Acid-activated Bentonite Research Articles

Hydrophobic Cetyltrimethylammonium Bromide-Pillared Bentonite as an Effective Palm Oil Bleaching Agent.

To promote a minimal use of acid in the activation of bentonite and to maintain oil quality during refinery and storage, a new class of bleaching agent, cetyltrimethylammonium bromide (CTAB)-pillared bentonite (CTAB@Bent), is fabricated. The influences of three independent intercalation variables, including temperature T (40, 50, and 60 °C), time t (2, 4, and 6 h), and CTAB loading mc (0.2, 0.25, 0.33, 0.50, and 1.00%, w/w), on the β-carotene removal rate are studied. The multilevel factorial design combined with the response surface methodology and three-way analysis of variance is employed to design and optimize experiments in regard to the three independent variables. Based on the optimization results, the highest β-carotene removal rate is monitored at 71.04% (w/w) using CTAB@Bent obtained at optimum intercalation conditions (CTAB@Ben-Opt): T = 40 °C, t = 3.2 h, mc = 1.00% (w/w). The mechanism study shows that the adsorption of β-carotene onto CTAB@Bent-Opt is spontaneous and endothermic, with the governing steps of physical interaction and ion exchange between β-carotene and the cationic head of CTAB. CTAB@Bent-Opt also exhibits characteristics superior to those of commercial raw bentonite and acid-activated bentonite, indicating that a more efficient β-carotene removal can be achieved using this new bleaching agent.

Butylamine-resadiye bentonite composite characterization

The acid activation process increased the specific surface area of raw Resadiye bentonite (33.5 m2/g) by ∼ 4-fold whereas the interaction with n-butylamine caused a surface area reduction of acid-activated bentonite by 40% along with the broadening of the Si-O stretching peak at 1041 cm−1 and the decrease of the d001 value from 14.5 to 13.5 Å. The thermal analysis data confirmed the stability of the mesoporous n-butylamine/acid-activated bentonite composite up to 499 °C which was followed by the cleavage of the interlayer n-butylamine species between 500 and 700 °C.

Facile modification of montmorillonite by intercalation and grafting: The study of the binding mechanisms of a quaternary alkylammonium surfactant

Modified clays are among the most investigated organic-inorganic hybrid materials. Traditionally, they are prepared via reaction of the clay mineral with an organic substrate that can be bonded by cation exchange or by covalent grafting. However, the possibility of bonding one organic substrate to the clay mineral via these two mechanisms simultaneously has not been deeply investigated. In this study, a simple modification of a clay mineral was investigated via the reaction of a quaternary alkylammonium surfactant that possesses an alkoxysilane group [(3-trimethoxysilylpropyl)octadecyldimethylammonium chloride] (TPODAC) with raw bentonite that contains montmorillonite (Mt) as the main phase (~ 90%) and acid-activated bentonite (H5-Mt). The structures, morphologies, and compositions of natural and modified montmorillonites were investigated via various methods, which evidenced successful organic modification. The surface area of Mt. (50 m2g−1) was as expected for sodium bentonite. After acid activation, an increase of the BET area (120 m2g−1), a decrease of the cation-exchange capacity (CEC), and a loss of crystalline order were observed. The presence of TPODAC in the hybrid materials was evidenced by three IR absorption bands at approximately 2930 cm−1, 2860 cm−1, and 1475 cm−1. Negligible leaching of TPODAC from the hybrid materials in aqueous media at pH 3, 7, and 10, in hydrophobic media, and in high–ionic strength media were observed, thereby demonstrating the excellent chemical stability of these materials. A quantitative evaluation of the contribution of each binding mechanism of TPODAC in the hybrid materials was conducted by applying a surfactant-mineral interaction model in which grafting, cross-linking, and cation exchange mechanisms were proposed. The amounts of surfactant in the hybrid materials that were predicted by the model were in agreement with the results that were obtained via TGA.

