Reduksi Logam Berat Hg, Ag, Dan Cr Limbah Laboratorium Menggunakan Metode Presipitasi Dan Adsorpsi

Abstract

Laboratory operational activities produce solid, liquid, and gasions wastes. Increased laboratory activities such as research and other laboratory ser vices result in increasing of the wastes quantity. Some types of wastes contain heavy metals such as Hg, Ag, and Cr. This heavy metals are toxic and pollute the environment. Appropriate treatment can reduce the heavy metals concentration in liquid waste. The objectives of this research were to determine the optimum condition of precipitation and adsorption, to determine the removal efficiency and the quality of the treated liquid. The studied liquid wastes is cha racterized by very highly acidi zand highly content of heavy metals. The characteristics are pH values of 1.3 – 1.4, COD of 320 – 360 mg/L, Hg of 77.6 – 391.6 mg/L, Ag of 2.6 – 9.14 mg/L, and Cr of 11.36 – 21.9 mg/L. Additition of NaOH 50% resulted in reduction of 97% for Hg at pH 11.63, 98.95% for Ag at pH 11.63 and 96.85% for Cr at pH 9 .77. Based on the results, Hg did not meet the requairement, the others me tal Ag and Cr concentrations met the requirement. Adsorption using activated carbon in the forms of granule and powder reduced COD and heavy metals (Hg, Ag, Cr) significanly. The qu ality of treated liquid waste was high and met the requirement according to Kepmen N0. 51/1995.