The Environmental Friendly Route to Obtain Sodium Silicate Solution from Rice Husk Ash: A Comparative Study with Commercial Silicates Deflocculating Agents

2019 ◽  
Vol 11 (11) ◽  
pp. 6295-6305 ◽  
Author(s):  
Fernanda Andreola ◽  
Luisa Barbieri ◽  
Isabella Lancellotti
2014 ◽  
Vol 1010-1012 ◽  
pp. 1015-1019
Author(s):  
Ze Xin Yang ◽  
Lin Dong ◽  
Meng Wang ◽  
Huan Li

The main purpose of this article is to develop an environmentally friendly and economically effective process to produce silica from rice husk ash. Sodium silicate solution was prepared by the reaction of rice husk ash and sodium hydroxide solution, and then the sodium silicate solution was used as the raw material for the preparation of silica with sodium bicarbonate. During the reaction, the by-product can be passed into CO2 to prepare sodium bicarbonate what can be reutilized. Experimental route achieved resource recycling and environment-friendly, low energy consumption, zero emissions and so on. Meanwhile the microstructures of the silica powders were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Thermo gravimetric/Differential thermal analyzer (TG-DTA).The purity of silicon was up to 99.43% and the particle size was 200-300nm.


2017 ◽  
Vol 126 (1C) ◽  
pp. 37
Author(s):  
Hoàng Văn Đức

<p>In the present paper, a synthesis of MCM-41 mesoporous material with the sodium silicate solution prepared from the rice husk ash as a silica source by the hydrothermal process was demonstrated. The influence of synthesized conditions such as CTAB concentration, SiO<sub>2</sub>/CTAB molar ratio, stirring time and hydrothermal time were investigated. The samples were characterized by XRD, FT–IR and N<sub>2</sub> adsorption–desorption measurement. The obtained results showed that the samples possessed highly ordered hexagonal mesostructure with uniform mesopore size distribution in a large range of CTAB concentration (1,98-4,81% mass) and the SiO<sub>2</sub>/CTAB molar ratio (4-15). The sample had a high surface area (1071 m<sup>2</sup>/g) and large pore diameter (33,5 Å) with the molar ratio of CTAB: SiO<sub>2</sub>: H<sub>2</sub>O = 1: 6: 1000.</p><p>Keywords: MCM-41, sodium silicate solution, rice husk ash</p>


2020 ◽  
Vol 28 ◽  
pp. 03005
Author(s):  
Krismonalia Rizki ◽  
Deni Pranowo ◽  
Tri Joko Raharjo

A free lipase is one of the biocatalysts used for industrial applications, especially to catalyze the hydrolysis of palm oil. However, it is unstable in an extreme condition so it is easy to denature. Immobilization of lipase improve the enzyme's stability since the cage of the immobilization matrix around the lipase can minimalize denaturation. Silica gel is the most chosen matrix because of its high thermal stability and inertness. Lipase was immobilized in silica gel extracted from rice husk ash. Silica gel was prepared in a sodium silicate solution. Sol-gel process occurred when phosphoric acid was added into the sodium silicate solution until it reached a pH of 7. The immobilization process was initiated by reacting lipase in Phosphate Buffer Solution (PBS) added to the sol solution to produce hydrogel. Hydrogel was got into the dry process to form xerogel. The activity assay was conducted in the hydrolysis reaction by titrimetric method. The immobilized lipase resulted had an immobilization percentage of 67.71% and reusability for 6 cycles.


2019 ◽  
Vol 8 (1) ◽  
pp. 1-9
Author(s):  
Dilma Purnama Ubit ◽  
Yusmaniar Yusmaniar ◽  
Erdawati Erdawati

Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed                         into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1.   Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1.   Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash  


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2811
Author(s):  
Okpin Na ◽  
Kangmin Kim ◽  
Hyunjoo Lee ◽  
Hyunseung Lee

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.


2021 ◽  
Vol 10 (1) ◽  
pp. 268-283
Author(s):  
Yunlong Zhao ◽  
Yajie Zheng ◽  
Hanbing He ◽  
Zhaoming Sun ◽  
An Li

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.


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