26 results on '"Xia, Mingzhu"'
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2. Facile hydrothermal synthesis of magnetic adsorbent CoFe2O4/MMT to eliminate antibiotics in aqueous phase: tetracycline and ciprofloxacin
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Zhang, Juan, Khan, Muhammad Asim, Xia, Mingzhu, Abdo, Abdelnasir Mahmoud, Lei, Wu, Liao, Chuan, and Wang, Fengyun
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- 2019
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3. Microstructural modification of organo‐montmorillonite with Gemini surfactant containing four ammonium cations: molecular dynamics (MD) simulations and adsorption capacity for copper ions.
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Chu, Yuting, Khan, Muhammad Asim, Zhu, Sidi, Xia, Mingzhu, Lei, Wu, Wang, Fengyun, and Xu, Ying
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MONTMORILLONITE ,ADSORPTION capacity ,COPPER ions ,MOLECULAR dynamics ,SURFACE active agents ,LANGMUIR isotherms ,CATIONS ,POLYAMINES - Abstract
BACKGROUND: Copper is a heavy metal that is widely available in nature and has attracted people's attention because of its toxicity and difficult biodegradability. Using modified montmorillonite to adsorb copper ions (Cu2+) was widely adopted because of its simple operation, high efficiency, and easy availability. RESULTS: Na‐montmorillonite (Na‐Mt) was modified through a Gemini surfactant (containing four ammonium cations) to explore the adsorption capacity for Cu2+ in aqueous media. The resulting product is called G‐Mt. FT‐IR XRDBET results indicated that Gemini surfactant has significantly intercalated into the montmorillonite interlayers. The results ofbatch adsorption experiments presented that the amount of adsorbed (qe) depend on pH value and qe (G‐Mt) can reach to 29.30 mg/g, which was greater than that of Na‐Mt (25.30 mg/g) when pH is 6.0 and initial Cu2+ concentration is 75 mg/L. The experimental data matched well with Langmuir isotherm. The thermodynamic analysis implied that adsorption of Cu2+ was endothermic and a spontaneous process. Molecular dynamics (MD) models were carried out to investigate the microstructure and kinetic information of Gemini cations in the interlayer of G‐Mt. The results elucidated that the distribution and interaction characteristic of ammonium cations of Gemini surfactant including four ammonium cations were completely different from that of the quaternary ammonium salts containing asingle ammonium cation. CONCLUSION: Generally, considering the comprehensive performances, polyamine Gemini surfactant to modify montmorillonite can improve its ability to adsorb Cu2+. The micro environment in the interlayer space and adsorption properties of G‐Mt on Cu2+, which will improve the potential utilization of G‐Mt in soil remediation or wastewater treatment. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]
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- 2019
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4. Adsorption and Desorption of Pb(II) on l-Lysine Modified Montmorillonite and the simulation of Interlayer Structure.
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Zhu, Sidi, Xia, Mingzhu, Chu, Yuting, Khan, Muhammad Asim, Lei, Wu, Wang, Fengyun, Muhmood, Tahir, and Wang, Along
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LEAD , *LYSINE , *MONTMORILLONITE , *CRYSTAL structure , *ADSORPTION (Chemistry) , *COMPUTER simulation - Abstract
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]
- Published
- 2019
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5. Facile hydrothermal synthesis of magnetic adsorbent CoFe2O4/MMT to eliminate antibiotics in aqueous phase: tetracycline and ciprofloxacin.
