Silica Extraction Research Articles

Extraction of Silica from Palm Ash Using Organic Acid Leaching Treatment

Agricultural wastes such as palm ash and rice husk have a possibility to be used as a usefully renewable source for production of energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes such as rice husk, due to silica as a useful raw material for industrial application. In the previous studies, the strong acid leaching treatment was carried out to remove metallic impurities and organics contained in rice husk. A strong acid leaching treatment, however, is significantly hazardous to the environment and people [. In this study, the environmentally benign and economically effective process to produce SiO2 materials from palm ash has been established by using citric acid leaching, not the conventional strong acids. Results showed that silica can be extracted from palm ash using citric acid leaching treatment under the optimum extracting conditions with 70°C of solution temperature, 60 minutes of reaction time and concentration of citric acid of more than 2%. The purity of silica extracted is more than 90%.

Preparation of Melt Derived 45S5 Bioactive Glass from Rice Hull Ash and Its Characterization

Bioactive glasses are inorganic bone regeneration materials which have been used for bone and cartilage reconstruction in orthopedics, oral, maxillofacial and otological surgery applications, especially based on mainly silicate or phosphate systems [1]. The bioactive glass can be prepared through sol-gel or melting method. Conventionally, commercial silica products such as tetraethylorthosilicate and tetramethylorthosilicate were used as silica sources [2]. Rice husk ash consists high grade (87-97%) of amorphous silica. The extraction of amorphous silica is simple and thus rice husk ash can be used as an alternative low cost silica precursor [3].

Extraction of Silica from Palm Ash Using Citric Acid Leaching Treatment: Preliminary Result

Large quantities of agricultural wastes such as palm ash and rice husk are found throughout Malaysia, have a possibility to be used as a usefully renewable source for production of energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes such as rice husk, due to silica as a useful raw material for industrial application. In the previous studies, the strong acid leaching treatment was carried out to remove metallic impurities and organics contained in rice husk. Since leaching treatment is a proper route to extract the silica, sulphuric acid (H2SO4), hydrochloric acid (HCl) and nitric acid (HNO3) solutions are currently used in leaching treatment to prepare silica materials [. A strong acid leaching treatment, however, is significantly hazardous to the environment and people. In this study, the weaker acid, citric acid solutions were used to replace strong acid in leaching processes. Preliminary results showed that silica can be extracted from palm ash using citric acid leaching treatment under the optimum extracting conditions with 70°C of solution temperature, 60 minutes of reaction time and concentration of citric acid of more than 2%. The purity of silica extracted is more than 90%.

Synthesis of zeolite T powders by direct dissolution of rice husk ash: an agro-waste material

Rice husk ash (RHA), an agro-waste material, was used for the synthesis of zeolite T powders following a simple and cost-effective process. In this process, silica as silicate was directly extracted from solid RHA particles in the presence of aluminate and other aqueous-based precursor materials. The synthesized powders were characterized by thermogravimetry analysis, differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, N2 physisorption measurements, and field emission scanning electron microscopy (FESEM). Crystallization of zeolite T powders was noticed at 100 °C/24 h. The vibration bands of the powders at around 580 and 630 cm−1 indicated the characteristic double six ring of zeolite T. Micropore surface area and micropore volume of zeolite T increased significantly at 100 °C/72 h. FESEM images showed ellipse-shaped morphology of the powders, and their aspect ratio increased with increase in reaction time. A tentative mechanism was proposed for direct extraction of silica as silicate from RHA, and its conversion to zeolite T in the presence of other aqueous-based precursors by a single step process.

Efficient Method for Recycling Silica Materials from Waste Powder of the Photonic Industry

An efficient and economic approach is proposed for the fast and direct recovery of silica materials from photonic waste powder. Unlike the conventional alkaline fusion method for the extraction of silica from waste materials, this method possesses advantages of a rapid and low-energy-consumed process with total recovery yield. The obtained mesoporous silica material, denoted as MCM-41(DU)-F, was recovered directly from photonic waste powder at room temperature with the assistance of cationic surfactant, hydrofluoric acid, and ammonia hydroxide. The recycled MCM-41(DU)-F with a high specific surface area (788 m(2)/g), ordered mesoporous structure (4.5 nm), and large pore volume (1.1 cm(3)/g) was used as support of tetraethylenepentamine (TEPA) for the capture of CO2 from a flue gas stream. The results demonstrated that TEPA-impregnated MCM-41(DU)-F had an adsorption capacity of 120 mg of CO2/g of adsorbent. This is higher than the amount adsorbed by TEPA-MCM-41(NaSi) made from pure chemicals (113 mg of CO2/g of adsorbent) and TEPA-MCM-41(AF) made from alkaline fusion (112 mg of CO2/g of adsorbent) under the same testing conditions. This novel recycling process, which can improve cost effectiveness for the mass production of valuable mesoporous silica materials from cheap and abundant resources through convenient preparation steps, is surely beneficial from the viewpoint of economical use of photonic industrial waste powder.

