Green synthesis of silver nanoparticles and its application towards As(V) removal from aqueous systems

Abstract

Arsenic (As) contamination in one of the most serious water quality concern due to its toxic effects and worldwide availability. To avoid its poisoning effects, especially in the form of As(V), it is important to develop new techniques for its treatment. The current study was conducted to investigate the As(V) removal from aqueous systems using silver (Ag) nanoparticles (NPs). The Ag NPs were synthesized through a simple method by using Vernonia Anthelmintica (L.) plant extract and characterized by using UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Energy dispersive X-ray (EDX) spectroscopy and Scanning electron microscopy (SEM). The removal of As(V) was tested with respect to time, optimum dose, effect of light and pH, treatment with ultra-sonication and continuous flow process. The results showed that Ag NPs can effectively remove As(V) from aqueous systems in the presence of sunlight (100%), ultra-sonication process (100%), neutral pH (100%), and continuous flow (71.6%). While the same NPs could not show effective removal of As(V) with respect to low dose (15%), darkness (38.9%), low pH of 3.4 (21.4%) and high pH of 11 (11.1%). Using Ag NPs can reduce As(V) to the permissible limits set by World health organization (WHO). Moreover, the Ag NPs work efficiently in sunlight and in the neutral pH range, therefore adjustment of pH is not required to activate these NPs.