Interlayer Of Montmorillonite Research Articles

Optimization of preparation conditions of Bi-doped TiO2/montmorillonite composites and its photodegradation of Rhodamine B

In order to improve the photocatalytic degradation performance of titanium intercalated montmorillonite composites, the sol-gel method was used to intercalate bismuth/titanium polymerized hydroxyl cations into the interlayer of sodium-based montmorillonite (Na-MMT). The optimum synthesis conditions of Bi-doped TiO2/montmorillonite composite photocatalytic material (Bi/Ti-MMT) were investigated. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and UV–vis diffusion reflectance spectrum (UV-Vis DRS) had been used to study the formation of Bi/Ti-MMT. Under the conditions of Bi/Ti molar ratio of 7 %, montmorillonite suspension mass fraction of 2 %, calcination temperature of 600 ℃ and calcination time of 3 h, the Bi/Ti-MMT had the highest photocatalytic activity, the degradation rate of Rhodamine B (RhB) was 88.16 %. In Bi/Ti-MMT composites, TiO2 existed in anatase phase. Bi3+ replaced Ti4+ and was doped into the TiO2 lattice, which can inhibit the growth of TiO2 crystals and reduce the band gap. The photoresponse range of the composite material was broadened to visible light, which improved the utilization of light.

Interlayer and surface characteristics of carboxymethyl cellulose and tetramethylammonium modified bentonite

This study aims to evaluate interlayer and surface characteristics of carboxymethylcellulose (CMC) and tetramethylammonium (TMA) modified bentonite, named as TCMB, as a potential material in contamination containment systems. The study employed a variety of experimental methods, including zeta-potential, scanning electron microscopy, X-ray diffraction (XRD), transmission electron microscopy, and Fourier transform infrared spectroscopy (FTIR), along with molecular dynamics (MD) simulations. Zeta potential results revealed increased electronegativity in TCMB compared to the conventional bentonite. By forming three-dimensional hydrogel networks capable of filling inter clusters pore spaces, CMC effectively maintained the low hydraulic conductivity of TCMB. XRD results confirmed the presence of TMA in the interlayer of montmorillonite. MD simulations and FTIR analyses validated the successful adsorption of CMC and TMA, which can be jointly attributed to hydrogen bonds between hydroxyl groups in CMC and the surface oxygen of montmorillonite, and electrostatic attraction between TMA and montmorillonite. The comparatively weak bonding between CMC and montmorillonite may facilitate CMC elution in the TCMB exposed to aggressive permeants. Furthermore, the electrical double layer thickness of TCMB and CB was estimated as 31.54 Å and 18.76 Å, respectively. Overall, the CMC and TMA treatments effectively enhance the suitability of bentonite for contamination containment applications.

Montmorillonite-Silica-Graphene oxide composite incorporating with chiral thiourea for the Strecker reaction

The present study has successfully intercalated graphene oxide (GO) nanosheets and silica into the montmorillonite (MMT) interlayer and deposited them onto its external surface to make montmorillonite, silica, and graphene oxide composite (MMT-silica-GO). The as-prepared composite demonstrates improved thermal stability compared to neat MMT and GO. It was followed by incorporating chiral thiourea (CTU) scaffold into MMT-silica-GO-based composite to establish chiral MMT-silica-GO-CTU-based heterogeneous system and tested over Strecker reaction, revealing high activity and selectivity. FTIR, Raman spectroscopy, powder X-ray diffraction, SAXS, XPS, BET, SEM, EDAX, and thermogravimetric analysis were used to characterize the samples. It was credited to the synergistic effect between the composite components that enhanced access to active sites and dispersion of catalyst. Across the board, the chiral MMT-silica-GO-CTU-based heterogeneous system appears to be a promising candidate for the Strecker reaction.