Studies on the performance of bentonite and its composite as phosphate adsorbent and phosphate supplementation for plant

Organo-bentonite (OrB) was prepared by modifying bentonite with chitosan, and natural surfactant extracted from Sapindus rarak fruit. The physical alteration post-modification, performance of phosphates (Pi) adsorption, and possibility as a Pi-supplementation for plants of OrB were assessed and compared to acid-activated bentonite (AAB). The physical alteration due to modification of bentonite was characterized. SEM images were not indicating significant morphology differences between OrB and AAB. Existence of chitosan layers in OrB causes a decrease in basal spacing as characterized using XRD. The BET surface area of OrB was decreased compared to AAB due to pore coverage by chitosan. Adsorption studies reveal that OrB has a higher adsorption capacity towards Pi than AAB, which is 97.608 and 131.685 mg/g at 323 K for AAB and OrB, respectively. The H-shape isotherm curve indicates that chemisorption is dominantly controlling the adsorption. The isotherm and kinetics adsorption were well fitted to Langmuir and Pseudo-second order models, respectively. Performance of AAB and OrB as Pi-supplementation was assessed based on growth phenotypes of Arabidopsis thaliana; seedlings show that supplementation of Pi@AAB and Pi@OrB (at half doses) can promote primary root extension. These results also demonstrate the safety of direct disposal of the materials into the soil.

Characterization of activated bentonite clay mineral and the mechanisms underlying its sorption for ciprofloxacin from aqueous solution

The presence of emerging pollutants such as hazardous chemicals, pharmaceuticals, pesticides, and endocrine-disrupting chemicals in water sources is a serious concern to the environment and human health. Thus, this study focused on exploring the interaction mechanisms between ciprofloxacin (CIP) (antibiotic) and clay (a low-cost adsorbent) during sorption process. Acid activation technique was opted for modifying natural bentonite (NB) to enhance the adsorptive removal of CIP from water. The BET surface area analysis revealed that acid-activated bentonite (AAB) possessed more than two fold higher surface area as compared to NB. Combining pHzpc measurements, effect of solution pH and CIP speciation revealed that CIP sorption onto bentonite is highly dependent on solution pH. Kinetic studies confirmed that CIP sorption mechanism was chemisorption which included ion-exchange and surface complexation mechanisms. The mechanism of CIP sorption onto AAB was successfully explored with the assistance of characterization techniques. Maximal monolayer sorption capacity of AAB was found to be 305.20 mg/g, compared to 126.56 mg/g for NB. Reusability studies demonstrated that AAB could be reused successfully up to 5 cycles. Furthermore, column studies showed satisfactory results confirming that AAB can be successfully used in continuous mode for practical applications.

Synthesis and characterization of acid-activated bentonite from Aceh Tamiang

Bentonite is new class of microporous materials with high surface areas which have been extensively studied as interesting material in catalyst application and adsorbents. The characterization of bentonite were performed using Infrared spectrophotometer, X-ray Diffraction, and Transmission Electron Microscopy (TEM) instruments. The results showed that the characteristic of natural bentonite and acid-activated bentonite does not give significant different results. XRD pattern of natural bentonite and acid-activated bentonite indicates those bentonites have the main content such as montmorillonite, quartz and alumina. The TEM profile showed the basal spacing in layered structure of acid-activated bentonite was increasing compared to the natural bentonite. The natural bentonite showed the characteristic absorption peaks such as Si-O, Al-O, Si-O-Si which is observed at wave numbers 1149,57 cm−1, 945,12 cm−1, 640 cm−1, and 459 cm−1 but the acid-activated bentonite only showed the characteristic absorption peaks such as Si-O and Al-O which is observed at wave numbers 1018,41 cm−1and 493,78 cm−1. The absorption intensity of streching – OH peak on acid-activated bentonite higher than natural bentonite. It indicates that the bentonite after activation is more pure compared to bentonite before activated.

Studies on the Performance of Shale and Bentonite for the Removal Cr3+ and Mn2+ ions from Wastewater using Batch Experimental Techniques and Inferential Statistics

To investigate the performance of locally available shale for the treatment of wastewater containing chromium and manganese, six different adsorbents were prepared from shale and bentonite, namely; raw shale (RSA), raw bentonite (RBA), calcinated shale (CSA), calcinated bentonite (CBA), acid activated shale (AAS) and acid activated bentonite (AAB). The textural characteristics and chemical composition of the adsorbents were determined using scanning electron microscopy (SEM) and X-Ray fluorescence (XRF). The effects of selected adsorption variables such as initial metal ion concentration, adsorbent dose, pH, and contact time on the sorption of Cr 3+ and Mn 2+ ions were studied using batch adsorption techniques while inferential statistics was employed to select the best adsorbent for specific metal ion removal. Result of the microstructural analysis using SEM revealed that the surface characteristics of the shale and bentonite materials changes drastically with calcination and acid treatment with the acid treated shale and bentonite showing a better irregular porous surface structure. XRF analysis revealed that aluminum oxide and silicon oxide are the dominant oxides present in both shale and bentonite. Inferential statistical analysis revealed that acid activated shale was the most suitable adsorbent for the removal of manganese while acid activated bentonite was the best for chromium ion removal. Keywords: Calcination, acid activation, inferential statistics, SEM and XRF DOI : 10.7176/JEES/9-10-14 Publication date :October 31 st 2019