Utilization of Third-Stage Waste from a Rice Production for Removal of H2S, NO2 and SO2 from Air

Materials derived from rice husk fly ash were tested as adsorbents of hydrogen sulphide, sulphur dioxide and nitrogen dioxide. Breakthrough experiments were carried out at ambient temperature either in dry or moist air. The second-stage waste obtained in the extraction of silica from fly ash using sodium hydroxide exhibits the better adsorption capacity compared with that of caustic-modified activated carbons. The high performance is related to the presence of residual sodium hydroxide and other metals such as calcium, which react with acidic gases forming corresponding salts. Moreover, a high dispersion of the alkali and alkaline earth metal sites in the mesopores renders the pH of the solution basic, aiding in the dissociation of hydrogen sulphide, thereby facilitating its oxidation. The oxidation of species is also catalyzed by the carbonaceous surface. While in the case of hydrogen sulphide and sulphur dioxide, water helps in acid-base reactions, the opposite effect is found for NO2. Because its react...

Kinetics of Leaching Silicon from the Acid Leaching Residue of Pyrolusite

The content of SiO2 was more than 60% in the residue of pyrolusite detached manganese by reduction roasted and acid leached, and it was a better siliceous raw material because of less other impurities. Through leaching silicon process in the residue of pyrolusite with alkali at atmospheric pressure, leaching kinetics of silica in the sodium hydroxide solution was researched. The effects of the leaching temperature and the concentration of sodium hydroxide solution on the leaching behavior of silica from acid-leached pyrolusite slag were examinted. It was found that the extracting rate of silica is significantly influenced by the temperature, and the concentration of NaOH solution. The experimental datas were well interpreted with a shrinking core model under chemical control. On the basis of the Arrhenius expression the apparent activation energy of 77.69 kJ/mol and a reaction order of 0.34 for the extraction of silica was evaluated.

Review of Extraction of Silica from Agricultural Wastes Using Acid Leaching Treatment

Large quantities of agricultural wastes such as palm ash and rice husk are found in Malaysia, have a large possibility to be employed as usefully renewable to produce energy and silica (SiO2). Extensive researches have been carried out to extract silica from agricultural wastes such rice husk, because silica is useful raw material for industrial application. In the previous studies, the strong acid leaching treatment was carried out on rice husk to remove metallic impurities and organics contained in them. Leaching treatment is a proper route to extract the silica. Sulphuric acid (H2SO4), hydrochloric acid (HCl) and nitric acid (HNO3) solutions are conventionally used in leaching treatment to prepare silica materials [. A strong acid leaching treatment, however, is significantly hazardous to the environment and humans. This paper reviews the common extraction method used and the latest research trends in extraction of silica.

Organic template-free synthesis of ZSM-5 zeolite particles using rice husk ash as silica source

ZSM-5 zeolite particles were synthesized through in-situ extraction of silica from rice husk ash in the absence of organic template by a simple hydrothermal condition at 150°C/72–96h. The powders were characterized by XRD, TGA, DTA, FTIR, N2 physisorption studies, and field emission scanning electron microscopy (FESEM). Crystallization of ZSM-5 started at 150°C/72h. The vibration bands at around 540 and 1220cm−1 indicated the presence of characteristic double 5-ring of ZSM-5. The BET surface area and pore volume increased with increase in synthesis time from 72 to 96h at 150°C. FESEM images showed coffin-shaped morphology of ZSM-5 particles.

Nanosilica from rice husk: Extraction and characterization

Rice husk are generated from the rice cultivation. Silica is the major inorganic constituent of the rice husk, and by carrying out an acid chemical treatment followed by the process of burning, it is possible to extract high-surface area amorphous silica. This paper reports the extraction and characterization of nanosilica from two types of rice husk, namely agulhinha and cateto, using milder acid solutions. Thermogravimetry was used to characterize the burning behavior and to determine the activation energies. FT-IR results showed a good peak correlation between the commercial silica and burnt rice husk residue. There were found both nano- and microparticles with a large particle size distribution. The results showed the potential of silica extraction from rice husk, and additionally exhibited lower levels of corrosion damage to the reactor that generated weak acid residues due to the use of milder acid solutions.

