Synthesis and characterisation of new cationic polyelectrolytes by inverse emulsion polymerisation and their application in activated sludge dewatering

摘要

Water soluble hydrophobically associated polyelectrolytes were copolymerised with dimethyl- [2-(2-methyl-acryloyloxy)-cthyl]-alkyl ammonium bromide (alkyl: propyl, hcxyl, dodecyl) (DEACn) and acrylamide (AM) in inverse emulsion. Cationic hydrophobically modified polyacrylamides having different molecule weight and cationic degree were obtained by varying the total monomer concentration and DEACn/AM mole ratio. Polyelectrolytes were characterised by 'H-NMR and l C-NMR. The dewatering indexes, such as CST, settling rate and water content in sludge cake were investigated and used to evaluate the dewatcrability and scttleability of activated sludge conditioned by these polyelectrolytes. Afterwards, some characteristics of sludge floe, such as: floe size, sludge viscosity and floe strength were measured. The function of hydrophobic association in sludge conditioning was elucidated by comparing dewatering performances with these polyelectrolytes.