- Author
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Zhang, Juan, Khan, Muhammad Asim, Xia, Mingzhu, Abdo, Abdelnasir Mahmoud, Lei, Wu, Liao, Chuan, and Wang, Fengyun
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MONTMORILLONITE ,TETRACYCLINES ,CIPROFLOXACIN ,WATER pollution ,LANGMUIR isotherms - Abstract
A highly resourceful, eco-friendly, and recyclable magnetic adsorbent based on montmorillonite (CoFe
2 O4 /MMT) was fabricated via a facile hydrothermal method to harvest tetracycline (TC) and ciprofloxacin (CIP) from pollutant water. The prepared adsorbent was characterized by XRD, FT-IR, SEM, and VSM methods to comprehend its structure, morphology, and magnetism. Effects of experimental parameters including solution pH, adsorption time, initial concentration, and ion strength were studied in details. The experimental adsorption data of TC and CIP fitted into pseudo-second-order kinetic model and Langmuir isotherm, respectively. The maximum adsorptions of TC and CIP could reach up to 240.91 and 224.00 mg/g. The thermodynamic study indicates that the adsorption process is spontaneous. In addition, the antibiotics can be further degraded under visible light environment and the magnetic sorbent can also be thermally regenerated.ᅟ [ABSTRACT FROM AUTHOR]- Published
- 2019
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6. Adsorption properties and mechanism of montmorillonite modified by two Gemini surfactants with different chain lengths for three benzotriazole emerging contaminants: Experimental and theoretical study.
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Zhang, Hongling, Xia, Mingzhu, Wang, Fengyun, Li, Pingping, and Shi, Mingxing
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BENZOTRIAZOLE derivatives , *MONTMORILLONITE , *POLLUTANTS , *BENZOTRIAZOLE , *SURFACE active agents , *ADSORPTION (Chemistry) , *MOLECULAR dynamics - Abstract
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]
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- 2021
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7. The adsorption performance and micro-mechanism of MoS2/montmorillonite composite to atenolol and acebutolol: Adsorption experiments and a novel visual study of interaction.
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Shi, Wenyan, Chu, Yuting, Xia, Mingzhu, Wang, Fengyun, and Fu, Chenlu
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MONTMORILLONITE ,SURFACE area measurement ,ADSORPTION (Chemistry) ,HYDROGEN bonding interactions ,X-ray photoelectron spectroscopy ,ADSORPTION capacity - Abstract
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]
- Published
- 2021
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8. The single/co-adsorption characteristics and microscopic adsorption mechanism of biochar-montmorillonite composite adsorbent for pharmaceutical emerging organic contaminant atenolol and lead ions.
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Fu, Chenlu, Zhang, Hongling, Xia, Mingzhu, Lei, Wu, and Wang, Fengyun
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ATENOLOL ,MONTMORILLONITE ,ADSORPTION (Chemistry) ,NONBONDING electron pairs ,IONIZATION energy ,ELECTRIC potential ,SORBENTS ,FUNCTIONAL groups - Abstract
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]- Published
- 2020
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9. The synergistic effect and microscopic mechanism of co-adsorption of three emerging contaminants and copper ion on gemini surfactant modified montmorillonite.
- Author
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Li, Pingping, Zhang, Hongling, Xia, Mingzhu, Wang, Fengyun, Zhu, Sidi, and Lei, Wu
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COPPER ions ,POLLUTANTS ,CATIONIC surfactants ,ADSORPTION capacity ,IONIZATION energy ,MONTMORILLONITE ,TRICLOCARBAN - Abstract
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 Cu
2+ 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]- Published
- 2019
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10. The enhanced adsorption of Ampicillin and Amoxicillin on modified montmorillonite with dodecyl dimethyl benzyl ammonium chloride: Experimental study and density functional theory calculation.
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Li, Yuan, Shi, Mingxing, Xia, Mingzhu, and Wang, Fengyun
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BENZYL chloride , *DENSITY functional theory , *AMMONIUM chloride , *FREUNDLICH isotherm equation , *MICROPOLLUTANTS , *AMOXICILLIN , *ANTIBIOTICS - Abstract
[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]
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- 2021
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11. The adsorption and mechanism of benzothiazole and 2-hydroxybenzothiazole onto a novel ampholytic surfactant modified montmorillonite: Experimental and theoretical study.
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Zhang, Hongling, Xu, Haihua, Xia, Mingzhu, Wang, Fengyun, and Wan, Xia
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MONTMORILLONITE , *BENZOTHIAZOLE , *ADSORPTION (Chemistry) , *MOLECULAR dynamics , *SURFACE active agents , *ADSORPTION capacity - Abstract
[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]
- Published
- 2021
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12. Synthesis and micro-mechanistic studies of histidine modified montmorillonite for lead(II) and copper(II) adsorption from wastewater.
