Arsenic removal from water employing a combined system: photooxidation and adsorption

Abstract

A combined system employing photochemical oxidation (UV/H2O2) and adsorption for arsenic removal from water was designed and evaluated. In this work, a bench-scale photochemical annular reactor was developed being connected alternately to a pair of adsorption columns filled with titanium dioxide (TiO2) and granular ferric hydroxide (GFH). The experiences were performed by varying the relation of As concentration (As (III)/As (V) weight ratio) at constant hydrogen peroxide concentration and incident radiation. Experimental oxidation results were compared with theoretical predictions using an intrinsic kinetic model previously obtained. In addition, the effectiveness of the process was evaluated using a groundwater sample. The mathematical model of the entire system was developed. It could be used as an effective tool for the design and prediction of the behaviour of these types of systems. The combined technology is efficient and promising for arsenic removal to small and medium scale.

In situ X-ray absorption spectroscopic studies of photocatalytic oxidation of As(III) to less toxic As(V) by TiO2 nanotubes

“…TiO 2 , possessing unique characteristics such as effective band-gap energy (3.0 eV) and high photo-stability, oxidation potential and availability, has been widely used in photocatalytic degradation of toxic organics, splitting of H 2 O, and reduction of NO to N 2 (Meng et al, 2015;Mikhaylov et al, 2013;Ali & Metwally, 2014). Photocatalytic oxidation of As(III) effected by TiO 2 , considered an environmentally friendly and economically attractive method, has gained great attention (Ryu & Choi, 2006;Yazdani et al, 2017;Lescano et al, 2014). However, a better understanding of the chemical structure of arsenic during photocatalytic oxidation is still lacking in the literature (Ryu & Choi, 2006).…”

Optimization of Arsenic Adsorption onto Cativated Carbon Dreived from Potato Peel Using Response Surfase Methodology

“…Wastewaters contaminated with high levels of arsenic should be treated to avoid a discharge into environment and subsequently drinking waters. Different technologies have been employed in order to remove arsenic from wastewater including chemical precipitations, reverse osmosis, ion exchange, lime softening and microbial transformation (Bibi et al, 2015;Genç-Fuhrman et al, 2008;Hasanzadeh et al, 2015;Lescano et al, 2015;Zhang et al, 2002). Recently, adsorption is extensively utilized for removing heavy metals from contaminated water sources.…”