Construction of ternary (1D/2D/3D) Fe2O3-supported micro pillared Cu-based MOF on chitosan with improved photocatalytic behavior on removal of paraquat.

A hetero-structured metal organic framework of Cu-BTC and Fe2O3 nano-photocatalyst were tethered over chitosan using the hydrothermal method and fabricated a hybrid porous nanocomposite (CS-Fe@Cu-BTC). X-ray diffractometer results exposed the existence of Fe2O3 peaks. Surface area measurements using BET showed a mesoporous structure and the formation of type IV adsorption isotherm for nanocomposite. XPS and SEM-EDAX confirmed the existence of Fe2O3 nanoparticles in the hybrid porous structure. The UV-vis diffuse reflectance absorption shape emphasized the role of Fe2O3 in enhancing the band gap of CS-Fe@Cu-BTC nanohybrid. The lower intensity photoluminescence spectra of the CS-Fe@Cu-BTC shows a competent charge partition and delayed the recombination of electron-hole pairs. The photo-mineralization efficiency of Cu-BTC and CS-Fe@Cu-BTC was evaluated in terms of electronic interactions using paraquat (PQT) as the probe molecule, which shows a mineralization of 91% at the pH range of ~ 5. The contribution of •OH in the degradation of PQT over CS-Fe@Cu-BTC nanocomposites revealed using the trapping test and the degradation mechanism follows the Langmuir-Hinshelwood model and pseudo-first-order kinetics. The durability of the CS-Fe@Cu-BTC nanocomposite was also established after four cycling processes.

Applications of chitin and chitosan based biomaterials for the adsorptive removal of textile dyes from water - A comprehensive review.

The presence of pollutants in the water bodies deteriorate the water quality and make it unfit for use. From an environmental perspective, it is essential to develop new technologies for the wastewater treatment and recycling of dye contaminated water. The surface modified chitin and chitosan biopolymeric composites based adsorbents, have an important role in the toxic organic dyes from removal wastewater. The surface modification of biopolymers with various organics and inorganics produces more active sites at the surface of the adsorbent, which enhances dye and adsorbent interaction more reliable. Herein, the work brought in the thought of the application of various chitin and chitosan composites in wastewater remediation and suggested the versatility in composites for the development of rapid, selective and effective removal processes for the detoxification of a variety of organic dyes. It further emphasizes the existing obstruction and impending prediction for the deprivation of dyes via adsorption techniques.

Photocatalytic performance of chitosan tethered magnetic Fe2O3-like (3D/2D) hybrid for the dynamic removal of anionic dyes: Degradation and mechanistic pathways.

Efficient photocatalysis methods with a production of less number of toxic intermediates are extremely advantageous for water decontamination. The degradation efficiency, specific surface area, stability and porosity will be improving by wrapping of Fe2O3 using appropriate biopolymers. In this work, Fe2O3 reinforced chitosan (Fe2O3@CS) nanocomposite was fabricated using co-precipitation method. The chitosan makes available its surface for the useful generation of the nanocomposite. These wrapping of Fe2O3 on chitosan provides synergistically improved properties that could be attributed to the elevated partition efficiency and faster transfer of the photo-generated charge carriers, which was substantiated by the experimental outcomes from photoluminescence and ESR spectroscopy. The results obtained from DRS analysis entail the reduction in band gap of Fe2O3@CS (2.52 eV) as compared with 3.52 eV of Fe2O3. The results indicated that 89.2% and 94.6% were the maximum degradations correspondingly for MO and OG. The trapping investigation emphasized the involvement of OH radicals in the degradation of dyes over Fe2O3@CS composites. The five cycles of regeneration experiment recommended the superior photostability of the fabricated Fe2O3@CS composite. This work proposed a practical arrangement and subsequent influence of an advanced photocatalyst for the useful remediation dyes from contaminated water without causing any secondary pollution.

Complex interior and surface modified alginate reinforced reduced graphene oxide-hydroxyapatite hybrids: Removal of toxic azo dyes from the aqueous solution.

