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

<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>

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.


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.


Silicon ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1913-1923 ◽  
Author(s):  
José A. S. Costa ◽  
Victor H. V. Sarmento ◽  
Luciane P. C. Romão ◽  
Caio M. Paranhos

2017 ◽  
Vol 729 ◽  
pp. 24-29
Author(s):  
Thitipob Sirisoontornpanit ◽  
Atichat Wongkoblab ◽  
Supunnee Junpirom

SUZ-4 zeolite was synthesized by the sol-gel technique, followed by hydrothermal process. The effect of the molar ratio of rice husk ash based silicon dioxide to silica solution was investigated. The synthesized zeolite was characterized by XRD, SEM, N2 adsorption and temperature programmed desorption. The results show that the SUZ-4 zeolite was formed for all investigated conditions. However, the formation of MER zeolite occurred as an impurity for the content of rice husk ash higher than 75%. A needle shape crystal with mainly microporous structure is the feature of synthesized SUZ-4 zeolite. The result of temperature programmed desorption indicated that the chemical surface property of obtained SUZ-4 zeolite was weak acid sites.


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  


2011 ◽  
Vol 11 (3) ◽  
pp. 279-284 ◽  
Author(s):  
Suyanta Suyanta ◽  
Agus Kuncaka

The research about synthesis and characterization of MCM-41 from rice husk has been done. Silica (SiO2) was extracted from rice husk by refluxing with 3M hydrochloric solution at 80 °C for 3 h. The acid-leached rice husk was filtered, washed, dried and calcined at 650 °C for 6 h lead the rough powder of rice husk silica with light brown in color. Characterization was carried out by X-ray diffraction (XRD) and FTIR spectroscopy method. Rice husk silica was dissolved into the sodium hydroxide solution leading to the solution of sodium silicate, and used as silica source for the synthesis of MCM-41. MCM-41 was synthesized by hydrothermal process to the mixture prepared from 29 g of distilled water, 8.67 g of cetyltrimethyl ammonium bromide (CTMAB), 9.31 g of sodium silicate solution, and amount mL of 1 M H2SO4. Hydrothermal process was carried out at 100 °C in a teflon-lined stainless steel autoclave heated in the oven for 36 h. The solid phase was filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcination at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined crystals were characterized by using FTIR spectroscopy, X-ray diffraction and N2 physisorption methods. In order to investigate the effect of silica source, the same procedure was carried out by using pure sodium silicate as silica source. It was concluded that silica extracted from rice husk can be used as raw materials in the synthesis of MCM-41, there is no significant difference in crystallinity and pore properties when was compared to material produced from commercial sodium silicate.


2018 ◽  
Vol 21 (3) ◽  
pp. 139-143
Author(s):  
Arnelli Arnelli ◽  
Bara Yunianto Fathoni ◽  
Teguh Iman Prastyo ◽  
Ahmad Suseno ◽  
Yayuk Astuti

Zeolite was successfully synthesised from ash bagasse and from rice husk ash as source of silica and applied to surfactant builder. The removal of silica from bagasse ash and from rice husk ash was influenced by NaOH concentration to obtain sodium silicate. This research aimed to synthesize zeolite, determine the optimum concentration of NaOH to synthetic zeolite, identify the zeolite mineral type, morphology, determine cation exchange rate and detergency by using synthesized zeolite as builder. Synthesis of zeolite was undertaken by sol-gel method followed by hydrothermal process. The stages of this study included the production of bagasse and rice husk ashes, isolation of silicate using a variation of NaOH concentration of 1.67, 3.33, 5.00, 6.67 and 8.30 M in the form of sodium silicate. Synthesis of zeolite was carried out by reacting sodium silicate and sodium aluminate using hydrothermal method. The synthesized zeolites were characterized using XRD and SEM. The results of this research indicated the types of zeolite minerals formed, namely, zeolite A, Na-A, Na-Y and sodalite. The morphology of the synthesized zeolites from both samples was quite homogeneous, NaOH concentration used to produce zeolite from bagasse ash was 1.67 M with value of cation exchange capacity (CEC) and detergency were respectively 121.14 mek/100 gram and 92.09% while synthesis zeolite from rice husk ash was generated using 8.3 M NaOH concentration with value of cation exchange capacity (CEC) and detergency were 65,71 mek / 100 gram and 94,313%, respectively.


2005 ◽  
Vol 494 ◽  
pp. 333-338 ◽  
Author(s):  
J. Krstić ◽  
N. Vukelić ◽  
Zoran Nedić ◽  
A. Milutinović-Nikolić ◽  
A. Šućurović ◽  
...  

The aim of this paper was the investigation of the influence of synthesis parameters, as well as the order of synthesis steps, in procedure of chemical precipitation, on the properties of synthesized nickel precursor. The starting materials were always the same aqueous solutions of Ni(NO3)2×6H2O and Mg(NO3)2×6H2O of constant molar ratio, 2% solution of SiO2 in the form of sodium silicate solution (module SiO2/Na2O = 3.0) and 10% solution of Na2CO3, while synthesis steps and addition modes were varied. Complete pH and temperature monitoring was performed during entire synthesis at 90°C. The formed precipitate aged 30 minutes at synthesis temperature. By changing the order and conditions of adding SiO2 and Na2CO3 solutions and keeping the treatment of precipitates the same (rinsing with hot distilled water followed by drying at 110°C for 24 hours) six different precursors were obtained. Samples characterizations were performed using different experimental techniques: XRD analysis, IR spectroscopy, reflection spectroscopy, TG analysis, N2 physisorption. The relation between synthesis procedure and precursor properties was established.


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