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Chu, Yuting, Khan, Muhammad Asim, Xia, Mingzhu, Lei, Wu, Wang, Fengyun, Zhu, Sidi, and Yan, Xin
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ION exchange (Chemistry) , *ADSORPTION (Chemistry) , *ADSORPTION capacity , *COPPER , *MONTMORILLONITE , *HEAVY metals - Abstract
• 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]
- Published
- 2020
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13. Methionine-montmorillonite composite – A novel material for efficient adsorption of lead ions.
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Chu, Yuting, Zhu, Sidi, Xia, Mingzhu, Wang, Fengyun, and Lei, Wu
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METHIONINE , *IONS , *ADSORPTION (Chemistry) , *COMPLEX ions , *ADSORPTION capacity , *MONTMORILLONITE , *CARBOXYL group - Abstract
• 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]
- Published
- 2020
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14. The enhanced adsorption of diclofenac sodium (DCF) and ibuprofen (IBU) on modified montmorillonite with benzyldimethylhexadecylammonium chloride (HDBAC).
- Author
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Chu, Yuting, Dai, Yong, Xia, Mingzhu, Xing, Xiaoping, Wang, Fengyun, Li, Yuan, and Gao, Hao
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LANGMUIR isotherms , *ADSORPTION (Chemistry) , *DICLOFENAC , *IBUPROFEN , *ADSORPTION capacity - Abstract
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]
- Published
- 2024
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15. Effective adsorption of heavy metal ions by sodium lignosulfonate reformed montmorillonite.
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Ma, Jianzhe, Khan, Muhammad Asim, Xia, Mingzhu, Fu, Chenlu, Zhu, Sidi, Chu, Yuting, Lei, Wu, and Wang, Fengyun
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METAL ions , *HEAVY metals , *SODIUM ions , *ADSORPTION (Chemistry) , *SULFONATES , *MONTMORILLONITE , *ADSORPTION capacity - Abstract
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]
- Published
- 2019
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16. Efficient preparation and molecular dynamic (MD) simulations of Gemini surfactant modified layered montmorillonite to potentially remove emerging organic contaminants from wastewater.
- Author
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Li, Pingping, Khan, Muhammad Asim, Xia, Mingzhu, Lei, Wu, Zhu, Sidi, and Wang, Fengyun
- Subjects
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ORGANIC water pollutants , *MONTMORILLONITE , *POLLUTANTS , *FOURIER transform infrared spectroscopy , *LANGMUIR isotherms , *SURFACE active agents , *SCANNING electron microscopes - Abstract
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]
- Published
- 2019
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17. Adsorption of two β-blocker pollutants on modified montmorillonite with environment-friendly cationic surfactant containing amide group: Batch adsorption experiments and Multiwfn wave function analysis.
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Zhang, Hongling, Ma, Jianzhe, Shi, Mingxing, Xia, Mingzhu, Wang, Fengyun, and Fu, Chenlu
- Subjects
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ANGIOTENSIN converting enzyme , *WAVE functions , *WAVE analysis , *CATIONIC surfactants , *POLLUTANTS , *AMIDES , *LANGMUIR isotherms , *MONTMORILLONITE - Abstract
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]
- Published
- 2021
- Full Text
- View/download PDF
18. Microscopic adsorption mechanism of montmorillonite for common ciprofloxacin emerging contaminant: Molecular dynamics simulation and Multiwfn wave function analysis.
- Author
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Zhang, Hongling, Zhao, Feng, Xia, Mingzhu, and Wang, Fengyun
- Subjects
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MONTMORILLONITE , *MOLECULAR dynamics , *WAVE analysis , *WAVE functions , *FOURIER transform infrared spectroscopy , *ADSORPTION (Chemistry) - Abstract
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]
- Published
- 2021
- Full Text
- View/download PDF
19. Mechanism of carboxymethyl chitosan hybrid montmorillonite and adsorption of Pb(II) and Congo red by CMC-MMT organic-inorganic hybrid composite.
