PH value affects the chitosan in the process of flocculation and coagulation

The pH value is a key factor in the coagulation-flocculation process of chitosan. The pH affects the structure of chitosan and the hydration of the coagulant-flocculant system, as well as the chemical nature of the species removed from the aqueous phase. In addition, pH has a significant effect on the amount of coagulant-flocculant system due to structural changes caused by ionization effects.
Due to the presence of abundant amine groups, chitosan is a cationic biopolymer in acidic media. Therefore, pH affects the charge state of chitosan and its overall solubility, as well as its efficacy in the flocculation process. Chitosan was protonated and used as a suitable flocculant because of its potential for favorable electrostatic interactions with impurities in acidic media to remove turbidity. An increase in the pH of the medium will result in ionization of chitosan and a decrease in water solubility. In turn, this can alter flocculation efficiency by reducing removal efficiency or requiring higher doses of chitosan to work effectively. The pH value is a key parameter that provides variable chitosan water solubility and flocculation efficiency under different solution conditions.