Adsorption investigation of polyacrylic acid on sub-micron titanium dioxide surface and associated effects on flocculation

• Published in: Journal of polymer research Vol. 31; no. 8
• Main Authors: Sun, Xianfeng, Zheng, Shenke, Cai, Zhonghao, Wang, Dong, Zhou, Boxin, Chen, Chubin, Wang, Daowei
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2024; Springer Nature B.V
• Subjects: Adsorption; Characterization and Evaluation of Materials; Chelation; Chemical bonds; Chemistry; Chemistry and Materials Science; Electron microscopes; Fourier transforms; Industrial Chemistry/Chemical Engineering; Infrared analysis; Infrared photometry; Infrared reflection; Isotherms; Molecular structure; Original Paper; Photoelectrons; Polyacrylic acid; Polymer Sciences; Quartz crystals; Real time; Thickness; Titanium; Titanium dioxide; X ray photoelectron spectroscopy; X ray reflection; Sub-micron titanium dioxide; Adsorption conformation; Flocculation; Polyacrylic acid
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-024-04058-5

This work investigated the flocculation of sub-micron titanium dioxide (TiO 2 ) by polyacrylic acids (PAAs), with a focus on studying the correlation between the PAAs adsorption conformation and the flocculation efficiency/floc property. The adsorption analysis of PAAs on the TiO 2 surface was studied by attenuated total reflection Fourier transform infrared, Raman, X-ray photoelectron spectroscopy, CHNS elemental analyzer coupled with quartz crystal microbalance with dissipation monitoring. Adsorption densities were fitted using Langmuir and Freundlich isotherm models. The flocculation process of TiO 2 by PAAs of different molecular weights (MWs) was monitored in real-time by a photometric dispersion analyser, and the floc structure was studied by scanning electron microscope. The results showed that the adsorption of PAAs followed the Langmuir isotherm, and formed monolayer adsorption on the TiO 2 surface regardless of MWs through hydrogen and bidentate chelating chemical bonds. The thickness of adsorption layer increased with increasing MW, which could promote floc size by providing molecular "bridges"; but impeded the flocculation rate. For sub-micron particles, polyacrylic acid with a medium MW (512 kDa) was the optimum polymer owing to obtaining the fastest flocculation rate and relatively dense flocs in this work. PAA with high MW resulted in larger flocs with greater porosity, whereas the low MW PAA can only generate smaller flocs with a slower flocculation rate.