Development of a low-cost activated mesoporous bauxite for the reclamation of used transformer oil

Abstract

Regeneration/reclamation of used oil using active adsorbents with high surface area is considered as one of the most efficient methods for the waste management and treatment of oil pollutants. In this work, we developed a mesoporous active γ-bauxite (DABa) from a low-grade raw boehmite ore (RBa) through a two-stage thermal activation process followed by an acid treatment. Acid leaching in hydrochloric acid resulted in the high specific surface area and optimum pore distribution in γ-bauxite. The surface area of the mesoporous γ-bauxite was as high as 130.66 m2/gr, approximately 11-fold larger than its parent ore. The regeneration performance of developed adsorbents to remove contaminants from used transformer oil was compared with three high-performance commercial adsorbents; Brazilian activated bauxite (BABa), Japanese activated bentonite (JABe), and Iranian activated alumina (IAA). The results showed DABa has the best oil reclamation performance and significantly improves the used oil characteristics such as its color, acidity, interfacial tension, dielectric dissipation factor, dibenzyl disulfide (DBDS) content, and corrosive sulfur.