|Bambang Poerwadi||Department of Chemical Engineering, Faculty of Engineering, Universitas Brawijaya, Jl. Mayjen Haryono 167, Malang 65145, Indonesia|
|Christina W. Kartikowati||Department of Chemical Engineering, Faculty of Engineering, Universitas Brawijaya, Jl. Mayjen Haryono 167, Malang 65145, Indonesia|
|Rama Oktavian||Department of Chemical Engineering, Faculty of Engineering, Universitas Brawijaya, Jl. Mayjen Haryono 167, Malang 65145, Indonesia|
|Oyong Novareza||Department of Industrial Engineering, Faculty of Engineering, Universitas Brawijaya, Jl. Mayjen Haryono 167, Malang 65145, Indonesia|
The superhydrophobic composite membrane was successfully manufactured by a sol-gel method by drying the surrounding pressure. Tetraethylorthosilicate (TEOS) was used as a hydrophobic agent, while waterglass was used as a source of silica. The effect of the water to waterglass ratio (noted at 16:1 and 19:1) was evaluated to study the hydrophobic properties of the silica film coated composite membrane surface. By measuring the water contact angle on the film surface, the highest contact angle was found to occur at the ratio of 19:1, which is 143.86°. The stability of the composite membrane was also investigated by immersing the membrane in water until day 6. The results show that the synthesized composite membrane has good stability until day 6. The hydrophobicity of the surface of the silica film membrane was found to be unaffected by immersion time. Furthermore, the hydrophobicity increased after 6 days due to the interaction of alkyl groups with the humidified environment, and the surface was more stable in hydrophobicity (i.e., the contact angle of water is 153.79°). In addition, hydrophobic properties were obtained, confirming that this film has the potential to be applied to the separation of oil-water emulsions.
Composite membrane; Hydrophobic membrane; Oil-water emulsions; Silica film; Sol-gel
separation of oil-water emulsions has become a major concern since the increase
in oil-producing industries, which generate liquid waste and oil-contaminated
water bodies due to oil spills. Oil pollution has caused severe environmental
problems. The technology of oil-water separation is also important for the
purification of biodiesel production (Atadashi et
al., 2012). One of the most developed methods for oil-water separation
is the absorption of oil using porous adsorbent materials, such as aerogels (Xue et al., 2014), sponges (Su et al., 2017), and sawdust (Jung et al., 2008). These adsorbents must have
special properties, namely hydrophobicity. This property allows adsorbents to
absorb oil without absorbing water. Besides its use for oil-water separation,
the hydrophobic membrane is also applicable for other separation systems (Kartohardjono et al., 2017; Kartohardjono et al., 2019).
Recently, it was found that hydrophobic properties can be formed using
chemicals by means of surface modification of adsorbents with hydrophobic material such as organosilanes,
thus forming hydrophobic films.
Various methods have been developed to prepare these hydrophobic films, such as sol-gel processes (Xiu et al., 2008; Xue et al., 2010), layer by layer of self-assembly (Ismijan et al., 2012), etching (Guo et al., 2005; Dong et al., 2011), chemistry (Rezaei et al., 2014), and electrochemical deposition (Benoit et al., 2013; Khorsand et al., 2014). Among these methods, the sol-gel method is a relatively simple and inexpensive option for hydrophobic film preparation. In addition, this method does not require high temperatures for the preparation process, so it can be applied to large-scale production.
Silica is widely known as a basic ingredient in making porous adsorbents (Mahadik et al., 2010; Bhagat et al., 2008), and the synthesis of hydrophobic silica films using the sol-gel method has also been reported (Bois et al., 2003; Rao et al., 2009; Liu et al., 2014). The hydrophobic properties are obtained during the silylation process by modifying the surface of the silica film in a hydrophobic material, a process that increases the hydrophobic properties through the replacement of silanol groups on the surface of silica with alkyl groups (Roach et al., 2008; Celia et al., 2013; Prihandana et al., 2015;). Three alkoxysilanes are common hydrophobic agents, including tri methyl chloro silicate (TMCS), which is widely used in a variety of applications to improve adhesion between organic matter and inorganic substrates. This alkoxysilane molecule has two key clusters. One of these clusters is an organic compound that can be hydrolyzed and can react with other chemicals or groups that are not reactive and hydrolyzed (Corriu, 2003; Lung and Matinlinna, 2012) and the other is silica. The drawback is that most of these hydrophobic agents are expensive and limited in supply.
In a previous study, tetraethylorthosilicate (TEOS) was generally preferred as a precursor to synthesize silica (Jyoti et al., 2009). TEOS is alkoxysilane that has four alkyl groups, one of which is C2H5, meaning that it is possible to use TEOS as a hydrophobic agent. TEOS is more economical than most of the other available hydrophobic agents, and its abundance is greater than silylation agents with three functional groups. Concerning silica sources, waterglass is the cheapest source of silica; there is also an abundance of large raw waterglass sources and it does not endanger the environment, which gives it good potential for industrial scale applications. On the other hand, the drying process of the silylation process is usually carried out through supercritical methods that require large amounts of energy, which limits commercial applications for this material. To reduce production costs, drying at atmospheric pressure can be applied.
composite membrane consisting of cotton cloth coated with silica film was
successfully manufactured. It was found that this composite membrane with the
support of cotton cloth combined with coating with silica film using TEOS as a
surface modification agent was effective for delivering hydrophobic properties.
