New insights into electrocatalytic ozone generation using Pt/Ni-Sb-SnO2 and GC/Ni-Sb-SnO2 electrodes

Optimization of Electrochemical Oxidation Process with Boron Doped Diamond (BDD) for removing COD, Color, Ammonium, and Phosphate in Landfill Leachate

This study investigated the electrooxidation (EO) of mature landfill leachate from the Brady Road Resource Management Facility, Winnipeg (Canada). EO using boron-doped diamond (BDD) electrodes were applied to treat real landfill leachate using a batch reactor. Response surface methodology (RSM) was used to determine the optimum process parameter levels. This research mainly focused on how different current densities (64, 95, and 125 mA/cm²) and operational time (30 minutes, 1 hr, 1.5 hr, 2 hr, 2.5 hr, and 3 hr.) influenced the optimization of parameters such as chemical oxygen demand (COD), color, ammonium, and phosphate removal in mature landfill leachate at varied pH. To attain a high percentage of removal for the parameters mentioned above, the optimal conditions were found to be a current density (J) of 125 mA/cm² and a pH of 8. The optimum conditions resulted in removal percentages of 95.47%, 80.27%, 71.15%, and 47.15% for color, NH₄⁺, COD, and PO₄^3- respectively, with an energy consumption of 0.05 kWh/dm³. The removal is related to a mechanism of the decomposition of water molecules to hydroxyl radicals and by direct anodic oxidation where the pollutants are transformed to CO₂ and H₂O. The novelty of this research lies in the optimization of BDD electrode-based treatment for the simultaneous removal of COD, ammonium, phosphate, and color from mature leachate collected from a severely cold climatic region of Canada. The BDD electrode showed excellent removal efficiencies for the targeted contaminants with lower energy consumption, making it a feasible method for on-site landfill leachate treatment.

Electrodisinfection of bacteria-laden in surface water using modified Ti electrode by antimony-and nickel-doped tin oxide composite

Providing clean and safe drinking water by point of use (POU) disinfection methods has become a critical issue, especially in crises and epidemics. In this study, antimony-and nickel-doped tin oxide electrode (Ni-Sb-SnO₂) was employed as an electrode for electro-catalytic disinfection of surface water. The synthetized electrodes were characterized using scanning electron microscope, linear sweep voltammetry and X-Ray diffraction techniques. The results revealed that the highest electrochemical disinfection efficiency was achieved by the Ni-Sb-SnO₂ electrode under weak acidic conditions and its performance decreased with increasing pH towards alkaline environment. Based on the results, total coliform (TC) and fecal coliform (FC) were completely removed at current density of 0.67 mA cm^-2. Moreover, the electrochemical disinfection of microorganisms showed that the process efficiency was directly proportional to increasing time and at 0.6 C cm^-2 of charge passed, 3-log removal of the both indicators occurred after 15 min. The highest removal efficiency of TC and FC was also achieved at 8 mmol of NaCl concentration at <10 min of detention time. The results of this study depicted that the Ti/Ni-Sb-SnO₂ electrode provides higher disinfection efficiency for the removal of TC and FC compared with Ti and SS/PbO₂ electrodes. Moreover, the proposed system was able to completely eliminate heterotrophic, Streptococcus faecalis and Pseudomonas aerogenes indicators under optimal conditions. Therefore, it can be concluded that the proposed electrochemical system can be efficiency applied as a POU disinfection system for disinfection of water contaminated with microbial indicators, especially for crises and epidemics.