| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 96 === Chitosan obtained by deacetylation of chitin, is a natural cationic biopolymer. Because of its high contents of amine and carboxyl group, Chitosan is apt to form complexes with metal ions. Therefore, it possesses a strong absorption of heavy metal ions in raw water. Additionally, it is also biodegradable, non-toxic, and has been used in the coagulation of suspended solids from raw water
This research includes two parts: (1) using chitosan to treatment high-turbidity raw water. (2) removel copper in raw water by chitosan.
The waterworks occasionally encounter high-turbidity raw water during typhoon season in Taiwan. That may force the waterworks to reduce output or even closedown completely.
Therefore treatment of high-turbidity raw water by coagulation process was investigated in this research. Raw water of various turbudities were prepared with reservoir sludge. Alum and chitosan were used as coagulant in coagulation reactions.
Jar tests were carried out to assess optimum conditions for turbidity removal. Experimental results indicate that chitosan at concentration higher than 1 mg/L could yield good removal efficiency of water with initial turbidity of 1000 NTU.
Among raw water treatment processes, adsorption is a relatively inexpensive method for the removal copper in raw water. The target of this research is to develop a low cost adsorbent for the application to raw water treatment.
Studies on copper adsorption on chitosan by Ngah et al. (2002) stated that chitosan had an excellent loading capacity of copper and concerning the sorption of metal ions since the amine and hydroxyl groups on their chemical structures act as chelation sites for metal ions.
At pH=5.5, the adsorption capacity of Cu2+ was reached to 94.5 mg/g for chitosan .
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