Synthesis of calcium silicate hydrate (csh) from vietnam rice hush - Pham Trung Kien

Mạc Xuân Hòa, Nguyễn Lâm Nhu, Nguyễn Thị Hồng Hạnh 66 16. Wong Y.-M. and Siow L.-F. - Effects of heat, pH, antioxidant, agitation and light on betacyanin stability using red-fleshed dragon fruit (Hylocereus polyrhizus) juice and concentrate as models, Journal of Food Science and Technology 52 (2015) 3086-3092. ABSTRACT COMPARISON OF MICROWAVE AND ULTRASOUND-ASSISTED EXTRACTION FOR LEACHING BETACYANIN FROM DRAGON FRUIT PEELS Mac Xuan Hoa, Nguyen Lam Nhu, Nguyen Thi Hong Hanh* Ho Chi Minh City University of Food Industry *Email: hanhnguyen300995@gmail.com Extraction of betacyanin from dragon fruit peels by microwave and ultrasound was studied by experimental method. In both microwave and ultrasound-assisted extractions, effects of extraction time (10-110 sec for microwave; 5-25 min for ultrasound) and different powers (200 W, 400 W, 600 W for microwave; 150 W, 187.5 W, 225 W for ultrasound) were investigated. In microwave-assisted extraction, the highest betacyanin (0.456 mg/100 g) was obtained in 30 sec and 600 W powers. For ultrasound-assisted extraction, the condition which acquired the highest betacyanin (0.409 mg/100 g) was 10 min and 187.5 W powers. Microwave reduced extraction time by 95% and betacyanin obtained in this method was higher (0.456 mg/100 g) compaired with (0.409 mg/100 g). Key words: Microwave, ultrasound, betacyanin, dragon fruit peels. Tạp chí Khoa học công nghệ và Thực phẩm 12 (1) (2017) 67-72 SYNTHESIS OF CALCIUM SILICATE HYDRATE (CSH) FROM VIETNAM RICE HUSH 1* 1 1 2Pham Trung Kien , Phan Viet Hoang , Huynh Dai Phu , Nguyen Van Tam , 2 3 4Ngo Vo Ke Thanh , Nguyen Hoc Thang , Hirofumi Hinode 1Ho Chi Minh City University of Technology (HCMUT) 2Research Laboratories Center Saigon Hi-Tech Park 3Ho Chi Minh City University of Food Industry (HUFI), 4Tokyo Institute of Technology *Email: phamtrungkien@hcmut.edu.vn Received: 25 June 2017; Accepted for publication: 12 September 2017 ABSTRACT Vietnam is an agricultural country, which produces lot of rice and its by product is rice husk ash (RHA). The RHA is considered as waste in agriculture, and treated by burn in the open air. This process causes air pollution, thus attracted Vietnamese researchers to find alternative method to reduce the impact of rice husk ash on environment. The research group in Department of Ceramic Materials aims to reuse rice husk ash as source of silica (SiO2). It needs to emphasize that the main content of rice husk ash is silica. This research reports new technology to mixing RHA and CaO with the Ca/Si molar ratio of 1.0, in order to synthesize calcium silicate hydrate (CSH) such as tobermorite (C5S6H5) and xonotlite (C6S6H) as environmental materials. The advantage of our study is to utilize the Vietnam RHA and to reduce the environmental impacts by using hydrothermal treatment technique. Key words: Calcium silicate hydrate, rice hush ash, hydrothermal treatment, ceramic. 1. INTRODUCTION Vietnam is an agricultural country, which produces lot of rice and its by product is rice husk ash (RHA). The RHA is considered as waste in agriculture, and treated by burn in the open air. This process causes air pollution, thus attracted researchers to find alternative method to reduce the impact of rice husk ash on environment [1-3]. The research group in Department of Ceramic Materials aims to reuse rice husk ash as source of Silica (SiO2) [4-8]. The obtained silica can be used as stating materials to reaction with calcium source to form calcium silicate hydrate (CSH). By this chemical reaction, we can utilize the Vietnam rice hush for sustainable development. 2. METHODOLOGY Preparation of Vietnam Rice Husk Ash (VRH): Rice husk is burned at 600 oC with the heating rate of 10 oC/min (Naberthem 1400, Nabertherm, Germany), then soaking for 4 hours to complete burning. The phase composition of obtained VRHA is characterized using X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The chemical composition of VRHA is analyzed using X-Ray Fluorescent (XRF) method. Preparation of CaO: CaO is used from the commercial without purified (Xilong 67 Pham Trung Kien, Huynh Dai Phu, Nguyen Van Tam, Ngo Vo Ke Thanh, 68 Chemical, China). The phase composition of commercialized CaO using XRD. Hydrothermal treatment the mixture of VRHA and CaO: The mixture of VRHA and CaO is mixed with the Ca/P molar ratio of 1.0 with the