A new adsorbent for creatinine by starch esterification with 3.5-dinitrobenzoyl chloride DNBZ-ST was prepared．The chemical structures of DNBZ-ST products were characterized by FTIR

elemental analysis and 13C-NMR．The adsorption properties of DNBZ-ST for creatinine were examined．A structure model of complex of 3

5-dinitrobenzoic acid with creatinine was proposed

and the adsorption mechanism was explored fundamentally．Results showed that starch 3

5-dinitrobenzoate has good adsorption properties．The adsorption is complete in 4 h．The adsorption capacity increases with the degree of substitution of adsorbent

as well as with the creatinine concentration．However

the concentration has no apparent effect on adsorption capacity

when the creatinine concentration is higher than 300 mg·L-1．The adsorption capacity decreases with temperature in the range from 19℃ to 37℃．The adsorption capacity first increases and then decreases with the increase of the pH value and has a maximum around pH=8．The adsorption capacity may reach ～25 mg of creatinine per gram of adsorbent at 37℃

pH=7 and a creatinine concentration of 100 mg·L-1．