Response surface methodology application in optimizing mercury removal from leachate via electrocoagulation using an iron electrode

Abstract

Leachate is wastewater containing various pollutants that are harmful not only to the environment, but also to the human beings. The current study aimed to analyze the efficacy of electric voltage, time, and electrode spacing to obtain optimum mercury (Hg) removal using an electrocoagulation method with iron electrodes. Leachate samples were collected from the TPA Terjun (Medan City, Indonesia). The mercury level in the leachate was categorized as exceeding the quality standard. Response surface methodology (RSM) was used to build models, design experiments, evaluate the effects of independent variables, and determine optimal conditions for efficient mercury removal. Leachate cannot be decomposed naturally; therefore, certain processing steps are needed to prevent leachate from polluting the environment. Electrocoagulation is an alternative to leachate treatment that can remove heavy metals, including Hg. In this study, the electrocoagulation process was used with iron plate of various voltages (8, 10, 12 V), the distance between electrodes amounted to 1, 2, and 3 cm, and contact time 10, 20, and 30 minutes. To maximize the efficiency of mercury (Hg) removal, data analysis was conducted using RSM. The results showed removal efficiency of 98.86% with recommended voltage, time, and electrode spacing of 12 V, 29.52 minutes, and 1.11 cm, respectively.