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[Display omitted] In the adsorption process of functionalized layered double hydroxide (LDH) to target pollutants it, is essential to investigate the role of functional groups. In this work, 2‑mercaptoethane sulfonic acid (MS) was used as an intercalation modifier to prepare functionalized NiFe-LDH by solvothermal method. The interfacial interaction between the functional groups and the NiFe-LDH surface was studied via molecular dynamics simulation. During the intercalation process, the more negatively charged sulfonic acid group tends to self-assemble electrostatically with the LDH laminate, while the sulfhydryl group is involved in complexing heavy metal ions. The adsorption experiments showed that the adsorption performance of the adsorbent for the three ions of Cd2+, Mn2+, and Co2+ at 298.15 K was 266.16 mg/g, 175.60 mg/g, and 106.56 mg/g, respectively, which were 10 times, 8.7 times, and 4.9 times higher than that of unmodified NiFe-LDH. Meanwhile, Multiwfn wavefunction analysis combined Visual Molecular Dynamics (VMD) was applied to analyze and visualize the reaction active sites & the interactions between MS and NiFe-LDH, and the complexation of the functional group of MS with metal ions, to insight the role of the functional groups in MS molecule, and to reveal the cause that the adsorption capacity of modified NiFe-LDH for heavy metals greatly improves from the view of atoms. [ABSTRACT FROM AUTHOR]

MoS 2 /montmorillonite (MoS 2 /Mt) composite was successfully synthesized through a simple hydrothermal method, and its adsorption performance for two emerging contaminants-atenolol (ATE) and acebutolol (ACE) was researched. The batch experiments revealed that the adsorption process can be described by the Pseudo-second order model and Langmuir model, and the adsorption capacity of MoS 2 /Mt, MoS 2 and Mt for ATE were 132.08 mg/g, 60.68 mg/g and 74.23 mg/g, for ACE were 113.82 mg/g, 33.01 mg/g and 36.05 mg/g, respectively. Besides, Fourier-transform infrared spectroscopy (FTIR), BET specific surface area measurement and X-ray photoelectron spectroscopy (XPS) were also employed to analyze the adsorption mechanism. Moreover, quantitative molecular surface analysis and weak intermolecular interaction analysis with independent gradient model were combined to probe the microscopic interaction between the adsorbent and adsorbate. The results indicated the interactions included hydrogen bonding and vdW interaction. Mt and MoS 2 interacted more strongly with ATE than ACE, which revealed the reason MoS 2 /Mt, Mt and MoS 2 possessed higher adsorption capacity for ATE. [Display omitted] • MoS 2 /Mt composite was successfully synthesized. • Compared with MoS 2 and MT, MoS 2 /Mt has better adsorption capacity for ATE and ACE. • Adsorption capacity of MoS 2 /Mt composite for ATE is larger than that for ACE. • The adsorption of ATE and ACE on MoS 2 /Mt was fitted to the Langmuir model. • Interactions of MoS 2 /Mt with ATE or ACE include hydrogen bonding and vdW interaction. [ABSTRACT FROM AUTHOR]

The corresponding adsorption mechanism of the adsorbent in the process of adsorbing phosphate. As shown, three adsorption mechanisms of the adsorbent in the process of adsorbing phosphate: 1: The combination of PO 4 3− and La3+ produces LaPO 4 with smaller Ksp. 2: H 2 PO 4 − and HPO 4 2− enters the interlayer through a substitution reaction with OH− between the LDH layers to realize the adsorption of phosphate. 3: The electrostatic mutual attraction between quercetin and phosphate realizes the adsorption of phosphate. [Display omitted] Severe water eutrophication due to large releases of phosphorus has become a worldwide environmental problem. Adsorption active sites is less of traditional adsorbents in the phosphorus removal process resulting in low removal efficiency, so the new high-efficiency phosphorus removal adsorbents become an effective way to solve the problem. In this work, quercetin modified MnFe layered double hydrotalcite three-dimensional composites structures encapsulated by lanthanum (La(III)) nanoparticles (QLa@MnFe-LDH) were successfully prepared by a classical hydrothermal method. The results of the adsorption experiments show that La(III) nanosphere-encapsulated MnFe-LDH provides a more adequate binding site for phosphate adsorption. The adsorption performance of QLa@MnFe-LDH for phosphate was outstanding, the maximum adsorption capacity was 346.5 mg/g at 298.15 K, which was 300 % higher than that of MnFe-LDH. Moreover, QLa@MnFe-LDH retained its high adsorption capacity (>315.5 mg/g) over a wide range of pH (4.0 ∼ 7.0). The active sites of the reactions were predicted by Multiwfn and Visual Molecular Dynamics (VMD), and novel visualization studies of weak interactions were applied to theoretical studies. The modified MnFe-LDH encapsulated by La nanospheres has a strong adsorption capacity for phosphate adsorption. Therefore, the modified QLa@MnFe-LDH was expected to become an effective adsorption material for phosphorus removal. [ABSTRACT FROM AUTHOR]

