State-of-the-art adsorption and adsorptive filtration based technologies for the removal of trace elements: A critical review

Water and wastewater are contaminated with various types of trace elements that are released from industrial activities. Their presence, at concentrations above the permissible limit, will cause severe negative impacts on human health and the environment. Due to their cost-effectiveness, simple design, high efficiency, and selectivity, adsorption, and adsorptive fil-tration are techniques that have received lots of attention as compared to other water treatment techniques. Adsorption isotherms and kinetic studies help to understand the mechanisms of adsorption and adsorption rates, which can be used to develop and optimize different adsorbents. This state-of-the-art review provides and combines the advancements in different conventional and advanced adsorbents, biosorbents, and adsorptive membranes for the removal of trace elements from water streams. Herein, this review discusses the sources of different trace elements and their impact on human health. The review also covers the adsorption technique with a focus on various advanced adsorbents, their adsorption capacities, and adsorption isotherm modeling in detail. In addition, biosorption is critically discussed together with its mechanisms and biosorption isotherms. In the end, the application of various advanced adsorptive membranes is discussed and their comparison with adsorbents and biosorbents is systematically presented.