Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266000, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266000, China.
Water Res. 2022 Aug 1;221:118826. doi: 10.1016/j.watres.2022.118826. Epub 2022 Jul 6.
In view of the insufficient coagulation efficiency of traditional inorganic coagulants, a series of Al-Ti gels with different Ti/triethanolamine (TEA), Ti/HO, and Ti/Al molar ratios were prepared by sol-gel process in this study. Fourier transform infrared (FTIR) spectra of the Al-Ti gels preliminarily confirmed the interaction between Al and Ti by detecting the appearance of the Al-O-Ti bond. The peak shift of the chemical bonds in X-ray photoelectron spectra (XPS) and the transformation of the hydrolysate species in the Al-Ti gels were analyzed to further explore the interaction mechanism between Al and Ti. It was found that moderate TEA could inhibit the hydrolysis of Ti precursors by taking up the coordination sites of HO to form a CO-Ti bond. Density functional theory (DFT) calculation results showed that Ti could be incorporated into the framework of aluminum hydrolysates to form an Al-O-Ti bond, and [AlTi(OH)(TEA)(HO)] was the most possible copolymerization hydrolysate. Based on the above research results, the most efficient Al-Ti gel was selected and applied to the actual lake water treatment. The highest UV removal efficiency with the addition of Al-Ti gel was > 60%, nearly 25% higher than that of Ti gel. The hydrolysates of Al-Ti gel, such as TiO(OH), Al(OH), and [AlTi(OH)(TEA)(HO)], could remove organic matters through the incorporation of charge neutralization, adsorption, complexation, and sweeping effects. These results provide a new idea for studying the interaction mechanism between Al and Ti in composite coagulants, and have theoretical guiding significance to actual water treatment.
鉴于传统无机混凝剂的混凝效率不足，本研究通过溶胶-凝胶法制备了一系列不同 Ti/三乙醇胺（TEA）、Ti/HO 和 Ti/Al 摩尔比的 Al-Ti 凝胶。Al-Ti 凝胶的傅里叶变换红外（FTIR）谱初步证实了 Al 和 Ti 之间的相互作用，通过检测 Al-O-Ti 键的出现来检测。X 射线光电子能谱（XPS）中化学键的峰位移和 Al-Ti 凝胶中水解产物的转化进一步探讨了 Al 和 Ti 之间的相互作用机制。结果表明，适量的 TEA 可以通过占据 HO 的配位位来抑制 Ti 前体的水解，形成 CO-Ti 键。密度泛函理论（DFT）计算结果表明，Ti 可以掺入铝水解物的骨架中形成 Al-O-Ti 键，[AlTi(OH)(TEA)(HO)]是最有可能的共聚水解产物。基于上述研究结果，选择了最有效的 Al-Ti 凝胶并应用于实际湖水处理。添加 Al-Ti 凝胶的 UV 去除效率最高可达>60%，比 Ti 凝胶高近 25%。Al-Ti 凝胶的水解产物，如 TiO(OH)、Al(OH)和[AlTi(OH)(TEA)(HO)]，可以通过电荷中和、吸附、络合和扫掠作用去除有机物。这些结果为研究复合混凝剂中 Al 和 Ti 的相互作用机制提供了新的思路，对实际水处理具有理论指导意义。
