A Study on a Green Route to Preparation of Silica Powders with Rice Husk Ash

2014 ◽  
Vol 1010-1012 ◽  
pp. 1015-1019
Author(s):  
Ze Xin Yang ◽  
Lin Dong ◽  
Meng Wang ◽  
Huan Li
Keyword(s):  
Sodium Bicarbonate ◽  
Sodium Silicate ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Raw Material ◽  
Transmission Electron ◽  
Thermal Analyzer

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.

scholarly journals A STUDY ON SYNTHESIS OF MCM-41 MESOPOROUS MATERIAL WITH SOURCE OF SODIUM SILICATE SOLUTION FROM RICE HUSK ASH

2017 ◽  
Vol 126 (1C) ◽  
pp. 37
Author(s):  
Hoàng Văn Đức
Keyword(s):  
Sodium Silicate ◽  
Rice Husk ◽  
Mesoporous Material ◽  
Rice Husk Ash ◽  
Hydrothermal Process ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Molar Ratio ◽  
Ctab Concentration ◽  
Mcm 41

<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>

scholarly journals Immobilization of lipase in silica gel from rice husk ash and its activity assay to hydrolyze palm oil

2020 ◽  
Vol 28 ◽  
pp. 03005
Author(s):  
Krismonalia Rizki ◽  
Deni Pranowo ◽  
Tri Joko Raharjo
Keyword(s):  
Sodium Silicate ◽  
Silica Gel ◽  
Rice Husk ◽  
Palm Oil ◽  
Rice Husk Ash ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Extreme Condition ◽  
Activity Assay ◽  
Dry Process

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.

scholarly journals Adsorbsi Pewarna Direct Black 38 Menggunakan Komposit Silika Mesopori Dari Abu Sekam Padi/Karbon Aktif Dari Tempurung Kelapa

2019 ◽  
Vol 8 (1) ◽  
pp. 1-9
Author(s):  
Dilma Purnama Ubit ◽  
Yusmaniar Yusmaniar ◽  
Erdawati Erdawati
Keyword(s):  
Activated Carbon ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Dye Adsorption ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Carbon Composite ◽  
Activated Carbon Adsorption ◽  
Composite Adsorbent ◽  
Carbon Adsorption

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  

Effect of Alkali on the Geopolymer Strength

2010 ◽  
Vol 168-170 ◽  
pp. 1827-1832 ◽  
Author(s):  
Ting Sheng Qiu ◽  
Jing Zhong Kuang ◽  
Fang Shi
Keyword(s):  
Liquid Phase ◽  
Sodium Silicate ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Alkali Solution ◽  
Raw Material ◽  
Alkali Activator ◽  
Content Ratio ◽  
And Tungsten ◽  
Trigger Action

In this study, geopolymer was synthesized with metakaolin and tungsten-tailing as the main raw material and alkali activator composed of sodium silicate solution and alkali solution. By the contrast of the experiments with five kinds of alkali activators, the result was obtained. When the concentration of the NaOH or KOH was 10mol/L,the content of NaOH or KOH in the liquid phase was 35%,while the concentration of the Ca(OH)2was 3mol/L, the content in the liquid phase was 35%,the property of geopolymer was the best. For the combined alkali, when the content ratio of Ca(OH)2to KOH or Ca(OH)2to NaOH of 2:3,there was a balance between the activator of alkali and the resistance of Ca2+.The trigger action of the alkali activator on the activity of slag was accelerated.

Effects of Alkaline Solution on the Properties of Slag Based Geopolymer

2018 ◽  
Vol 877 ◽  
pp. 193-199 ◽  
Author(s):  
Suman Saha ◽  
C. Rajasekaran
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
Sodium Hydroxide Solution ◽  
Setting Time ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Hydroxide Solution ◽  
Geopolymer Paste

Production of Ordinary Portland Cement (OPC) requires huge quantity of natural resources and energy and it releases large amount of carbon - di - oxide to the environment. Therefore, enormous studies have been carried out throughout the world to establish geopolymer as an alternative binder material for the replacement of OPC to protect the environment. This study intends to explore the effects of alkaline solution on the properties of geopolymer produced with ground granulated blast furnace slag. Properties such as Standard consistency, setting time of slag based geopolymer paste has been determined using Vicat’s apparatus (according to the guidelines given by Indian Standards for OPC). In order to determine the effects of alkaline solution on the properties of geopolymers, the concentration of sodium hydroxide solution has been varied from 6M to 16M and the ratio of sodium silicate solution to sodium hydroxide solution is also varied from 1.0 to 2.0. Results indicate higher standard consistency and significant less setting time for slag based geopolymer paste than that of OPC paste. Compressive strength of the geopolymer paste and mortar cube samples, cured in ambient conditions till the day of testing, is increasing with the increase of the concentration of sodium hydroxide solution. Highest compressive strength is obtained for the samples prepared with alkaline solution having the ratio of sodium silicate solution to sodium hydroxide solution as 1.5. But when the concentration of sodium hydroxide solution is beyond 14M, decreasing trend in compressive strength is observed.

