Adsorption of chlorinated acetic acids by quaternary ammonium cationic cellulose

Abstract

Etherifying agent, 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTA) was modified by grafting on cellulose to make quaternary ammonium cationic cellulose (QACC) with 2.01% nitrogen content and a degree of substitution of 0.289. The experiment results showed that at 318 K, the adsorption capacities of QACC on monochloroacetic acid (MCAA), dichloroacetic acid and trichloroacetic acid (TCAA) were 1.80, 1.87 and 2.01 mmol/g, respectively. The adsorption process could be modeled by pseudo second-order kinetics very well. The adsorption rate constant increased with temperature, and the adsorption pattern fitted Langmuir isotherms, which was monomolecular layer absorption. ΔH of the three chlorinated acetic acids were all above zero, and ΔS of them were above zero too. At 298 K, ΔG of the adsorption processes were below zero. These experiment results showed that it was main chemical adsorption accompanied by physical adsorption.