Determination of Pb(II) ion Adsorption Isotherm Model by Regenerated Spent Bleaching Earth (RSBE)

Abstract

Waste water from several industries such as paint plant, printing, tin smelting, plastic factory, also fuel leaking from ships and ship welding are the main causes of the presence of Pb(II) ions in the water. Lead is a heavy metal that can adversely affects all organisms in the waters and can accumulate in the food chain, it is harmful to human and animal if exposed to it. Adsorption is one of the technologies for separating dissolved metal ions in liquid that easy handling and very effective. The concentration of heavy metal ions in solution can be reduced by using a adsorbent, such as zeolte, activated charcoal, regenerated spent bleaching earth (RSBE). Spent bleaching earth (SBE) is a disposal from edible of the bleaching unit in oil refinery industries, it can be regenerated to a adsorbent RSBE. The treatment SBE into RSBE, oil of SBE is separated by the solvent extraction method at 72°C for 5 hours with n-hexane as a solvent, followed by washing it with HCl 3%, then physically activated at 470°C for 12 hours. The goal of this study are to increase SBE value and reduce the level of Pb(II) ions in solution with RSBE. Several works done in this study, namely characterization of SBE and RSBE, determination of the absorption capacity of RSBE against Pb (II) ions at equilibrium conditions, and an adsorption isotherm model of Pb (II) ion by RSBE. Results, RSBE has a specific surface area of 165.88 m2/g, a total pore volume of 0.21 cc/g with an average pore diameter of 6.90 nm. Based on these values, RSBE is categorized as a mesoporous adsorbent. The adsorption of Pb (II) ion by RSBE reaches equilibrium after 150 minutes contact time.The adsorption Pb (II) ion by RSBE is follows the Langmuir isotherm adsorption model with a correlation coefficient (R2) value of 0.9935 and a maximum adsorbing capacity value of 4.29 mg Pb (II)/g RSBE.