Laboratory of Materials Technology, Faculty of Mechanic and Engineering Processes, USTHB, BP 32, El-Alia, Bab-Ezzouar, 16111 Alger, Algeria E-mail:
Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, USTHB, BP 32, El-Alia, Bab-Ezzouar, 16111 Alger, Algeria.
Water Sci Technol. 2021 Jan;83(1):137-151. doi: 10.2166/wst.2020.566.
In this study, the microporous metal organic framework-5 (MOF-5) has been synthesized to be used to remove methyl orange by adsorption. The adsorption experiments exhibit a good adsorption capacity at a catalyst dose of 0.1 g L and for an initial concentration of 200 mg L, whereas the performance is stable over a wide pH range. The equilibrium adsorption data showed a sigmoidal course, which is well fitted by the Dubinin-Astakhov model applicable for physical adsorption processes (E = 0.055 kJ mol) onto heterogeneous surfaces and a more homogeneous pore structure (n = 9.9), with a maximum adsorption capacity of 1248.35 mg g. As can be observed from the evaluation of the kinetic data, the surface of the adsorbent is heterogeneous with different active sites for methyl orange (MO) adsorption. Moreover, based on the rate constant, it can be suggested that there is a specific interaction like electrostatic interaction between MO and the adsorbent for rapid and high uptake of the dye, whereas the adsorption phenomenon is reversible. According to the adsorption mechanisms, intra-particle and film diffusion models simultaneously controlled the rate sorption, which was confirmed by the calculated intra-particle diffusion and the film diffusion coefficients. The evaluation of the thermodynamic parameters revealed that the MO adsorption is spontaneous, endothermic and the randomness increases with the adsorption of MO.
在这项研究中，合成了微孔金属有机骨架-5（MOF-5），用于通过吸附去除甲基橙。吸附实验表明，在催化剂剂量为 0.1 g/L 和初始浓度为 200 mg/L 的情况下，具有良好的吸附能力，而在较宽的 pH 范围内性能稳定。平衡吸附数据显示出类正弦曲线的过程，非常适合用于物理吸附过程的 Dubinin-Astakhov 模型（E = 0.055 kJ/mol），适用于非均相表面和更均匀的孔结构（n = 9.9），最大吸附容量为 1248.35 mg/g。从吸附动力学数据的评估可以看出，吸附剂的表面是不均匀的，有不同的活性位点用于吸附甲基橙（MO）。此外，根据速率常数，可以认为 MO 和吸附剂之间存在特定的相互作用，如静电相互作用，以实现染料的快速和高效吸收，而吸附现象是可逆的。根据吸附机制，内扩散和膜扩散模型同时控制着吸附速率，这通过计算的内扩散和膜扩散系数得到了证实。热力学参数的评估表明，MO 的吸附是自发的、吸热的，并且随着 MO 的吸附，随机度增加。
