Comparative study between adsorption and membrane technologies for the removal of mercury

Mercury is one of the most detrimental by-products of industrial activities, such as mining and fossil fuel combustion. What differentiates this contaminant from other pollutants is its bioaccumulation and rapid distribution in the food chain. This review paper provides a comprehensive comparison between two competing wastewater treatment technologies for the removal of mercury in aqueous systems. Adsorption and membrane separation technologies both yield high percentage removals and high selectivity distinguishing them from other treatment options. This review offers a critical summary of recent research works dedicated to developing unique adsorbents and membranes for the removal of mercury from wastewaters. The assessment of the two technologies is based on the removal performance, regeneration efficiency, selectivity and effect of experimental conditions. This work reveals that both techniques can be further enhanced by the addition of functional groups such as thiols where sulfur serves as a strong binding site for mercury ions. However, the main issues that normally entail adsorption and membrane separation are waste disposal and fouling respectively. Given that the adsorption process offers several benefits in comparison to membrane technologies including low capital and operating costs, ease of operation in addition to the potential application of a wide range of solid media for the removal of hazardous substances, the adsorption process is the feasible option.