Developments in supported liquid membranes for treatment of metal-bearing wastewater

ABSTRACT

Harmful effects of aqueous metal pollutants and benefits of recycling drive the need for wastewater treatment and recovering metals for reuse. Supported liquid membrane (SLM) separation is one of the potential energy-efficient techniques that can recover metal ions selectively, but improvements in transport rate and stability are needed to improve treatment capacity and SLM lifetime. Many lab studies on SLM could demonstrate metal removal efficiencies above 70% and mass transfer coefficient in the range of 10⁻⁶ m/s, but there is more variation in reported SLM stability for different setups tested. Recently, researchers started exploring the use of green chemicals in constructing SLM. In this review, factors affecting selectivity, transport kinetics, and stability of SLMs are presented. Improvement strategies for maturing SLM technique into a technology capable for treating metal-bearing wastewater on an industrial scale are discussed.

KEYWORDS:

• Supported liquid membranes
• selective separation
• transport kinetics
• stability
• environmentally friendly carrier
• green solvent

Acknowledgments

This work was supported by the Ministry of Energy, Science, Technology, Environment and Climate Change (MESTECC), Malaysia under Grant 305.PTEKIND.613332