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. • The physico-chemical features of LCK hybrid composite characterized by XRD, BET, TGA-DTA, FTIR, EDAX and SEM techniques • The adsorption of nitrate and phosphate was followed by Freundlich isotherm and pseudo-second-order kinetics. • The LCK hybrid composite prepared at optimum conditions could effectively adsorb nitrate and phosphate ions from water. • LCK hybrid composite revealed superior recyclable performance during 5 cycles. [ABSTRACT FROM AUTHOR]