An eco-friendly corncob biochar based montmorillonite composite (Cc-Mt) was synthesized for the single adsorption and co-adsorption of lead (Pb(II)) and a pharmaceutical emerging organic contaminant Atenolol (ATE). In single adsorption system, the maximum equilibrium capacity of Cc-Mt for Pb (II) and ATE were 139.78 mg g−1 and 86.86 mg g−1, respectively, but for montmorillonite just 98.69 mg g−1 and 69.68 mg g−1, for corncob biochar just 117.54 mg g−1 and 47.29 mg g−1. Meanwhile,co-adsorption properties of ATE and Pb(II) on Cc-Mt composite were performed and found that the influence of ATE on the adsorption of Pb(II) was greater than the effect of Pb(II) on that of ATE. Moreover, Multiwfn program based on quantum chemical calculation was used to quantitatively analyze electrostatic potential (ESP) distribution, average local ionization energy (ALIE) distribution and their minimum points on neutral ATE and protonated ATE (PATE) molecules to reveal the microscopic adsorption mechanism of Cc-Mt composite to ATE, the results showed that the amino N and amide oxygen atom were easier to provide lone pair of electrons, generating hydrogen bonds or strong electrostatic interactions with functional groups on the surface of Cc-Mt, meanwhile hydroxyl O atom was also a possible reaction site. For PATE molecules, only the oxygen atom of the amide group was the most likely reactive site. Image 1 • Synthesized biochar-montmorillonite composite showed high absorption efficiency of Pb(II) and β-blocker (atenolol). • Coadsorption characteristic of Pb(II) and atenolol onto biochar-montmorillonite composite was studied. • Multiwfn program based on quantum chemical calculation was used to reveal the microscopic adsorption mechanism. [ABSTRACT FROM AUTHOR]

Montmorillonite (G-Mt) modified by a gemini quaternary ammonium cationic surfactant (Propyl bis (hexadecyl dimethyl ammonium) chloride, 16-3-16) was used to remove emerging contaminants (ECs) (such as 1H-Benzotriazole (BTA), 5-Methyl-1H-benzotriazole (TTA) and 1-Hydroxybenzotriazole (HOBT)) and Cu2+ from wastewater. Based on the adsorption of the above three ECs in our previous studies, single adsorption of Cu2+ and the simultaneous adsorption of three ECs with Cu2+ on G-Mt were also investigated. G-Mt showed much lower adsorption amount on Cu2+ comparing with original montmorillonite (Ca-Mt) in single adsorption system due to the difficulty of ion-exchange property of G-Mt. In co-adsorption system, three organic pollutants and Cu2+ played a synergistic effect and the adsorption capacity of G-Mt on them increased, the influence sequence of Cu2+ on the adsorption of three ECs or the effect of ECs on the adsorption of Cu2+ both followed as: TTA > BTA > HOBT. The results of FT-IR, EDS and XPS revealed that the complex of Cu2+ and ECs were adsorbed onto G-Mt via forming complexes and hydrophobic interaction in co-adsorption system. The pH experiment showed that the optimum pH of the co-adsorption of ECs and Cu2+ on G-Mt was 5. Molecular dynamics (MD) simulations showed that three ECs or ECs combining with Cu2+ were dominantly adsorbed in the interlayer space of G-Mt, which resulted in the arrangement manner of 16-3-16 between the layer of G-Mt before and after adsorption of three organic pollutants was different. Furthermore, by quantitatively analyzing electrostatic potential (ESP) distribution, average local ionization energy (ALIE) distribution and their minimum points on three ECs molecules surfaces, Multiwfn program has been applied to probe the microscopic mechanism. The synergistic effect of co-adsorption will promote enrichment of copper ions and ECs to remove them more efficiently in polluted waters. Image 1 • Three ECs and Cu2+ played co-adsorption synergistic effect. • G-Mt internal microstructure changed after adsorption of three ECs by MD simulations. • The microscopic mechanism of co-adsorption was studied by Multiwfn program. • Complexation ability of three ECs with Cu2+ was: TTA > BTA > HOBT. [ABSTRACT FROM AUTHOR]