The optimal ratio of the water to waterglass in the solution occurred at
19:1—that is, at a contact angle with water of 143.86°—which provided the best
hydrophobicity. The hydrophobicity test results on day 6 increased to 153.79°,
and this membrane was stable until day 6. This hydrophobicity provides the main
factor for a more efficient oil-water emulsion separation. In addition, the
method we propose can be used to prepare superhydrophobic silica-coated
composite membranes with relatively easy production for oil-water separation.
This work was supported by INSINAS (INSENTIF RISET SISTEM INOVASI NASIONAL) 2017 through grant Number of 733.1.2/UN10.C10/PN/2017 and 2018 through grant Number of 338.169/UN10.C10/PN/2018. The authors thank Mila Baarik Imansari and Nadia Sjavira Mahardana for their assistance in conducting the experiment.
Al-Oweini, R., El-Rassy, H., 2009. Synthesis and Characterization by FTIR Spectroscopy of Silica Aerogels Prepared using Several Si(OR)4 and R”Si(OR’)3 Precursors. Journal of Molecular Structure, Volume 919(1-3), pp. 140–145
Atadashi, I.M., Aroua, M.K., Abdul Aziz, A.R., Sulaiman, N.M.N., 2012. The Effects of Water on Biodiesel Production and Refining Technologies: A Review. Renewable and Sustainable Energy Reviews, Volume 16(5), pp. 3456–3470
Benoit, C., Galarneau, A., Roland, J.M., Pellen, Q., Francesco, D.R., 2013. Adsorption, Intrusion, and Freezing in Porous Silica: The View from the Nanoscale. Chemical Society Reviews, Volume 42(9), pp. 4141–4171
Bertoluzza, A., Fagnano, C., Morelli, M.A., Gottardi, V., Guglielmi, M., 1982. Raman and Infrared Spectra on Silica Gel Evolving Toward Glass. Journal of Non-Crystalline Solids, Volume 48(1), pp. 117–128
Bhagat, S.D., Kim, Y.H., Suh, K.H., Ahn, Y.S., Yeo, J.G., Han, J.H., 2008. Superhydrophobic Silica Aerogel Powder with Simultaneous Surface Modification, Solvent Exchange, and Sodium Ion Removal from Hydrogels. Macroporous and Mesoporous Materials, Volume 112(1–3), pp. 504–509
Bois, L., Bonhomme, A., Ribes, A., Pais, B., Raffin, G., Tessier, F., 2003. Functionalized Silica for Heavy Metal Ions Adsorption. Colloids and Surface A: Physicochemical and Engineering Aspects, Volume 221(1–3), pp. 221–230
Brinker, C.J., Scherer, G.W., 1990. Sol-gel Science: The Physics and Chemistry of Sol-gel Processing. New York, NY: Academic
Celia, E., Darmanin, T., de Givenchy, E.T., Amigoni, S., Guittard, F., 2013. Recent Advances in Designing Superhydrophobic Surfaces. Journal of Colloid and Interface Science, Volume 402, pp. 1–18
Corriu, R., 2003. Organosilicon Chemistry and Nano Science. Journal of Organometallic Chemistry, Volume 686(1–2), pp. 32–41
Dong, C., Gu, Y., Zhong, M.L., Li, L., Sezer, K., Ma, M.X., Liu, W.J., 2011. Fabrication of Superhydrophobic Cu Surfaces with Tunable Regular Micro and Random Nano-Scale Structures by Hybrid Laser Texture and Chemical Etching. Journal of Materials Processing Technology, Volume 211(7), pp. 1234–1240
Drelich, J., Marmur, A., 2013. Physics and Applications of Superhydrophobic and Superhydrophilic Surfaces and Coatings. Surface Innovation, Volume 2(4), pp. 211–227
Duran, A., Serna, C., Fornes, V., Navarro, J.M.F., 1986. Structural Consideration about SiO2 Glasses Prepared by Sol-gel. Journal of Non-Crystalline Solids, Volume 82(1–3), pp. 69–77
Gopal, N.O., Narasimhulu, K.V., Rao, J.I., 2004. EPR, Optical, Infrared and Raman Spectral Studies of Actinolite Mineral. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Volume 60(11), pp. 2441–2448
Guo, Z., Zhou, F., Hao, J., Liu, W., 2005. Stable Biomimetic Super-Hydrophobic Engineering Materials. Journal of American Chemical Society, 127(45), pp. 15670–15671
Ismijan, T.T., Wang, T.Y., Rohani, S., 2012. A Novel Method to Prepare Superhydrophobic, UV Resistance and Anti-Corrosion Steel Surface. Chemical Engineering Journal, Volume 210, pp. 182–187
Jung, S.H., Kang, B.S., Kim, J.S., 2008. Production of Bio-Oil from Rice Straw and Bamboo Sawdust under Various Reaction Conditions in a Fast Pyrolysis Plant Equipped with a Fluidized Bed and a Char Separation System. Journal of Analytical and Applied Pyrolysis, Volume 8(2), pp. 240–247