moisture of 10% (weight percent) then pressing at 30 MPa to form the compact disk with diameter of 9 mm. The compacted cylinder is hydrothermally treated at different temperature levels for 24 hours to obtain calcium silicate hydrate such as tobermorite and xonotlite. Phase analysis: The powder X-ray Diffraction (XRD) patterns of disk samples were recorded with a vertically mounted diffractometer system (Bruker-AXS: D8 ADVANCE, Germany) using Ni filtered CuKa generated at 40 Kv, 20 mA. The chemical compositions of sample were characterized by XRF (ZSX, Rigaku, Japan) operated at 40 kV and 40 mA. The bonding chemical of sample was characterized by FTIR analysis: the sample were ground into fine powder, mixed with KBr powder at the ratio 1:200. Infrared spectra were measured at a resolution of 2 cm-1 using a Fourier transform infrared (FTIR) spectrometer (PerkinElmer 2000, USA). 3. RESULTS AND DISCUSSIONS The chemical composition of RHA is shown in Table 1: Table 1. The chemical composition of RHA (weight percent) SiO2 K2O CaO P2O5 MgO Al2O3 MnO Fe2O3 SO3 other LOI Total 92.7 3.16 1.33 0.596 0.466 0.306 0.291 0.242 0.126 0.153 0.63 100 The phase analysis of VRHA is given in Figure 1, indicating that VRHA is composed of crystabalite, which shows the peak at 22o (PDF# 01-082-0512). Figure 1. XRD pattern of VRHA 5 10 15 20 25 30 35 40 45 50 55 60 Int en sit y / ar b. un it 2theta / degree Int en sit y / ar b. un it Pham Trung Kien, Huynh Dai Phu, Nguyen Van Tam, Ngo Vo Ke Thanh, 68 Chemical, China). The phase composition of commercialized CaO using XRD. Hydrothermal treatment the mixture of VRHA and CaO: The mixture of VRHA and CaO is mixed with the Ca/P molar ratio of 1.0 with the moisture of 10% (weight percent) then pressing at 30 MPa to form the compact disk with diameter of 9 mm. The compacted cylinder is hydrothermally treated at different temperature levels for 24 hours to obtain calcium silicate hydrate such as tobermorite and xonotlite. Phase analysis: The powder X-ray Diffraction (XRD) patterns of disk samples were recorded with a vertically mounted diffractometer system (Bruker-AXS: D8 ADVANCE, Germany) using Ni filtered CuKa generated at 40 Kv, 20 mA. The chemical compositions of sample were characterized by XRF (ZSX, Rigaku, Japan) operated at 40 kV and 40 mA. The bonding chemical of sample was characterized by FTIR analysis: the sample were ground into fine powder, mixed with KBr powder at the ratio 1:200. Infrared spectra were measure at a resolution of 2 cm-1 using a Fourier transform infrared (FTIR) spectrometer (PerkinElmer 2000, USA). 3. RESULTS AND DISCUSSIONS The chemical composition of RHA is shown in Table 1: Table 1. The chemical composition of RHA (weight percent) SiO2 K2O CaO P2O5 MgO Al2O3 MnO Fe2O3 SO3 other LOI Total 92.7 3.16 1.33 0.596 0.466 0.306 0.291 0.242 0.126 0.153 0.63 100 The phase analysis of VRHA is given in Figure 1, indicating that VRHA is composed of crystabalite, which shows the peak at 22o (PDF# 01-082-0512). Figure 1. XRD pattern of VRHA 5 10 15 20 25 30 35 40 45 50 55 60 Int en sit y / ar b. un it 2theta / degree Int en sit y / ar b. un it Synthesis of calcium silicate hydrate (CSH) from Vietnam rice hush 69 The FTIR of VRHA is given in Figure 2, indicating that the main chemical bonding of VRHA is O-Si-O, go well with XRD data given in Figure 1. Figure 2. FTIR spectrum of VRHA The phase analysis of CaO is given in Figure 3, indicating that commercialized CaO is puried (which the peak of CaO at 32o, 37o and 54o corresponding to PDF# 01-077-2376) and can be used for further reaction. Figure 3. XRD pattern of CaO The phase analysis of mixture of VRHA/CaO before and after hydrothermal treatment at 110 oC, and 200 oC for 24 hours. Before hydrothermal treatment, the phase composition of sample is crystobalite and Ca(OH)2. The present of Ca(OH)2 is given by hydration of CaO and water during the mixing process. After hydrothermal treatment, we can observe the new phase of Calcium Silicate Hydrate (CSH), Tobermorite (at 110 oC for 24 hours) and Xonotlite (at 200 oC for 24 hours). The morphology of sample before and after hydrothermal treatment at 110 oC and 200 oC for 24 hours also is given at Figure 5. 