Investigation on Sol-Gel Facilitated Synthesis of Silica Nanoparticles Using Kariba weed(KW-NS) and Its Efficiency in Cr(VI) Removal

Abstract: Environmental pollution is an aggressive change in the surroundings mainly because of heavy metals, dyes and organic pollutants, which are responsible for crucial natural and health issues. The undiscerning industrial activities make the water resources inappropriate for utilization and the accumulation of these pollutants in water is accountable for harmful effects on aquatic plants and animals. An eco-benign approach was explored for the synthesis of silica nanoparticles (KW-NS) using waste aquatic weeds. In the present study, waste aquatic Kariba weedswere utilized to synthesize and characterize silica nanoparticles and to investigate their applicability in the removal of Cr(VI) ions from aqueous as well as industry effluent. The silica nanoparticles using Kariba weeds(KW-NS) were prepared using sol-gel method and characterized using SEM, FTIR and BET analysis. Various parameters such as pH, adsorbent dosage, initial metal concentration and contact time on the adsorption of Cr(VI) were investigated and optimized. Adsorption isotherm, kinetics, thermodynamics, and regeneration mechanism were studied to determine the efficacy of KW-NS. The adsorption equilibrium for Cr(VI) was achieved at an optimum pH of 4.3 with 4 g L^–1adsorbent dosage at 60 min with 10 mg L^–1metal ion concentration and maximum adsorption capacity reached up to 96.54 mg g^–1. The applicability of the synthesized KW-NS was checked with the tannery and electroplating industry effluent and posed 72 and 60% removal efficiency, respectively. Results obtained from this study indicate that the waste aquatic Kariba weedhas the potential to synthesize silica nanoparticles in a more efficient and economical way than the conventional synthesis. These nanoparticles can be effectively applied as an adsorbent to treat industrial effluents for heavy metal removal.