- Author
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Zhang, Hongling, Ma, Jianzhe, Wang, Fengyun, Chu, Yuting, Yang, Lei, and Xia, Mingzhu
- Subjects
- *
CARBOXYMETHYL compounds , *MONTMORILLONITE , *HYDROXYL group , *VAN der Waals forces , *ADSORPTION (Chemistry) , *ADSORPTION capacity , *CARBOXYL group , *MOLECULAR dynamics - Abstract
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]
- Published
- 2020
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20. Facile synthesis of protonated g-C3N4 and acid-activated montmorillonite composite with efficient adsorption capacity for PO43− and Pb(II).
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Wan, Xia, Khan, Muhammad Asim, Wang, Fengyun, Xia, Mingzhu, Lei, Wu, Zhu, Sidi, Fu, Chenlu, and Ding, Yong
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ADSORPTION capacity , *ADSORPTION isotherms , *ZETA potential , *POLLUTANTS , *METALLOTHIONEIN , *ADSORBATES , *MONTMORILLONITE - Abstract
• 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]
- Published
- 2019
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21. Phytic acid-doped polyaniline nanofibers-clay mineral for efficient adsorption of copper (II) ions.
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Ben Ali, Monaam, Wang, Fengyun, Boukherroub, Rabah, Lei, Wu, and Xia, Mingzhu
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POLYANILINES , *LANGMUIR isotherms , *PHYTIC acid , *RAMAN spectroscopy , *ADSORPTION (Chemistry) , *X-ray photoelectron spectroscopy - Abstract
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]
- Published
- 2019
- Full Text
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22. Kinetics and equilibrium isotherms of adsorption of Pb(II) and Cu(II) onto raw and arginine-modified montmorillonite.
- Author
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Chu, Yuting, Khan, Muhammad Asim, Wang, Fengyun, Xia, Mingzhu, Lei, Wu, and Zhu, Sidi
- Subjects
- *
ADSORPTION isotherms , *MONTMORILLONITE , *X-ray powder diffraction , *SCANNING electron microscopes , *ADSORPTION capacity - Abstract
• Modification of Na-Mt with Arg salt is green and environmentally-friendly. • The isotherm model was well matched with the Langmuir curve. • The kinetic adsorption fitted well with the pseudo-second-order rate equation. • Arg-Mt removed 124.69 and 29.15 mg/g of Pb(II) and Cu(II) respectively. Arg-Mt, was fabricated by modifying sodium montmorillonite (Na-Mt) with Arginine monohydrochloride (Arg salt), to adsorb Pb(II) and Cu(II) in aqueous solution. The X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectrum, thermal analysis (TG/DTG), Brunauer-Emmett-Teller (BET) and Scanning electron microscope (SEM) were employed to investigate the properties of Na-Mt and Arg-Mt. The effects of the amount of modifier, pH value, the initial concentration of M(II), temperature and contact time were tested in a single adsorption system. The isotherm model was well matched with the Langmuir curve and the kinetic adsorption fitted well with the pseudo-second-order rate equation. The saturated adsorption of Pb(II) and Cu(II) by Arg-Mt were 124.69 and 29.15 mg/g, respectively, which were higher than that of Na-Mt (89.08 and 23.93 mg/g). The thermodynamic equation indicated that the adsorption process was spontaneous, endothermic, and the randomness of the samples changed a little after adsorption. The adsorption capacity of heavy metal ions in the binary co-adsorption system was poor than single adsorption system. Furthermore, the adsorbed M(II) onto Arg-Mt can hardly be dissolved under weak acidic condition (pH > 4) according to the desorption experiments. High-efficiency and low-cost make Arg-Mt to be used in the removal of heavy ions in aqueous solution. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
