Synthesis of Nano-silica from Boiler Ash in the Sugar Cane Industry using the Precipitation Method

Boiler ash is a second layer by-product of the combustion of fuel, usually an agro-waste, in any industry. In the sugarcane industry, boiler ash is obtained from the combustion of bagasse. The boiler ash of the sugarcane industry contains 49.69% silica, which can be transformed into nano-silica using the precipitation method, which is easier and cheaper than other methods. Precipitation pH and aging time are the main factors that influence nano-silica’s characteristics. The objectives of this research were to determine the effect of various precipitation pH levels and aging times on the characteristics of nano-silica and to identify the potential applications of nano-silica based on these characteristics. An increase in precipitation pH affected the number of the crystal phase and the intensity of the diffraction peaks. An increase in aging time also affected the intensity of the diffraction peaks and the number of crystal phases. The degree of crystallinity varied from 66.40% to 93.53%, the crystal size ranged from 37.77 nm to 56.87 nm, the particle size ranged from 214.04 nm to 698.24 nm, and the polydispersity index (PDI) ranged from 0.21 to 0.83. The nano-silica in this research had polygonal morphology. Increases in precipitation pH and aging time increased the number of siloxane groups, creating nano-silica dominated by a crystalline form with three crystal phases: tridymite, quartz, and cristobalite. Nano-silica have various potential applications based on their characteristics, including as filler for membranes, composite resin, rubber airbags, and supplementary cementitious material.

Boiler ash; Characteristics; Nano-silica; Precipitation; Silica

Boiler ash from the sugar cane industry is 49.69% silica, while furnace ash is 78.75% silica (Ismayana et al., 2017). The synthesis of silica from boiler ash not only produces valuable silica but also reduces pollution problems caused by the uncontrolled combustion of the ash (Dhaneswara et al., 2020). The development of nanoscale particles (nanoparticles) has recently become the object of attention for researchers due to their unique properties, such as their very small size, high surface area, and surface activity (Dileep and Narayanankutty, 2020). One of the nanoparticles focused upon in current research is nano-silica. In some applications, nano-silica has been used as an adsorbent, catalyst support material, a semiconductor, thermal insulation, and a ceramic filler (Adam et al., 2011).

The high content of silica-induced boiler ash is transformed into nano-silica, and its characteristics and utilization are more extensive because of the larger surface area. There are several methods for synthesizing nano-silica, such as microemulsion, thermal decomposition, the sol-gel method (Okoronkwo et al., 2013), ultrasonication (Ismayana et al., 2017), and precipitation (Mahdavi et al., 2013).

The precipitation method has many advantages; it is easy and cheap, operates at a low process temperature, uses a low amount of energy, and produces nano-silica of high purity and good quality (Mahdavi et al., 2013). It is also safe and environmentally friendly (Shahmiri et al., 2013). The main factors that influence the nano-silica produced through the precipitation method are precipitation pH and aging time. Various combinations of precipitation pH and aging time result in nano-silica with different characteristics. According to Singh et al. (2012), an increase in pH increases crystal size. Allaedini and Muhammad (2013) found that the crystal size of a nanoparticle is closely linked to the diffraction pattern, the crystalline phase, the particle size, and the degree of crystallinity. In addition, a longer aging time causes a higher degree of crystallinity (Jalilpour and Fathalilou, 2012).

   The objectives of this research were to synthesize nano-silica from the boiler ash in the sugarcane industry using the precipitation method and to determine the effect of pH precipitation and aging time on the characteristics of the nano-silica. This research also aimed to identify potential applications based on the characteristics of the nano-silica produced.

The precipitation method produced nano-silica with polygonal morphology. Precipitation pH and aging time affected the characteristics of the nano-silica, including the particle size, PDI, crystal size, crystallinity degree, and crystal phase. The combination of various precipitation pH and aging times resulted in nano-silica with different characteristics. Overall, the nano-silica in this research had a semi-crystalline to crystalline form with three crystal phases: tridymite, quartz, and cristobalite. Nano-silica has several potential applications, namely, as filler for DMFC membranes, ultrafiltration membranes, rubber airbag launchers, composite resin, and SCM.

       This research was supported by the General Directorate of Strengthening Research and Development of the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia through the Grant of Competence (Hibah Kompetensi) Scheme (Grant Number: 011/SP2H/LT/IV/2017 and Contract Addendum: 011/SP2H/LT/DRPM/VIII/2017).

