Optimization of a three-dimensional electrochemical process with granular activated carbon for diclofenac removal using response surface methodology

Abstract

In this study, a three-dimensional electrochemical process with aluminum electrodes in the presence of granular activated carbon derived from walnut shell (WGAC) was employed to remove Diclofenac from synthetic water. Optimum operating conditions were determined using response surface methodology, also, an empirical relationship was established between response and independent variables (activated carbon amount, contact time, pH, and electrolyte concentration). The results showed that activated carbon amount and NaCl concentration were the most influential factors on the removal efficiency, and the most significant factor affecting electrical energy was NaCl concentration. Additionally, three-dimensional electrochemical process with granular activated carbon has the potential to work in the pH range from 1 to 9. The optimal conditions to gain maximum removal efficiency and minimum electrical energy were determined to be 4.36 g granular activated carbon, 40 min contact time, and 4390 ppm of NaCl. In addition, to show the physical characteristics of activated carbon, the field emission scanning electron microscopy and BET analysis were applied, and Spectrophotometric technique was used to determine diclofenac concentration. Considering high removal efficiency and low electrical energy consumption, the three-dimensional electrochemical process with WGAC can be considered a cost-effective and practicable method to remove diclofenac from water and wastewater.