Bahaidarah Effat A
Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
Int J Anal Chem. 2024 Aug 6;2024:3152894. doi: 10.1155/2024/3152894. eCollection 2024.
In the modern era, sol-gel plays a key role in the progress of a new generation of dispersive solid-phase microextractors (d- SPMEs) for the removal of organic and inorganic pollutants in complex matrices. Thus, the current study reports the use of sol-gel-functionalized polyurethane foams (PUFs) as a novel solid platform for complete extraction of chromium (VI) species from aqueous media. The planned protocol was based upon the complete extraction of the formed binary complex ion associates between the protonated ether and/or urethane groups of PUFs and chlorochromate anion [CrOCl] in aqueous HCl (≥1M) medium in addition to H-bonding and the electrostatic - interaction that resulted between the CrOCl and the silanol group (Si/ZrO, Si-O-Zr) and siloxane (Si-O-Si) groups of the sol-gel. The impact of the analytical parameters (solution pH, natural mineral acids, shaking time, temperature, and chromium (VI) concentrations) was critically studied. At the optimal conditions, the uptake capacity of the established extractor (9.9 mg·g) was in agreement with the Langmuir adsorption capacity (12.08 mg·g) of the monolayer. The sorption data fitted well with the pseudo first-order kinetic model ( = 0.9961) with an overall rate constant ( ) of 0.081 min and an equilibrium capacity ( ) of 8.6 mg·g, which is in a good agreement with the experimental value (9.9 mg·g). The sorption of the oxyion [CrOCl] onto the solid sorbent is an endothermic and spontaneous process as reflected from the values of ΔH (6.99 kJ·mol) and Δ (-8.14 kJ·mol at 293 K), respectively. The Δ value (15.13 kJ·mol·K) reflects that the [CrOCl] retention onto the sol-gel-treated PUFs sorbent proceeded in a more unplanned fashion. Sol-gel-treated PUFs sorbent-packed minicolumns were successfully used for the complete removal of trace levels of chromium (VI) species from water samples. Sorbed chromium (VI) species were recovered with NaOH (0.5 M) and analysed by spectrophotometry, which supports the utility of the sol-gel-treated PUFs as a low-cost solid extractor for water treatment.
在现代，溶胶 - 凝胶在新一代分散固相微萃取器（d - SPMEs）用于去除复杂基质中的有机和无机污染物的发展过程中发挥着关键作用。因此，本研究报告了使用溶胶 - 凝胶功能化聚氨酯泡沫（PUFs）作为一种新型固体平台，用于从水介质中完全萃取六价铬（Cr(VI)）物种。所规划的方案基于在HCl（≥1M）水介质中，PUFs的质子化醚基和/或氨基甲酸酯基与氯铬酸根阴离子[CrOCl]形成的二元络合离子缔合物的完全萃取，此外还有氢键以及溶胶 - 凝胶的硅醇基（Si/ZrO，Si - O - Zr）和硅氧烷基（Si - O - Si）之间产生的静电相互作用。对分析参数（溶液pH值、天然无机酸、振荡时间、温度和六价铬浓度）的影响进行了严格研究。在最佳条件下，所建立的萃取器的吸附容量（9.9 mg·g）与单层的朗缪尔吸附容量（12.08 mg·g）一致。吸附数据与伪一级动力学模型拟合良好（= 0.9961），总速率常数（）为0.081 min，平衡容量（）为8.6 mg·g，这与实验值（9.9 mg·g）吻合良好。从ΔH（6.99 kJ·mol）和Δ（293 K时为 - 8.14 kJ·mol）的值分别反映出，氧离子[CrOCl]在固体吸附剂上的吸附是一个吸热且自发的过程。Δ值（15.13 kJ·mol·K）表明[CrOCl]在溶胶 - 凝胶处理的PUFs吸附剂上的保留过程较为无序。溶胶 - 凝胶处理的PUFs吸附剂填充的微型柱成功用于从水样中完全去除痕量的六价铬物种。吸附的六价铬物种用NaOH（0.5 M）回收并用分光光度法分析，这支持了溶胶 - 凝胶处理的PUFs作为一种低成本的水处理固体萃取器的实用性。
