Correlation Studies and Kinetic Modelling of Electrocoagulation Treatment of Pepper Wastewater

Abstract

Pepper processing is one of the largest productions that significantly contribute (98%) to Sarawak, Malaysia’s economic and agricultural sectors. The prolonged retting process of pepper berries would cause undesirable dark colour and acidic wastewater. This study aims to evaluate the performance of an electrocoagulation treatment using nickel and copper electrodes for the changes in turbidity and pH of pepper wastewater. Some analyses (correlation studies and kinetic modelling) were studied. The electrocoagulation treatment was conducted by having two conditions nickel and copper electrodes immersed in 400 mL of pepper wastewater for 30 minutes. Every 5 minutes, it was monitored, and the sample was taken for further analysis. The results indicated a significant decrease in the turbidity of pepper wastewater for nickel (98.25%) and copper electrodes (86.32%) was noticed with the increase in the electrocoagulation treatment time. At the same time, the pH values for nickel and copper electrodes were increased by 27.43% and 31%, respectively. The results were evaluated by using Principal Component Analysis (PCA). PCA describes the correlation between the wastewater qualities in this study within less time. Among four models (zero, first and second-order) applied in this study, the turbidity for nickel and copper electrodes had the highest R2 values (0.9457 and 0.9899) in the zero-order model. For pH, the second-order model had the highest R2 values (0.9508 and 0.9657) for nickel and copper electrodes. Electrocoagulation using nickel and process electrodes is a practical method to treat pepper wastewater.