Arsenic (v) Adsorption by Using Synthesized Iron Oxide Nanoparticles (Fe2O3-NPs) and Aluminum Oxide Nanoparticles (Al2O3-NPs)

Abstract

Arsenic, is one of the most harmful elements to humans, health of chronic diseases, and continuously causing a threat to the world. Arsenic is found in combined form in rocks under the earth's surface and when it dissolves, it contaminates groundwater. In the current research study synthesized iron oxide nanoparticles (Fe2O3-NPs) and aluminum oxide nanoparticles (Al2O3-NPs) for the removal of arsenic (As) (˅) from an aqueous medium and characterized the synthesized material by different analytical techniques such as FT-IR spectroscopy and XRD spectroscopy. The results show successful synthesis of Fe2O3-NPs and Al2O3-NPs. Furthermore, the synthesized material was used as an adsorbent for extraction of as (V) from water. The effect of different parameters such as pH, temperature, contact time, and adsorbent dose on the adsorption process was investigated. The adsorption efficiency was determined by Fe2O3-NPs at about 20 mg/g and Al2O3-NPs at 19.5 mg/g. The quantitative removal of as (V) from industrial water required a minimum amount (0.2 g) of Fe2O3-NPs and Al2O3-NPs. various kinetic and isotherms were investigated in the current study. The result showed that the obtained data for Fe2O3-NPs was more fitted to Pseudo second order kinetic and Freundlich equation, while for Al2O3-NPs the data was more fitted to Pseudo second order kinetic and Elovich model equation, which confirms the interaction among as (V) and adsorbents. Thermodynamic parameters were also investigated which shows the process is spontaneous and endothermic. This model was used to estimate the site energy distribution for each adsorbent. Thermodynamic parameters were also investigated which shows the non-spontaneous and endothermic nature of the adsorbent. According to the results of the analysis of the approximate site energy distribution, adding Fe2O3 and Al2O3-NPs to arsenic decreased the area under the frequency distribution curve of the sorption site energies, which in turn decreased the number of sorption sites that were open to arsenic. This might be explained by the hydrophobic interaction between synthesized materials and arsenic being reduced due to the blocking of the Fe2O3 and Al2O3-NPs hydrophobic surface.