Adsorpsi Ion Logam Fe dan Zn pada Air Limbah Menggunakan Karbon Aktif dari Batubara Peringkat Rendah

Abstract

Indonesia has abundant low rank coal reserves. This coal has high moisture content and low calorific value, so that it will cause a lot of losses in its utilization as an energy source. So it is necessary to find an alternative to the use of low rank coal as a raw material for the synthesis of activated carbon. The purpose of this study is the synthesis of activated carbon from low rank coal which can be used as an adsorbent for heavy metals in wastewater, especially chemical laboratory waste. The synthesis of activated carbon was conducted through activation stage with ZnCl2 as an activator and carbonization stage by heating coal. The concentration of Fe and Zn metal ions were analyzed using AAS. The adsorption test was carried out by varying the adsorbent dose and adsorption contact time. Two types of activated carbon with different grain sizes, namely 80 mesh and 100 mesh were made and then selected activated carbon with the highest iodine number for use in the adsorption test. The 80 mesh activated carbon produced a yield of 41% and the highest iodine value was 1323 mg/g so it was used in the adsorption test. In the analysis of the effect of grain size, the weight of 1200 mg activated carbon produced the highest Fe and Zn absorptions of 43% and 81%, respectively. Meanwhile, the optimal contact time for Fe adsorption was 48 hours with an absorption value of 59% and a contact time of 24 hours for Zn adsorption with an absorption value of 41%. The synthesized activated carbon has the ability to remove Fe and Zn metal ions in wastewater.