Malaysian Journal of Analytical Sciences Vol 21 No 2 (2017): 372 - 380

DOI: https://doi.org/10.17576/mjas-2017-2102-12

 

 

 

Surface modification of PSF/TiO₂ membranes using silane coupling agents and DC plasma technique

 

(Modifikasi Permukaan Membran PSF/TiO₂ Menggunakan Ejen Gandingan Silana dan Teknik Plasma DC)

 

Soraya Ruangdit¹, Thawat Chittrakarn¹*, Sudkhet Anuchit¹, Yutthana Tirawanichakul¹, Chalad Yuenyao²

 

¹Membrane Science and Technology Research Center, Department of Physics, Faculty of Science,

Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand

²Department of Physics, Faculty of Science and Technology,

Phetchabun Rajabhat University, 83 M.11 St.Saraburi-Lom Sak, Muang, Phetchabun 67000, Thailand

 

*Corresponding author: tawat.c@psu.ac.th

 

 

Received: 26 August 2016; Accepted: 8 January 2017

 

 

Abstract

Preparation and surface modification of PSF/TiO₂ membranes by DC Ar-plasma were conducted to improve membrane hydrophilicity and gas permeation efficiency. Using TiO₂ as a photocatalyst, photocatalysis could be induced upon the plasma exposure. Radicals from this process led to an increase in the membrane hydrophilicity. In order to improve the dispersion quality of TiO₂ in an organic membrane, methyltrimethoxysilane (TMMS) or ethyltrimethoxysilane (TEMS) was utilized as coupling agents to modify the TiO₂ surface prior to blending. The coupling agents caused organic silane bonds on the TiO₂ surface leading to a better dispersion of nanoparticle on the membrane matrix. The incorporation of modified-TiO₂ tended to decrease membrane water contact angles (WCA) to the lowest value when compared with PSF membranes with unmodified TiO₂ and neat PSF membranes. Results also showed that TMMS could produce better outcomes compared to TEMS. It was found that the modified-TiO₂ could decrease the WCA. More importantly, pressure normalized flux of CO₂ and CH₄ gases of PSF/modified-TiO₂ membrane was found to increase with slightly decrease in the selectivity of CO₂/CH₄.

 

Keywords:    silane coupling agent, surface modification, gas separation membrane, low pressure DC-plasma, polysulfone

 

Abstrak

Penyediaan dan modifikasi permukaan membran PSF/TiO₂ oleh DC Ar-plasma telah dijalankan untuk meningkatkan kehidrofilikan membran dan kecekapan penyerapan gas. Menggunakan TiO₂ sebagai foto-pemangkin, fotopemangkinan dapat didorong apabila terdedah kepada plasma. Radikal daripada proses ini membawa kepada peningkatan dalam kehidrofilikan membran. Untuk meningkatkan kualiti penyebaran TiO₂ dalam membran organik, metiltrimetoksisilana (TMMS) atau etiltrimetoksisilana (TEMS) telah digunakan sebagai agen gandingan untuk mengubah suai permukaan TiO₂ sebelum campuran. Ejen-ejen gandingan menyebabkan ikatan silana organik di permukaan TiO₂ yang membawa kepada penyebaran nanopartikel yang lebih baik pada matriks membran. Penggabungan TiO₂ yang diubahsuai cenderung untuk mengurangkan sudut sentuhan air membran (WCA) kepada nilai yang paling rendah berbanding membran PSF dengan TiO₂ yang tidak diubahsuai dan membran PSF kawalan. Keputusan juga menunjukkan bahawa TMMS boleh menghasilkan hasil yang lebih baik berbanding PPSMI. Ia telah mendapati bahawa TiO₂ yang diubahsuai boleh mengurangkan WCA. Lebih penting lagi, tekanan fluks normal gas CO₂ dan CH₄ daripada membran PSF/TiO₂ yang diubahsuai didapati meningkat dengan sedikit penurunan kepilihan CO₂/CH₄.

 

Kata kunci:    ejen gandingan silana, modifikasi permukaan, membran pemisahan gas, tekanan rendah dc-plasma, polisulfon

 

References

1.       Yuenyao, C., Tirawanichakul, Y. and Chittrakarn, T. (2015). Asymmetric polysulfone gas separation membranes treated by low pressure DC glow discharge plasmas. Journal of Applied Polymer Science, 132(24): 42116 – 42126.