In this study, alginate reinforced reduced graphene oxide@hydroxyapatite (rGO@HAP-Alg) hybrids have been fabricated via co-precipitation technique. The developed adsorbent was effectively utilized for the removal of Reactive Blue 4 (RB4), Indigo Carmine (IC) and Acid Blue 158 (AB158) azo dyes from aqueous solution, and found to have the adsorption efficiency of 45.56, 47.16 and 48.26 mg/g, respectively. The thermodynamic parameters demonstrated the endothermic and spontaneous nature of the adsorption process. The adsorption system was pH-dependent and showed maximum dye removal at pH 6-7, which was indicative of the electrostatic interactions, surface complexation and the hydrogen bonding mechanisms involved between the adsorbate and adsorbent during the adsorption process. Furthermore, the renewability studies demonstrated the reusability and stability of rGO@HAP-Alg hybrids up to five successive cycles. This study delivers a promising strategy for removing dye molecules and extends the potential application of rGO@HAP-Alg hybrids to treat practical dye contaminated water/wastewater.

Fabrication of hybrid chitosan encapsulated magnetic-kaolin beads for adsorption of phosphate and nitrate ions from aqueous solutions.

Phosphate and nitrate are commonly used industrial and agricultural nutrients that are of great anxiety because of their ubiquitous existence in water and wastewater sources and association with harmful health effects. Herein, we aimed to fabricate a novel and environmental-friendly chitosan encapsulated magnetic kaolin beads for the first time and applied for the adsorption of phosphate and nitrate ions from water. The physico-chemical properties of MK-chitosan beads were established by XRD, FTIR, and TGA-DSC techniques. Surface area (BET) analysis shows that MK-chitosan beads have a specific surface area of 2.12 m2/g. Surface morphology and elemental studies (SEM and EDAX) revealed the porous nature of MK-chitosan beads. The synthesized bead material employed as selective and effective adsorbent material for the remediation of phosphate and nitrate from water/ wastewater. The impact of external adsorption influencing effects likes, adsorbent dose, contact time, co-anions, pH of the solution, and temperature experiments have been performed. Adsorption isotherm and kinetic experiments have been studied and the data have been well tailored by the Freundlich isotherm and pseudo-second-order kinetic models. Thermodynamic parametric studies revealed endothermic and spontaneous nature of the overall sorption system. Besides, MK-chitosan beads were found to regeneration performance up to eight consecutive cycles. Furthermore, the adsorbent-adsorbate system implying that MK-chitosan beads could be a promising candidate for the removal of phosphate and nitrate ions from aqueous solutions.

Facile synthesis of Zr4+ incorporated chitosan/gelatin composite for the sequestration of Chromium(VI) and fluoride from water.

The development of industrialization and agricultural activities have carried various negative impacts to living organisms in recent decades and also, the frequent problem of inorganic pollution have been environmental anxiety to the community. Among these, Cr6+ and F- are priority poisonous pollutants from many industries. In this work, we present a low-cost synthesis procedure to obtain biocompatible zirconium incorporated chitosan-gelatin composite (CS-Zr-GEL) were fabricated and explored for the adsorptive removal of toxic Cr6+ and F- from water. The adsorption mechanism of toxic Cr6+ and F- was done by batch mode as a function of contact time, solution pH and co-existing ions. The obtained materials were extensively studied by several physico-chemical techniques to access their properties by X-ray diffraction (XRD), scanning electron microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analysis. Additionally, the fabricated adsorbent is highly dependent on solution pH. The kinetic and isotherm data were fitted using pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity for CS-Zr-GEL is 138.89 and 12.13 mg/g at 323K for Cr6+ and F- respectively. These findings demonstrate that the CS-Zr-GEL adsorbent represents a promising candidate that would have a practical influence on water/wastewater treatments.

Magnesium ferrite-reinforced polypyrrole hybrids as an effective adsorbent for the removal of toxic ions from aqueous solutions: Preparation, characterization, and adsorption experiments.

Contaminated waters with high contents of toxic anions are detrimental to the human health and wildlife. Thus, the quality of drinking water should be carefully monitored. Adsorption technique has been determined to be a reasonable strategy out of several methods used to remove toxic anions from water. Novel MgFe2O4-reinforced polypyrrole (Ppy@x%MgFe2O4) (x = 1%, 2%, and 5% of MgFe2O4) hybrids were synthesized from a pyrrole monomer and MgFe2O4 using a simple chemical oxidation method. The fabricated hybrids were studied for their capability to remove PO43-, NO3-, and Cr(VI) from aqueous solutions. The results showed that PO43-, NO3-, and Cr(VI) removal was highly pH-dependent. The adsorption isotherms of hybrids were fitted well by the Langmuir model, with the maximum adsorption efficiency of 116.90, 76.14, and 138.60 mg/g for PO43-, NO3-, and Cr(VI), respectively. In addition, the above-mentioned toxic anions could be efficiently desorbed from spent Ppy@x%MgFe2O4 using a 0.1 M NaOH solution, and the hybrids exhibited good regenerability. The prepared materials are promising candidates for PO43-, NO3-, and Cr(VI) removal and exhibit high adsorption efficiency, rapid adsorption-desorption behavior, and appropriate recovery from the aqueous medium under external magnetic field.

