Study on the influence characteristics of carboxyethyl chitosan with different degrees of substitution on composite fouling: Experiments, functional group analysis and molecular dynamics simulations

This study investigates the scale inhibition performance of carboxyethyl chitosan (CEC) on composite fouling by employing experimental methods, functional group analysis, and molecular dynamics (MD) simulations to evaluate its effects on CaCO₃ and Al₂O₃ composite fouling. Experimental findings demonstrate that CEC, synthesized through functional group substitution, serves as an effective green scale inhibitor, significantly preventing the formation of composite fouling. Functional group analysis reveals that the carboxyl group on the molecular chain exhibits strong adsorption affinity for Ca²⁺. MD simulations further confirm significant interactions between Ca²⁺ and the carboxyl groups of CEC in the solution. CEC's impact on composite clustering includes delaying the adsorption of particles and ions, modifying the aggregation behavior of the cluster, and reducing both the probability and strength of Ca²⁺ and CO₃²⁻ adsorbing onto the particle surface. As the degree of substitution of CEC increases, the adsorption probability and intensity of crystallizing ions on the particle surface decrease, leading to enhanced scale inhibition efficiency.