Formation mechanism of a novel core–shell with tetradecyl dimethyl benzyl ammonium–modified montmorillonite interlayer nanofibrous membrane and its antimicrobial properties

A novel core–shell with a tetradecyl dimethyl benzyl ammonium chloride–modified montmorillonite (TDMBA/MMT) interlayer silk fibroin (SF)/poly(lactic acid) (PLLA) nanofibrous membrane was fabricated using a simple conventional electrospinning method. Scanning electron microscopy and pore size analyses revealed that this core–shell with TDMBA/MMT interlayer maintained its nanofibrous morphology and larger pore structure more successfully than SF/PLLA nanofibrous membranes after treatment with 75% ethanol vapor. Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses testified that the SF/PLLA–TDMBA/MMT nanofibers exhibited a core–shell with an interlayer structure, with SF/PLLA in the core–shell layer and TDMBA/MMT in the interlayer. The formation of a core–shell with interlayer nanofibers was primarily attributed to the uniform dispersion of TDMBA/MMT nanosheets in a solution owing to its exfoliation using hexafluoroisopropanol and then preparing a stable spinning solution similar to an emulsion. Compared to SF/PLLA nanofibrous membranes, the core–shell structure with TDMBA/MMT interlayers of SF/PLLA nanofibrous membranes exhibited enhanced hydrophilicity, thermal stability, mechanical properties as well as improved and long-lasting antimicrobial performance against Escherichia coli and Staphylococcus aureus without cytotoxicity.

A comparative study on the Cs adsorption/desorption and structural changes in different clay minerals.

We investigated the structural changes in clay minerals after Cs adsorption and understood their low desorption efficiency using an ion-exchanger. We focused on the role of interlayers in Cs adsorption and desorption in 2:1 clay minerals, namely illite, hydrobiotite, and montmorillonite, using batch experiments and XRD and EXAFS analyses. The adsorption characteristics of the clay minerals were analyzed using cation exchange capacity (CEC), maximum adsorption isotherms (Qmax), and radiocesium interception potential (RIP) experiments. Although illite showed a low CEC value, it exhibited high selectivity for Cs with a relatively high RIP/CEC ratio. The Cs desorption efficiency after treatment with a NaCl ion exchanger was the highest for illite (74.3%), followed by hydrobiotite (45.5%) and montmorillonite (30.3%); thus, Cs adsorbed onto planar sites, rather than on interlayers or frayed edge sites (FESs), is easily desorbed. After NaCl treatment, XRD analysis showed that the low desorption efficiency was due to the collapse of the interlayer-fixed Cs, which tightly narrowed the interlayers' hydrobiotite due to the ion exchange of divalent cations (Mg2+ or Ca2+) into the monovalent cation (Na+). Moreover, EXAFS analysis showed that hydrobiotite formed inner-sphere structures after NaCl desorption, indicating that it was difficult to remove Cs from NaCl desorption due to the collapsed hydrobiotite and montmorillonite interlayers as well as the strong bonding in FESs of illite. In contrast, chelation desorption using oxalic acid effectively dissolved the narrowed interlayers of hydrobiotite (98%) and montmorillonite (85.26%), enhancing the desorption efficiency. Therefore, low desorption efficiency for Cs clays using an ion exchanger was caused by the collapsed interlayer due to the exchange between monovalent cation and divalent cation.

Molecular dynamics simulation of dodecyl dimethyl benzyl ammonium cation-intercalated montmorillonite

Abstract Dodecyl dimethyl benzyl ammonium (DDBA) is a novel cation surfactant used to modify clay minerals. DDBA-intercalated montmorillonite is formed by the ion exchange between DDBA cations in the solution and cations in the montmorillonite interlayers. By using molecular dynamics simulations, we investigated the basal spacings, interlayer structures and dynamics of DDBA-montmorillonites. The results showed that the calculated basal spacings agreed well with experimental values and that the layering behaviours of DDBA had been revealed. The ammonium groups of DDBA ions preferred staying close to the centre of Si–O six-member rings. The benzyl group and lauryl group were oriented in parallel in the monolayer state, whereas they were tilted in other states. DDBA ions have very low mobility in the interlayer region, indicating that the negatively charged montmorillonite surfaces can effectively fix this positively charged surfactant. The microscopic structures and dynamics obtained in the present study provide atomic-scale insights into the properties of DDBA-intercalated clay minerals.