Immobilization of MIL-88(Fe) anchored TiO2-chitosan(2D/2D) hybrid nanocomposite for the degradation of organophosphate pesticide: Characterization, mechanism and degradation intermediates.

In this study, we have rationally designed and grafted a bio-assisted 2D/2D TiO2/MIL-88(Fe) (TCS@MOF) heterojunction by growing granular TiO2 on the surface of MIL-88(Fe) nanosheet, as hybrid photocatalyst. The hierarchical TCS@MOF composite was prepared via the one-pot solvothermal process and employed for monocrotophos (MCP) degradation under visible light region, since its persistent nature on soil and water causes major threat to the environment. The TCS@MOF promotes a number of packed high-speed nano-tunnels in the (p-n) heterojunctions, which significantly enhance the migration of photo-induced electrons (e-) and holes (h+), respectively and thus limits the charge recombination of e-s. The optimized photocatalyst achieves significant catalytic activity of ~98.79% for the degradation of MCP within 30 min of irradiation. The prominent oxidative radicals namely •OH, •O2- etc., were involved in the oxidation of organic pesticide. Besides, TCS@MOF exhibits outstanding stability even after five repetitive cycles for the oxidation of MCP with a negligible decrease in photo-activity. The proposed mechanism and oxidative pathways of MCP were rationally deduced in detail subject to experimental results. The mechanism renders insight into the oxidation and consequent bond rupture of pollutant as well as into the formation of products such as H2O, CO2, etc. This report unveils a novel architecture of proficiently optimized TCS@MOF material structure for the perceptive oxidation of organic contaminants.

Environment responsive Al3+ networked chitosan-gelatin spherical beads for the effective removal of organic pollutants from aqueous solutions.

In order to remove noxious Congo Red (CR), Acid Red 1 (AR1) and Reactive Red 2 (RR2) dye molecules from water, an environment responsive and biodegradable spherical chitosan-gelatin biopolymeric beads were designed and embedded with Al3+ ions. The surface morphology, specific surface area, crystalline phases, elemental composition and thermal properties of the CAG spherical beads had examined. Adsorption experiments were explored to investigate the adsorption properties of dye molecules on CAG spherical beads. The adsorption parameters like solution pH, contact time, co-existing ions, adsorbent dosage and regeneration studies were optimized using batch experiment method. The maximum adsorption efficiency of CR, AR1, and RR2 dye molecules on CAG spherical beads were 34.89, 32.36 and 33.63 mg/g, respectively. The adsorption system fits well with pseudo-second-order kinetics and Freundlich isotherm model. The molecular interactions followed in the adsorption mechanisms were the electrostatic force of attraction, surface complexation and hydrogen bondings that exist between dye molecules and the CAG spherical beads. The CAG spherical beads could be regenerated up to six consecutive cycles using an aqueous 0.1 M NaOH solution. The study emphasizes that the fabricated CAG spherical beads could act as a potential adsorbent in the water/wastewater treatment process.

Boosted insights of novel accordion-like (2D/2D) hybrid photocatalyst for the removal of cationic dyes: Mechanistic and degradation pathways.

In the present work, a novel (2D/2D) accordion like CS@g‒C3N4/MX hybrid composite was prepared through one-pot hydro-thermal synthesis method and utilized as a catalyst for the degradation of organic persistent dyes such as methylene blue (MB) and rhodamine B (RhB). Because the removal of such organic compounds is a major dispute in environmental aspects. In this study, the bio-assisted g‒C3N4/MX nanosheets was utilized for the removal of organic dyes from aqueous solution under visible light irradiation, respectively. The CS@g-C3N4/MX photocatalyst showed high catalytic activity based on ~99% and ~98.5% degradation of MB and RhB within 60 and 40 min using visible light irradiation. This outcome could have resulted in greater catalytic enactment towards the degradation of other persistent pollutants with enhanced light absorption property and it can efficiently suppress photo-generated charge recombination, thus improving the interfacial charge transfer rate. The OH radical was being effective oxidative species involved in the CS@g-C3N4/MX system for the degradation of organic contaminants. Furthermore, CS@g-C3N4/MX showed excellent photo-stability over five consecutive cycles for the degradation of organic dyes with negligible loss of photocatalytic activity. Finally, the purposed catalytic mechanisms and degradation pathways of MB and RhB were systematically discussed in detail based on experimental results. Thus, the organics which oxidized into ring-opened compounds such as ethoxyethane, butadiene etc., to non-toxic products like H2O, CO2 and some mineral salts.

