Abstract: The modified Chitosan polymer (PCTS) containing schiff-base group was synthesized by the chemical modificationof an amino group of chitosan with pyruvic acid. The experimental results showed that the optimum conditions were:1.8gchitosan reacted with 1.48g pyruvic acid under the aqeous solution at pH4～5 for 4h and then was reduced by 1.7g NaBH4 for1.5h to produce 1.6g PCTS. The product(PCTS) could be dissolved in distilled water, 1% sodium hydroxide solution and 0.3mol/L hydrochloric acid. The analysis showed that the substituted rate of schiff-base group was 88.14%. In comparison withchitosan, the PCTS had a higher absorption rate of Cu(Ⅱ)and Zn(Ⅱ). The PCTS could also remove the NO2 with its removingrate as high as 50.57%.

Key words: chitosan, pyruvic acid, chitosan modified by pyruvic acid, absorption of Cu(Ⅱ)and Zn(Ⅱ)