• International Journal of Technology (IJTech)
  • Vol 12, No 1 (2021)

Valorization of Geothermal Silica and Natural Bentonite through Geopolymerization: A Characterization Study and Response Surface Design

Valorization of Geothermal Silica and Natural Bentonite through Geopolymerization: A Characterization Study and Response Surface Design

Title: Valorization of Geothermal Silica and Natural Bentonite through Geopolymerization: A Characterization Study and Response Surface Design
Himawan Tri Bayu Murti Petrus, Muhammad Olvianas, Widi Astuti, Muhammad Istiawan Nurpratama

Corresponding email:


Cite this article as:
Petrus, H.T.B.M., Olvianas, M., Astuti, W., Nurpratama, M.I., 2021. Valorization of Geothermal Silica and Natural Bentonite through Geopolymerization: A Characterization Study and Response Surface Design. International Journal of Technology. Volume 12(1), pp. 195-206

138
Downloads
Himawan Tri Bayu Murti Petrus 1. Sustainable Mineral Processing Research Group, Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2 Kampus UGM Bulaksumur, Yogyakarta 55281, Indone
Muhammad Olvianas Sustainable Mineral Processing Research Group, Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada, Jl. Grafika No. 2 Kampus UGM Bulaksumur, Yogyakarta 55281, Indonesia
Widi Astuti Research Unit for Mineral Technology, Indonesian Institute of Sciences (LIPI), Jl. Ir. Sutami Km. 15, Tanjung Bintang, Lampung Selatan, Indonesia
Muhammad Istiawan Nurpratama PT. Geo Dipa Energi (Persero) Unit Dieng, Jl. Dieng RT. 01/ RW. 01, Area Industri, Sikunang, Banjarnegara, Kabupaten Wonosobo, Jawa Tengah 56354, Indonesia
Email to Corresponding Author

Abstract
Valorization of Geothermal Silica and Natural Bentonite through Geopolymerization: A Characterization Study and Response Surface Design

Geothermal silica is a potential source of amorphous silica for producing geopolymer concrete. The valorization of geothermal silica as a geopolymer concrete provides an opportunity for an added value to the geothermal-based power industry. In this study, silica content, NaOH molarity, and curing temperature effect were investigated and optimized for compressive strength using response surface methodology. The effect of the single parameter on geopolymerization was qualitatively observed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-coupled with energy dispersive X-ray spectroscopy (SEM-EDS). The characterization of the geopolymer samples using FTIR and SEM-EDS revealed that the aluminosilicate structure was formed in all geopolymer samples. The geopolymerization rate can be accelerated using the lower level of geothermal silica and the high level of NaOH molarity and curing temperature. Based on optimization studies, the R-square value was 99.89%. The optimum formulation was found at a silica content of 130 g, NaOH molarity of 10 M, and curing temperature of 80°C with a desirability value of 0.99. At the optimum condition, the compressive strength was calculated as 7.73 MPa.

Bentonite; Geopolymer; Geothermal silica; Response surface design; Valorization.