Synthesis and characterization of La(III) supported carboxymethylcellulose-clay composite for toxic dyes removal: Evaluation of adsorption kinetics, isotherms and thermodynamics.

The discharge of organic dyes into the aquatic environment is a serious problem owing to the persistence of possible health risks and ecological hazards of these pollutants. This paper reports a facile method for the preparation of composite material consisting of lanthanum incorporated carboxymethylcellulose-bentonite (LCB) composite and utilized for the removal of Indigo Carmine (IC), Acid Blue 158 (AB158) and Reactive Blue 4 (RB4) dyes from water by batch adsorption techniques. The optimal conditions for the dye adsorption were found to be pH = 3, initial dye concentration: 50 mg/L and adsorbent dosage of 100 mg. The adsorption efficiency of IC, AB158 and RB4 dye molecules were 80.41%, 83.54% and 86.91% respectively. The entire adsorption process was completed within 40 min. The adsorption data fits well with the pseudo-second-order kinetic model, demonstrating the physico-chemical adsorption of the dyes on LCB matrix. The Langmuir, Freundlich, and D-R isotherm models were used to describe saturation point. The fabricated adsorbent material was characterized using PXRD, FTIR, SEM-EDAX, TGA-DSC and surface area measurements. The thermodynamic studies revealed that the adsorption was spontaneous and endothermic in nature. The LCB composite showed remarkable adsorption-desorption efficiency for dye removal in water/wastewater treatment process; hence it can be considered as a competent and potential adsorbent for dye removal.

Chitosan modified zirconium/zinc oxide as a visible light driven photocatalyst for the efficient reduction of hexavalent chromium.

Metal-sensitized biopolymeric hybrid materials can be strategically utilized in photo catalysis due to the behavior of their absorption band lying in the solar radiation spectrum. Herein, chitosan supported zirconium(Zr)/zinc oxide (ZnO)) in the preparation of photo catalyst (Zr-ZnO@CS) for photocatalytic reduction of hexavalent chromium(Cr6+). Moreover, photocatalytic testing factors like exposure time of light, pH, initial Cr6+ concentration, and influence of co-anions on the removal of Cr6+ by Zr-ZnO@CS were also examined. Langmuir-Hinshelwood kinetic model suggested the surface reaction was the rate-controlling step. The removal mechanism of Zr/ZnO@CS was because of enhanced properties like positive positioning of the band gap, boosted charge excitation, and higher dynamic sites. Field trial results showed that Zr-ZnO@CS hybrid photocatalyst demonstrates the potential application for the reduction of Cr6+ ions.

Adsorptive performance of lanthanum encapsulated biopolymer chitosan-kaolin clay hybrid composite for the recovery of nitrate and phosphate from water.

Nitrate and phosphate are primary pollutants of water/wastewaters for eutrophication and methemoglobinemia diseases, harshly threatening the security of aquatic environments and human health as well as all living beings. The present work investigates the adsorption performance and mechanism of lanthanum encapsulated chitosan-kaolin clay (LCK) hybrid composite was prepared and utilized for the remediation of nitrate and phosphate from water. The fabricated LCK hybrid composite was characterized using XRD, SEM, BET, EDAX, TGA-DTA and FTIR analysis. The removal of nitrate and phosphate onto the LCK composite defined by pseudo-second-order kinetic model whereas the isotherms are described by Freundlich adsorption isotherm model and thermodynamic experiments showed spontaneous and exothermic nature of the adsorption process. Results also demonstrated that the LCK hybrid composite exhibited extremely high nitrate and phosphate adsorption capacity and stability which followed the mechanisms by ion exchange, complexation and electrostatic interactions. Adsorption-desorption experiments revealed that the LCK hybrid composite could be potentially reused with maintaining high adsorption efficiency. This study highlights the novel low-cost, eco-friendly and promising adsorbent for efficient denitrification and dephosphorization from water/ wastewater.

