Aouan Badr, Alehyen Saliha, Fadil Mouhcine, El Alouani Marouane, Saufi Hamid, El Herradi El Hassania, El Makhoukhi Fadoua, Taibi M'hamed
Mohammed V University in Rabat, Centre des Sciences des Matériaux, Laboratoire de Physico-Chimie des Matériaux Inorganiques et Organiques (LPCMIO), Ecole Normale Supérieure (E.N.S), Rabat, Morocco.
Mohammed V University in Rabat, Centre des Sciences des Matériaux, Laboratoire de Physico-Chimie des Matériaux Inorganiques et Organiques (LPCMIO), Ecole Normale Supérieure (E.N.S), Rabat, Morocco.
J Environ Manage. 2023 Jul 15;338:117853. doi: 10.1016/j.jenvman.2023.117853. Epub 2023 Apr 2.
The current paper refers to the study of a new approach to optimizing the adsorptive properties of geopolymers by varying the aluminosilicate precursors from kaolin (K), metakaolin (MK), and coal fly ash (CFA) as internal synthesis factors. The simplex-augmented-centroid mixture design was applied to identify the optimal formulation from the three aluminosilicate precursors to develop a geopolymer (GP) with a distinctive structure that positively affects its dye adsorption efficiency. The variously formulated GP samples were tested for the removal of both methylene blue (MB-dye) and crystal violet dye (CV-dye) from an aqueous solution. The mathematical-statistical analysis of the experimental readings suggested that the generated special cubic models were significant, and thus the chosen approach was adequate for determining the optimum blending proportion. The optimization tools indicated that the optimal mixture from the three aluminosilicate precursors for developing a GP with high adsorption efficiency was 58% MK, 42% K, and 0% CFA. The optimized geopolymer (GP) was synthesized and then analyzed using a variety of physicochemical techniques, which revealed the presence of an amorphous N-A-S-H gel-rich porous structure as an influencing property on the geopolymer's organic dye adsorption efficiency. The dependence of the adsorption mechanism of both MB-dye and CV-dye by GP on the adsorbent dosage, contact time, initial dye concentration, temperature, and solution pH was evaluated. The isothermic and kinetic experimental readings for MB and CV-dyes adsorption by GP were well fitted to the pseudo-second-order and Freundlich models, with an exothermic, favorable, and spontaneous adsorption reaction thermodynamically. The experimental studies in the lab scale on GP produce comparable results. From these results, it has been concluded that the accuracy and feasibility of the mixture design simulation succeeded in optimizing and developing a geopolymeric sorbent material with great potential as an excellent economical agent for removing cationic dyes from aqueous media. This point represents an added value compared to traditional non-optimized geopolymer absorbents. Besides, this geopolymer material represents a significant application possibility for water treatment and remediation of hazardous dye pollutants.
本文涉及一项新方法的研究，即通过改变高岭土（K）、偏高岭土（MK）和粉煤灰（CFA）等硅铝酸盐前驱体作为内部合成因素，来优化地质聚合物的吸附性能。采用单纯形-增强形心混合物设计，从三种硅铝酸盐前驱体中确定最佳配方，以开发一种具有独特结构的地质聚合物（GP），这种结构对其染料吸附效率有积极影响。对不同配方的GP样品进行了从水溶液中去除亚甲基蓝（MB染料）和结晶紫染料（CV染料）的测试。对实验读数的数学统计分析表明，所生成的特殊立方模型具有显著性，因此所选方法足以确定最佳混合比例。优化工具表明，用于开发具有高吸附效率的GP的三种硅铝酸盐前驱体的最佳混合物为58% MK、42% K和0% CFA。合成了优化后的地质聚合物（GP），然后使用各种物理化学技术进行分析，结果表明存在富含无定形N-A-S-H凝胶的多孔结构，这是影响地质聚合物对有机染料吸附效率的一个特性。评估了GP对MB染料和CV染料的吸附机制对吸附剂用量、接触时间、初始染料浓度、温度和溶液pH值的依赖性。GP对MB和CV染料吸附的等温线和动力学实验读数与伪二级模型和Freundlich模型拟合良好，从热力学角度来看，吸附反应是放热、有利且自发的。实验室规模对GP的实验研究产生了可比的结果。从这些结果可以得出结论，混合物设计模拟的准确性和可行性成功地优化和开发了一种具有巨大潜力的地质聚合物吸附剂材料，作为从水性介质中去除阳离子染料的优良经济试剂。与传统的未优化地质聚合物吸附剂相比，这一点代表了一个附加值。此外，这种地质聚合物材料在水处理和有害染料污染物修复方面具有重要的应用可能性。
