Level Decreasing Kinetics Model of Heavy Metal Contents in the Coal Stockpile Wastewater with Electrocoagulation

Abstract

Electrocoagulation is one of methods used to treat wastewater in the coal stockpile without using coagulants. Characteristics of wastewater observed are heavy metals (Fe and Mn) and pH.  The decrease in the heavy metals content and the increase in the pH of this wastewater treatment process will then be proposed in the adsorption kinetics model. The influence of  variations in currents and processing time were observed. The time variation of the adsorption process were 60 to 120 minutes with current variations from 1.3 to 3.0 Ampere at a fixed 12 voltages. The results obtained that the Fe content could be decreased to 0.03 ppm at 90 minutes while the content of Mn was decreased to 0.01 ppm at the same time. The increase in pH (7.11) was achieved when applying 2.5 A current at 90 minutes process time. The results obtained from the electrocoagulation method was then proposed in the model of the Langmuir isotherm adsorption kinetics and Freundlich isotherm.