Enhanced photocatalytic response of ZnO embedded chitosan/ß-cyclodextrin towards the detoxification of Cr(VI) under visible light.

The present work focused on the assessment of heterogenous photocatalytic efficacy of ZnO@CS-ß-CD towards the degradation of hexavalent chromium under visible light illumination. The prepared ZnO@CS-ß-CD was extensively characterized using XRD, FTIR, SEM, EDX with mapping, TGA, DSC and UV/vis DRS techniques and the photoreduction of Cr(VI) to Cr(III) was confirmed by X-ray photoelectron spectroscopy. The DRS results revealed that the band gap of ZnO@CS-ß-CD was narrowed than ZnO from 3.23 to 2.01 eV. The photocatalyst hold excellent reusability up to seven cycles and the field trail results demonstrated for the practical application for the treatment of wastewater.

In-situ fabrication of zirconium entrenched biopolymeric hybrid membrane for the removal of toxic anions from aqueous medium.

The eutrophication of water bodies resulting from the excessive amounts of phosphate and nitrate ions in the water systems will cause serious environmental problems. This study deals with the adsorptive removal of toxic anions from aqueous medium using zirconium entrenched chitosan-starch membrane (Zr-CS-ST). The optimization of several influencing key factors like adsorbent dosage, shaking time, solution pH, aggressive ions, zero point charge and temperature were examined by batch mode adsorption experiments. In addition, Freundlich isotherm model showed an outstanding fit with the experimental data's, yielding the maximum adsorption capacities of 86.28 and 70.88 mg/g for phosphate and nitrate, respectively. Thermodynamic parameters, including the Gibbs free energy, entropy and enthalpy change indicated that the removal of both anions by Zr-CS-ST membrane was feasible, spontaneity and endothermic in nature. The diffusion and reaction based kinetic models were exposed to study about the kinetics and adsorption process were followed by pseudo-second-order and intra-particle diffusion kinetic models. The removal mechanism involved by different types of interactions such as complexation, ion exchange and electrostatic interaction, which were adopted for the removal mechanisms. We exposed that, Zr-CS-ST was successfully developed and will be effectively employed for the remediation of phosphate and nitrate ions in field/practical applications.

Fabrication of nano-graphene oxide assisted hydrotalcite/chitosan biocomposite: An efficient adsorbent for chromium removal from water.

Recently, nanomaterials based adsorbents play a prominent role in the removal of toxic ions from aqueous solution. Hence in the present study, nano-graphene oxide (n-GO) fabricated hydrotalcite (n-GO@HT) composite was prepared by hydrothermal method for chromium removal. To improve the mechanical strength and chromium removal capacity, GO@HT composite was reinforced with chitosan (CS) to form hybrid composite namely n-GO@HTCS biocomposite. The synthesized biocomposite was characterized using various instrumental techniques like FTIR, SEM, TEM and EDAX with mapping analysis. To get the maximum chromium retention, the various sorption experiments like agitation time, dosage, pH, competing ions and temperature were optimized. The sorption capacity (SC) of n-GO@HTCS biocomposite was found to be 42.64 mg/g within 50 min. The obtained equilibrium data was explained with Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms wherein the chromium sorption process was best fitted with Langmuir isotherm. The thermodynamic results prove that the chromium sorption of n-GO@HTCS biocomposite was endothermic and spontaneous. The chromium sorbed n-GO@HTCS biocomposite could be easily regenerated with 0.1 M NaOH. The synthesized n-GO@HTCS biocomposite was also utilized in the field conditions.

Development of chitosan encapsulated tricalcium phosphate biocomposite for fluoride retention.

The powder form of tricalcium phosphate (TCP) causes the significant pressure drop which limit its application under field conditions. To trounce such technological troubles and to enhance the defluoridation capacity (DC) of TCP, chitosan (CS) encapsulated TCP polymeric composite was prepared by dispersing TCP particles into chitosan polymeric matrix to produce tricalcium phosphate/chitosan (TCPCS) composite which could be made into any desirable form. The synthesized TCPCS composite possesses an enhanced DC of 1034 mgF-/kg than the individual components viz., TCP and chitosan which has got DC of 490 and 52 mgF-/kg respectively. The prepared adsorbents were characterized by FTIR, SEM and EDAX analysis. The various physico-chemical properties such as contact time, solution pH, co-anions and temperature were optimized to get maximum defluoridation. The equilibrium and kinetic experiments were conducted for TCPCS composite toward fluoride removal. The practical applicability of TCPCS composite was examined at field conditions.