scholarly journals KARAKTERISASI SILIKA DARI ABU AMPAS TEBU

KOVALEN ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 290-298
Author(s):  
Tifa Paramitha ◽  
Tri Reksa Saputra ◽  
Amelia Nur Aliah ◽  
Arijan Vevayose Tarigan ◽  
Mukhtar Ghozali
Keyword(s):  
Sodium Silicate ◽  
Water Adsorption ◽  
Sodium Hydroxide Solution ◽  
Condensation Reaction ◽  
Silanol Group ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Extraction Time ◽  
Adsorption Ability ◽  
Acidity Level

Silica has been successfully extracted from sugarcane bagasse ash by using alkali method. Extraction was carried out using sodium hydroxide solution to obtain sodium silicate solution and solid residue. Then, hydrochloric acid solution was added to sodium silicate solution until pH of solution was 7 and silica was formed. Furthermore, silica was heated in oven at 150 ˚C and calcined at 700 ˚C. Variation of this study were extraction time (1, 2 and 3 hours). The synthesized silica were characterized functional groups, acidity level, water adsorption ability and adsorption ability of Cu2+ ion. The results of FTIR analysis showed that all silica contain siloxane group. Silanol group did not appear because during calcination process occured the condensation reaction of silanol group. Other characterization results showed that silica with extraction time of 2 hours had highest acidity level, water adsorption ability and adsorption ability of Cu2+ ion, which were 6.201 mmol/gram, 86.41% and 92.55%. Keywords : bagasse ash, extraction, silica, siloxane

Effect of Alkaline Activators to Engineering Properties of Geopolymer-Based Materials Synthesized from Red Mud

2018 ◽  
Vol 777 ◽  
pp. 508-512 ◽  
Author(s):  
Van Quang Le ◽  
Minch Quang Do ◽  
Minh Duc Hoang ◽  
Vo Thi Ha Quyen Pham ◽  
Thu Ha Bui ◽  
...  
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Red Mud ◽  
Raw Materials ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
High Heat ◽  
Engineering Properties ◽  
Alumina Production

Geopolymer is an inorganic polymer material formed from alumino-silicate structures. Geopolymer has many outstanding functions in comparison with ordinary materials such as high mechanical strength, high heat and chemical resistance, and lightweight property. The engineering properties of geopolymer-based materials depend on raw materials and synthesized conditions. In which, the aluminosilicate materials having high activity and consisting of many alkaline activators have the possibility of increasing pH in geopolymer paste. In the solution of paste, aluminosilicate compounds are solubilized and then react with alkali-activated ions to form geopolymeric networks. The geopolymer can be synthesized in many different conditions depending on factors of temperature, pressure, and curing conditions. In this study, red mud (RM) was used as the main alumino resource for geopolymerization process. RM is a solid waste residue being left from the mining process of bauxite ores with caustic soda for alumina production. Its disposal remains a global issue in terms of environmental concerns. Formation of RM-based geopolymer was affected by many factors, in which, the alkaline activators are the most important factor. This research was conducted with sodium hydroxide and sodium silicate solutions to elucidate the effect of alkaline activator ratio to the engineering properties of RM-based geopolymers. The results showed that the RM-based geopolymer used sodium silicate solution has more outstanding properties than RM-based geopolymer using sodium hydroxide solution.

Synthesis of Nanosized NaY Molecular Sieve under Dynamic Hydrothermal Crystallization

2014 ◽  
Vol 609-610 ◽  
pp. 288-297
Author(s):  
Ying Chen ◽  
Peng Liu ◽  
Zhi Wu Yu ◽  
Juan Tan
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Sodium Silicate ◽  
Molecular Sieves ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Mixed Solution ◽  
Relative Crystallinity ◽  
Synthesis Conditions ◽  
Transmission Electron

Nanosized NaY molecular sieves with high crystallinity was synthesized using sodium silicate solution (industrial water glass) without the presence of additive via dynamic hydrothermal method. The influences of aging time of the seed-gel, the temperature and route of gelation, and the alkalinity of the feed-stock gel on the grain size, relative crystallinity and framework SiO2/Al2O3 ratios of NaY nanoparticles were investigated by XRD(X-ray diffraction, XRD), SEM(Scanning electron microscope, SEM) and TEM(Transmission electron microscope, TEM). The results shown that the grain size could be effectively controlled by adding seed-gel of aging at 20°C for 4 days, and adopting the gelation route of putting sodium silicate solution into NaAlO2 and NaOH mixed solution. The grain size and framework SiO2/Al2O3 ratios decreased with reducing the alkalinity of synthetic system. The nanoNaY products with the grain size at a range of 82-105 nm and the framework SiO2/Al2O3 ratios at 3.9-4.0 could be synthesized by optimizing the synthesis conditions.

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