Introduction

Geopolymers can be produced by combining various solid aluminosilicate materials with a mixture of high concentrations of alkaline hydroxide and silicate solution (Hajimohammadi et al., 2008). Geopolymer possesses a three-dimensional structure that consists of an amorphous polymeric Si-O-Al framework (Hajimohammadi et al., 2010). These materials can be categorized as eco-friendly in comparison with Portland cement in terms of CO2 emission during the production process (Duxson et al., 2007; Hajimohammadi et al., 2008). Geopolymers exhibit excellent physical properties, such as relatively high mechanical strength, resistance to an acid environment, and heat resistance (Nurjaya et al., 2015) and possesses low thermal conductivity (Skvara et al., 2005; Duxson et al., 2007). Having those excellent properties, geopolymer has been recognized as a promising technology to substitute conventional cement in the construction industry and as a new method to utilize industrial and radioactive waste (Xua and van Deventer, 2003). Raw materials for geopolymer synthesis are varied and include fly ash, bottom ash, natural clays, and minerals, as well as metal slags (Heath et al., 2014; Ashadi et al., 2015). Many studies have concentrated on fly ash-based geopolymer due to its chemical suitability and relative abundant availability (Zhang et al., 2012). Fly ash and metakaolinite, which are classified as calcined materials, have a faster dissolution and gelation and exhibit higher compressive strength (Xua and van Deventer, 2003; Skvara et al., 2005). Recently, there has been a new trend to use a different source of aluminosilicate precursors, instead of fly ash, for geopolymerization (Perná et al., 2014). Xua and van Deventer (2003) studied the geopolymerization process using different sources of material (kaolinite, albite, and fly ash). Mixing these source materials can produce geopolymers of a higher mechanical strength. Alshaaer (2013) showed that additional immersion of kaolinite-based geopolymer in 6 M of alkaline solution for 1 hour can modify the geopolymer surface and enhance its compressive strength. Red mud and bauxite have also been utilized as geopolymer materials (Hairi et al., 2015).

Moreover, geothermal silica can also potentially be used as a geopolymer precursor due to its reactivity. At the geothermal power plant operated by PT. Geodipa Energy in Dieng, Jawa Tengah, Indonesia, approximately 250 tons of geothermal silica (inset of Figure 1a) are removed from the process equipment, collected in sedimentation ponds, and then dumped into landfills. The study of geopolymerization using geothermal silica is still lacking. Previous studies have presented the effect of a single variable on geopolymerization using a mixture of geothermal silica-kaolinite and geothermal silica-bentonite (Olvianas et al., 2015; Petrus et al., 2016). However, the effect of combined variables and associated optimization studies have not been reported. To analyze the various factors of geopolymerization, this study adopted response surface methodology (RSM). RSM is a statistical technique for process evaluation and optimization used in industries and research fields to control process response or independent variables (Dhakal et al., 2014; Ferdana et al., 2018; Petrus et al., 2020; Januardi and Widodo, 2020). It has been used in the field of geopolymer and concrete to optimize various parameters (Dhakal et al., 2014; ?im?ek et al., 2015; Gao et al., 2016; Mohammed et al., 2018). To this end, the present work was conducted to optimize the compressive strength of geopolymer material from a mixture of geothermal silica and bentonite. The combined effect of silica content, NaOH molarity, and curing temperature were investigated using a full two-level factorial design in RSM. The effect of a single variable on the chemical bond and microstructure was also observed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-coupled with energy dispersive X-ray spectroscopy (SEM-EDS).

Conclusion

A geopolymer has been successfully produced by using geothermal silica and bentonite. Its characterization using FTIR and SEM-EDS showed that the aluminosilicate structure was formed in all prepared samples. The effects of combined variables have been studied and optimized using the RSM technique. The geopolymerization rate can be accelerated using the lower level of geothermal silica and the high level of NaOH molarity and curing temperature. Based on optimization studies, the coefficient of correlation (R2) obtained was 99.89%. The optimum formulation (desirability value = 0.99) for geopolymer production from geothermal silica and bentonite is using 136 g of silica content, 10 M of NaOH molarity, and 80°C of curing temperature. At the optimum condition, the compressive strength was 7.73 MPa.

Acknowledgement

This research was financially supported by AUN-SEED-Net JICA Common Regional Issues (CRC) 2016. The authors also acknowledge PT. Geodipa Energy, Dieng for providing geothermal silica, Unconventional Georesources Research Center, UGM and LIPI' Science Services for Research Laboratories for supporting this research.

