纳米二氧化铈分离富集-分光光度法测定环境水样中铬(Ⅵ)量

Spectrophotometric Determination of Chromium(Ⅵ) in Environmental Water Samples after Separation and Enrichment by Adsorption on CeO_2 Nanoparticles

提出了纳米二氧化铈吸附富集痕量铬,2mol.L-1氢氧化钠溶液作洗脱剂洗脱,用二苯卡巴肼分光光度法测定环境水样中铬(Ⅵ)含量的方法。在pH 4.0的介质中、吸附时间为40min、吸附剂用量为20mg时,纳米二氧化铈对铬(Ⅵ)的吸附容量为696μg.g-1。铬(Ⅵ)与二苯卡巴肼络合物的最大吸收波长为540nm,其质量浓度在0.012～1.2mg.L-1之间呈线性,检出限(3σ)为0.01mg.L-1。方法用于环境水样中铬的测定,加标回收率为99.4%。

Trace amounts of Cr（Ⅵ） was adsorbed and enriched on the surface of CeO2 nanoparticles, and desorbed by eluting with 2 mol·L-1 NaOH solution. The solution obtained was used for spectrophotometric determination of Cr（Ⅵ） with diphenylcarbazide as color reagent. In a medium of pH 4. 0, with the adsorption time of 40 min and amount of adsorbent of 20 mg, the adsorption capacity of CeO2 nanoparticles toward Cr （Ⅵ） was found to be 696μg·g-1. Measurement of absorbance was made at the absorption maximum of 540 nm. Linearity range of Cr（Ⅵ） was kept between 0. 012 to 1. 2 mg·L-1, with detection limit （3σ） of 0. 01 mg·L-1. The proposed method was used in the determination of Cr（Ⅵ） in environmental water samples, and values of recovery found by standard addition method was 99.4%.