Density Functional Theory Simulation of Iron-Montmorillonite as Carbon Dioxide Adsorber

Carbon dioxide (CO2) is a greenhouse gas that naturally keep the Earth^s surface temperature warm but currently the levels cause environmental problem such as climate change. Carbon capture and storage (CCS) technology is built to reduce CO2 gas emissions by binding carbon dioxide molecules and then storing them or utilising them as more useful products. In this study, simulations were carried out for the addition of iron (Fe) impurities as additional cation in montmorillonite to see the increase in the ability to bind carbon gas. Density Functional Theory calculations were carried out using additional corrections such as Van der Waals (vdW) and Hubbard-U. Here we got that Fe cation can help CO2 adsorbtion compare with other site without Fe atom by adding acid cite condition. But to adsorb CO2, the structure need initial process to swell the montmorillonite interlayer to certain optimum distance.

Insights on adsorption of pyocyanin in montmorillonite using molecular dynamics simulation.

Pyocyanin is an important virulence factor in the resistance of Pseudomonas aeruginosa to antibiotics. Pyocyanin is a planar three ring aromatic molecule that occurs as zwitterionic (PYO) or protonated species (PYOH+). Our earlier studies have shown that montmorillonite, through adsorption and transformation, can inactivate both PYO and PYOH+ in the interlayer space. The objective of this study was to elucidate the interaction mechanisms between montmorillonite and the adsorbed pyocyanin and to characterize the structure of the pyocyanin-montmorillonite complex via molecular dynamics (MD) simulations. The MD simulations were performed for the complexes of hydrated Na-montmorillonite (HM) with (i) neutral pyocyanin (HMP) and (ii) protonated pyocyanin (HMPH); and dehydrated Na-montmorillonite (DM) with (iii) neutral pyocyanin (DMP) and (iv) protonated pyocyanin (DMPH). The simulations indicated that in dry conditions, both PYO and PYOH+ were well-ordered in the midplane of the interlayer of montmorillonite, with the three aromatic rings almost parallel to the basal surface and sandwiched in-between basal surface-adsorbed Na+ planes. In humid conditions, the pyocyanin and Na+ were solvated in the interlayer space and the pyocyanin was less ordered compared to dehydrated models. Ion-dipole interaction (Na-O) was the dominant interaction for the dehydrated complexes DMPH and DMP but the interaction was stronger in the latter. The Na-O ion-dipole interaction remained the dominant interaction in hydrated HMP while in HMPH, water outcompeted PYOH+ for Na+ resulting in water-Na interaction being the dominant interaction. These results revealed the arrangement of the two species of pyocyanin in the interlayer spaces of montmorillonite and the mechanism of interaction between the pyocyanin and montmorillonite.

Cotransport of fullerene nanoparticles and montmorillonite colloids in porous media: Critical role of divalent cations of montmorillonite

While the cotransport of carbon nanoparticles (CNPs) and clay colloids in porous media has been widely studied, the influence of the cation exchange capacity (CEC) of clay colloids on the transport process remains unclear. In this study, batch adsorption and column transport experiments were conducted to investigate the fate and transport of CNPs and clay colloids in quartz sand, with respect to the effect of monovalent-cation exchange capacity (mono-CEC), divalent-cation exchange capacity (di-CEC) and total CEC of clays. Fullerene nanoparticles (nC60) and six types of montmorillonite (ML) with different CEC were selected as modeled CNPs and clay colloids, respectively. Transport behavior of nC60 and ML was characterized using breakthrough curves (BTCs) and fitted with two-kinetic-sites colloid transport model. Results of the adsorption experiments showed a good linear correlation between the deposition of nC60 on the sand surface and the di-CEC of ML. Transport of ML and nC60 was inhibited by each other. The calculated mass recovery of nC60, as well as the fitted maximum deposition capacity and attachment rate coefficients of nC60 exhibited a strong linear relationship with the di-CEC of ML. These results indicate that divalent cations in ML interlayers play a significant role in aggregation between nC60 and ML and their cotransport. Through measurements of the particle size and zeta potentials of sole nC60 and mixtures of ML and nC60, FTIR and XPS analysis of nC60 under different conditions, and a release experiment of nC60 in a sand column, it demonstrated cation bridging (Ca2+-π) between nC60 and ML mediated by the divalent cations in ML interlayers. The study highlighted the potential of using di-CEC of clays as an indicator to predict the mobility of nC60 in clay-containing porous media and added insights to the transport behavior of CNPs in porous media.

