TY - JOUR
T1 - Reductive Electrochemical Activation of Hydrogen Peroxide as an Advanced Oxidation Process for Treatment of Reverse Osmosis Permeate during Potable Reuse
AU - Weng, Cindy
AU - Chuang, Yi-Hsueh
AU - Davey, Bradley
AU - Mitch, William A.
N1 - Copyright:
This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of Medicine
PY - 2020/10/6
Y1 - 2020/10/6
N2 - The UV/hydrogen peroxide (H2O2) advanced oxidation process (AOP) frequently employed to generate hydroxyl radical (•OH) to treat reverse osmosis permeate (ROP) in potable reuse treatment trains is inefficient, using only 10% of the H2O2. This study evaluated ·OH generation by electron transfer from a low-cost stainless steel cathode. In deionized water, the electrochemical system achieved 0.5 log removal of 1,4-dioxane, a benchmark for AOP validation for potable reuse, within 4 min using only 1.25 mg/L H2O2. Hydrogen peroxide and 1,4-dioxane degradations were maximized near -0.18 and + 0.02 V versus standard hydrogen electrode, respectively. Degradations of positively and negatively charged compounds were comparable to neutral 1,4-dioxane, indicating that degradation occurs by ·OH generation from neutral H2O2 and that electrostatic repulsion of contaminants from the electrode is not problematic. For ROP without chloramines, 0.5 log 1,4-dioxane removal was achieved in 6.7 min with 7 mM salts for ionic strength and 2.5 mg/L H2O2. For ROP with 1.4 mg/L as Cl2 chloramines, 0.5 log 1,4-dioxane removal was achieved in 13.2 min with 7 mM salts and 4.5 mg/L total H2O2 dosed in three separate injections in 5 min intervals. Initial estimates based on lab-scale electrochemical AOP treatment indicated that, except for the cost of salts, the electrochemical AOP featured lower reagent costs than the UV/H2O2 AOP but higher electricity costs that could be reduced by optimization of the electrochemical design.
AB - The UV/hydrogen peroxide (H2O2) advanced oxidation process (AOP) frequently employed to generate hydroxyl radical (•OH) to treat reverse osmosis permeate (ROP) in potable reuse treatment trains is inefficient, using only 10% of the H2O2. This study evaluated ·OH generation by electron transfer from a low-cost stainless steel cathode. In deionized water, the electrochemical system achieved 0.5 log removal of 1,4-dioxane, a benchmark for AOP validation for potable reuse, within 4 min using only 1.25 mg/L H2O2. Hydrogen peroxide and 1,4-dioxane degradations were maximized near -0.18 and + 0.02 V versus standard hydrogen electrode, respectively. Degradations of positively and negatively charged compounds were comparable to neutral 1,4-dioxane, indicating that degradation occurs by ·OH generation from neutral H2O2 and that electrostatic repulsion of contaminants from the electrode is not problematic. For ROP without chloramines, 0.5 log 1,4-dioxane removal was achieved in 6.7 min with 7 mM salts for ionic strength and 2.5 mg/L H2O2. For ROP with 1.4 mg/L as Cl2 chloramines, 0.5 log 1,4-dioxane removal was achieved in 13.2 min with 7 mM salts and 4.5 mg/L total H2O2 dosed in three separate injections in 5 min intervals. Initial estimates based on lab-scale electrochemical AOP treatment indicated that, except for the cost of salts, the electrochemical AOP featured lower reagent costs than the UV/H2O2 AOP but higher electricity costs that could be reduced by optimization of the electrochemical design.
UR - http://www.scopus.com/inward/record.url?scp=85092680771&partnerID=8YFLogxK
U2 - 10.1021/acs.est.0c02144
DO - 10.1021/acs.est.0c02144
M3 - Article
C2 - 32822532
AN - SCOPUS:85092680771
SN - 0013-936X
VL - 54
SP - 12593
EP - 12601
JO - Environmental Science & Technology
JF - Environmental Science & Technology
IS - 19
ER -