Studies of rice husk adsorbent in reducing heavy metal from landfill leachate

Abstract

This study aimed to investigate the rate of absorption of activated carbon from rice husk to reduce heavy metal concentrations in the leachate that is focused on ion Pb and Zn. The main objective of this study was to investigate the rate of absorption and the best condition of rice husks to absorb ions Pb and Zn. The study included parameters such as pH leachate, mass of activated carbon, contact time and concentration of leachate. The activated carbon produced by using rice husk untreated and treated with NaOH solution mixed with leachate and shaken using shaker with variable pH (5, 6, 7, 8, and 9), the mass of activated carbon (0.05, 0.10, 0.125 and 0.75 grams), contact time (30, 60, 90, 120 and 150 minutes) and leachate concentrations (20, 40, 60, 80 and 100 %), shaken at 150 rpm. The concentrations of lead and zinc were determined by atomic absorption spectrometer. From the results obtained optimum percent reduction of Pb and Zn ions respectively 86.6 and 86.8 % for the pH factor, 87.0 and 87.7 % of the time factor, 85.3 and 88.2 % for the mass factor and 86.8 and 85.7 % for the concentration factor. Conclusions from the study of the optimum conditions the absorption of Pb ions in leachates using rice husk is at pH 6, 0.25 gram of rice husk, shaken time of 120 minutes and 100 % concentration of leachate and the results for the optimal absorption of Zn ion is at pH 7, 0.05 gram of rice husk, shaken 90 minutes and 100 % concentration of leachate.