[Display omitted] • ACNF/PPy/MIL-100-Fe with stable 3D-supporting skeleton and hierarchical porous structure was fabricated. • ACNF/PPy/MIL-100-Fe possessed admirable adsorption capacity, adsorption kinetics and reusability. • Easy-to-recyclable "electrode-type" ACF/PPy/MIL-100-Fe was redesigned achieving prominent adsorption performance. • Deductive uptake mechanism was electrostatic, hydrogen bonding and π–π interaction. Developing advanced adsorbents for removing the alarming level of pharmaceuticals active compounds (PhACs) pollution is an urgent task for environmental treatment. Herein, a novel acid-treated carbon nanofiber/polypyrrole/MIL-100-Fe (ACNF/PPy/MIL-100-Fe) with stable 3D-supporting skeleton and hierarchical porous structure had been fabricated to erasure ceftriaxone (CEF) and indomethacin (IDM) from aqueous solution. ACNF as scaffold achieved the highly uniform growth of MIL-100-Fe and PPy. Viewing the large BET surface area (S BET , 999.7 m2/g), highly exposed accessible active sites and copious functional groups, ACNF/PPy/MIL-100-Fe separately showed an excellent adsorption capacity for CEF (294.7 mg/g) and IDM (751.8 mg/g), outstripping the most previously reported adsorbents. Moreover, ACNF/PPy/MIL-100-Fe reached rapid adsorption kinetics and standout reusability property. Further, the redesigned easy-to-recyclable ACF/PPy/MIL-100-Fe inspired by the electrode formation craft achieved prominent adsorption capacity and good reusability property. The adsorption mechanism was evaluated via Fourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The outcomes revealed that the splendid adsorption capability mainly depended on the electrostatic interactions, hydrogen bonding and π-π interactions. This work sheds light on one facile practical strategy to exploit advanced materials in water environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] The tunable porous structure of metal organic frameworks (MOFs) plays a crucial role in determining their adsorption performance. In this study, we developed and employed a strategy involving monocarboxylic acid assistance to synthesize a series of zirconium-based MOFs (UiO-66-F 4) for the removal of aqueous phthalic acid esters (PAEs). The adsorption mechanisms were investigated by combining batch experiments, characterization and theoretical simulation. By adjusting the affecting factors (i.e., initial concentration, pH values, temperature, contact time and interfering substance), the adsorption behavior was confirmed as a spontaneous and exothermic chemisorption process. The Langmuir model provided a good fit, and the maximum expected adsorption capacity of di- n -butyl phthalate (DnBP) on UiO-66-F 4 (PA) was calculated to be 530.42 mg·g−1. Besides, through carrying out the molecular dynamics (MD) simulation, the multistage adsorption process in the form of DnBP clusters was revealed on a microcosmic scale. The independent gradient model (IGM) method showed the types of weak interactions of inter-fragments or between DnBP and UiO-66-F 4. Furthermore, the synthesized UiO-66-F 4 displayed excellent removal efficiency (>96 % after 5 cycles), satisfactory chemical stability and reusability in the regeneration process. Hence, the modulated UiO-66-F 4 will be regarded as a promising adsorbent for PAEs separation. This work will provide referential significance in tunable MOFs development and actual applications of PAEs removal. [ABSTRACT FROM AUTHOR]

