Hydrolysis characteristic of polyferric sulfate coagulant and its optimal condition of preparation

Polyferric sulfate (PFS) has become a focus of many studies involving coagulation since the 1980s because of its many advantages over traditional coagulants. Many studies have been carried out on the applications of PFS but very few are concerned with its preparation and characterization. In this study an easy and reliable method for characterizing the composition of PFS was developed. The optimum conditions for PFS preparation from the waste acids were also explored. Results indicated that the viscosity of the product was affected by the percentage of sulfuric acid and the temperature of the reaction. The r value derived from a formation function was used to evaluate the quality of PFS prepared from waste acids. It was proven that the ORP electrode was an excellent tool for monitoring the extent of ferrous sulfate oxidation. The polynucleic characteristic of the PFS was confirmed by the chromatography.