(733d) Electrocatalysts for the Simultaneous Removal of Nitrate and Ammonia from Wastewater

Nitrogen contamination of water resources is considered an environmental and human health issue that causes serious problems e.g., algae bloom, ecological harmful effects like food web changes, and fatal illnesses especially for newborn infants under 6 months [1]. Electro-reduction of NO₃^- and electro-oxidation of NH₃ have attracted lots of attention because they are considered a the straightforward, energy-efficient, environmentally-friendly, and easy to control techniques for NO₃^-/NH₃detoxification [2].

Electrochemical methods for separate removal of NO₃^- and NH₃ has been extensively investigated [1, 3-5]. However, in this work, we demonstrate a new process that addresses both water pollutants simultaneously in an undivided flow cell that leads to a remarkable energy saving in the order of 35-65 % and 90 % less energy per grams of NO₃^- and NH₃ removal, respectively. A new catalyst composition material is introduced to perform both NO₃^- /NH₃ removal simultaneously. The concentration of NO₃^- andNH₃ were measured according to the Environmental Protection Agency (EPA) standards, i.e., an UV-vis spectrophotometric based technique [6], and NH₃ Ion Selective Electrode (ISE-THERMO), respectively. Effect of catalyst loading and other process operational conditions on the NO₃^- and NH₃ removal rates were investigated. Findings of this work will be presented at the meeting.

References

[1] A. Estejab, and G.G. Botte, “Ammonia Oxidation Kinetics on Bimetallic Clusters of Platinum and iridium: A Theoretical Approach” , Molecular Catalysis, vol. 445, pp. 279–292, February 2018.

[2] M. Li, Ch. Feng, Z. Zhang, Z. Shen, and N. Sugiura, “Electrochemical Reduction of Nitrate Using Various Anodes and a Cu/Zn Cathode”, Electrochemistry Communications, vol. 11, pp. 1853–1856, October 2009.

[3] C. Wanag, S. Chang, M. Ye, and Q. Ren, “Current Efficiency and Energy Consumption of Electrochemical Oxidation for Ammonia Removal from Coking Wastewater using Boron-doped Diamond Electrodes”, Applied Mechanics and Materials, vol. 298, pp. 1327-1332, January 2013.

[4] H. Cheng, K. Scott, and P. A. Christensen, “Paired Electrolysis in a Solid Polymer Electrolyte reactor—Simultaneously Reduction of Nitrate and Oxidation of Ammonia”, Chemical Engineering Journal, vol. 108, pp. 257–268, April 2005.

[5] M. Majlesi, S. Mohseny, M. Sardar, S. Golmohammadi, and A. Sheikhmohammadi, “Improvement of Aqueous Nitrate Removal by Using Continuous Electrocoagulation/Electroflotation Unit With Vertical Monopolar Electrodes”, Sustainable Environment Research, vol. 26, pp. 287-290, November 2016.

[6] T.A. Doane, and W.R. Horwath, “Spectrophotometric Detection of Nitrate with a Single Reagent”, Analytical Letters, vol. 36, pp. 2713-2722, January 2003.