弱碱性离子交换纤维对六价铬吸附性能的研究

Cr(VI) Adsorption Properties of Weak Alkaline Ion Exchange Fiber

以一种腈纶基弱碱性离子交换纤维为材料,探讨了纤维型式（氯型、氢氧型）对吸附量和再生性能的影响。考察了溶液pH、温度对氯型纤维吸附量的影响,并进行相应的动力学实验。结果表明：转为氯型的纤维吸附与再生性能明显优于相应的氢氧型纤维,该纤维在pH 2~3时吸附性能最好,温度越高吸附量越大。吸附过程符合准二级动力学模型（R2〉0.998）,吸附在30 min内基本达到平衡。纤维对六价铬的吸附容量可达376 mg g 1（pH=2,C0=300 mg L 1）,明显高于国外商品化的Fiban A-1离子交换纤维（152.9 mg g 1）;且经100次含铬电镀废水吸附再生循环后,六价铬去除率与纤维质量基本保持不变。

A kind of PAN-based weak alkaline fiber was synthesized and was used as adsorbent for Cr（Ⅳ）. The adsorption capacity and regeneration performance of the prepared counter ion forms （CI- and OH-） of ion exchange materials were investigated. Effects of acidity and temperature on Cr（Ⅳ） adsorption properties of Cl^- form fiber and the corresponding adsorption kinetics were observed. The results show that the static adsorption capacity and regeneration property of Cl^- form fiber are superior to that of the corresponding OH^- form fiber. The maximum adsorption capacity is obtained under pH 2-3 and adsorption capacity increases with the increase of temperature. It was found that the adsorption kinetic model is consistent with the pseudo-second order kinetic model （R2〉 0.998） and the adsorptive equilibrium can be achieved within 30 min. Under the condition ofpH 2 and initial Cr（Ⅳ） concentration of 300 mg.L^-1, the Cr（Ⅳ） adsorption capacity of the fresh ion exchange fiber （376 mg.g^-1） is much higher than that of commercial Fiban A-1 ion exchange fiber （152.9 mg.g^-1）. When it was used as adsorbent to treat the electroplating wastewater containing chromium, after 100 cycles of adsorption and desorption, the refreshed functional fiber still keeps excellent adsorption capacity and high removal ratio for Cr （Ⅳ）.