5 10 15 20 25 30 35 40 45 50 55 60 Int en sit y / ar b. un it 2theta / degree Int en sit y / ar b. un it Pham Trung Kien, Huynh Dai Phu, Nguyen Van Tam, Ngo Vo Ke Thanh, 70 Figure 4. XRD pattern of mixture of VRHA/CaO before and after hydrothermal treatment at different temperature levels: (a) before; (b) 110 oC to obtain Tobermorite; and (c) 200 oC to obtain Xonotlite. We can observe the morphological change of sample before and after hydrothermal treatment with the increase of hydrothermal treatment temperature. At 110 oC and 200 oC, we can observe the new pore, while the morphology transitionally changes from polyonal- like shape to needle-like shape and these needle-like shape crystals are interlocked together (Figure 5c). The size of new needle-like shape also increased with the increase of hydrothermal treatment temperature (Figure 5b, 5c). Figure 5. SEM images of sample before and after hydrothermal treatment at different temperature levels: (a) before; (b) 110 oC; and (e) 200 oC. 50 Before 110oC, 24h 200oC, 24h Tobermorite Xonotlite Ca/Si 1.0 a) b) c) a) Before b) 110oC/24h c) 200oC/24h 10m 10m10m Pham Trung Kien, Huynh Dai Phu, Nguyen Van Tam, Ngo Vo Ke Thanh, 70 Figure 4. XRD pattern of mixture of VRHA/CaO before and after hydrothermal treatment at different temperature levels: (a) before; (b) 110 oC to obtain Tobermorite; and (c) 200 oC to obtain Xonotlite. We can observe the morphological change of sample before and after hydrothermal treatment with the increase of hydrothermal treatment temperature. At 110 oC and 200 oC, we can observe the new pore, while the morphology transitionally changes from polyonal- like shape to needle-like shape and these needle-like shape crystals are interlocked together (Figure 5c). The size of new needle-like shape also increased with the increase of hydrothermal treatment temperature (Figure 5b, 5c). Figure 5. SEM images of sample before and after hydrothermal treatment at different temperature levels: (a) before; (b) 110 oC; and (e) 200 oC. 50 Before 110oC, 24h 200oC, 24h Tobermorite Xonotlite Ca/Si 1.0 a) b) c) a) Before b) 110oC/24h c) 200oC/24h 10m 10m10m Synthesis of calcium silicate hydrate (CSH) from Vietnam rice hush 71 4. CONCLUSIONS By using hydrothermal treatment of the compaction of VRA and CaO with the molar ratio of Ca/Si 1.0, we can synthesize Tobermorite (C5S6H5) at 110 oC and Xonotlite (C6S6H) at 200 oC. Both Tobermorite and Xonotlite are calcium silicate hydrate, and can be used as environmental materials. Thus, this research can contribute to the sustainability of Vietnam rice hush industry. ACKNOWLEDGEMENTS The research group would like to thank the Ho Chi Minh City University of Technology (HCMUT-VNU), and Department of International Engineering Development (Tokyo Institute of Technology), HUFI for supporting the research facilities. Thanks also go to the R&D Saigon Hi Tech Park (SHTP) the organization supported the financial aid for this study. REFERENCES 1. Tiggemann M. H., Tomacheski D., Celso F., Ribeiro V. F., Nachtigall S. M. B. - Use of wollastonite in a thermoplastic elastomer composition, Polymer Testing 32 (2013) 1373–1378. 2. Soliman A. M., Nehdi M. L. - Effects of shrinkage reducing admixture and wollastonite microfiber on early-age behavior of ultra-high performance concrete, Cement & Concrete Composites 46 (2014) 81–89. 3. Saadaldin S., Rizkalla A. - Synthesis and characterization of wollastonite glass– ceramics for dental implant applications, Dental Materials 30 (2014) 364-371. 4. Pham Trung Kien, Nguyen Hoc Thang, Do Quang Minh, Do Minh Hien, S. M. 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TÓM TẮT TỔNG HỢP KHOÁNG CALCIUM SILICATE HYDRATE (CSH) TỪ NGUỒN NGUYÊN LIỆU TRẤU Pham Trung Kien1*, Phan Viet Hoang1, Huynh Dai Phu1, Nguyen Van Tam2, Ngo Vo Ke Thanh2, Nguyen Hoc Thang3, Hirofumi Hinode4 1Đại học Bách Khoa TP.HCM, 2Trung tâm Nghiên cứu triển khai - Khu Công nghệ cao TP.HCM, 3Đại học Công nghiệp Thực phẩm TP.HCM, 4Viện Công nghệ Tokyo. *Email: phamtrungkien@hcmut.edu.vn Việt Nam là nước nông nghiệp, sản xuất nhiều gạo và sản phẩm phụ là trấu. Trấu được xem là chất thải nông nghiệp và được đốt bỏ. Quá trình này gây ô nhiễm môi trường, thu hút nhiều nghiên cứu để tận dụng trấu. Nhóm nghiên cứu ở bộ môn Ceramic tận dụng trấu như nguồn cung cấp silica (SiO2). Cần nhấn mạnh rằng thành phần chính của trấu là silica. Nghiên cứu này công bố kỹ thuật mới phối trộn tro và CaO với tỷ lệ mol Ca/Si 1.0 để tổng hợp khoáng xonotlite như vật liệu môi trường. Ưu điểm của nghiên cứu này là tận dụng nguồn trấu Việt Nam và giảm tác hại lên môi trường bằng phản ứng thủy nhiệt. Từ khóa: Calcium silicate, trấu, thủy nhiệt, ceramic.