Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7476277 | Journal of Environmental Management | 2018 | 10 Pages |
Abstract
In this work, the electrochemical oxidation of antibiotic ampicillin (AMP) on a boron-doped diamond anode in the presence of sodium persulfate (SPS) was investigated (EO/SPS process). Experiments were conducted at AMP concentrations between 0.8 and 3â¯mg/L, SPS concentrations between 100 and 500â¯mg/L, current densities between 5 and 110â¯mA/cm2, in three water matrices (ultrapure water, bottled water and secondary treated wastewater), using 0.1â¯M Na2SO4 as the supporting electrolyte. AMP degradation follows a pseudo-first order kinetic expression with the apparent rate constant increasing with (i) increasing SPS concentration (from 0.08 minâ1 to 0.36â¯minâ1â¯at 0 and 500â¯mg/L SPS, respectively, 1.1â¯mg/L AMP, 25â¯mA/cm2), (ii) increasing current (from 0.08 minâ1 to 0.6â¯minâ1â¯at 5 and 110â¯mA/cm2, respectively, 1.1â¯mg/L AMP, 250â¯mg/L SPS), and (iii) decreasing AMP concentration (from 0.16 minâ1 to 0.31â¯minâ1â¯at 3 and 0.8â¯mg/L, respectively, 250â¯mg/L SPS, 25â¯mA/cm2). The presence of various anions (mainly bicarbonates) in bottled water did not impact AMP degradation. The observed kinetic constant decreased by 40% in the presence of 10â¯mg/L humic acid. On the other hand, process efficiency was enhanced almost 3.5 times in secondary effluent due to the electrogeneration of active chlorine species that promote indirect oxidation reactions in the bulk solution. The efficacy of the EO/SPS process was compared to and found to be considerably greater than a process where SPS was activated by simulated solar irradiation at an intensity of 7.3â¯Ãâ¯10â7â¯E/(L.s) (SLR/SPS process). Coupling the two processes (EO/SLR/SPS) resulted in a cumulative, in terms of AMP degradation, effect. The combined process was tested for AMP degradation, mineralization and inhibition to Vibrio fischeri in wastewater; fast AMP removal was accompanied by low mineralization and incomplete toxicity removal.
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Authors
Zacharias Frontistis, Dionissios Mantzavinos, Sureyya Meriç,