Akl Magda A, Fahim Azza A H, El-Gharkawy El-Sayed R H
Department of Chemistry, Faculty of Science, Mansoura University, Mansoura, 31556, Egypt.
Sci Rep. 2025 Aug 13;15(1):29751. doi: 10.1038/s41598-025-14609-5.
In this study, 2,4-dihydroxybenzaldehyde hydrazone (CELL@HBH) adsorbent was prepared from microcrystalline cellulose powder (CELL) through a simple and effective method. The investigated materials were characterized by Fourier Transform Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), elemental analysis, Proton Nuclear Magnetic Resonance (HNMR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area measurements. The prepared (CELL@HBH) adsorbent was applied to remove anionic food colorants carmoisine (E122), ponceau 4R (E124), and Cr(VI) from polluted water samples. The effects of pH, initial concentration, contact time, dosage, temperature, and competing ions have been investigated to maximize the adsorption capacities to reach 476.709 mg/g, 338.789 mg/g, and 190.072 mg/g for E122, E124, and Cr(VI) ions, respectively, at the optimum conditions. The results showed that the adsorption of E122, E124, and Cr(VI) follows pseudo-2nd-order kinetic and Langmuir isotherm models due to the more subordinate error functions and increased correlation coefficient (R ≥ 0.999). Thermodynamic studies indicate the adsorption of E122 and E124, as well as Cr(VI) ions, by CELL@HBH adsorbent to be exothermic and spontaneous. DFT calculations were employed to verify the molecular structure, analysis of Frontier Molecular Orbitals (FMOs), molecular electrostatic potential (MEP), and geometry reactivity descriptors (GRDs) for all phases. The prepared adsorbent effectively removed E122, E124, and Cr(VI) from polluted water samples, synthetic mixtures, and colored soft drinks, with a recovery rate of ~ 97%. The CELL@HBH adsorbent has good recycling performance. Under five regeneration and adsorption cycles, it still has removal effect greater than 85% of E122, E124, and Cr(VI), which indicates its high structural stability. The adsorption mechanism of E122, E124, and Cr(VI) onto CELL@HBH adsorbent is elucidated. Ultimately, this study demonstrates that the fast-responsive CELL@HBH adsorbent can be effectively utilized to eliminate E122, E124, and Cr(VI) from a wide range of real water sources. Collectively, the results indicate that the as-prepared CELL@HBH adsorbent is promising for anionic pollutant adsorption and our mechanistic results are of guiding significance in environmental cleanup. This work contributes significantly to understanding how experimental conditions influence the mechanism of E122, E124, and Cr(VI) adsorption by CELL@HBH adsorbent, offering valuable and new insights for future applications and optimizations in the treatment of effluent-containing anionic species.
在本研究中，通过一种简单有效的方法，由微晶纤维素粉末（CELL）制备了2,4 - 二羟基苯甲醛腙（CELL@HBH）吸附剂。采用傅里叶变换红外光谱（FT - IR）、扫描电子显微镜（SEM）、元素分析、质子核磁共振（HNMR）、热重分析（TGA）、X射线衍射（XRD）以及布鲁诺尔 - 埃米特 - 特勒（BET）表面积测量等手段对所研究的材料进行了表征。将制备的（CELL@HBH）吸附剂应用于去除污染水样中的阴离子食用色素胭脂红（E122）、丽春红4R（E124）和Cr(VI)。研究了pH值、初始浓度、接触时间、剂量、温度和竞争离子等因素的影响，以在最佳条件下使对E122、E124和Cr(VI)离子的吸附容量分别达到476.709 mg/g、338.789 mg/g和190.072 mg/g。结果表明，由于误差函数较小且相关系数增加（R≥0.999），E122、E124和Cr(VI)的吸附遵循准二级动力学和朗缪尔等温线模型。热力学研究表明，CELL@HBH吸附剂对E122和E124以及Cr(VI)离子的吸附是放热且自发的。采用密度泛函理论（DFT）计算来验证所有相态的分子结构、前线分子轨道（FMOs）分析、分子静电势（MEP）和几何反应性描述符（GRDs）。制备的吸附剂能有效去除污染水样、合成混合物和有色软饮料中的E122、E124和Cr(VI)，回收率约为97%。CELL@HBH吸附剂具有良好的循环性能。在五个再生和吸附循环下，其对E122、E124和Cr(VI)的去除效果仍大于85%，这表明其具有较高的结构稳定性。阐明了E122、E124和Cr(VI)在CELL@HBH吸附剂上的吸附机理。最终，本研究表明快速响应的CELL@HBH吸附剂可有效用于从各种实际水源中去除E122、E124和Cr(VI)。总体而言，结果表明所制备的CELL@HBH吸附剂对于阴离子污染物吸附具有前景，我们的机理研究结果对环境净化具有指导意义。这项工作对于理解实验条件如何影响CELL@HBH吸附剂对E122、E124和Cr(VI)的吸附机理有显著贡献，为未来含阴离子物种废水处理的应用和优化提供了有价值的新见解。
