Enhanced Dewatering ofWaste Sludge With Polyacrylamide/Montmorillonite Composite and Its Conditioning Mechanism

摘要

In order to improve the waste sludge dewaterability of polyacrylamide (PAM), the composite conditioner of PAM/montmorillonite (MMT) was prepared. The structure and intermolecular hydrogen bonding of the composite were studied, and the effects of PAM/MMT weight ratio and dosage on the dewaterability of the waste sludge were systematically investigated. The results revealed that the MMT platelets were in an exfoliated state in the PAM matrix, and hydrogen bonding between –OH groups of MMT and –NH groups of PAM led to relatively high elastic modulii (G’) values and low tan δ values, indicating the possible formation of a physically cross-linked network in aqueous solution. The addition of MMT significantly reduced the specific resistance to filtration (SRF) of the waste sludge, with a minimum value being achieved at a 1:1 PAM/MMT weight ratio. The UV transmittance and the turbidity of the supernatant of the waste sludge were also improved at a proper PAM/MMT weight ratio. The synergistic effect of the two components in the composite through the charge neutrality and bridging action of PAM as well as the adsorption capacity of MMT resulted in an enhanced dewaterability of waste sludge.