Optimization of a combined approach for the treatment of carbide slurry and capture of CO₂

The aim of this study is to evaluate the potential use of electrocoagulation in the treatment of carbide slurry, a wastewater generated during the production of acetylene, and in the capture of carbon dioxide. An electrochemical batch reactor was used to carry out several experiments at different current densities, ranging between 140-290 A/m². Pure air and a mixture of 10% of carbon dioxide in air were injected into the reactor system to ensure good mixing and solution homogeneity. Samples were collected from the treated effluent and analyzed for Total Hardness (TH), Total Dissolved Solids (TDS) and Chemical Oxygen Demand (COD). Response Surface Methodology (RSM) was conducted to design a matrix of experiments to optimize the conditions for the treatment process and determine the optimum response in terms of water treatment and CO₂ capture efficiency. For the pure air system, the overall optimum conditions were found to be 12, 27.5 and 284 A/m² as pH, temperature and current density, respectively. The percent reduction efficiencies were 47.5, 47.8 and 71.4% for COD, TH and TDS, respectively. For the air-CO₂ system, the overall optimum conditions were 12, 35 and 213.5 A/m² for pH, temperature and current density, respectively; the reduction efficiencies were 42, 75 and 74% for COD, TH and TDS, respectively.