Selenium-contaminated water: Recent advances in material function and adsorption performance

The direct discharge of large quantities of selenium-containing wastewater into water bodies can have a negative impact on ecology and human health. The adsorption method is considered to be an effective way to remove selenium from aqueous solutions due to its wide range of adaptability, good treatment effect, recyclability and reusability of the adsorbent. Among the different types of adsorbents, iron-based adsorbents and surface modified materials account for the majority, due to the high affinity of iron oxides for selenium oxygen anions. After modification and modification of MOFs, the researchers obtained composites with significantly higher and improved adsorption capacity for selenium oxide anions, reaching 325 mg/g for Se(IV), while regeneration and reusability of the adsorbent materials need to be considered to achieve indirect continuity while saving costs. Various functional groups on polymer-based adsorbents can provide more adsorption sites, exhibiting high adsorption capacity and high adsorption efficiency (99%) for selenoxylate anions, and resistance to interference and applicability in real water samples needs to be taken into account. Therefore, the objective of this review study is to encourage researchers to learn from the strengths and weaknesses of various adsorbent materials, to identify gaps in current research and to develop innovative and environmentally friendly adsorbent materials with low cost benefits for the adsorption, separation and recovery of selenium from selenium-containing wastewater as well as water bodies, which are essential for the environment and for realising the value of selenium itself.