本文制备了聚乙烯醇一海藻酸钠一钙一铁(PVA—SA—Ca—Fe)凝胶球,研究了该凝胶球对V(V)的吸附性能和解吸条件。采用石墨炉原子吸收光谱法测定V(V)含量,利用吸附等温线讨论了凝胶球对V(V)的吸附机理。结果表明,在pH-4.5溶液中,凝胶球用量为10mL,吸附时间为60min,吸附温度为30℃,V(V)的吸附率可达99.6%,饱和吸附容量为369.4μg/g。以2mol/L HC1作为洗脱剂室温下洗脱30min,解吸率可达98.8%。PVA—SA—Ca—Fe凝胶球对V(V)的吸附符合Freundlich吸附等温方程,属于不均匀的多分子层吸附模式。V(V)的质量浓度在0~300μg/L之间与其吸收值呈良好的线性关系,方法的检出限为0.26“g/L。将拟定的方法用于水样中微量V(V)的分离富集和测定,结果的相对标准偏差为0.7%~1.6%,加标回收率为94.0%~105.4%。
The polyving akohol(PVA)-sodium alginate(SA)-calcium-iron gel ball was prepared, and the adsorption properties and desorption of vanadium (V) on the gel ball was investigated by graphite furnace atomic absorption spectrometry. The adsorption mechanism of the gel ball was also discussed by using the adsorption isotherm. The results showed that the best adsorption rate reached 99.6% and the saturation adsorption capacity reaches 369.4 ~g/g,with 10 mL gel ball dosage at 30 ~C and pH 4. With 2 mol/L HC1 as an eluant, the desorption rate was up to 98. 8% after 30 min at room temperature. Adsorption of V by the PVA-SA-Ca-Fe gel ball correspond with the Freundlich adsorption isothermal equation at the room temperature, indicating a multi-molecular layer inhomogeneous adsorption model. The linear range was 0-300 μg/L with detection limit of 0.26 μg/L for V(V ). The method has been applied successfully to the determination of trace V( V ) in water samples with the recoveries of 94.0%- 105.4%, and the relative standard deviation was 0.7%-1.6%.