Electrolysis of Ammonia Effluents: A Remediation Process with Co-generation of Hydrogen
The electrolysis of ammonia (NH3) was studied to propose a remediation process for the removal of ammonia from waste water and produce hydrogen while returning clean water to the environment. An electrocatalyst able to support such reaction at low concentrations of ammonia was designed. Two substrates were tested, Raney nickel and carbon fiber. The performance of noble metals such as Rh, Pt and Ir, electroplated on the surface of the substrates was also evaluated. Electrodes made on the carbon fiber substrate presented more reactivity towards the electrolysis of ammonia than the Raney nickel substrate at the conditions tested. The best catalyst found was Rh-Pt-Ir with 5.1 mg cm-1 of carbon fiber bundle, based on the highest current response of the system. Electrochemical techniques such as cyclic voltammetry and galvanostatic polarization were used to evaluate the electro-catalysts. An Ion Selective Electrode Meter was used to measure the ammonia concentrations. The minimum solution concentration was determined for ammonia (1.83 mM) and potassium hydroxide (0.2 M). The maximum conversion determined at the initial concentrations typically found in sewage water was 91.488 ¡Ó 0.003% and faradaic efficiency (ƒØ) of 91.81 ¡Ó 0.13%.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:ammonia electrolysis hydrogen production waste water treatment effluents catalyst carbon fiber electro deposition fuel cells
Date of Publication:01/01/2006