Nanoparticle-nanofiber synergistic matrix for highly effective arsenic adsorption: material design and performance evaluation

Abstract

Arsenic in groundwater poses serious health risks. Over the last decade, adhering to World Health Organization (WHO) directives, permissible arsenic levels in drinking water were reduced, requiring efficient, cost-effective, and user-friendly technologies. In this work, a hybrid nanocomposite membrane (HNM) with adsorbent mesoporous silica nanoparticles (MSN) covalently linked to organic electrospun nanofibers was developed. MSN were synthesized and superficially modified in order to be physical and chemically effective for both the conformation of the HNM and the adsorption of arsenic(V). Materials were structurally characterised by N2 adsorption/desorption, SEM, TEM, TGA, FTIR and evaluated for As(V) removal in synthetic and real groundwater samples at pH 8. In synthetic solutions, HNM lowers arsenic below WHO limits in less than 60 minutes, showing a very fast adsorption kinetic during the first 15 minutes. The adsorption mechanism adheres to a pseudo-second order reaction, signifying chemical bonding of As(V) to active sites. Also, Langmuir model aligns with the adsorption isotherm, indicating surface saturation with a monolayer of arsenate species. HNM sustains capacity (>94%) over five adsorption/desorption cycles, enhancing viability for reuse. When exposed to real contaminated water, HNM achieves more than 60% adsorption within 60 minutes and 90% surface regeneration, an outstanding result for the treatment of real environmental samples without prior treatments. Therefore, this hybrid nanocomposite membrane offers an effective and viable alternative for the removal of arsenate ions from contaminated water. These outcomes could forward the design of new treatment devices with an effective and environmentally acceptable technology for arsenic removal.