Department of Chemical Engineering, Ordos Institute of Technology , Ordos 017000, China.
Department of Chemical Engineering, Redbud Innovation Institute of Ordos , Ordos 017000, China.
ACS Appl Mater Interfaces. 2017 Feb 22;9(7):5992-5999. doi: 10.1021/acsami.6b14273. Epub 2017 Feb 8.
Single-molecule aluminum salt AlCl, medium polymerized polyaluminum chloride (PAC), and high polymerized polyaluminum chloride (HPAC) were prepared in a laboratory. The characteristics and coagulation properties of these prepared aluminum salts were investigated. The Langmuir, Freundlich, and Sips adsorption isotherms were first used to describe the adsorption neutralization process in coagulation, and the Boltzmann equation was used to fit the reaction kinetics of floc growth in flocculation. It was novel to find that the experimental data fitted well with the Sips and Boltzmann equation, and the significance of parameters in the equations was discussed simultaneously. Through the Sips equation, the adsorption neutralization reaction was proved to be spontaneous and the adsorption neutralization capacity was HPAC > PAC > AlCl. Sips equation also indicated that the zeta potential of water samples would reach a limit with the increase of coagulant dosage, and the equilibrium zeta potential values were 30.25, 30.23, and 27.25 mV for AlCl, PAC, and HPAC, respectively. The lower equilibrium zeta potential value of HPAC might be the reason why the water sample was not easy to achieve restabilization at a high coagulant dosage. Through the Boltzmann equation modeling, the maximum average floc size formed by AlCl, PAC, and HPAC were 196.0, 188.0, and 203.6 μm, respectively, and the halfway time of reactions were 31.23, 17.08, and 9.55 min, respectively. The HPAC showed the strongest floc formation ability and the fastest floc growth rate in the flocculation process, which might be caused by the stronger adsorption and bridging functions of Al and Al contained in HPAC.
实验室制备了单分子铝盐 AlCl、中聚合聚合氯化铝 (PAC) 和高聚合聚合氯化铝 (HPAC)。研究了这些制备的铝盐的特性和混凝性能。首次采用 Langmuir、Freundlich 和 Sips 吸附等温线描述混凝中的吸附中和过程，采用 Boltzmann 方程拟合絮凝过程中絮体生长的反应动力学。发现实验数据很好地符合 Sips 和 Boltzmann 方程是新颖的，同时讨论了方程中参数的意义。通过 Sips 方程，证明了吸附中和反应是自发的，并且吸附中和容量为 HPAC > PAC > AlCl。Sips 方程还表明，随着混凝剂用量的增加，水样的 ζ 电位会达到一个极限，对于 AlCl、PAC 和 HPAC，平衡 ζ 电位值分别为 30.25、30.23 和 27.25 mV。HPAC 的平衡 ζ 电位值较低，可能是水样在高混凝剂用量下不易重新稳定的原因。通过 Boltzmann 方程建模，AlCl、PAC 和 HPAC 形成的最大平均絮体尺寸分别为 196.0、188.0 和 203.6 μm，反应的半衰期分别为 31.23、17.08 和 9.55 min。HPAC 在絮凝过程中表现出最强的絮体形成能力和最快的絮体生长速率，这可能是由于 HPAC 中 Al 和 Al 的吸附和桥联作用更强。