Effect of Irrigation Regime on Mineralogical Properties of Clay Fraction in some Iraqi Rice Soils

Five soil pedons were chosen from two sites in Najaf and Diwaniyah, governorates, represent some of the soils of Middle Euphrates area. The soils are exploited by rice crop, and irrigated by two methods (flooded and dry) during the growing season. The mineralogical composition of < 2μm fractions for two depths (0-30 and 31-60 cm) in all studied soils were examined by X-ray diffractions. Results showed the presence of Mica, Smectite, Real chlorite and Kaolinite minerals in clay fraction of soils irrigated by the wet method. Results also, showed the precipitation of Brucite layer into Montmorillonite interlayers and caused to shifting Montmorillonite towards Chlorite mineral in soils irrigated by the dry method, and this was attributed to creation a suitable conditions from continuous wet-dry cycling, which encouraged a chloritization phenomenon to occur in these soils.. While, the continuous waterlogging process did not affect much on the weathering of mica minerals, and transformed it towards of expandable 2:1 minerals in these soils.

Migration of nanocolloid-carrying antibiotics in paddy red soil during the organic fertilization process

Soil nanocolloids are highly mobile and can act as carriers for the transport of antibiotics to a wider and deeper range of soils; however, the inherent behavior and mechanism of nanocolloid-carrying antibiotics in soil remain unclear. In this study, we conducted a comprehensive investigation of the migration of antibiotics in paddy red soil during the organic fertilization process using four common soil nanocolloids: kaolin (KL), montmorillonite (MT), hematite (HT), and humic acid (HA). The results showed that nanocolloid carriers promoted the intra-medium (from soil surface to the bottom) and inter-medium transfer (from organic fertilizers to soil) of antibiotics. The migration mechanisms of antibiotics carried by the nanocolloids differed: the phenolic hydroxyl and carboxyl groups of HA esterified with the carboxyl groups of quinolones and phenolic hydroxyl groups of tetracyclines, respectively, while the oxygen atoms of HT formed stabilizing complexes with the soil, which could further adsorb antibiotics using their functional group-rich complexes. Smaller antibiotic compounds were adsorbed in the metal oxide interlayer of MT via cation exchange, whereas KL adsorbed antibiotics on its metal oxide surface layer in the same way but were susceptible to desorption. Additionally, nanocolloids changed the adsorption capacity of soil for antibiotics and influenced the enrichment of dominant/functional bacteria (e.g., Burkholderiaceae) and thus varied the vertical distribution of antibiotics in soil. These findings enhance our understanding of the migration behavior and mechanism of nanocolloid-carrying antibiotics in red paddy soil and provide a theoretical foundation for preventing and controlling antibiotic pollution in arable systems.

Regulating interlayer and surface properties of montmorillonite by dodecyl dimethyl betaine for enhanced lead ion capture

Developing low-cost and high-performance adsorbents is of great significance for the treatment of wastewater containing heavy metal ions. Herein, dodecyl dimethyl betaine modified Na-based montmorillonite (BS-MMT) is successfully prepared by a facile wet method for enhanced lead ion (Pb2+) adsorption. The interlamellar spacing of Na-MMT is effectively regulated ranges from 1.25 to 1.79 nm by changing the ratio of BS-12 content from 5% to 150% (vs. MMT). The Pb2+ capacity adsorption of BS-MMT could reach up to 255.36 mg/g when the usage of BS-12 is 15%. Pb2+ adsorption process on BS-MMT follows the Langmuir model and is endothermic. Mechanism analysis suggests that the main Pb2+ adsorption pathways on BS-MMT include ion exchange, functional group complexation, electrostatic attraction and precipitation by CO32−. Moreover, the modification of BS-12 could not only brings carboxyl and amine functional groups to trap of Pb2+ on the surface and interlayer of MMT, but also optimize the layer spacing of MMT since its long carbon chain. This work provides a feasible strategy to optimize the adsorption capacity of organic modified MMT for heavy metals.

Effects of iron corrosion products on the degradation of bentonite structure and properties

Bentonite is a key material for engineering barriers to prevent groundwater and nuclide migration in the multi-barrier system of high-level radioactive waste (HLW) geological disposal. However, its barrier property will be degraded under the action of iron corrosion products of steel disposal containers. In this paper, the effects of iron corrosion products on the degradation of bentonite structure and properties were investigated in the simulated environments for HLW geological disposal. The results showed that Fe2+/Fe3+ dissolved from iron powder could enter montmorillonite (Mt) interlayer and substituted part of Na+, which caused the decrease of the volume and interlayer spacing of Mt, and the structural integrity of Mt was destroyed. Macroscopically, the water absorption and swelling property of bentonite were significantly decreased. The degradation mechanism of Mt structure was mainly that Fe2+/Fe3+ generated by iron corrosion entered the interlayer domain of Mt to compensate for the interlayer charge deficit.

