The size fractions of the sludge samples taken at

FT-IR characteristics
The VX809 of all of the titrated samples was adjusted to 7 after the titration and then treated by dialysis membrane tubes with a molecular weight cut-off (MWCO) of 3.5 kDa (Thermo, Snake Skin® Dialysis Tubing) for 48 h to remove the monovalent ions introduced by the titration. The dialysis membrane-treated effluent was lyophilized at −50 °C using a Labconco one-liter bench-top freezing drier (Labconco, USA) for the FT-IR analysis.