Separable alginate gel spheres encapsulated with La-Fe modified biochar for efficient adsorption of Sb(III) with high capacity

Sb and its compounds have been widely used in various industrial applications. Therefore, the preparation of Sb adsorbents with easy recovery and excellent adsorption levels is an urgent problem that must be resolved. By calcining and treating La/Fe metal–organic frameworks (MOF) biochar as a precursor, a loaded La-Fe-modified water hyacinth biochar was synthesised and used as a filler to synthesise iron alginate composite gel spheres, MBC/algFe. Through a series of static adsorption experiments, the effects of different filler addition ratios, solution pH, reaction time, coexisting ions, and other factors on the adsorption of Sb(III) were investigated. According to the Langmuir model, the maximum adsorption capacity of MBC/algFe at 25 ℃ was 277.8 mg·g-1. The adsorption mechanism mainly involved hydrogen bonding and metal-organic complexation interactions. China is the world's largest producer of antimony and its compounds. Antimony mining activities will cause serious water pollution in surrounding areas, making the concentration of antimony in the water dozens or even hundreds of times higher than the national standard. Therefore, developing a feasible method to remove Sb(III) from water is of great importance for environmental protection. In this study, an easily separable centimetre composite alginate gel sphere was designed for the efficient removal of Sb from water, with a maximum adsorption capacity of 277.8 mg g-1 at room temperature.