Amine grafting of acid-activated bentonite for carbon dioxide capture

A low-cost bentonite (ZBent) and acid-activated derived samples have been employed as clay adsorbents to assess their performance for pure CO2 adsorption in a thermogravemetric system. The raw bentonite reached a CO2 uptake of only 6.2 mg/g ads due to its low specific surface area and pore volume. After acid modification, an increase in its specific surface area and pore volume was observed, due to the leaching of octahedral cations and the generation of an amorphous silica phase. However, the degradation of the clay structure only improved slightly the adsorption of CO2. In a next step, raw and acid-treated clay minerals were functionalized with two different amine species (aminopropyl-trimethoxysilane; AP, and diethylene-triamine-trimethoxysilane; DT) by grafting. Unlike the case of DT species, the incorporation of AP moieties favored the chemical interaction between the amines species and the CO2 molecules in all cases. Functionalization with AP molecules increased the adsorption capacity of CO2 up to 29.2 mg/g ads at 30 °C for ZBent-24 h-AP, the material obtained after longer acid treatment time and functionalized with AP. AP-functionalized samples also had good stability and reusability during eight cyclic adsorption/desorption tests.

Congo red dye removal from aqueous solution by acid-activated bentonite from sarolangun: kinetic, equilibrium, and thermodynamic studies

The abundant natural bentonite from Sarolangun deposit of Jambi Province, Indonesia, has been successfully activated by a wet acid activation method and applied as a low-cost, and environmental-friendly adsorbent for Congo red dye removal from aqueous solution. The activated bentonite samples were characterized by powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption-desorption, and X-ray fluorescence (XRF). The batch adsorption technique has been conducted to study the adsorption behavior of Congo red on activated bentonite. The effects of operational parameters toward the Congo red adsorption on activated bentonite, including adsorbent dosage, initial pH, contact time, initial concentration, and temperature were investigated. Moreover, the properties of adsorption kinetics, adsorption isotherm, and adsorption thermodynamic were also investigated. The results of material characterization showed that acid-activated bentonite has better properties than natural bentonite. For instance, the surface area of acid-activated bentonite elevated almost five-fold compared with natural bentonite. The batch adsorption study showed that the Congo red adsorption on acid-activated bentonite was significantly affected by adsorbent dosage, initial pH, contact time, dye concentration, and temperature. The adsorption kinetics investigation revealed that adsorption was best evaluated by a pseudo-second-order model rather than pseudo-first-order model. The adsorption equilibrium study described that the adsorption process followed the Langmuir isotherm model. The result of thermodynamic investigation revealed that the adsorption process occurred spontaneously and favorably in high-temperature conditions.

Highly adsorptive chitosan/saponin-bentonite composite film for removal of methyl orange and Cr(VI).

Robust and simple composite films for the removal of methyl orange (MO) and Cr(VI) have been prepared by combining chitosan, saponin, and bentonite at a specific ratio. There are several composite films (chitosan-saponin-bentonite (CSB)) prepared; among them, the composite films CSB2:3 and CSB1:1 have the highest removal efficiency toward MO and Cr(VI) where the maximum removal is 70.4% (pH 4.80) and 92.3% (pH 5.30), respectively. It was found that different types of adsorbate have different thermodynamic properties of the adsorption process; the adsorption of MO onto CSB2:3, chitosan, and acid-activated bentonite (AAB) proceeded endothermically, while the adsorption of Cr(VI) onto CSB1:1, chitosan, and AAB proceeded exothermically. The parameters of the adsorption were modeled by using isotherm and kinetic equations. The models of Langmuir, Freundlich, Redlich-Peterson, Sips, and Toth were used for fitting the adsorption isotherm data at a temperature of 30, 45, and 60°C; all of the isotherm models could represent the data well. The result indicates that CSB2:3 has the highest adsorption capacity toward MO with qm of 360.90mgg-1 at 60°C; meanwhile, CSB1:1 has the highest adsorption capacity toward Cr(VI) with qm 641.99mgg-1 at 30°C. The pseudo-second-order model could represent the adsorption kinetics data better than the pseudo-first-order equation. The adsorption mechanism was proposed, and the thermodynamic properties of the adsorption were also studied.