Adam, F., Thiam-Seng, C., Andas, J., 2011. A Simple Template-free Sol Gel Synthesis of Spherical Nano-silica from Agricultural Biomass. Journal of Sol-Gel Science Technology, Volume 59(3), pp. 580–583

 Allaedini, G., Muhammad, A., 2013. Study of Influential Factors in the Synthesis and Characterization of Cobalt Oxide Nanoparticles. Journal of Nanostructure in Chemistry, Volume 3, pp. 77–94

Arif, E., Clark, M.W., Lake, N., 2017. Sugar Cane Bagasse Ash from a High-efficiency Co-generation Boiler as Filler in Concrete. Construction and Building Materials, Volume 151, pp. 692–703

Atai, M., Pahlavan, A., Moin, M., 2012. Nano-porous Thermally Sintered Nano Silica as Novel Fillers for Dental Composites. Dental Materials, Volume 28(2), pp. 133–145

Bauccio, M., 1993. ASM Metals Reference Book Third Edition. ASM International, United States of America

Dhaneswara, D., Fatriansyah, J.F., Situmorang, F.W., Haqoh, A.N., 2020. Synthesis of Amorphous Silica from Rice Husk Ash: Comparing HCl and CH₃COOH Acidification Methods and Various Alkaline Concentrations. International Journal of Technology, Volume 11(1), pp. 200–208

Dileep, P., Narayanankutty, S.K., 2020. A Novel Method for Preparation of Nano-silica from Bamboo Leaves and its Green Modification as a Multi-functional Additive in Styrene-butadiene Rubber. Materials Today Communications, Volume 24, pp. 1–40

Eddhie, J., 2017. Strength Development of High-performance Concrete using Nano-silica. International Journal of Technology, Volume 8(4), pp. 728–736

Faisal, M., Machar, I., Gani, A., Daimon, H., 2016. The Combination of Air Flotation and a Membrane Bioreactor for the Treatment of Palm Oil Mill Effluent. International Journal of Technology, Volume 7(5), pp. 767–777 

Ha, S.W., Weiss, D., Weitzmann, M.N., Beck, G.R., 2019. Applications of Silica-based Nanomaterials in Dental and Skeletal Biology. Nanobiomaterials in Clinical Density Second Edition, pp. 77–112, Lincoln, United Kingdom

Happy, Tok, A.I.Y., Su, L.T., Boey, F.Y.C., Ng, S.G., 2007. Homogeneous Precipitation of Dy₂O₃ Nanoparticles—Effects of Synthesis Parameters. Journal of Nanoscience and Nanotechnology, Volume 7(3), pp. 1–9

Indrasti, N.S., Ismayana, A., Damayanti, R., Maddu, A., Aryanto, A.Y., 2018. Utilization of Nanosilica from Boiler Ash Sugar Cane Industry for Filler of Chitosan Sulfate Membrane on Direct Methanol Fuel Cell. In: IOP Conferece Series: Earth and Environmental Science, Volume 196, pp. 1–6

Ismayana, A., Maddu, A., Sailah, I., Mafquh, E., Indrasti, N.S., 2017. Synthesis of Nano-silica from Boiler Ash of Sugar Cane Industry with Ulrasonication Method and Addition of Surfactant. Journal of Agroindustrial Technology, Volume 27(2), pp. 228–234

Ismayana, A., Maddu, A., Istifani, Y., Indrasti, N.S., 2018. Nanosilica from the Boiler Ash of the Sugar Cane Industry as a Filler of Polysulfone and Sulfonated Polyetheretherketone Membranes in Direct Methanol Fuel Cell. Journal of Agroindustrial Technology, Volume 28(1), pp. 104–112

Jalilpour, M., Fathalilou, M., 2012. Effect of Aging Time and Calcination Temperature on the Cerium Oxide Nanoparticles Synthesis via Reverse Co-precipitation Method. International Journal of the Physical Sciences, Volume 7(6), pp. 944–948

Jarvenin, G., 2013. Precipitation and Crystallization Processes. Los Alamos National Laboratory, Los Alamos, New Mexico

Lee, Y.R., Soe, J.T., Zhang, S., Ahn, J.W., Park, M.B., Ahn, W.S., 2017. Synthesis of Nanoporous Materials via Recycling Coal Fly Ash and Other Solid Wastes: A Mini Review. Chemical Engineering Journal, Volume 317, pp. 821-843