Supplementary Material
FilenameDescription
R3-CE-3537-20200829120848.pdf ---
References

Alshaaer, M., 2013. Two-Phase Geopolymerization of Kaolinite-Based Geopolymers.  Applied Clay Science, Volume 86, pp. 162–168

Ashadi, H.W., Aprilando, B.A., Astutiningsih, S., 2015. Effects of Steel Slag Substitution in Geopolymer Concrete on Compressive Strength and Corrosion Rate of Steel Reinforcement in Seawater and an Acid Rain Environment. International Journal of Technology, Volume 6(2), pp. 227–235

Bezerra, M.A., Santelli, R.E., Oliveira, E.P., Villar, L.S., Escaleira, L.A., 2008. Response Surface Methodology (RSM) as a Tool for Optimization in Analytical Chemistry. Talanta, Volume 76(5), pp. 965–977

Bing-hui, M., Zhu, H., Xue-min, C., Yan, H., Si-yu, G., 2014. Effect of Curing Temperature on Geopolymerization of Metakaolin-Based Geopolymers. Applied Clay Science, Volume 99, pp. 144–148

Deb, P.S., Sarker, P.K., Barbhuiya, S., 2015. Effects of Nano-Silica on the Strength Development of Geopolymer Cured at Room Temperature. Construction and Building Materials, Volume 101(1), pp. 675–683

Dhakal, M., Kupwade-Patil, K., Allouche, E.N., la Baume Johnson, C.C., Ham, K., 2014. Optimization and Characterization of Geopolymer Mortars using Response Surface Methodology. In: Developments in Strategic Materials and Computational Design IV, Kriven, W. M., Wang, J., Zhou, Y., Gyekenyesi, A. L. (Eds.), John Wiley and Sons, pp. 135–149

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

Duxson, P., Fernández-Jiménez, A., Provis, J.L., Luckey, G.C., Palomo, A., van Deventer, J.S.J., 2007. Geopolymer Technology: The Current State of the Art. Journal of Material Science, Volume 42, pp. 2917–2933

Ferdana, A.D., Petrus, H.T.B.M., Bendiyasa, I.M., Prijambada, I.D., Hamada, F., Sachiko, T., 2018, Optimization of Gold Ore Sumbawa Separation using Gravity Method: Shaking Table. AIP Conference Proceedings, Volume 1945, p. 020070

Fernández-Jiménez, A., Palomo, A., 2005. Mid-Infrared Spectroscopic Studies of Alkali-Activated Fly Ash Structure. Microporous and Mesoporous Materials, Volume 86(1-3), pp. 207–214

Gao, Y., Xu, J., Luo, X., Zhu, J., Nie, L., 2016. Experiment Research on Mix Design and Early Mechanical Performance of Alkali-Activated Slag using Response Surface Methodology (RSM). Ceramic International, Volume 42(10), pp. 11666–11673

Gomez-Zamorano, L.Y., Vega-Cordero, E., Struble, L., 2016, Composite Geopolymers of Metakaolin and Geothermal Nanosilica Waste. Construction and Building Materials, Volume 115, pp. 269–276

Hajimohammadi, A., Provis, J.L., van Deventer, J.S.J., 2008. One-Part Geopolymer Mixes from Geothermal Silica and Sodium Aluminate. Industrial & Engineering Chemistry Research, Volume 47(23), pp. 9396–9405

Hajimohammadi, A., Provis, J.L., van Deventer, J.S.J., 2010. Effect of Alumina Release Rate on the Mechanism of Geopolymer Gel Formation. Chemistry of Materials, Volume 22(18), pp. 5199–5208

Hairi, S.N.M., Jameson, G.N.L., Rogers, J.J., MacKenzie, K.J.D., 2015. Synthesis and Properties of Inorganic Polymers (Geopolymers) Derived from Bayer Process Residue (Red Mud) And Bauxite. Journal of Material Science, Volume 50, pp. 7713–7724

Hassan, I., Peterson, R.C., Grundy, H.D., 1985. The Structure of Lazurite, Ideally Na6Ca2(Al6Si6O24)S2, a Member of the Sodalite Group. Acta Crystallographica Section C, Volume 41, pp. 827–832

Heath, A., Paine, K., McManus, M., 2014. Minimising the Global Warming Potential of Clay-Based Geopolymers. Journal of Cleaner Production, Volume 78, pp. 75–83