Application of activated bentonite for the removal of direct and reactive dye from aqueous solutions

The aim of this study was to determine adsorptive properties of acid activated bentonite clay for the removal of Direct Red 173 (DR 173) and Reactive Red 22 (RR 22) dyes from aqueous solutions. Raw and modified clay were characterized by the following methods: Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). The efficiency of activated clay adsorption was investigated depending on process parameters: the adsorbent dose, pH, temperature, initial dye concentration, and contact time. Experimental data were analyzed by Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm as well as kinetic models of pseudo-first order, pseudo-second order and intra-particle diffusion. The process of dye adsorption was best described by Langmuir, Temkin, and Dubinin-Radushkevich isotherm (R2 > 0.97). Pseudo-second order model (R2 > 0.99) had the highest correlation with the obtained kinetic results. The positive value of ?H? indicated that adsorption of dyes by activated bentonite clay is endothermic process. The activated bentonite exhibited good regenerative ability in the 0.1 M NaOH solution. Maximum adsorption capacities of acid activated bentonite clay at 25?C for DR 173 and RR 22 dyes were 356.65 and 109.58 ?mol g-1, respectively.

Potential of Acid-Activated Bentonite and SO3H-Functionalized MWCNTs for Biodiesel Production From Residual Olive Oil Under Biorefinery Scheme

Application of acid-activated bentonite and SO3H-functionlized multiwall carbon nanotubes (SO3H-MWCNTs) for lowering free fatty acids (FFAs) content of low-quality residual olive oil, prior to alkali-catalyzed transesterification was investigated. The used bentonite was first characterized by Scanning Electron Microscopy (SEM), Inductively Coupled Plasma mass spectrometry (ICP-MS), and X-ray fluorescence (XRF), and was subsequently activated by different concentrations of H2SO4 (3, 5, and 10 N). Specific surface area of the original bentonite was measured by Brunauer, Emmett and Teller (BET) method at 45 m2/g and was best improved after 5 N-acid activation (95-98°C, 2 h) reaching 68 m2/g. MWCNTs was synthesized through methane decomposition (Co-Mo/MgO catalyst, 900°C) during the chemical vapor deposition (CVD) process. After two acid-purification (HCl, HNO3) and two deionized-water-neutralization steps, SO3H was grafted on MWCNTs (concentrated H2SO4, 110°C for 3 h) and again neutralized with deionized water and then dried. The synthesized SO3H-MWCNTs were analyzed using Fourier-Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). The activated bentonite and SO3H-MWCNTs were utilized (5 wt.% and 3 wt.%, respectively) as solid catalysts in esterification reaction (62°C, 450 rpm; 15:1 and 12:1 methanol-to-oil molar ratio, 27 h and 8 h, respectively) to convert FFAs to their corresponding methyl esters. The results obtained revealed an FFA to methyl ester conversion of about 67% for the activated bentonite and 65% for the SO3H-MWCNTs. More specifically, the acid value of the residual olive oil was decreased significantly from 2.5 to 0.85 and 0.89 mg KOH/g using activated bentonite and SO3H-MWCNTs, respectively. The total FFAs in the residual olive oil after esterification was below 0.5%, which was appropriate for efficient alkaline-transesterification reaction. Both catalysts can effectively pretreat low quality oil feedstock for sustainable biodiesel production under a biorefinery scheme. Overall, the acid-activate bentonite was found more convenient, cost-effective, and environment-friendly than the SO3H-MWCNTs.

Rarasaponin-bentonite-activated biochar from durian shells composite for removal of crystal violet and Cr(VI) from aqueous solution

This paper presents the preparation of composite material and its application for the adsorption of crystal violet and Cr(VI) from aqueous solution onto acid-activated bentonite (AAB) and rarasaponin-bentonite-activated biochar from durian shells composite (RBAB). The influence of initial pH of the solution and the temperature of adsorption on the adsorbents adsorption performance was also studied. Langmuir and Freundlich models could represent the adsorption equilibria equally well. Thermodynamic parameters such as ∆G°, ∆H°, and ∆S° were evaluated based on the adsorption isotherms. The values of ∆G°, ∆H°, and ∆S° for crystal violet adsorption system demonstrate behavior contrary to the Cr(VI) adsorption system. Where crystal violet adsorption is preferred at high temperatures with qmax, value is 518.64mg/L; while adsorption Cr(VI) is better at low temperature with qmax, value is 106.30mg/L. Pseudo-first-order and pseudo-second-order kinetic models could represent the kinetic data well.

