Authors: Jingyu Wu Xiaoming Du Zhenzhu He Chunyong Zhang Degang Fu
Publish Date: 2015/11/18
Volume: 23, Issue: 6, Pages: 5609-5617
Abstract
This work reported a comparative study on the electrochemical incineration of nitrilotriacetic acid NTA in the presence of different supporting electrolytes Na2SO4 and NaCl Galvanostatic electrolyses were conducted in an undivided electrochemical cell containing borondoped diamond BDD anode and platinum cathode Initial solution pH flow rate applied current density and supporting electrolyte concentration were selected as variables besides the mineralization efficiency of NTA that was selected as response Central composite rotatable design and response surface methodology were employed here to examine the statistical significance of the selected variables as well as to determine the optimal conditions of the degradation process Under the same operating conditions two regression models were thus constructed to illustrate the differing impact of supporting electrolytes in BDD anode cells The kinetics for NTA degradation followed different reaction orders for the two scenarios in the absence and presence of NaCl indicating the complex interaction between hydroxyl radicals and active chlorine Despite this the experimental results demonstrated that effective mineralization of NTA might also be achieved in the presence of chlorides of lower concentrations Besides in the case of chlorides the average mass transfer coefficient of the system was found to be strongly dependent on the initial solution pH Lastly a plausible reaction sequence concerning the electrolytic oxidation of NTA in chloride media was also proposed
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