This work describes a thorough research of the iron oxy-hydroxides’ preparation using the most common low cost iron salts (FeSO4•H2O and FeCl2) and their evaluation as As(III) and As(V) adsorbents. It is the first study that summarizes the role of synthesis parameters on the arsenic adsorption efficiency of iron oxy-hydroxides under the perspective of large-scale production and application in water treatment plants and, therefore, suggests an optimization approach for the improvement of commercial arsenic adsorbents.
The study deals with the optimization of a procedure for the kilogram-scale continuous flow synthesis considering a variety of pH-values while preserving maximum reaction yield and high redox values. According to the obtained efficiency of the products, the mechanisms that lead to maximum arsenic adsorption capacity are further analyzed. The discussion is focused on the implementation of realistic arsenic concentrations found in natural water and the achievement of residual arsenic levels conforming to the regulation limit. The research was implemented within the frame of the European Commission FP7/Research for SMEs “AquAsZero”, Project No: 232241.