Juzsakova Tatjana, Salman Ali Dawood, Abdullah Thamer Adnan, Rasheed Rashed Taleb, Zsirka Balázs, Al-Shaikhly Rasha R, Sluser Brindusa, Cretescu Igor
Sustainability Solutions Research Lab, Research Centre for Biochemical, Environmental and Chemical Engineering, Faculty of Engineering, University of Pannonia, P.O. Box 158, H-8201 Veszprem, Hungary.
Department of Chemical and Petroleum Refining Engineering, College of Oil and Gas Engineering, Basra University for Oil and Gas, Basra 61004, Iraq.
Materials (Basel). 2023 Feb 15;16(4):1618. doi: 10.3390/ma16041618.
The purpose of this work was to develop, characterize and test new low-cost materials suitable for removing methylene blue dye from water and wastewater by adsorption. The solid materials consisted of silica gel powder (SG), silica gel mixed with eggshell powder (SG-ES) and a mixture of silica gel with sand from the western Iraqi desert (SG-SI). The samples were milled by using an electrical mixer and a ball mill, followed by a drying step. In addition, desert sand was acid-treated in order to remove impurities. The structure and chemical composition of the samples were investigated by X-ray diffraction (XRD), a scanning electron microscopy technique equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), a low-temperature nitrogen adsorption (BET) technique, thermo-analytical (TG/TGA) measurements and Fourier-transformed infrared spectroscopy (FTIR). The previously mentioned materials were tested to remove methylene blue from an aqueous solution. The adsorption experiments were monitored by ultraviolet-visible (UV-Vis) spectrophotometry and showed that SG and SG-ES gave promising results for the methylene blue removal from water. After 40 min of treatment of the aqueous solution containing 10 mg/L of MB at room temperature, the tested SG, SG-ES and SG-SI materials were found to have 86%, 80% and 57% dye adsorption efficiency, respectively. Taking into consideration not only the adsorption activity of the studied material but their availability, cost and concepts of cleaner production and waste minimization, the developed silica gel with eggshell can be considered as a good, cost-effective alternative to commercially available activated-carbon-based adsorbents. Different kinetic and isotherm models were fitted to the experimental results. A pseudo-second-kinetics-order model revealed high correlation fitting, while the Freundlich model was found to appropriately describe the adsorption isotherm. The thermal stability during the possible regeneration process of the SG-ES adsorbent mixture and its interaction mechanism with cationic dye was discussed.
这项工作的目的是开发、表征和测试适用于通过吸附从水和废水中去除亚甲基蓝染料的新型低成本材料。固体材料包括硅胶粉末（SG）、与蛋壳粉末混合的硅胶（SG-ES）以及与伊拉克西部沙漠沙子混合的硅胶（SG-SI）。样品使用电动搅拌器和球磨机研磨，随后进行干燥步骤。此外，对沙漠沙子进行了酸处理以去除杂质。通过X射线衍射（XRD）、配备能量色散X射线光谱仪的扫描电子显微镜技术（SEM-EDX）、低温氮吸附（BET）技术、热分析（TG/TGA）测量和傅里叶变换红外光谱（FTIR）对样品的结构和化学成分进行了研究。对上述材料进行了从水溶液中去除亚甲基蓝的测试。吸附实验通过紫外可见（UV-Vis）分光光度法进行监测，结果表明SG和SG-ES在从水中去除亚甲基蓝方面取得了有前景的结果。在室温下对含有10 mg/L亚甲基蓝的水溶液处理40分钟后，测试的SG、SG-ES和SG-SI材料的染料吸附效率分别为86%、80%和57%。不仅考虑所研究材料的吸附活性，还考虑其可用性、成本以及清洁生产和废物最小化的概念，所开发的含蛋壳硅胶可被视为市售活性炭基吸附剂的一种良好、具有成本效益的替代品。将不同的动力学和等温线模型拟合到实验结果中。准二级动力学模型显示出高度的相关性拟合，而弗伦德利希模型被发现能恰当地描述吸附等温线。讨论了SG-ES吸附剂混合物在可能的再生过程中的热稳定性及其与阳离子染料的相互作用机制。
