Effect of SO42- on coagulation performance using different coagulants in nano-TiO2 recovery process [Nano-TiO2回收过程中SO42-对不同混凝剂混凝过程的影响]

作者：Liu Y.; Li H.-L.; Xu H.^*; Li M.-S.; Xiang Y.; Lyu P.; Wang Y.-B.

来源：China Environmental Science, 2021, 41(12): 5627-5636.

• Aluminum speciation
• Coagulation
• Floc
• Nano-TiO2
• SO42-

In order to reduce the practical cost of nano-TiO2, the TiO2 was isolated via solid-liquid process by applying different coagulants. By investigating the turbidity removal rate, effluent pH value, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), solid state nuclear magnetism (NMR), scanning electron microscopy (SEM), and energy spectrum analysis (EDS), the effects of SO42- on the coagulation efficiency during nano-TiO2 recycling process was studied. The results showed that the turbidity removal rate decreased by 0.80%, and the floc size decreased from 450μm to 215μm when the concentration of SO42- increased from 0.0mmol/L to 20.0mmol/L under AlCl3 (0.1mmol/L), while the strength factor of flocs did not change significantly. The low polymerization species Ala could not react with SO42-, and generated large amount of amorphous Al(OH)3 via adsorption bridging and flocculation sweeping effects during coagulation process. When Al13 was used as coagulant, the size of re-growth flocs decreased with the increasing of SO42- concentration. The occurrence of red shift for S-O peak indicated that the new S-containing polymers were produced. The movement of Al 2p peak toward higher binding energy revealed that no Al(OH)3 was generated in the flocs.

• 单位
  中国科学院大学