Facile synthesis of chitosan-La3+-graphite composite and its influence in photocatalytic degradation of methylene blue.

Integrated photocatalytic composite adsorbents (IPCA) are used to degrade toxic organic and inorganic compounds in presence of UV/visible light irradiation. The compound preserves all the existing features of individual components and at the same time overcome drawbacks like rapid recombination of photogenerated electrons, low absorptivity and hindrance effect of the photocatalyst. Herein, an integrated Photocatalytic Chitosan-La3+-Graphite composite adsorbent was synthesized and the resultant composites were characterized by FTIR, XRD, TGA, EDX and SEM analysis. The UV-visible diffusion reflectance spectroscopy (UV-vis DRS) was used for the band gap measurement and it was found to be 3.2 eV. An aqueous solution of methylene blue (MB) dye (30 mL of 100 mg/L) was used to study the photocatalytic efficiency of the prepared IPCA. The Chitosan-La3+-Graphite Composite (CS-La-GR) (100 mg of dosage) exhibits enhanced photocatalytic degradation efficiency (93.5% in 40 min) for Methylene blue under UV light irradiation. The highest photodegradation was due to the stronger adsorption of MB dye on the surface of highly porous IPCA. Moreover, the reactive species, ·OH radical and O2·- radical ions play a major role in the photocatalytic degradation of Methylene blue over composite photocatalyst.

Removal of chlorpyrifos, an insecticide using metal free heterogeneous graphitic carbon nitride (g-C3N4) incorporated chitosan as catalyst: Photocatalytic and adsorption studies.

The present study investigates the photocatalytic degradation of an organic pesticide using a metal free heterogeneous graphitic carbon nitride (g-C3N4) incorporated into chitosan as catalyst. Chlorpyrifos (O, O-diethylO-3,5,6-trichloro-2-pyridyl phosphorothioate (CPFS)), an insecticide includes in a class of Organophosphate pesticides with a chemical formula (C9H11Cl3NO3PS). It is widely used in agricultural lands to control pests in cotton, fruit and vegetables. The acute toxicity of chlorpyrifos is still dangerous to all aquatic living organisms. The CS/g-C3N4 materials have been characterized using UV-vis spectrophotometer (UV-vis), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Energy Dispersive X-ray Analysis (EDX), Thermal analysis (TGA-DSC), Chemical oxygen demand (COD), X-ray diffraction (XRD), Diffuse reflectance spectra (DRS) and Electron spin resonance (ESR). The degradation of pesticide using CS/g-C3N4 showed good efficiency of about 85%. The results suggest that CS/g-C3N4 composite is a good alternative for the treatment of chlorpyrifos in aqueous solution. We have proposed a novel photocatalyst by metal free heterogeneous graphitic carbon using melamine and its recombination effects were minimized by chitosan which act as an electron carrier. The enhanced photocatalytic performance could be attributed to an efficient separation of electron-hole pairs through a Z-scheme mechanism, in which chitosan acted as charge separation carriers.

Hydrothermal synthesis of magnetic iron oxide encrusted hydrocalumite-chitosan composite for defluoridation studies.

A magnetic adsorbent namely magnetic iron oxide encrusted hydrocalumite-chitosan (Fe3O4@HCCS) composite was prepared by the fabrication of magnetic iron oxide (Fe3O4) particles on hydrocalumite-chitosan (HCCS) composite for fluoride sorption studies in batch mode. The prepared magnetic Fe3O4@HCCS composite possesses an enhanced defluoridation capacity (DC) of 6.8mg/g compared to hydrocalumite (HC) which possesses the DC of 2.4mg/g. The various physico-chemical parameters such as contact time, pH, co-existing anions, initial fluoride concentration and temperature were optimized for the maximum fluoride removal. The structural changes of the sorbent, before and after fluoride sorption were studied using FTIR and SEM with EDAX techniques. The equilibrium data was well modeled by Freundlich and Langmuir isotherms. The thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of fluoride sorption. The field performance and efficiency of Fe3O4@HCCS composite was examined with the waste-water sample collected from a fluoride endemic area of Dindigul district, Tamilnadu, India using standard protocols.