Januardi, J., Widodo, E., 2020, Response Surface Methodology of Dual-Channel Green Supply-Chain Pricing Model by Considering Uncertainty. Supply Chain Forum: An International Journal, DOI: 10.1080/16258312.2020.1788904, pp. 1–12

Król, M., Minkiewicz, J., Mozgawa, W., 2016. IR Spectroscopy Studies of Zeolites in Geopolymeric Materials Derived from Kaolinite. Journal of Molecular Structure, Volume 1126, pp. 200–206

Mohammed, B.S., Khed, V.C., Nuruddin, M.F., 2018. Rubbercrete Mixture Optimization using Response Surface Methodology. Journal Cleaner Production, Volume 171, pp. 1605–1621

Montgomery, D.C., 2013. Design and Analysis of Experiments 8th ed., New Jersey: John Wiley & Sons

Nurjaya, D.M., Astutiningsih, S., Zulfia, A., 2015, Thermal Effect on Flexural Strength of Geopolymer Matrix Composite with Alumina and Wollastonite as Fillers. International Journal of Technology, Volume 6(3), pp. 462–470

Olvianas, M., Najmina, M., Prihardana, B.S.L., Sutapa, F.A.K.G.P., Nurhayati, A., Petrus, H.T.B.M., 2015. Study on the Geopolymerization of Geothermal Silica and Kaolinite. Advanced Materials Research, Volume 1112, pp. 528–532

Perná, I., Hanzlí?ek, T., Šupová, M., 2014. The Identification of Geopolymer Affinity in Specific Cases of Clay Materials. Applied Clay Science, Volume 102, pp. 213–219

Petrus, H.T.B.M., Hulu, J., Dalton, G.S.P., Malinda, E., Prakosa, R.A., 2016. Effect of Bentonite Addition on Geopolymer Concrete from Geothermal Silica. Materials Science Forum, Volume 841, pp. 7–15

Petrus, H.T.B.M., Putra, A.E., Gustiana, H.S.A., Prasetya, A., Bendiyasa, I.M., Astuti, W., 2020, Gold Leaching from Printed Circuit Boards (PCBs) as one of the Urban Mine Resources using Thiosulphate: Optimization using Response Surface Methodology (RSM). In: IOP Conference Series: Materials Science and Engineering, Volume 778, pp. 012166

Provis, J.L., Lukey, G.C., van Deventer, J.S.J., 2005. Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results. Chemistry of Materials, Volume 17, pp. 3075–3085

Skvara, F., Jilek, T., Kopecky, L., 2005. Geopolymer Material based on Fly Ash. Ceramics-Silikáty, Volume 49(3), pp. 195–204

van Deventer, J.S.J., Provis, J.L., Duxson, P., Lukey, G.C., 2007. Reaction Mechanisms in the Geopolymeric Conversion of Inorganic Waste to Useful Products. Journal of Hazardous Materials, Volume 139(3), pp. 506–513

Xua, H., van Deventer, J.S.J., 2003. Effect of Source Materials on Geopolymerization. Industrial & Engineering Chemistry Research, Volume 42(8) pp. 1698–1706

Ye, N., Yang, J., Liang, S., Hu, Y., Hu, J., Xiao, B., Huang, Q., 2016, Synthesis and Strength Optimization of One-Part Geopolymer based on Red Mud. Construction and Building Materials, Volume 111, pp. 317–325

Zhang, Z., Wang, H., Provis, J.L., 2012. Quantitative Study of the Reactivity of Fly Ash in Geopolymerization by FTIR. Journal of Sustainable Cement-Based Materials, Volume 1(4), pp. 154–166

?im?ek, B., Iç, Y.T., ?im?ek, E.H., 2015. A RSM-Based Multi-Response Optimization Application for Determining Optimal Mix Proportions of Standard Ready-Mixed Concrete. Arabian Journal for Science and Engineering, Volume 41, pp. 1435–1450