Effect of electrochemical cell structure on natural organic matter (NOM) removal from surface water through electrocoagulation (EC)

This study analyzed the effect of electrocoagulation cell construction on NOM removal from Finnish surface water. Three types of cells were used in this research: one that only had aluminum electrodes, one that had aluminum anodes and inert cathodes, and one that had inert anodes and aluminum cathodes. Main water quality parameters such as TOC, apparent color, and concentrations of residual metals were measured from the samples. A statistical model was made from the results using partial least squares (PLSs) regression. According to the results, electrocoagulation was able to produce high quality water with low NOM concentration. Lowest measured TOC concentration was 4.02 mg/l (78% removal). The potential applications of water after the treatment could be potable water or industrial fresh water. Aluminum originating from the anodes or cathodes had similar NOM removal efficiency. According to TOC and ζ-Potential results, the mechanism of NOM removal was similar to chemical coagulation in different pHs. It seems that in low pH, double layer compression was the main destabilization mechanism whereas in higher pH, adsorption and bridging dominated.

► We studied NOM removal with three EC cells made from aluminum and inertelectrodes.
► The efficiency of EC was similar when aluminum originated from either anodes or cathodes.
► Destabilization mechanisms of NOM are similar compared to chemical coagulation.
► Electrocoagulation can produce high quality water with low NOM and metal concentration.