Preparation of FeOOH supported by melamine sponge and its application for efficient phosphate removal

Water eutrophication caused by the excessive discharge of phosphate has been a topic theme in decades and phosphate removal from aqueous solution is of great significance. Adsorbents of iron (hydroxyl)oxides particles exhibited its great potential in environmental pollution remediation. However, iron (hydroxyl)oxides are easy to aggregate, resulting in the decreased reactivity. In this study, we immobilized FeOOH on the surface of melamine sponge (MS). The characterization results of scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) revealed that FeOOH was well-dispersed on melamine sponge. Further phosphate removal experiments results elucidated that the maximum phosphate adsorption capacity of the synthesized material (FeOOH@MS) was 115.5 mg P/g when the theoretical mass ratio of Fe to MS was 5:1. Meanwhile, the physical adsorption with electrostatic attraction and chemical adsorption with the formation inner-sphere complex were involved for phosphate treated by FeOOH@MS without pH adjustment. Subsequently, we investigated the phosphate removal performance of FeOOH@MS in a packed column, and found that capacity of phosphate removed by FeOOH@MS reached 11.3 mg/g, and the packed column with FeOOH@MS would be penetrated at 1201 BVs around 41 h, suggesting that application of FeOOH@MS to treat phosphate-contained wastewater was feasible. Moreover, when the phosphate-containing lake water was treated with FeOOH@MS, the algae growth in the treated water was significantly inhibited, indicating that FeOOH@MS could be utilized to control the water eutrophication. Overall, this study provided a promising adsorbent for phosphate-contained water treatment.