Adsorption and characterization of exopolysaccharides from Rhizobium tropici on clay minerals

Exopolysaccharides (EPS) are extracellular macromolecular carbohydrate polymers secreted by microorganisms. EPS significantly improves soil structure, fertility and decreases erosion. Montmorillonite and kaolinite are two major clay minerals in soil. Interaction of EPS with clay minerals is important for understanding mechanisms of soil microaggregate and maintaining soil nutrients. The objectives of this study were to investigate mechanisms of EPS from Rhizobium tropici interaction with these clays and their adsorption capacity. Results show that EPS adsorption on clays were better described with Langmuir than Freundlich models, but kinetics followed the parabolic diffusion model. This suggested that EPS adsorption occurred on both surface and interlayers of montmorillonite as controlled by diffusion processes. The maximum adsorption capacity of EPS on montmorillonite and kaolinite were 236.4 mg/g and 168.6 mg/g, respectively. After initial adsorption of EPS on montmorillonite, the d-spacing was slightly increased, but further increase in EPS adsorption significantly decreased the d-spacing. This indicated the partial entrance of EPS into interlayers of montmorillonite, but high EPS presence possibly dehydrated metal ions within interlayers, shrinking montmorillonite. Thus, the current study provides an insight understanding of mechanisms of EPS from Rhizobium tropici interaction with clay minerals.

Slow release fertilizers based on polyphosphate/montmorillonite nanocomposites for improving crop yield

Nanocomposites are promising materials for the development of novel and environmentally friendly fertilizers that can delay the release of nutrients. In this study, a novel high-strength spherical nanocomposite fertilizer was prepared via agglomeration and granulation using montmorillonite, urea phosphate, urea, and potassium chloride as raw materials. The properties and morphology of the prepared fertilizer were characterized by Fourier Transform Tnfrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Thermogravimetric Analysis (TGA) and X-ray Computed Tomography (XCT) techniques. FT-IR analysis identified the formation of polyphosphate in fertilizer and hydrogen bonds between polyphosphate and montmorillonite. XRD analysis showed increased montmorillonite interlayer spacing and confirmed the formation of polyphosphate-montmorillonite nanocomposites. The effects of raw material mass ratio, reaction time, and reaction temperature on the strength and fluidity of nanocomposite fertilizer granules and the optimum preparation process was obtained by the response surface method (RSM-CCD). The optimum preparation process was obtained as follows: reaction temperature, 103 °C; reaction time, 237 min; and mass ratio, 1:1:0.93:1 (urea phosphate: urea: potassium chloride: montmorillonite). Under these optimum conditions, the particle hardness and angle of repose of the prepared fertilizer were 64.75 ± 0.48 N and 30.84 ± 0.95°. Nutrient release and agronomic effectiveness of the fertilizer was evaluated using column leaching and pot experiments, respectively. The column leaching experiment and XCT analysis demonstrated that the nanocomposite structure was responsible for the slow nutrient release. The pot experiment showed that compared with the traditional fertilizer, the soil nitrate and available phosphorus was increased by 28.02% and 43.45%, respectively, and the maize yield was increased by 24.27% with the application of prepared fertilizer. This work provides support for the preparation of high-strength spherical nanocomposite fertilizers and their large-scale applications in modern mechanical agriculture.

