Advances in Phenol Separation Using Supported Liquid Membranes: Challenges, Mechanisms, and Future Directions

Industrial effluents frequently contain phenol, a hazardous and highly soluble organic contaminant that poses significant health and environmental concerns. Traditional techniques of phenol elimination include adsorption, chemical oxidation, and distillation, which have some drawbacks, such as high energy utilization, formation of hazardous compounds, and complexity. This review discusses the latest advancements in innovative membrane-based separation processes for removal of phenols. It emphasizes the Supported Liquid Membrane (SLM) as an environmentally friendly and effective technology. SLMs include extractants and strippers in one stage and offer advantages such as low power consumption, high selectivity, and economical setup. The SLM components (carriers, diluents, and strippers) and mechanisms focussing on phenol removal are presented. The current developments in SLMs for phenol removal based on ionic liquids are discussed, covering topics such as membrane fabrication methods and stability. The effects of different process variables on the performance of SLM for phenol extraction, are investigated. They include phenol concentration, feed pH, stirring speed, stripping agent nature, and liquid membrane nature. The SLM challenges and future directions are also discussed. The findings highlight the potential of employing SLMs to treat phenol-contaminated industrial effluents.