Limbah Arang Sekam Padi Sebagai Adsorben Ion Cr(III) dan Cr(VI)

Abstract

The major sources of heavy metal contaminations are industrial effluents. Chromium metal and its compound have wide application in industrial sector. Its two most stable states are Cr(III) and Cr(VI). Trivalent chromium toxicity is negligible because it often forms insoluble hydroxide at netral pH. Hexavalent chromium is considered powerful carcinogenic agent Lots of waste treatment efforts are conducted; one of which is to make use of agricultural by products that are potential to be utilized as adsorbent. This paper utilizes carbonized rice husk from rice husk stove as Cr(III) and Cr(VI) adsorbent. Carbonized rice husk was activated potassium hydroxide (KOH). As a comparison, activated carbon that originated from coconut shell, a commercially-used adsorbent, was used. Adsorption was carried out by varying adsorption time, adsorbent weight, and initial concentrations of Cr(III) and Cr(VI). The optimum condition of carbonized rice husk adsorbent for Cr(III) and Cr(VI) were 60 minutes; 0.5 g; and 250 ppm. The optimum conditions for activated carbon, as comparison, for Cr(III) were 90 minutes; 0.5 g; and 250 ppm. And the optimum conditions for activated carbon, as comparison, for Cr(VI) were 90 minutes; 0.5 g; and 250 ppm. In single solution test of Cr(III) and Cr(VI), adsorption capacity for carbonized rice husk were 8.400 mg/g; with adsorption efficiency were 84.00 %.