Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP 05508-000, Brazil E-mail:
Water Sci Technol. 2017 Apr;2017(1):134-143. doi: 10.2166/wst.2018.097.
A sequential injection - square wave anodic stripping voltammetry (SI-SWASV) method for determination of Se(IV) at a gold working electrode was developed to investigate the adsorption of Se(IV) onto vermiculite intercalated with Fe(III) polyhydroxy cations. The limits of detection and quantification were 0.060 and 0.20 μmol L, respectively (4.7 and 15.7 μg L). The linearity was up to 1.0 μmol L, and the sampling throughput was 18 analyses h. The proposed approach is a low-cost alternative to more expensive spectrometric methods. Adsorption onto vermiculite intercalated with Fe(III) polyhydroxy cations removed 93% of Se(IV) from a 1.0 μmol L solution (250 mL) after 5 min of contact time with 625 mg of adsorbent. Adsorption isotherms (25.0 ± 0.5 °C) were fitted by the Freundlich equation resulting in 1/n = 0.51 ± 0.03 and K = (1.584 ± 0.002) × 10 μmol g L (r = 0.995). Fitting by the Langmuir equation resulted in an adsorption constant of 0.026 ± 0.008 L g and adsorption capacity of 47 ± 5 μmol g (3.7 ± 0.4 mg g) (r = 0.97). This capacity was higher than that found for several other iron oxides, but lower than that obtained for oxide/hydroxide-based Fe(III) nanoparticles.
一种基于顺序注射-方波阳极溶出伏安法（SI-SWASV）的方法，用于在金工作电极上测定硒（IV），以研究 Fe(III)多羟基阳离子插层蛭石对硒（IV）的吸附。检测限和定量限分别为 0.060 和 0.20 μmol L，（4.7 和 15.7 μg L）。线性度高达 1.0 μmol L，采样通量为 18 次分析 h。与更昂贵的光谱方法相比，该方法是一种低成本的替代方法。将 Fe(III)多羟基阳离子插层蛭石吸附到溶液中，可在 5 分钟的接触时间内从 1.0 μmol L（250 mL）溶液中去除 93%的硒（IV），用量为 625 mg 吸附剂。吸附等温线（25.0 ± 0.5 °C）符合 Freundlich 方程，得到 1/n = 0.51 ± 0.03 和 K = (1.584 ± 0.002) × 10 μmol g L（r = 0.995）。用 Langmuir 方程拟合得到吸附常数为 0.026 ± 0.008 L g，吸附容量为 47 ± 5 μmol g（3.7 ± 0.4 mg g）（r = 0.97）。这个容量高于几种其他的铁氧化物，但低于氧化物/氢氧化物基 Fe(III)纳米粒子。
