Highly efficient removal of arsenic using amine-modified silica incorporating in PLA adsorptive membrane

The environmental applications of pristine silica (SiO ₂ ) nanoparticles (NPs) for arsenic removal have been limited by their severe aggregation and lack of functional groups. Amine-modified SiO ₂ (NH ₂ ) NPs were incorporated in PLA for the removal of 100 ppb of arsenic; a concentration much higher than what has been reported for surface water in Iran. FTIR analysis has demonstrated that the amine modified SiO ₂ NPs have been successfully prepared. Addition of SiO ₂ and SiO ₂ (NH ₂ ) increased the porosity, water uptake, mechanical strength, hydrophilicity and permeability of the membrane up to 1.0 and 1.5 wt.%, respectively. The batch adsorption experiments were conducted to assess the equilibrium adsorption capacity and kinetics of adsorptive membranes. The Langmuir and Freundlich models demonstrated good correlation for membranes containing SiO ₂ and SiO ₂ (NH ₂ ) NPs, respectively. Both kinds of the membranes demonstrated behavior consistent with the pseudo-second-order kinetic model, which can be linked to rapid electrostatic adsorption. Dynamic adsorption of the PLA- SiO ₂ (NH ₂ )-1.0 membrane was assessed through three adsorption-desorption cycles. The results confirmed the favorable properties of the SiO ₂ (NH ₂ ), effectively reducing As (V) concentration in contaminated water (100 ppb) to levels below the maximum concentration level (MCL).