Progress and perspectives on cost-effective and eco-friendly mineral functional materials for efficient capture of fluoride and phosphorus

With the development of society and the acceleration of industrialization, a large amount of wastewater containing pollutants such as phosphate and fluoride have been discharged into natural environment, leading to excessive levels of phosphate and fluoride in natural water. Excessive amount of phosphate in water can cause eutrophication of water, resulting in the death of a large number of aquatic animals; and fluorides can accumulate in aquatic environments and eventually enter the food chain, posing a threat to human health. Therefore, it is imperative to remove harmful phosphate and fluoride pollutants from water. Adsorption method can remove effectively and thoroughly pollutants (i.e. phosphate and fluoride) from water, and is commonly recognized as an effective strategy for purification of the wastewater containing phosphate and fluoride. However, adsorbents with application potential in a large scale require multiple conditions such as low price, environmental friendliness, excellent performance, and easy availability of raw materials, which limits the application of adsorbents derived from fossil resources and artificially synthesized adsorbents such as MOFs. Natural non-metallic minerals have abundant reserves, low price, and are environmentally friendly. The unique charge, adsorption sites, and surface activity of minerals enable them to serve as promissing cost-effective, efficient and safe adsorbent for capturing various pollutants. In view of this, this paper reviews the research progress of natural non-metallic minerals (e.g. montmorillonite, kaolinite, attapulgite, bentonite, zeolite) and their derivatives on the adsorption and removal of phosphate and fluoride pollutants in the past decades. By comparing and analyzing the preparation methods, structures, and properties of different adsorbents, the structure-activity relationship and adsorption mechanism of different types of adsorbents for adsorption of phosphate and fluoride were summarized. The perspectives on the design and preparation of new minerals-based adsorbents in future were proposed, providing support for the development of more cost-effective adsorption materials for phosphate and fluoride.