Flocculation Performance and Mechanism of Removing Pectin by N-hydroxypropyl Trimethyl Ammonium Chloride Chitosan

Abstract

The cationic organic flocculant N-hydroxypropyl trimethyl ammonium chloride chitosan (HTCC) was used for flocculation of pectin, which was an impurity widespread in Chinese medicine water extractions, and the effects of the flocculant dosage, the pectin concentration, pH value, and the solution temperature on the flocculation efficiency were studied. FTIR spectra of pectin and its flocs were analyzed to determine the flocculation mechanism. The results showed that HTCC effectively flocculated the high-methoxyl pectin (HMP) and low-methoxyl pectin (LMP). The removal rate of HMP and LMP were above 85% and 90%, respectively. The flocculant dosage and pH value were the key influential factors. The pectin flocculation mechanism was mainly adsorption bridging and charge neutralization by hydrogen bonding, electrostatic adsorption, and hydrophobic interaction. The optimal flocculation conditions of HMP and LMP by HTCC were achieved.