Ionic Liquid-Intercalated Montmorillonite Interfacial-Reinforced Polymer Composite Scaffold

Montmorillonite is often used to enhance the mechanical and biological properties of polymer materials, but the weak interaction between the enhanced phase and the matrix limits the enhancement effect. Herein, ionic liquids were introduced as interfacial compatibilizer to improve the dispersion of the enhanced phase in the matrix and interaction between them, and a composite scaffold with enhanced mechanical properties was prepared by selective laser sintering. Specifically, the positively charged terminations of 1-n-butyl-3-methylimidazolium in ionic liquids were anchored to the montmorillonite interlayer domain under electrostatic action. At the same time, the long carbon chain at the other end extends in the opposite direction to increase the layer spacing of the montmorillonite, which provides enough space for the intercalation of the polyetheretherketone molecular chain. First, the blue shift of the diffraction peak in the small-angle X-ray diffraction pattern proves the successful insertion of ionic liquids into the interlayered domain of montmorillonite. In addition, the compression test results show that the compressive strength of the modified composite scaffold was increased by 23%, reaching 31.53 MPa. Besides, the composite scaffold exhibits good biomineralization capacity, which may be attributed to ion modification providing more apatite-shaped nucleation sites. These results suggested that the method of modifying inorganic fillers with ionic liquids to enhance mechanical properties and promote mineralization may be an effective means for bone scaffold modification.

Essential role of the interlayer of montmorillonite, vermiculite, and illite for Ni(II) sorption

Essential role of the interlayer of montmorillonite, vermiculite, and illite for Ni(II) sorption

Photo-induced mode change for CO2 capture/release on spiropyran in a polar-gradient environment.

Photo-induced mode change of CO2 capture/release was achieved by a rationally designed system composed of spiropyran introduced into a polar-gradient field in the interlayer of montmorillonite. DFT calculations and CO2 adsorption tests demonstrated that spiropyran can interact with CO2 through not only weak physical interaction such as Coulombic or van der Waals interactions but also electronic interaction, while photo-isomerized merocyanine was in the CO2 release mode. Photo-induced CO2 concentration systems highly contribute to the realization of carbon neutrality, hence, this study could be a breakthrough for the world's environmental issues.

Atom-scale understanding the adsorption mechanism of uranyl in the interlayer of montmorillonite: Insight from DFT + U calculation

In this work, the adsorption mechanism of uranyl with varied water ligands (UO22+·xH2O; x = 3, 4 and 5) in the interlayer of montmorillonite (MMT) was studied theoretically based on the first-principles DFT + U calculation. The adsorption energy, adsorption geometry configuration and electronic properties (PDOS, electron density difference, Bader charge, ELF) of MMT-UO22+·xH2O systems were investigated systematically. It was found that UO22+·5H2O and UO22+·3H2O are more likely adsorbed above OM (the bridging oxygen on the six-membered ring of SiO4 tetrahedra sheet, signed as T site) and UO22+·4H2O is preferentially adsorbed between OM atoms (signed as B site). DFT + U calculations showed that the migration of uranyl in the interlayer of MMT could be inhibited by forming hydrogen bonds through OM and water ligands. In addition, with the decrease of water ligands, the positive charge of UO22+ increases and UO22+ is directly exposed to the internal surface of MMT. Resultantly, the U atom in UO22+ can form weak chemical bond with OM, thus blocking the migration of UO22+. In summary, this work can provide insights into the adsorption of uranyl in the interlayer of MMT at the microscopic atom-scale, which contributes to understanding the experimentally based internal surface complexation model.

Effect of layer charge density and cation concentration on sorption behaviors of heavy metal ions in the interlayer and nanopore of montmorillonite: A molecular dynamics simulation

Soil and ground water pollution by heavy metal is an identified global environment concern. Montmorillonite is widely adopted as an adsorbent used in retardation of heavy metals due to its excellent adsorption capacity, conveniency, and stability. However, the adsorption mechanism of heavy metal ions in the interlayer and nanopore of montmorillonite needs to be further studied. The classical grand canonical monte carlo (GCMC) and molecular dynamics (MD) simulations were performed to quantify the structural and dynamic properties of heavy metal ions in the interlayer and nanopore of montmorillonite (MMT). Two layer charge densities of MMT, two cation concentrations, and three typical heavy metal ions (Pb2+, Ba2+, and Cs+) were considered. With the increase of layer charge density, outer-sphere adsorption (OSA) was transformed into inner-sphere adsorption (ISA) for three heavy metal ions. The adsorption quantity increased with the increase of layer charge density and cation concentration. The calculated diffusion coefficients of three heavy metal caions in montmorillonite was bulk solution > nanopore > interlayer. The results and adsorption mechanism are helpful for understanding the natural processes of heavy metal ions in environment and developing more efficient remediation materials.