Efficient Removal of Arsenic Using Amine-Modified Silica Nanoparticles Incorporated in PLA Membrane

The environmental application of silica (SiO₂) nanoparticles for arsenic removal has been limited by severe aggregation and the lack of active functional groups. In this study, amine-modified silica nanoparticles (SiO₂–NH₂) were incorporated into polylactic acid (PLA) adsorptive membranes for the removal of arsenate (As(V)) from water using an adsorptive membrane filtration technique. The removal mechanism is based on adsorption-driven electrostatic interactions between negatively charged arsenate species and positively charged amine functional groups. The successful surface modification of silica nanoparticles was confirmed by Fourier-Transform InfraRed (FT-IR) spectroscopy. Incorporation of pristine SiO₂ and SiO₂–NH₂ nanoparticles enhanced membrane porosity, water uptake, hydrophilicity, mechanical strength, and permeability up to optimal loadings of ۱.۰ wt.% and ۱.۵ wt.%, respectively. Batch adsorption experiments were conducted to evaluate equilibrium adsorption behavior and kinetics. The adsorption data were well described by the Langmuir model for SiO₂-containing membranes and the Freundlich model for SiO₂–NH₂-containing membranes, indicating different adsorption site characteristics. In both cases, adsorption kinetics followed a pseudo-second-order model, suggesting a chemisorption-controlled process dominated by electrostatic interactions. Dynamic adsorption and regeneration studies demonstrated that the PLA–SiO₂–NH₂ membrane containing ۱.۰ wt.% nanoparticles consistently reduced the As(V) concentration from ۱۰۰ ppb to below the Maximum Contaminant Level (MCL, ۱۰ ppb) over filtration times up to ۳۰۰ min, confirming its effective performance and reusability.

کلیدواژه ها:

Adsorptive membrane ، silica ، Amine modification ، poly lactic acid ، As (V) removal