owing to the synergistic effects and the saturated adsorption capacities of PO 4 3− and Pb(II) on 2%-g-C3N4/Mt was 5.06 mg/g and 182.7 mg/g respectively. While the saturated adsorption capacity of bare g-C 3 N 4 was only 1.56 mg/g and 22.3 mg/g for PO 4 3− and Pb(II) respectively, and bare Mt showed adsorption capacity of 0.65 mg/g and 124.2 mg/g for PO 4 3− and Pb(II) respectively. The adsorption process for both contaminants showed well-fitting with the pseudo-second-order kinetic model, and the adsorption isotherm for both contaminants followed the Langmuir model. The thermodynamic study suggested that the adsorption of Pb(II) was a spontaneous and endothermic process. [ABSTRACT FROM AUTHOR]