Kinetics for ammonium ion removal using a three-dimensional electrode system

Abstract

Electrochemical oxidation of ammonium ions (NH(4)(+)) by using a three-dimensional electrode (TDE) composed of IrO(2)-Ta(2)O(5)/Ti anode and bamboo carbon was carried out in this paper. Experimental results reveal that the NH(4)(+) oxidation follows first-order kinetics at lower NH(4)(+) concentration and the rate constant is highly dependent on the applied current density, dosage of chlorine ions and initial NH(4)(+) concentration. In addition, increasing current density, more Cl(-) dosage and higher initial NH(4)(+) concentration are beneficial for NH(4)(+) removal. By inspecting the relation between rate constant and those operating factors, an overall empirical equation for estimation of the rate constant of NH(4)(+) oxidation is presented. The estimated model is in good agreement with the experimental results and it could also be used for accurate design of the TDE system.

Electrolytic treatment of industrial circulating cooling water using titanium–ruthenium–iridium anode and stainless steel cathode

“…Such increase is due the fact that a higher applied current density provides more electrons for Reaction (1) and then facilitates Reaction (2) and (3). Higher current density also leads to the rapid transfer of Ca 2+ to the electrode surface under a strengthened electric field, thus, increasing R Ca 2þ [19]. On the other hand, with the increase of C 0 CaSO 4 , R Ca 2þ increases initially and then starts decreasing.…”