23. Adsorption properties, kinetics & thermodynamics of tetracycline on carboxymethyl-chitosan reformed montmorillonite.
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Ma, Jianzhe, Lei, Yang, Khan, Muhammad Asim, Wang, Fengyun, Chu, Yuting, Lei, Wu, Xia, Mingzhu, and Zhu, Sidi
- Subjects
- *
ADSORPTION kinetics , *THERMODYNAMICS , *TETRACYCLINE , *CHITOSAN , *MONTMORILLONITE - Abstract
Abstract This paper describes a modification method of Na-montmorillonite (Na-Mt) with carboxymethyl-chitosan (CMC). The as-prepared samples were analyzed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analyzer and thermogravimetric analysis (TGA). Two common tetracycline antibiotics, tetracycline (TET) and chlortetracycline (CTC), were selected as the represented pollutants and adsorbed by CMC-Mt under different experimental conditions. The intercalation of CMC obviously amplified the basal spacing of the interlayers confirmed by XRD measurements and improved the adsorption capacities of montmorillonite to some degree. The results showed that the tetracycline antibiotic sorption onto CMC-Mt was mainly dependent on pH and was not affected by temperature. Besides, the removal of TET and CTC rapidly attained an equilibrium within 2 h of contact time. The kinetic data of adsorption was determined by first-order, second-order kinetics and intraparticle diffusion models. The kinetic study indicates that the TET and CTC adsorption processes obeyed the second-order kinetics. The Freundlich isotherm study was in agreement with the practical data, suggesting a heterogeneous sorption process. Furthermore, the thermodynamic studies revealed that the removal process was more spontaneous at a lower temperature, implying it an exothermic reaction. The synthesized adsorbent CMC-Mt can be widely used in the treatment of wastewater. Graphical abstract Unlabelled Image Highlights • Preparation of the modified Na montmorillonite with carboxymethyl-chitosan • The adsorption of tetracyclines from aqueous solution onto the as-prepared adsorbent was investigated. • The adsorption process is exothermic, heterogeneous and spontaneous at lower temperature. • The Freundlich isotherm study was in agreement with the practical data. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
24. Novel multi amine-containing Gemini surfactant modified montmorillonite as adsorbents for removal of phenols.
- Author
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Xu, Ying, Khan, Muhammad Asim, Wang, Fengyun, Xia, Mingzhu, and Lei, Wu
- Subjects
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SURFACE active agents , *MONTMORILLONITE , *SORBENTS , *PHENOLS , *AMINES , *CRYSTAL morphology - Abstract
A novel multi amine-containing Gemini surfactant (including four positively charged N) modified organo-montmorillonite (GMt) was prepared and served as adsorbents of phenol, o-chlorophenol (2-CP) and 2,4,6-trichlorophenol (2,4,6-TCP). The structure and morphology of GMt were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N 2 adsorption/desorption isotherms (BET) and thermo gravimetric analysis (TGA). A batch technique was applied to investigate the influence of various factors, and the results illustrated that the saturated intercalation concentration of the modifier was 0.8 times to the cation exchange capacity (CEC) of the original Na-Mt and the adsorption was pH dependent, the optimum adsorption occurred at pH = 10, 7, 5 for phenol, 2-CP and 2,4,6-TCP, respectively. At the same conditions, the adsorption capacities of original Na-Mt were only 8.29 mg/g, 26.20 mg/g and 39.13 mg/g for three phenolic pollutants, while the maximum equilibrium adsorption amounts were 81.68 mg/g, 336.59 mg/g and 535.49 mg/g for phenol, 2-CP and 2,4,6-TCP, respectively. The adsorption kinetics of all the three phenols was in good agreement with the pseudo-second order kinetics model. The adsorption isotherm of 2,4,6-TCP was abided by Langmuir and Freundlich isotherm, however, phenol and 2-CP were better modeled by Freundlich isotherm. The negative values of ∆ G ° and positive values of ∆ H ° got from thermodynamic study confirmed that the adsorption of 2-CP and 2,4,6-TCP on GMt was a physical, spontaneous and endothermic process. The adsorption process of phenol was an exothermic process. Both adsorption and partition contributed to the adsorption of these three phenols to organo-montmorillonite. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
25. The interaction and mechanism between threonine-montmorillonite composite and Pb2+ or Cu2+: Experimental study and theory calculation.
