Optimization Process of Spent Bleaching Earth Regeneration Using Nitric Acid Concentration and Heating Temperature
Dodyk Pranowo, Susinggih Wijana, Hanah Fatimah
Brawijaya University
Abstract
Bleaching is the most critical stage to improve the appearance, flavor, taste and stability of the final oil products in Crude Palm Oil (CPO) refining process. Bleaching process using a clay called bleaching earth (BE). The used BE will become a waste called spent bleaching earth (SBE). The surface of SBE is covered by impurities which are carried by CPO purification process so it cannot be reused. Regeneration using acid can increase the absorption capacity of SBE. The purpose research is to find the optimal combination of nitric acid concentration and heating temperature in the regeneration process of spent bleaching earth, so it can be reused as an adsorbent in refining crude palm oil. The research was arranged using Response Surface Method (RSM) with Central Composite Design (CCD) using 2 factors, concentration of nitric acid (0.4 M; 0.7 M; and 1 M) and heating temperature (100oC, 300oC and 500oC) and the response are color absorption efficiency and yield. The optimum condition was the treatment with the concentration of nitric acid 0.75 M and heating temperature 430.82oC. The result of prediction program produces color absorption efficiency 95.7557%, yield 52.4846%. The optimal solution was verified, the results of color absorption efficiency is 94,68% and yield is 51,43%. RSBE result from optimum condition is compared to BE. The value of color absorption efficiency using BE is 96.77%, while in RSBE with optimum conditions is 94.68%. The value of RSBE color absorption efficiency of optimum conditions approaches the value of BE color absorption efficiency.
Keywords: Spent Bleaching Earth, Bleaching Earth, Bentonite, Regeneration, Respon Surface Methodology
Topic: WASTE AND ENVIRONMENTAL MANAGEMENT