Composite Polysilicate Metal Coagulants for Simultaneous Removal of Organic Matter, Phosphorus, and Ammonium-Nitrogen: Effects of Metal/Silicate Molar Ratio and Basicity

Coagulation can effectively recover substances from wastewater; however, there is a lack of efficient coagulants for simultaneous recovery organic matter, nitrogen, and phosphorus. We prepared composite polysilicate metal (CSM) flocculant by combining Fe3+ Mg2+ ions in polysilicic acid (PSiA). According to the results scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), CSM exhibited larger amorphous phase along with new compounds, including Mg3Fe2(SiO4)3 hydroxyl metals. The demonstrated higher coagulation efficiency than PSiA polymeric ferric sulfate, particularly PO43−-P NH4+-N removal. metal/silicate molar ratio substantially influenced structure composition CSM, efficiency, an optimal 3:1. Additionally, we proposed novel preparation strategy achieve optimum basicity (B*) adjusting initial pH (pHInitial) without adding alkali agent. that B* be obtained pHInitial 0.5 or 1. overall performance removal PO43−P, wastewater was 68.5%, 99%, 17.5%, respectively. This study provides feasible approach synchronous pollutant wastewater.