Intrinsic affinity of acid-activated bentonite towards hydrogen and carbon dioxide

The effect of acid activation on bentonite affinity toward carbon dioxide (CO2) and hydrogen (H2) was investigated at ambient conditions. Characterization through X-ray diffraction and fluorescence, thermal gravimetric analysis, nitrogen adsorption-desorption isotherms, Fourier Transform Infrared spectroscopy and differential scanning calorimetry allowed correlating newly induced textural and structural features with adsorptive properties. Optimum acid treatment improved the specific surface area and porosity. The resulting decrease in dehydration temperature indicates decay in hydrophilic character. The affinity improvement towards hydrogen was due to Brønsted acidity suppression and surface basicity attenuation, which are essential requirements for adsorption on aluminosilicates (AS) via weak Lewis Acid-Base interactions, but excessive acid attack was detrimental. Low Si/Al surfaces should be suitable for CO2 capture, while moderately acid-treated clays should be interesting candidates as hydrogen adsorbents. This allows envisaging promising prospects for low-cost AS-based materials intended for selective CO2-free capture and storage of hydrogen without energy and safety constraints.

Acid-activated bentonite (Maghnite- $$\hbox {H}^{+})$$ H + ) as a novel catalyst for the polymerization of decamethylcyclopentasiloxane

In this study, we propose Maghnite-\(\hbox {H}^{+}\), as an ecological, cost-effective and easily renewable catalyst, for the polymerization of decamethylcyclopentasiloxane (D5). The Maghnite is a clay consisting primarily of smectite minerals (montmorillonite group), which can be activated/reactivated through a simple process, by replacing interlayer cations by protons. Linear polymers with higher molecular mass and narrower molecular mass distribution (MMD) can be obtained with less cyclic by-products, using Maghnite-\(\hbox {H}^{+}\). The reaction was investigated in bulk, taking into account the effect of time, temperature and amount of catalyst on the monomer conversion and MMD. When the yield rises to 96%, the MMD is broadened, suggesting the formation of cyclic oligomers and/or crosslinking bonds, this was confirmed experimentally by infra-red spectroscopy, proton nuclear magnetic resonance (\(^{1}\hbox {H}\) NMR) and \(^{13}\hbox {C}\) NMR analyses. The kinetics have been also studied; the reaction is first order in the monomer. The proposed reaction mechanism shows clearly the role of Maghnite-\(\hbox {H}^{+}\) for D5 polymerization.

Mycotoxin binder improves growth rate in piglets associated with reduction of toll-like receptor-4 and increase of tight junction protein gene expression in gut mucosa

BackgroundDeoxynivalenol (DON) is a mycotoxin produced by Fusarium species in the field, commonly found in cereal grains, which negatively affects performances and health of animals. Mycotoxin binders are supposed to reduce the toxicity of mycotoxins.MethodThe effect of a mycotoxin binder (containing acid-activated bentonite, clinoptilolite, yeast cell walls and organic acids) on growth performance and gut health was studied. Hundred and twenty weaning piglets were allocated to 4 treatments, with 5 pens of 6 piglets each, arranged in a 2 × 2 factorial design: control diet; control diet with 1 kg/t binder; control diet with DON; and control diet with DON and 1 kg/t binder. From d0–14, the diet of DON-challenged groups was artificially contaminated with a mixture of DON (2.6 mg/kg), 3-acetyl-deoxynivalenol (0.1 mg/kg) and 15-acetyl-deoxynivalenol (0.3 mg/kg), after which the total contamination level was reduced to 1 mg/kg, until d37. On d14, one pig from each pen was euthanized and distal small intestinal mucosa samples were collected for the assessment of intestinal permeability, and gene expression of tight junction proteins, toll-like receptor 4, inflammatory cytokines and intestinal alkaline phosphatase.ResultsAfter 37 d, there were no differences in growth performance between control and DON-challenged groups (P > 0.05). Nevertheless, groups that received diets with binder had a significantly higher average daily gain (ADG) and average daily feed intake (ADFI) for the first 14 d as well as for the whole period, compared to groups without binder (P ≤ 0.05). Groups with binder in the diet also exhibited lower expression of toll-like receptor 4 in distal small intestinal mucosa at d14, compared to groups without binder (P ≤ 0.05). Interestingly, comparing the two DON treatments, piglets fed DON and binder had significantly higher ADFI and ADG compared to those with only DON for the first 14-d (P ≤ 0.05). Addition of binder to DON contaminated diets, also down-regulated the gene expression of toll-like receptor 4 (P ≤ 0.05) and increased mRNA level zona occludens 1 (P ≤ 0.10) as compared to DON.ConclusionsThe present data provide evidence that the binder improves growth rate in piglets associated with reduction of toll-like receptor-4 and increase of tight junction protein gene expression. However, the current study does not allow to assess whether the effects of the binder are mediated by alterations in the toxicokinetics of the mycotoxin.

