The impact of suspended particulate matters on metals removal from water using a three-combined-dimensional photo-electrocatalytic reactor (case study: Sefidrud dam)

The Sefidrud dam's water contamination poses a significant health risk to millions of people. A study aimed to investigate the impact of water impurities (mostly emerging as suspended matter particles) and redox potential on the removal of heavy metals like copper, zinc, cadmium, and arsenic through a photo-electrocatalytic process. A three-dimensional photo electrocatalytic reactor with microparticles of Ti/TiO2 was used for experiments. Central Composite Design (CCD) response surface methodology was employed for optimization. The results showed removal rates of 78% for copper, 68% for zinc, 57% for cadmium, and 38% for arsenic under optimal conditions. The removal rates increased to 94%, 86%, 65%, and 52% for copper, zinc, cadmium, and arsenic in response to increased dissolved oxygen. Redox potential was found to be a governing parameter during the photo electrocatalytic removal of zinc. Furthermore, microparticles improved the removal percentage of copper and arsenic in acidic environments. Finally, chemical fractional analysis revealed that the presence of suspended matter particles (SPMs) has a detrimental impact on the performance of PEC systems. This was attributed to the desorption of metals from exchangeable and Fe-Mn bounds of SPMs during the PEC process.