Research progress of metal organic frameworks and their derivatives for adsorption of anions in water: A review.

Anion pollution in water has become a problem that cannot be ignored. The anion concentration should be controlled below the national emission standard to meet the demand for clean water. Among the methods for removing excess anions in water, the adsorption method has a unique removal performance, and the core of the adsorption method is the adsorbent. In recent years, the emerging metal-organic frameworks (MOFs) have the advantages of adjustable porosity, high specific surface area, diverse functions, and easy modification. They are very competitive in the field of adsorption of liquid anions. This article focuses on the adsorption of fluoride, arsenate, chromate, radioactive anions (ReO4-, TcO4-, SeO42-/SeO32-), phosphate ion, chloride ion, and other anions by MOFs and their derivatives. The preparation methods of MOFs are introduced in turn, the application of different types of metal-based MOFs to adsorb various anions were discussed in categories with their crystal structure and functional groups. The influence on the adsorption of anions is analyzed, including the more common and special adsorption mechanisms, adsorption kinetics and thermodynamics, and regeneration performance are briefly described. Finally, the current situation of MOFs adsorption of anions is summarized, and the outlook for future development is summarized to provide my own opinions for the practical application of MOFs.

Nanomaterials in Water Applications: Adsorbing Materials for Fluoride Removal.

Fluoride is an important pollutant in many countries, such as China, India, Australia, the United States, Ethiopia, etc [...].

Removal of fluoride from industrial wastewater by using different adsorbents: A review.

Many industries such as iron and steel metallurgy, copper and zinc smelting, the battery industry, and cement manufacturing industries discharge high concentrations of fluoride-containing wastewater into the environment. Subsequently, the discharge of high fluoride effluent serves as a threat to human life as well as the ecological ability to sustain life. This article analyses the advantages and drawbacks of some fluoride remediation technologies such as precipitation and flocculation, membrane technology, ion exchange technology, and adsorption technology. Among them, adsorption technology is considered the obvious choice and the best applicable technology. As such, several adsorbents with high fluoride adsorption capacity such as modified alumina, metal oxides, biomass, carbon-based materials, metal-organic frameworks, and other adsorption materials including their characteristics have been comprehensively summarized. Additionally, different adsorption conditions of the various adsorbents, such as pH, temperature, initial fluoride concentration, and contact time have been discussed in detail. The study found out that the composite synergy between different materials, morphological and structural control, and the strengthening of their functional groups can effectively improve the ability of the adsorbents for removing fluoride. This study has prospected the direction of various adsorbents for removing fluoride in wastewater, which would serve as guiding significance for future research in the field.