Production of aromatic hydrocarbons from catalytic pyrolysis of lignin over acid-activated bentonite clay

Natural bentonite clay (mainly sodium-rich montmorillonite) both purified and acid activated using HCl, H2SO4, and H3PO4 acids were applied to the catalytic fast pyrolysis (CFP) of lignin. The modifications in crystalline structure and acidity of the activated clay were investigated via XRD, N2-adsorption-desorption, FTIR, TGA and NH3-TPD analysis. The activity and selectivity of the clays were evaluated for lignin conversion in down- flow micro reactor in the temperature range 500–650°0C in flowing Nitrogen (oxygen-free). The yields of high value added monocyclic aromatics such as BTX (benzene- toluene- xylenes) and naphthalene were increased by catalytic upgrading using HCl-activated bentonite clay. The selectivity for o&p-xylenes, naphthalene, and methyl naphthalene were greatly enhanced using HCl-activated bentonite in the temperature range 550–650°C. The catalyst: lignin ratio 3:1 and the nitrogen flow rate 75ml/min, at 600°C were the optimum conditions.

Thin film nanocomposite (TFN) hollow fiber membranes incorporated with functionalized acid-activated bentonite (ABn-NH) clay: towards enhancement of water vapor permeance and selectivity

Functionalized acid-activated bentonite (ABn-NH) clay incorporated thin film nanocomposite (TFN) membranes can exhibit exceptional separation properties towards the improvement of water vapor permeance and selectivity.

Organic vapours sorption on simply modified bentonites

Modified materials based on bentonite (acid-activated bentonite, mineralogically defined clay obtained by sedimentation, and composite material composed of bentonite and humic substances) were prepared in this work and sorption properties of the prepared materials for organic vapours (cyclohexane, toluene, mixture of xylenes and acetone) were determined. The aim of modification was the specific surface area enlargement and reduction of hydrophilic character. Results of the organic vapours adsorption show that the polarity of adsorbate is very important factor. It was found that adsorption of less polar and nonpolar organic vapours on the prepared clay-based materials took place through weak interactions and the specific surface area was key factor influencing adsorption process. Influence of water content in the materials can be considered, too. Adsorbed amounts of weakly polar organics on the clay materials were at most on the half level in comparison with active carbon. In the case of polar acetone the studied bentonites show the comparable adsorbed amounts as active carbon. It was found that acetone replaced water molecules in the solvation shells of interlayer cations, which was proven by infrared spectroscopy. The specific surface area did not play a leading role during adsorption of acetone on the bentonites.

Adsorptive removal of Lead from water by the effective and reusable magnetic cellulose nanocomposite beads entrapping activated bentonite

Many efforts have been driven to decontaminate the drinking water, and the development of efficient adsorbents with the advantages of cost-effectiveness and operating convenience for the removal of Pb2+ from water is a major challenge. This work was aimed to explore the possibility of using cellulose-based adsorbents for efficient adsorption of Pb2+. The millimeter-scale magnetic cellulose-based nanocomposite beads were fabricated via an optimal extrusion dropping technology by blending cellulose with the carboxyl-functionalized magnetite nanoparticles and acid-activated bentonite in NaOH/urea aqueous solution, and then they had been tested to evaluate the effectiveness in the removal of Pb2+ from water. The effects of contact time, initial heavy metal ion concentrations, adsorption isotherms and solution pH on the sorption behavior were studied. The thermodynamic parameters (ΔG, ΔH and ΔS) indicated that the adsorption processes were feasible, spontaneous, endothermic and mainly controlled by chemical mechanisms. The reusability of the adsorbent was also studied.