Structural Features of Amorphous Silica from Plants

The data on the structural features of the plant and mineral silica studied by infrared spectroscopy, electron spin resonance and nuclear magnetic resonance 1H porometry methods are compared with analytical and the X-ray phase analysis data. It was shown that the structural features depend on the precursor raw material and on the silica extraction technique. However, the structure of silica obtained from plants principally is not different from that of silica of mineral origin. The pore size on plant silica is smaller than that on mineral silica.

Delamination Propensity of Pharmaceutical Glass Containers by Accelerated Testing with Different Extraction Media

The delamination of pharmaceutical glass is a serious issue, as it can cause glass particles to appear in vials, a problem that has forced a number of drug product recalls in recent years. In Type I pharmaceutical glass vials, delamination occurs generally at the bottom and shoulder, where extensive flaming during the conversion process can favor a strong evaporation of alkali and borate species and the formation of heavily enriched silica layers. The contact with parenteral preparations dissolved in an alkaline medium increases the rate of glass corrosion, while the differential hydration of these layers can cause the detachment of flakes. The purpose of this study was to investigate the effect of the pH and the composition of the extraction solutions on the propensity of different glass types to delaminate. Repeated autoclave extractions at 121 °C were carried out on different glass types with different extraction media, including organic extractants like citric and glutaric acid. When vials were in contact with alkaline solutions and similarly aggressive media, an increase in silica extraction values indicated glass corrosion and an increasing risk for further delamination. Under such conditions expansion 33 glass is extensively corroded, showing high silica concentration and heavy flaking as compared to other glass types. Sulfur-treated glass also showed early flaking, even if SiO(2) concentration was very low. A similar ranking was observed with extractions carried out with glutaric and citric acids, but at far much higher SiO(2) concentration levels. Extractions with 0.9% KCl solution can be used as an accelerated test to highlight the propensity of a glass to delaminate, but in no case it can be taken as a guarantee that the glass will not delaminate when exposed to the pharmaceutical drug, whose extraction ability requires case-by-case study. How can injectable drug manufacturers prevent glass delamination? The issue of delamination is a serious one, as it can cause glass particles to appear in vials, a problem that has forced a number of drug product recalls in recent years. To combat this, pharmaceutical and biopharmaceutical manufacturers need to understand the reasons for glass delamination. The most recent cases of product recall due to the presence of particles in the filling liquid have involved borosilicate glass containers carrying drugs made of active components with known ability to corrode glass and to dissolve the silica matrix. Sometimes these ingredients are dissolved in an alkaline medium that dramatically increases the glass corrosion and potentially causes the issue. As this action is strongly affected by time and temperature, flaking may become visible only after a long incubation during storage and requires systematic monitoring to be detected at its early stage. If the nature of the filling liquid is the driving force of the phenomenon, other factors are of primary importance. The surface morphology created during vial forming is a key issue, being a function of the forming temperature that is higher in the cutting step and the forming of the bottom. Delamination occurs generally on the vial's bottom and shoulder, where extensive flaming can favor a strong evaporation of alkali and borate species and the formation of heavily enriched silica layers. When these layers are in contact with a solution, they are subject to a differential re-hydration that may result in cracking and detachment of scales. The purpose of this investigation is to identify testing conditions and parameters that can be used as indicators of an incipient delamination process. Extractions with 0.9% KCl solution for 1 h at 121 °C can be used to simulate a long-term contact with aggressive pharmaceutical preparations, while SiO(2) concentration in the extract solution can be taken as an index of glass dissolution. The conclusions developed by this study can provide pharmaceutical manufacturers with information needed to help prevent glass delamination in their processes.

