Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE CO2-responsive cationic copolymers enable a disperse-then-activate flocculation strategy that decouples polymer dispersion from chain activation, overcoming the inherent trade-off between high molecular weight and homogeneous distribution in flocculation of sludge. Higher CO2-responsive group density accelerates sedimentation kinetics by 58%, while the in-situ protonation mechanism provides uniform charge generation inaccessible to conventional flocculants.


ABSTRACT
CO2-responsive cationic polymers offer a route to couple industrial kiln exhaust pretreatment with sludge deep dewatering, using the abundant CO2 in flue gas as a trigger to enhance flocculation. This study proposes a flocculation then activation strategy to enhance the flocculation effects of the CO2-responsive Poly-(DMC-DMAEMA) copolymer. The polymer is first dispersed in its low-viscosity, non-activated state to achieve uniform contact with suspended particles, followed by CO2 bubbling to trigger in situ protonation of the PDMAEMA blocks. Using a diatomaceous suspension as model sludge, flocculation behaviors under different CO2 addition modes were systematically compared. Pre-activation caused a sharp increase in solution viscosity and poor dispersibility, aggravating inhomogeneity. Post-activation-dispersion followed by CO2 activation effectively balanced uniform adsorption with in situ bridging reinforcement, yielding superior floc growth, turbidity removal, and dewatering efficiency. This mechanistic strategy directly resolves the dispersion problem characteristic of conventional high-molecular-weight flocculants, thereby establishing a foundation for the integrated application of kiln exhaust pretreatment and sludge deep dewatering.