Regeneration and reuse waste from an edible oil refinery.

A spent bleaching earth (SBE) from an edible oil refinery has been regenerated by thermal processing in oven, followed by washing with a cold solution of hydrochloric acid (1M). Optimal regeneration conditions have been controlled by decolorization tests of degummed and neutralized soybean oil. Optimal values of treatment (temperature 350°C, carbonization time 01 h, and HCl concentration 1M) gave a very efficient material. After bleaching oil by regenerated spent bleaching earth (RSBE), the chlorophyll-a and β-carotenes contained in crude edible oil and observed respectively at 430, 454, and 483 nm, value of λ max, are very much decreased. The results obtained after decolorization of edible oil by RSBE material indicate, that, during the process, the bleaching oil did not undergo any changes in the free fatty acid content. The peroxide value (PV) was reduced from 4.2 to 1.8 meq O2/kg, and the color has been improved (Lovibond color yellow/red: from 50/0.5 to 2.7/0.3, respectively). The RSBE material obtained was characterized by several techniques (FTIR, SEM). The results show that the heat treatment did not affect the mineral structure of RSBE, and the regenerated material recovered its porous structure.