Green synthesis of AgMgOnHaP nanoparticles supported on chitosan matrix: Defluoridation and antibacterial effects in groundwater

This study examined the sol-gel biosynthesis of metal-metal oxide nanoparticles impregnated on a chitosan polymer backbone (AgMgOnHaP@CSn) and its potential application in removing fluoride and pathogens simultaneously from groundwater. The formation of the nano-adsorbent from the different surface functionalization precursors and phases were supported by the various characterization methods. The bio-reduced core-shell MgO and Ag nanoparticles with peaks at 290 and 440 nm typical of the respective nanoparticles were confirmed by UV-vis spectroscopy. The nanoparticle reduction phase due to the presence of various metabolites was affirmed by FTIR. Surface morphology by SEM-EDS, TEM, and BET analysis showed a mesoporous nanosorbent with a surface area of 55.27 m(2)/g; whose average size was similar to 35.36 nm with a pore diameter of 33.67 nm. The batch fluoride sorption experiments conducted based on the optimization of several operational parameters indicate fluoride adsorption capacity of the AgMgOnHaP@CSn of 6.86 mg/g with maximum similar to 80 % F(- )removal at 303 K and pH 7. The pHpzc value of the synthesized nanosorbent based on surface binding functional groups was obtained to be similar to 10.6. The adsorption kinetic mechanisms followed the pseudo-second-order while the rate demining step was controlled by the diffusion model phenomenon. The sorption of fluoride by AgMgOnHaP@CSn on the surface and interfacial chemistry was best described by the Langmuir isotherm model. Also, the AgMgOnHaP@CSn exhibited excellent antibacterial activity against gram-positive and gram-negative bacteria. Overall, AgMgOnHaP@CSn displays its potential for the removal of fluoride and pathogens from contaminated drinking water resources.