Treatment of real printing wastewater using electrocoagulation process with titanium and zinc electrodes

Abstract

Electrocoagulation (EC) has numerous benefits over traditional coagulation. It is noteworthy that most researchers have studied EC using either iron electrodes or aluminum electrodes. The key objective of this study is to investigate the performance of the EC process with zinc and titanium electrodes for treating real printing wastewater through several experimental conditions. Experiments were done through batch systems. The effects of the operating variables, inclusive of varying current densities (CDs), spacing between electrodes, electrolysis time, and varying electrode materials (titanium and zinc) on the efficiency of the removal of different parameters were studied. Oil and grease, total dissolved solids (TDS), and chemical oxygen demand (COD) were among these parameters. The highest removal efficiency for COD after 90 min using a zinc electrode was approximately 50 % attained at 20 mA/cm2. For the titanium electrode, after 90 min, the highest removal efficiency for COD was 46 % attained at 15 mA/cm2. For the removal efficiency of TDS, the zinc electrode performance was better than that of the titanium electrode for every CD. After 90 min, the optimal TDS removal efficiencies were 9 % and 19 % for titanium and zinc electrodes, respectively. The titanium electrode offers the maximum efficiency of removal for oil and grease. The highest efficiencies of removal were attained at a separation distance of 4 cm. At a CD of 15 mA/cm2, the best COD elimination efficiencies using the titanium electrode at the separation distances of 6, 4, and 2 cm were 24 %, 47 %, and 30 %, respectively. At a CD of 15 mA/cm2, the best COD removal efficiencies using the zinc electrode at the separation distances of 6, 4, and 2 cm were 27 %, 41 %, and 38 %, respectively. In both the zinc and titanium electrodes, following the experiments, corrosion occurred in the anodes, which is evidence that the process of treatment took place. The EC performance was observed to be much better than that of conventional coagulation during the treatment of printing wastewater. Zinc and titanium electrodes demonstrated a good capability of removing pollutants when used in the EC process.