Asian Journal of Engineering and Technology Innovation

A Comparative Study on The Electrochemical Oxidation of Natural Organic Matter Using BDD and MMO Electrodes

Shasvat Rathod¹*^#, Robert Liang^1#, Azar Fattahi^1#, Monika R. Snowdon^1#, Mark R. Servos^2# and Norman Zhou^1#

¹Centre for Advanced Materials Joining, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada, N2L3G1
²Department of Biology, University of Waterloo, Waterloo, ON, Canada, N2L3G1
^#All Authors contributed equally to this work.

Abstract

Natural organic matter (NOM) is an extremely complex mixture of organic compounds. Although NOM has no direct impact on health, it can affect the drinking water treatment processes, lead to taste, color, odor challenges, bacterial growth, and carcinogenic disinfection by-products formation. Electrocoagulation combined with membrane filtrations are used to remove NOM. However, electrochemical methods such as electrooxidation (EO) are promising alternatives since they have proved humic acid and algae degradation. In this study, we compared BDD electrode electrolysis performance for Suwannee River NOM degradation to widely documented mixed-metal oxide (MMO) anodes under different initial pH (6-8) and applied current density (10-20 mA cm^-2). Total organic compound (TOC), chemical oxygen demand (COD) estimated by peCOD, COD/TOC ratio, specific ultraviolet absorbance (SUVA), and specific energy consumption were used to characterize NOM. Although NOM degradation demonstrated different behaviors upon operative parameters on these two electrodes, BDD electrodes performed better than MMO under higher current density and broader pH ranges and were proved to be more cost-effective. In

particular, BDD-stainless steal electrodes showed the lowest energy consumption at 442 × 10³ kWh dm^-3 while obtaining a TOC of 40.2%, COD of 75.4% and SUVA of 3.4 at the higher pH and higher current. BDD electrodes can apply be used in surface water treatment as a pre-treatment in combination with some other purification technologies to remove organic contaminants.

Keywords:

Electrochemical oxidation processes, Boron doped diamond electrodes, Mixed metal oxides anodes, Suwannee River NOM, Water treatment