Mahdavi, M., Ahmad, M.B., Haron, M.J., Namvar, F., Nadi, B., Rahman, M.Z.A., Amin, J., 2013. Synthesis, Surface Modification and Characterization of Biocompatible Magnetic Iron Oxide Nanoparticles for Biomedical Applications. Molecules, Volume 18(7), pp. 7533–7548

Munasir., Surahmat, H., Triwikantoro., Zainuri, M., Darminto., 2013. Pengaruh Molaritas NaOH pada Sintesis Nanosilika Berbasis Pasir Bancar Tuban (Effect of NaOH Molarity on Synthesis of Nano-silica from Tuban Bancar Sand). Jurnal Penelitian Fisika dan Aplikasinya, Volume 3(2), pp. 12–17 (in Bahasa)

Namazi, H., Fathi, F., Heydari, A., 2012. Nanoparticles based on Modified Polysaccharides. Intech, Iran

Nidhin, M., Indumathy, R., Sreeram, K., Nair, B.U., 2008. Synthesis of Iron Oxide Nanoparticles of Narrow Size Distribution on Polysaccharide Templates. Bulletin Material Sciences, Volume 31(1), pp. 93–96

Okoronkwo, E.A., Imoisili, P.E., Olusunle, S.O.O., 2013. Extraction and Characterization of Amorphous Silica from Corn Cob Ash by Sol-gel Method. Chemistry and Materials Research, Volume 3(4), pp. 68–72 

Quercia, G., Brouwers, H.J.H., 2010. Application of Nano-silica (nSi) in Concrete Mixtures. In: 8^th fib PhD Symposium in Civil Engineering, At Lyngby, Denmark

Setiawan, W.K., Indrasti, N.S., Suprihatin., 2015. Synthesis and Characterization of Nano-silica from Boiler Ash with Co-precipitation Method. In: Proceeding International Conference of Adaptive and Intelligent Agroindustry (ICAIA), pp. 160–164

Shahmiri, M., Ibrahim, N.A., Zainuddin, N., Asim, N.B., Bakhtyar, B., Zaharim, A., Sopian, K., 2013. Effect of pH on the Synthesis of CuO Nanosheets by Quick Precipitation Method. WSEAS Transactions on Environment and Development, Volume 9(2), pp. 137–145

Singh, N., Dhruvashi, Kaur, D., Mehra, R.M., Kapoor, A., 2012.  Effect of Aging in Structural Properties of ZnO Nanoparticles with pH Variation for Application in Solar Cells. The Open Renewable Energy Journal, Volume 5(1), pp. 15–18

Siswanto, Hamzah, M., Mahendra, A., Fausiah., 2012. Nano-silica Engineering Made from Local Silica as Filler of Compound Rubber Air Bag Ship Launcher from Shipyard. In: Proceeding  Incentives of National Innovation System Research (INSINAS), pp. 56–59

Sriyanti, S., Taslimah, T., Nuryono, N., Narsito, N., 2005. Pengaruh Keasaman Medium dan Imobilisasi Gugus Organik pada Karakter Silika Gel dari Abu Sekam Padi (The Effect of Medium Acidity and Organic Group Immobilized for Characters of Silica Gel from Rice Hull Ash). J. Kim. Sains & Apl., Volume 8(3), pp. 74–80 (in Bahasa)

Thuadaij, N., Nuntiya, A., 2008. Preparation of Nano-silica Powder from Rice Husk Ash by Precipitation Method. Chiang Mai Journal Sciences, Volume 35(1), pp. 206–211

Windiastuti, E., Suprihatin, Indrasti, N.S., 2016. Effectiveness of Polisulfon Membrane with Nano-silica Addition of Boiler Ash of Sugar Industry. In: Proceeding of the USR International Seminar of Food Security (UISFS), pp. 195–203

Yadav, V.K., Suriyaprabha, R., Khan, S.H., Singh, B., Gnanamoorthy, G., Choudhary, N., Yadav, A.K., Kalasariya, H., 2020. A Novel and Efficient Method for the Synthesis of Amorphous Nano-Silica from Fly Ash Tiles. Materials Today: Proceedings. pp. 1–5

 Yudhistira, A.D., Iswanto, F.B., Kusworo, T.D., 2012. Preparation of Asymmetric Membrane for Water Treatment: The Effect of Evaporation Rime on Membrane Performance. Journal of Chemical Technology and Industry, Volume 1(1), pp. 186–193