Advances in Oil-Water Separation : A Complete Guide for Physical, Chemical, and Biochemical Processes

Abstract

In the modern age of human civilization, consumption of different oils for example, petroleum oil (e.g., gasoline), mineral oil (mainly, the liquid by-product during refining of crude oil), diesel oil, lubricants (i.e., engine oil), vegetable oil (edible or nonedible), is increasing day-by-day. The oils are used in various applications including but not limited to running the vehicles or engines, cooking the food, manufacturing of the polymers, chemicals, cosmetics, medicine, etc. However, depletion of fossil fuels from the earth crust, and increase in environmental pollution (soil, water, and air) due to oil-spillage, emission of greenhouse gases during oil cracking, as well as accumulation of nondegradable polymer wastes. Moreover, the unconventional practices to discard the huge amount of used oils or oil-derived chemicals (e.g., organic solvents) are detrimental to the environment. In this scenario, it is necessary to implicate some conventional practices for making these “trash to treasure” through proper recycling of the waste oil or oil-based waste products. The process of this circular economy enabling the pollution-free environment is being started because of the grace of science and technology. In this chapter we have made attempts to summarize and discuss the research efforts undertaken by the researchers toward the management of oil wastes employing different chemical and physicochemical methods. The term “waste oil” in this chapter has been used to express all kinds of the oil wastes viz. used oil, waste oil, waste cooking oil, etc. Generally, the “used oil” means any oil derived from the crude oil or the mixtures containing synthetic oil including spent oil, used engine oil, gear oil, hydraulic oil, turbine oil, compressor oil, industrial gear oil, heat transfer oil, transformer oil, and their tank bottom sludges whereas “waste oil” means any oil which includes spills of crude oil, emulsions, tank bottom sludge and slop oil generated from petroleum refineries, installations or ships and can be used as fuel in furnaces for energy recovery. © 2022 Elsevier Inc. All rights reserved.