Lanthanum-based adsorbents for phosphate reutilization: Interference factors, adsorbent regeneration, and research gaps

Because of its Lewis acid property that can bind phosphate even at trace levels, Lanthanum (La) shows great potential for phosphorus (P) removal and recovery. Although many studies have reported the synthesis of novel La-based adsorbents with strong adsorption capacities, there is insufficient knowledge of reaction mechanisms, interfering factors, and application obstacles for different La-based adsorbents under varying water/wastewater compositions. To evaluate the potential and barriers for using La-based adsorbents for P recovery, this paper presents an analysis of various La-based adsorbents and factors that may affect their effectiveness during practical application. The conclusions show that the performance of a La-based adsorbent is closely related to its structure and effective La content. The toxicity of free La 3+ after adsorption and the adsorbent's regeneration performance are key factors dominating its applicability. Extra suggestions to adsorbent design for enhanced P adsorption capacity, regeneration performance, and selectivity are recommended for future research.