Arsenic Removal from Water by Adsorption onto Iron oxide/Activated Carbon Composite Prepared from Giant Reed

Abstract

Groundwater in the southern low land region of Nepal has been recognized as a major problem due to Arsenic contamination. Therefore, the present study aimed to remove arsenic from the water using iron/activated carbon composite prepared from Giant Reed cane (Arundo donax). Activated carbon (AC) was prepared by chemical activation with zinc chloride at 400°C in ratio 1:1 by weight for 3hrs. The resulting AC was compositedwith iron oxide particles, using facile hydrothermal treatment to improve its adsorption capacity for arsenic removal from water. Both, activated carbon and its composite adsorbent were characterized by scanning electron microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). Resultsshowed the presence of some iron oxide particles dispersed on the activated carbon. Batch adsorption experiments were conducted for the adsorption of As (III) onto the composite adsorbent. The experiment included the effect of process variables viz. contact time, pH, adsorbent dose, and adsorption isotherm. The obtained results showed that the percentage of As (III) removal using the composite adsorbent was much higher as compared to the plain AC. The optimum conditions for As(III) adsorption were achieved at pH 8, adsorbent dosage 1.8 g/L, and contact time 60 minutes. Adsorption data fits Langmuir better than Freundlich isotherm which indicates that the monolayer adsorption of As(III) onto the composite adsorbent. The maximum As (III) adsorption capacity of the composite adsorbent was 16.34 mg/g. Therefore, it can be concluded that the AC composite derived from Giant Reed cane can be potentially applied for the removal of As(III)from contaminated water.