Abstract: An anion exchange resin(MWS,modified wheat straw) was prepared by chemical modification of wheat straw grafting epichlorohydrin,triethylamine and diethylenetriamine to improve MWS performance,particularly for adsorption of NO^-₃ in water.The results showed that amine groups with positive-charge had been introduced into the structure of MWS,which resulted in improving significantly adsorption capacity for NO^-₃ in water.The analysis of zeta potential and surface elemental as well as FTIR and Raman spectra indicated that the adsorption mechanism of MWS for NO^-₃ was ion exchange.The adsorption data could be well fitted with the Langmuir model and the correlation coefficient(R²) was higher than 0.988.The results of competition adsorption indicated that the adsorption efficiency for co-present ions followed an order as SO^2-₄>H₂PO^-₄>NO^-₃>NO^-₂.The maximum adsorption capacity(Q_max) of MWS for NO^-₃ was 52.1 mg·g^-1,which could compared with that of commercial resin,and showed that there was a significant increase than that of raw WS(1.3 mg·g^-1).In addition,column adsorption test showed that the breakthrough adsorption capacity for NO^-₃ was about 45.2 mg·g^-1,and both 0.1 mol·L^-1 NaCl and HCl solutions could be used as regenerating agent for the desorption of NO^-₃ from the MWS.

Key words: wheat straw, nitrate, adsorption, maximum adsorption capacity, Raman spectrum

摘要： 采用环氧氯丙烷、二乙烯三胺和三乙胺等对麦草秸秆进行化学改性,制备改性麦草秸秆阴离子交换树脂（改性麦秸树脂），研究改性麦秸树脂的性能指标并重点考察其对水体中NO^-₃的吸附性能及效果。 研究结果表明,改性麦秸树脂引入了带正电荷的胺基基团,可以显著提高对NO^-₃的吸附性能；拉曼、红外光谱及zeta电位分析证明改性麦秸树脂对NO^-₃的吸附机理为离子交换；吸附过程符合Langmuir等温吸附模式；竞争吸附实验结果表明，改性麦秸树脂对不同阴离子的竞争吸附顺序为SO^2-₄>H₂PO^-₄>NO^-₃>NO^-₂,改性麦秸树脂对NO^-₃的最大吸附量为52.1 mg·g^-1,与商业树脂相当；柱吸附实验表明，改性麦秸树脂对NO^-₃的柱饱和吸附量为45.2 mg·g^-1，0.1 mol·L^-1的NaCl及HCl溶液均可有效再生改性麦秸树脂。

关键词: 麦草秸秆, 硝酸根, 吸附, 最大吸附量, 拉曼光谱