- Author
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Zhang, Hongling, Shi, Mingxing, Ma, Jianzhe, Xia, Mingzhu, Wang, Fengyun, and Liao, Chuan
- Subjects
- *
MONTMORILLONITE , *CARBOXYL group , *MOLECULAR dynamics , *INTERCALATION reactions , *DENSITY functional theory , *HYDROXYL group , *ADSORPTION capacity , *ELECTRON pairs - Abstract
The maximum adsorption capacities of threonine-montmorillonite (Thr–Mt) composite to Pb2+ and Cu2+ in aqueous solution were higher than that of original sodium-montmorillonite (Na–Mt). Molecular dynamics (MD) simulation and Multiwfn wavefunction program based on density functional theory (DFT) were exploited to probe the interaction and mechanism between threonine-montmorillonite composite and Pb2+ or Cu2+. Moreover, for the first time, Independent Gradient Model (IGM) analysis was utilized to decode the interaction essence among Thr, Mt. and Pb2+ or Cu2+ to reveal the removal mechanism of Thr-Mt to Pb2+ and Cu2+. MD results indicated that the arrangement of Thr+ presented a preferred almost vertical orientation, which was consistent with the X-ray diffraction (XRD) result. There was hydrogen bonding between carboxyl group or hydroxy group of Thr+ and Mt. surface. Multiwfn calculation implied that the minimum points of ESP and ALIE were located near the O atoms of hydroxyl group and carboxyl group, which were most likely providing the lone pair electron to form a complex with the metal ion,which was accordance with the result of basin analysis. IGM analysis vividly revealed that O atoms of carboxyl group and hydroxyl group were binding sites, and the interaction between Pb2+ and Na–Mt or Pb2+ and Thr-Mt was stronger than that of Cu2+, which was well consistent with the experimental conclusion. Unlabelled Image • Environmentally friendly threonine-montmorillonite composite was prepared. • Molecular dynamics simulation was used to reveal the intercalation mechanism of Thr+. • Multiwfn program was applied to quantitatively analyze the Thr+ molecule surface. • The microscopic mechanism of Thr-Mt on Pb2+ and Cu2+ were probed via IGM analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
26. Exploration of adsorption mechanism of 2-phosphonobutane-1,2,4-tricarboxylic acid onto kaolinite and montmorillonite via batch experiment and theoretical studies.
- Author
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Zhu, Sidi, Khan, Muhammad Asim, Wang, Fengyun, Bano, Zahira, and Xia, Mingzhu
- Subjects
- *
KAOLINITE , *ADSORPTION (Chemistry) , *MONTMORILLONITE , *CLAY minerals , *HYDROGEN bonding interactions , *DENSITY functional theory - Abstract
• Adsorption mechanism is elucidated by experimental and theoretical methods. • The Interface FF is introduced into Forcite module to study adsorption behavior. • Adsorption sites in PBTC are revealed by quantitative analysis on vdW surface. • Adsorption interactions are vividly shown by IGM and Hirshfeld surface analyses. • Hydrogen bond interaction may be the main force for the adsorption process. Two clay minerals, kaolinite (Kaol) and montmorillonite (Mt) with different crystal structures were chosen to investigate the comparative adsorption of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) through batch control experiments and theoretical studies. The systematical isotherm and kinetic studies agreed with Langmuir model and pseudo-second-order model, confirming a monolayer and chemisorption interaction process, respectively. The maximum removal capacities of Kaol and Mt for PBTC were 72.297 mg/g and 121.163 mg/g at pH=3.0 and T=298 K, respectively. Furthermore, the adsorption mechanisms were investigated by molecular dynamic (MD) simulations and density functional theory (DFT). The Interface force field (IFF) was firstly introduced into Materials Studio package to explore the microscopic mechanism of clay mineral interface. The dynamics behaviors verified that the oxygen (O) atom of carboxyl group has stronger affinity at the external surface of Mt, which consistent with the experimental data well. For DFT calculations, quantitative analysis around molecular van der Waals (vdW) surface was adopted to predict reactive sites for the electrophilic reaction. Independent Gradient Model (IGM) and Hirshfeld surface analyses in Multiwfn indicated that the high adsorption effect mainly attributes to hydrogen bond action. These findings improve our ability to explore the related properties occurring at the interface of different clay minerals. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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