Jyoti, L.G., Rao, A.V., Uzma, K.H.B., 2009. Hydrophobic and Low Density Silica Aerogel Dried at Ambient Pressure using TEOS Precursor. Journal of Alloys and Compounds, Volume 471(1–2), pp. 296–302
Kartohardjono, S., Paramitha, A., Putri, A.A., Andriant, R., 2017. Effects of Absorbent Flow Rate on CO2 Absorption through a Super Hydrophobic Hollow Fiber Membrane Contactor. International Journal of Technology, Volume 8(8), pp. 1429–1435
Kartohardjono, S., Saksono, N., Supramono, D., Prawati, P., 2019. NOx Removal from Air through Super Hydrophobic Hollow Fiber Membrane Contactors. International Journal of Technology, Volume 10(3), pp. 472–480
Khorsand, S., Raeissi, K., Ashrafizadeh, F., 2014. Corrosion Resistance and Long-term Durability of Super-hydrophobic Nickel Film Prepared by Electrodeposition Process. Applied Surface Science, Volume 305, pp. 498–505
Law, K.Y., 2014. Definitions for Hydrophilicity, Hydrophobicity, and Superhydrophobicity: Getting the Basics Right. Journal of Physical Chemistry Letters, Volume 5(4), pp. 686–688
Liu, Y., Yin, X., Zhang, J., Yu, S., Han, Z., Ren, L., 2014. A Electro-deposition Process for Fabrication of Biomimetic Super-hydrophobic Surface and its Corrosion Resistance on Magnesium Alloy. Electrochimica Acta, Volume 125, pp. 395–403
Lung, C.Y.K., Matinlinna, J.P., 2012. Aspects of Silane Coupling Agents and Surface Conditioning in Dentistry. Dental Materials, Volume 28(5), pp. 467–447
Mahadik, S.A., Kavale, M.S., Mukherjee, S.K., Rao, A.V., 2010. Transparent Superhydrophobic Silica Coatings on Glass by Sol-gel Method. Applied Surface Science, Volume 257(2), pp. 333–339
Nazriati, N., Setyawan, H., Affandi, S., Yuwana, M., Winardi, S., 2014. Using Bagasse Ash as a Silica Source when Preparing Silica Aerogels via Ambient Pressure Drying. Journal of Non-Crystalline Solids, Volume 400, pp. 6–11
Prihandana, G.S., Sriani, T., Mahardika, M., 2015. Review of Surface Modification of Nanoporous Polyethersulfone Membrane as a Dialysis Membrane. International Journal of Technology, Volume 6(6), pp. 1025–1030
Rao, A.V., Latthe, S.S., Nadargi, D.Y., Hirashima, H., Ganesan, V., 2009. Preparation of MTMS Based Transparent Superhydrophobic Silica Films by Sol-gel Methods. Journal of Colloid Interface Science, Volume 332(2), pp. 484–490
Rezaei, S., Manoucheri, I., Moradian, R., Pourabbas, B., 2014. One Step Chemical Vapor Deposition and Modification of Silica Nanoparticles at the Lowest Possible Temperature and Superhydrophobic Surface Fabrication. Chemical Engineering Journal, Volume 252, pp. 11–16
Roach, P. Shirtcliffe, N.J. Newton, M.I. 2008. Progress in Superhydrophobic Surface Development. Soft Matter, Volume 4, pp. 224–240
Socrates, G., 2001. Infrared and Raman Characteristic Group Frequencies: Tables and Charts. 3rd Ed. Chichester, UK: Wiley
Su, C., Yang, H., Song, S., Lu, B., Chen, R., 2017. Magnetic Superhydrophophic/Oleophobic Spone for Continuous Oil-Water Separation. Chemical Engineering Journal, Volume 309, pp. 366–373
Xiu, Y, Hess, D.W., Wong, C.R., 2008. UV and Thermally Stable Superhydrophobic Coatings from Sol-gel Processing. Journal of Colloid Interface Science, Volume 326(2), pp. 465–470
Xue, C.H., Jia, S.T., Zang, J, Ma, J.Z., 2010. Large-area Fabrication of Superhydrophobic Surfaces for Practical Applications: An Overview. Science and Technology of Advanced Materials, Volume 11(3), pp. 1–15
Xue, Z., Cao, Y., Liu, N., Feng, L., Jiang, L., 2014. Special Wettable Material for Oil/Water Separation. Journal of Materials Chemistry A, Volume 2, pp. 2445–2460
Xue, C.H., Ji, P.T., Zhang, P., Li, Y.R., Jia, S.T., 2013. Fabrication of Superhydrophobic and Superoleophilic Textiles for Oil-Water Separation. Applied Surface Science, Volume 284 pp. 464–471
Xue, C.H., Li, M., Guo, G.J., Li, X., An, Q.F., Jia, S.T., 2017. Fabrication of Superhydrophobic Textiles with High Water Pressure Resistance. Surface and Coatings Technology, Volume 310, pp. 134–142