Recovery of H2SO4 from spent acid waste using bentonite adsorbent

Spent acid waste is produced in the petroleum processing industry at the alkylation process unit that requires sulfuric acid as a catalyst to produce iso-octane. Therefore, spent acid contains sulfuric acid attached to a long chain carbon and other compounds. This compound is corrosive and has a pH below 1.0, so that it cannot be directly discharged into the environment. The processing and utilization of spent acid to meet environmental quality standards need to be conducted. This study aimed to conduct waste treatment of spent acid and to recover sulfuric acid from the spent acid solution because the level of H2SO4 is high at about 82%, then the sulfuric acid can be reused in the alkylation process or other processes. Adsorption method was selected to process the waste using bentonite as adsorbent in 3 stages adsorption columns. The results showed that the recovery of H2SO4 was successful in which the purity of H2SO4 generated after distillation reached 94.94%.