2.       Zhang, Y. and Liu, P. (2015). Polysulfone (PSF) composite membrane with micro-reaction locations (MRLs) made by doping sulfated TiO₂ deposited on SiO₂ nanotubes (STSNs) for cleaning waste water. Journal of Membrane Science, 493: 275 – 284.

3.       Xueli, G., Haizeng, W., Jian, W., Xing, H. and Congjie, G. (2013). Surface-modified PSF UF membrane by UV-assisted graft polymerization of capsaicin derivative moiety for fouling and bacterial resistance. Journal of Membrane Science, 445: 146 – 155.

4.       Yang, Y., Zhang, H., Wang, P., Zheng, Q. and Li, J. (2007). The influence of nano-sized TiO₂ fillers on the morphologies and properties of PSF UF membrane. Journal of Membrane Science, 288: 231 – 238.

5.       Konruang, S., Sirijarukul, S., Wanichapichart, P., Yu, L. and Chittrakarn, T. (2015). Ultraviolet-ray treatment of polysulfone membranes on the O₂/N₂ and CO₂/CH₄ separation performance.  Journal of Applied Polymer Science, 132(25): 42074 – 42082.

6.       Bae, Y.-S. and Lee, C.-H. (2005). Sorption kinetics of eight gases on a carbon molecular sieve at elevated pressure. Journal of Carbon, 43: 95 – 107.

7.       Huang, S.-Y., Ganesan, P. and Popov, B. N. (2010). Electrocatalytic activity and stability of niobium-doped titanium oxide supported platinum catalyst for polymer electrolyte membrane fuel cells. Journal of Applied Catalysis B: Environmental, 96: 224 – 231.

8.       Albiter, E., Valenzuela, M. A., Alfaro, S., Valverde-Aguilar, G. and Martínez-Pallares, F. M. (2015). Photocatalytic deposition of Ag nanoparticles on TiO₂: Metal precursor effect on the structural and photoactivity properties. Journal of Saudi Chemical Society, 19: 563 – 573.

9.       Djurišic, A. B., Leung, Y. H. and Ching Ng, A. M. (2014). Strategies for improving the efficiency of semiconductor metal oxide photocatalysis. Journal of Royal Society of Chemistry, 1: 400 – 410.

10.     Monllor-Satoca, D., Gómez, R., González-Hidalgo, M. and Salvador, P. (2007). The ‘‘Direct–Indirect’’ model: An alternative kinetic approach in heterogeneous photocatalysis based on the degree of interaction of dissolved pollutant species with the semiconductor surface. Journal of Catalysis Today, 129: 247 – 255.

11.    Hashimoto, K., Irie, H. and Fujishima, A. (2005). TiO₂ photocatalysis: A historical overview and future prospects. Japanese Journal of Applied Physics, 44(12): 8269 – 8285.

12.    Khatun, N., Rini, E. G., Shirage, P., Rajput, P., Jha, S. N. and Sen, S. (2016). Effect of lattice distortion on band gap decrement due to vanadium substitution in TiO₂ nanoparticles. Journal of Materials Science in Semiconductor Processing, 50: 7 – 13.

13.    Liu, H., Lv, T. and Zhu, Z. (2016). Direct band gap narrowing of TiO₂/MoO₃ heterostructure composites for enhanced solar-driven photocatalytic activity. Journal of Solar Energy Materials & Solar Cells, 153: 1 – 8.

14.    Madaeni, S. S., Badieh, M., Vatanpour, V. and Ghaemi, N. (2012). Effect of titanium dioxide nanoparticles on polydimethylsiloxane/polyethersulfone composite membranes for gas separation. Journal of Polymer Engineering and Science, 56: 2664 – 2674.

15.    Chen, Q. and Yakovlev, N. L. (2010). Adsorption and interaction of organic silanes on TiO₂ nanoparticles. Journal of Applied Surface Science, 257: 1395 – 1400.

16.    Zhao, J., Milanova, M., Marijn, M.C.G. and Dutschk, V. (2012). Surface modification of TiO₂ nanoparticles with silane coupling agents. Journal of Colloids and Surfaces A, 413: 273 – 279.

17.    Li, Z., Hou, B., Xu, D., Sun, Y., Hu, W. and Deng, F. (2005). Comparative study of sol–gel-hydrothermal and sol-gel synthesis of titania–silica composite nanoparticles. Journal of Solid State Chemistry, 178: 1395 – 1405.