Ahmad Izhar, Rahman Nafisur
Department of Chemistry Aligarh Muslim University, Aligarh 202002, India.
Langmuir. 2024 Dec 24;40(51):26956-26974. doi: 10.1021/acs.langmuir.4c03402. Epub 2024 Dec 13.
In this work, a novel pristine coordination polymer gel composed of zirconium and 2-amino-5-mercapto-1,3,4-thiadiazole is unveiled and explored to remove Cr(VI) from aqueous systems. A Box-Behnken design, coupled with a genetic algorithm and desirability function, was used for optimizing the controllable factors for maximum removal efficiency. Under optimized conditions (A = 50 mg L, B = 40 mg, C = 90 min, and D = 4), 99% of Cr(VI) was removed, and the saturation adsorption capacity recorded was 132.37 mg g. The adsorption data were investigated through statistical physics modeling. The most suited statistical physics model (monolayer with three energies; = 0.994-0.997, χ = 0.008-0.024), combined with site energy distribution analysis, XPS, and FTIR, unraveled the uptake mechanism. At the first and third active sites, Cr(VI) uptake was multimolecular ( > 1), while at the second active site, it was a mixed multimolecular (298 K, > 1) and multidocking (308 and 318 K, < 1). The adsorption energy values indicated the involvement of coordination exchange ( = 53.40-58.47 kJ mol), electrostatic interaction ( = 29.56-32.29 kJ mol), and hydrogen bonding ( = 24.68-28.35 kJ mol) in Cr(VI) adsorption. The BSf(1.5, α) model fitted best ( = 0.976-0.994, χ = 0.023-0.377) to the kinetic data under all conditions. Common coexisting ions had no significant impact on removal efficiency (% > 97% at 1:3), and the sorbent could be reutilized up to 5 uptake-elution cycles (>96% efficiency). The practical utility of ZrAMTD was investigated by remediating Cr(VI) contaminated real water samples (% ≥ 92.91%).
在这项工作中，一种由锆和2-氨基-5-巯基-1,3,4-噻二唑组成的新型原始配位聚合物凝胶被揭示并用于从水体系中去除Cr(VI)。采用Box-Behnken设计，结合遗传算法和期望函数，对可控因素进行优化以实现最大去除效率。在优化条件下（A = 50 mg L，B = 40 mg，C = 90 min，D = 4），99%的Cr(VI)被去除，记录的饱和吸附容量为132.37 mg g。通过统计物理建模对吸附数据进行了研究。最适合的统计物理模型（具有三种能量的单层； = 0.994 - 0.997，χ = 0.008 - 0.024），结合位点能量分布分析、XPS和FTIR，揭示了吸附机制。在第一和第三个活性位点，Cr(VI)的吸附是多分子的（ > 1），而在第二个活性位点，它是混合多分子的（298 K， > 1）和多对接的（308和318 K， < 1）。吸附能值表明在Cr(VI)吸附过程中涉及配位交换（ = 53.40 - 58.47 kJ mol）、静电相互作用（ = 29.56 - 32.29 kJ mol）和氢键（ = 24.68 - 28.35 kJ mol）。BSf(1.5, α)模型在所有条件下对动力学数据拟合最佳（ = 0.976 - 0.994，χ = 0.023 - 0.377）。常见共存离子对去除效率没有显著影响（在1:3时% > 97%），并且吸附剂可以重复使用多达5个吸附 - 洗脱循环（效率>96%）。通过修复受Cr(VI)污染的实际水样（%≥92.91%）研究了ZrAMTD的实际应用。
