Reactivation of Spent Bleaching Earth using Acid-Activation and Calcination Treatment for Enhancing Adsorption Abilities and Reducing Environmental Loading in Palm Oil Refining Industries

Abstract

Spent Bleaching Earth (SBE) is solid waste categorized as hazardous waste with code number B413 based on the Republic of Indonesian Government regulation number 101/2014 and number 22/2021. Improper processing of SBE can be triggering spontaneous ignition and pose environmental pollution due to the high of oil content which is about 20-30 %. SBE has the potential to be reused as an adsorbent in the crude oil bleaching process. In this research, the reactivation process was carried out using acid activation and followed by calcination. SBE was successfully reactivated using sulphuric acid (H2SO4) and hydrochloric acid (HCl) with various concentrations (5-20%), then, followed by a calcination process at 600-700°C for 90 and 120 min. The results showed that the physical appearance color of the bleaching earth (BE) after reactivation and calcination at temperatures above 600 °C resembled color of virgin bleaching earth (light brown). The characterization of reactivated spent bleaching earth (RSBE) product using X-Ray Fluorescence showed that the highest percentage value of silica content is 68.28 % and 74.42 %, under the reactivation condition using 15 % H2SO4 (calcination temperature and time at 600 °C and 120 min) and 20 % HCl (calcination temperature at 600 °C, and 90 min), respectively. The characterization results using Brunauer Emmett Teller (BET) analyzer, showed that the surface area of RSBE using HCl 20 % is about 150 m2/g. However, the surface area RSBE with activator H2SO4 15 % (146 m2/g). These results showed that the RSBE with HCl activator has a larger surface area than activator H2SO4, and has good absorption ability. As evidenced by the percentage of bleaching power that the RSBE with activator HCl has 72.92 % higher than RSEBE with activator H2SO4 15 % of 70.73 %. The best adsorption capacities of adsorbent were then tested for its performance to purify crude palm oil (CPO). The result shows that the RSBE met the Indonesian Industry standard (SNI 13-6336-2000) for the bleaching of CPO processes.