Spent bleaching earth; recycling and utilization techniques: A review
Sabah M. Abdelbasir, Ahmed I. Shehab, N. A. Abdel‐Khalek
Abstract
Spent bleaching earth (SBE) is a waste created by the vegetable oil refining industries that right now have restricted alternatives for advantageous reuse. An overabundance of about 2 million tons for each time of SBE is created worldwide with significant amounts accessible in the Middle East countries where noteworthy volumes of edible oils are developed. SBE is typically disposed of in landfill, which is costly, unfriendly to the environment, and represents an inefficient use of a potentially useful and valuable byproduct. The high oil content of SBE can rapidly oxidize to the point of spontaneous ignition posing fire hazard and a potential threat to the environment. Efforts have been made to transform it into a useful product. Utilizing SBE or the residual oil in SBE for various applications such as wastewater treatment, production of biodiesel, biofertilizer, fuel briquettes and non-fired wall tiles could reduce the waste generated by the edible oil refining industry and improve its sustainability. In this manner, this review compiled and reviewed a full overview of literature on recycling and utilization practices of SBE. Finally, future perspectives and considerations for the viable industrial-scale application of regenerated SBE as an economically significant waste with broad application prospects, are also discussed.