[Display omitted] Effective removal of antibiotics in the environment can be a demanding issue concerning the ecosystem and human health. Photocatalysis and peroxymonosulfate (PMS) oxidation have become important methods to effectively remove stubborn pollutants. In this work, by integrating these two technologies, an efficient system for degrading chloramphenicol (CAP) in water was proposed. The system was constructed by coupling strontium-doped lanthanum cobaltate (LSCO5) with chlorine-doped carbon nitride (CGCN). By doping, the increase of oxygen vacancy and the adjustment of bandgap were realized. Photoluminescence and electrochemical impedance experiments showed that the heterojunction can promote electron transfer and photogenerated carrier separation. Under the synergistic effect of PMS oxidation and photocatalysis, the prepared composite with an optimal loading of 40% LSCO5 can degrade 95.6% of CAP within 20 min. Degradation experiments on different pollutants proved the versatility of the catalytic system. The enhanced degradation mechanism of CAP was explored based on the assessment of the degradation efficiency of CAP, electron paramagnetic resonance (EPR), and quenching experiments. Through liquid chromatography-mass spectrometry (LC-MS) analysis, a possible route for CAP degradation was also proposed. This research provides some inspiration for the remediation of polluted water with perovskite-based catalyst under the synergistic effect of PMS and photocatalysis. [ABSTRACT FROM AUTHOR]

The novel environment-friendly hexadecanoamide propyltrimethy lammonium chloride (NQAS16-3) surfactant with different amounts (0.2, 0.4, 0.6, 0.8, 1.0, 1.2 CEC) was firstly used to modify montmorillonite, and the obtained organomontmorillonite (N-Mt) with the amount of surfactant equal to 1.0 CEC was utilized to adsorb two β-blocker pollutants- Atenolol (ATE) and acebutolol (ACE). The experimental results indicated that the equilibrium adsorption capacity of N-Mt(the organo-montmorillonite that the amount of modifier was 1.0 CEC) for ATE and ACE was 93.47 mg/g and 84.55 mg/g, respectively, which was more than twice that of raw montmorillonite for two pollutants, the adsorption was better fitted with the pseudo-second-order model and Langmuir isotherms model, and the adsorption was the spontaneous and exothermic process. Moreover, combining with the Zeta potential values of N-Mt, and with the help of Multiwfn wave function program based on density functional theory (DFT), the electrostatic interaction and the hydrophobic partitioning between N-Mt and two pollutant molecules were verified, p-π/π interaction between NQAS16-3 and ATE (or ACE) may be contributed to the increasing adsorption capacity of N-Mt for two β-blocker pollutants. The work provided novel organomontmorillonite for the removal of non-degradable β-blocker pollutants and the insight of the adsorption mechanism from the atomic level. [ABSTRACT FROM AUTHOR]

Polyaniline (PANi)-clay hybrids are an important class of materials in the field of catalysis and adsorption. Owing to their unique structural properties such as self-assembly with functional materials, intercalation and surface functionalization, they have demonstrated to be more efficient candidates for environmental remediation than clay or polyaniline taken separately. Here, we report on the synthesis of phytic acid-doped PANI@montmorillonite (P-PANi@Mt) composite material via radical polymerization by varying the amount of Mt in the composite material. The formation of functional groups is detected by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy and Raman analysis, which is consistent with the anchoring of phytic acid into PANi chains. Furthermore, the BET measurements revealed that the incorporation of Mt reduced the specific surface area of P-PANi-Mt hybrid due to the coating of Mt surface by P-PANi. The obtained materials were assessed for their capacity to adsorb copper (II) ions in aqueous media. Under optimized experimental conditions, P-PANi and P-PANi@Mt1 composites were found to be the most effective materials for Cu2+ ion capture with adsorption capacities of 66.6 mg g−1 and 87 mg g−1, respectively. By increasing the amount of montmorillonite in the composite, the adsorption capacity decreased substantially. This result could be explained by the tendency of clay particles to aggregate in the PANi matrix and therefore hinder the availability of active sites. The adsorption isotherm processes fit well with the Langmuir model and the enhanced adsorption process was ascribed to the existence of plenty of phosphoric acid groups doped to PANi-coated on Mt layers. [ABSTRACT FROM AUTHOR]