Preparation And Application Of Modified Chitosan Complex Flocculant

The study of Fe (Ⅲ) flocculant is currently a heated issue in the field of water treatment, with a tendency of combining organic and inorganic compound polymer flocculants. In the dissertation, a novel, highly effective and environmentally friendly complex flocculant, was prepared by using carboxymethyl chitosan and polysilicon ferric chloride.The carboxymethyl chitosan was obtained by the reaction of chloride acetic acid and chitosan. The structure of CMC was analyzed by IR.The results showed that turbidity and chemical oxygen demand (COD) can be removed effectively by CMC, according to the flocculation in seawater.The optimal condition of polysilicon ferric chloride (PFSC) flocculant was established by thinking of the factors , such as the reaction time,the pH value of the solution and Si/Fe molar ratios. The results showed that the rate of turbidity removal of seawater is up to 97.3%, and the rate of COD removal of seawater is to 51.1%, by adding 0.8mg PFSC to 1000mL seawater.The complex flocculant was prepared by polysilicon ferric chloride (PFSC) and carboxymethyl chitosan (CMC), and used in seawater. The effect of the proportion between PFSC and CMC, and adding order were investigated. The results show that the optimal mass ratio of PFSC and CMC is 1: 10. Under such a condition, the removal rates of the turbidity and COD of seawater are up to 98.6 % and 82.3% respectively.The result shows that the inorganic/organic complex flocculant prepared in the dissertation is high-effective in seawater pretreatment. The results demonstrate that the seawater treated with complex flocculant has not only higher removal rate of turbidity and COD but also fewer dosage of flocculant.