Antonysamy Jeyaseelan

Fluorosis is a health problem that affects many people worldwide. To solve this problem, we developed a hybrid composite using magnesia dispersed in hybrid biopolymers (pectin and alginate), which was doped with lanthanum (La) or cerium (Ce) to yield pectin-alginate-magnesia-lanthanum (PAML) and pectin-alginate-magnesia-cerium (PAMC) hybrid composites, respectively, for efficient fluoride removal. The fabricated PAML and PAMC composites were characterized by SEM, FTIR, and EDAX studies. The manipulating factors such as dosage, pH, reaction time, initial ion concentration, temperature, and co-ions were examined under batch method. In this exploration, fluoride adsorption onto the PAML and PAMC composites was studied to illuminate the defluoridation mechanism. The PAML and PAMC composites revealed that fast kinetics was reached within 30 min. Fluoride adsorption on the PAML and PAMC composites was in accordance with the Langmuir isotherm model, with an enhanced defluoridation capacities (DCs) of 4961 and 4957 mgF⁻ kg⁻¹ respectively within 30 min at pH 6.0, respectively. Based on the characterization data and experimental results, it was determined that complexation and electrostatic interaction contributed to the fluoride capture route. Moreover, the developed PAML and PAMC composites are reusable and suitable for real water sample analysis.

The magnetic hybrid material, namely, iron oxide/alginate–gelatin/hydroxyapatite/covalent organic framework (MAGHCOF)-based bio-hybrid beads were prepared and utilized for fluoride removal studies.

The present exploration was focused on the fabrication of environmental friendly adsorbent materials using graphene oxide (GO) and chitosan (CS). To modify GO by functionalization with sulphonic acid gives sulfonated GO (SGO), which possess high defluoridation capacity (DC) than GO. To boost the DC, easily separation and make it in an exploitable form of SGO material, SGO was incorporated onto biopolymer CS gives SGO/CS hybrid composite beads and employed for efficient defluoridation of water. The various influencing parameters of adsorption system viz., shaking time, adsorbate pH, initial fluoride concentration, adsorbent dosage, temperature, and interfering anions were optimized to obtain the highest DC. The DC of SGO/CS composite beads were found to be 4950 mg.kg⁻¹ within 30 min for 10 mg/L of preliminary adsorbate solution by 0.1 g dosage. The surface and structural characterization/properties of the prepared SGO/CS composite beads were evaluated by FTIR, TGA, SEM, and XPS investigations. The attained equilibrium data were predicted by isotherms like Fruendlich, Dubinin‐Radushkevich (D‐R), and Langmuir. The acquired equilibrium data of thermodynamic investigations facilitate to predict the nature of fluoride adsorption process onto SGO/CS composite beads. The plausible defluoridation mechanism of SGO/CS composite beads was discussed in detail. The applicability of SGO/CS beads was investigated at field environment with field water sample.

In this present work, we have developed the highly porous nature of cerium (Ce) assisted by amine functionalized benzene-1,4-dicarboxylic acid (ABDC) and benzene-1,4-dicarboxylic acid (BDC) based metal organic frameworks (MOFs), namely Ce@ABDC and Ce@BDC MOFs, using a hydrothermal technique for the defluoridation of water. The synthesized Ce@BDC and Ce@ABDC MOFs have improved fluoride adsorption quantities (q_e) of 4.88 and 4.91 mg g⁻¹, respectively. The various defluoridation influencing factors such as solution pH, shaking time, Ce-based MOF dosage, temperature and rival anions were explored at a batch scale. The physicochemical properties of Ce-based MOFs were examined by X-ray photoelectron spectroscopy (XPS), Fourier transformer infra-red (FTIR), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDAX) and powder X-ray diffraction (PXRD) studies. The obtained experimental data of fluoride adsorption onto Ce-based MOFs were best fitted with various isotherm and kinetic models. Thermodynamic parameters indicate the spontaneity and endothermic nature of fluoride sorption. The results of a field trial and recyclability of Ce-based MOFs show that Ce-based MOFs are suited to field conditions and are regenerable up to six cycles.