| description abstract | In this investigation, polyaluminum sulfate (PAFS), an inorganic flocculant, was synthesized using municipal solid waste incineration (MSWI) fly ash. The morphology and structure of PAFS were characterized using x-ray diffraction and Fourier-transform infrared spectroscopy (FTIR). A single-factor flocculation experiment explored the impact of polymerization duration, temperature, stirring speed, and pH on the preparation of PAFS. Optimal removal of kaolin turbidity was achieved with a polymerization time of 60 min, a stirring speed of 100 rpm, a temperature of 40°C, and a pH of 10, resulting in a maximum turbidity removal rate of 32.75%. To enhance the turbidity reduction capability of PAFS, upgraded experiments were conducted using FeSO4·7 H2O as an additive. These experiments demonstrated that the modified flocculant significantly improved turbidity removal, achieving 74.95% under consistent conditions with a pH of 3.5 and an FeSO4·7 H2O addition of 1 g, corresponding to a 1∶5 ratio to fly ash. The characterization of the flocculant revealed that PAFS is a composite material containing hydroxyl groups, iron ions, and chloride ions, forming a network structure of interconnected molecular chains with a dense configuration. The adsorption bridging by high-molecular-weight iron sulfate polymers with branch-like structures plays a critical role in turbidity elimination. This study presents a novel method for the utilization of MSWI fly ash in environmental management. | |
