Preparation of Fe/Zr bimetallic oxide beads and its performance and mechanism for advanced treatment of actual phosphorus-containing wastewater

Abstract

Phosphorus removal by adsorption method has unique advantages in the wastewater treatment. The granulation and recycling performance of adsorbent are key factors restricting its practical application. To solve these problems, this study used an environmentally friendly binder to prepare Fe/Zr bimetallic oxide beads (Fe/Zr-Bead) with high mechanical strength and recyclability. The batch experiment results confirmed that the maximum adsorption capacity of Fe/Zr-Bead was 24.60 mg/g. During extended operational trials, the Fe/Zr-Bead-filled fixed-bed column enables unhindered flow of wastewater without blockages, effectively treating simulated wastewater with varying initial concentrations of phosphorus. Furthermore, Fe/Zr-Bead exhibits prominent performance in the treatment of real wastewater plant effluent, reducing the initial phosphorus concentration from 0.416 mg/L to below 0.05 mg/L. Even after undergoing 11 cycles of adsorption and desorption, the phosphorus removal capacity of Fe/Zr-Bead only decreased by 5.5 %. Moreover, the desorption solution, which contains phosphorus, can reach up to 57.93 mg/L, making it suitable for phosphorus resource recovery. Ligand exchange between hydroxyl oxygen and phosphorus was found the main mechanism for phosphorus removal by Fe/Zr-Bead. This study is valuable for overcoming the limitations of adsorption materials in practical applications and also provide practical and technical support for advancing phosphorus treatment in the future.