Using the Response Surface Methodology to Optimize the Extraction of Silica and Alumina from Coal Fly Ash for the Synthesis of Zeolite Na-A

Response surface methodology and inductively coupled plasma-optical emission spectroscopy were used to analyze the silicon (Si) and aluminum (Al) ion concentrations extracted from microwave-assisted hydrothermal fusion reactions between coal fly ash (CFA) and sodium hydroxide solution. The extracts containing Si and Al ions were successfully converted to zeolites by hydrothermal treatment at 95°C for 72 h. Fifteen experimental conditions for the extraction process were obtained using Box–Behnken design through the manipulation of three independent variables. These variables include NaOH concentration (2, 4 and 6 M), power level of microwave irradiation (10, 50 and 100 W)+++ and exposure time (1, 3.5 and 6 min). The statistical analysis result indicated a significant interaction effect with a p value of 0.001. Increasing the values of all the three variables led to an increase in the concentration of Si and Al ions in the CFA extract. The optimized combinations of the three variables within the experimental range for Si and Al extraction were 5.6 M for NaOH concentration, 5.5 min time of exposure to microwave irradiation and 100 W of microwave power level. Based on the extracted concentration values of Si and Al, three products were isolated; zeolite Na-A, sodalite octahydrate and gibbsite which were characterized by their XRD images. Plots of percent yield of the final products versus [Si4+] and [Al3+] revealed a trend of the types of product for various ranges of concentrations of the ions in the extracts prior to hydrothermal treatment at 95°C.

MINERALOGICAL, GEOCHEMICAL AND STRUCTURAL CHARACTERISTICS OF QUARTZ-ARENITES OF THE WITPOORT FORMATION (CAPE SUPERGROUP) NEAR KIRKWOOD, EASTERN CAPE, SOUTH AFRICA

Research Article| December 01, 2011 MINERALOGICAL, GEOCHEMICAL AND STRUCTURAL CHARACTERISTICS OF QUARTZ-ARENITES OF THE WITPOORT FORMATION (CAPE SUPERGROUP) NEAR KIRKWOOD, EASTERN CAPE, SOUTH AFRICA W.C. OLIVIER; W.C. OLIVIER Department of Geosciences, P O Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031, South Africa, e-mail: wcolie4@gmail.com Search for other works by this author on: GSW Google Scholar P.W.K. BOOTH; P.W.K. BOOTH Department of Geosciences, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031 South Africa, e-mail: Peter.Booth@nmmu.ac.za (corresponding author) Search for other works by this author on: GSW Google Scholar C.R. ANDERSON C.R. ANDERSON Department of Geosciences, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031 South Africa, e-mail: Callum.Anderson@nmmu.ac.za Search for other works by this author on: GSW Google Scholar Author and Article Information W.C. OLIVIER Department of Geosciences, P O Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031, South Africa, e-mail: wcolie4@gmail.com P.W.K. BOOTH Department of Geosciences, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031 South Africa, e-mail: Peter.Booth@nmmu.ac.za (corresponding author) C.R. ANDERSON Department of Geosciences, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031 South Africa, e-mail: Callum.Anderson@nmmu.ac.za Publisher: Geological Society of South Africa First Online: 09 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2011 Geological Society of South Africa South African Journal of Geology (2011) 114 (3-4): 249–264. https://doi.org/10.2113/gssajg.114.3-4.249 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation W.C. OLIVIER, P.W.K. BOOTH, C.R. ANDERSON; MINERALOGICAL, GEOCHEMICAL AND STRUCTURAL CHARACTERISTICS OF QUARTZ-ARENITES OF THE WITPOORT FORMATION (CAPE SUPERGROUP) NEAR KIRKWOOD, EASTERN CAPE, SOUTH AFRICA. South African Journal of Geology 2011;; 114 (3-4): 249–264. doi: https://doi.org/10.2113/gssajg.114.3-4.249 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract A study of Late Palaeozoic Witteberg Group rocks (Cape Supergroup) near Kirkwood, Eastern Cape was carried out to determine the viability of extracting silica for solar cell production. Mineralogical, geochemical and structural analyses of selected outcrops of quartz-arenites showed that source rocks in the study area do not possess the appropriate chemical attributes to warrant extraction of silica. Despite this finding the study presents valuable information on strata composition and structural data which are compared and interpreted with known regional structural patterns of the Cape Fold Belt in the Eastern Cape.Samples from the Witpoort Formation were analyzed using petrographic light microscopy, scanning electron microscopy and X-ray fluorescent spectroscopy. Analyses indicate that samples are composed almost entirely of quartz, with accessory biotite, muscovite, sericite, baryte, apatite, rutile and monazite. Haematite occurs most frequently along fractures, and is more prevalent in the Rooirand Member than the Perdepoort Member, giving the former a reddish brown colour on outcrop. The presence of chemical impurities is thought to be partly controlled by the original depositional environment, namely, near-shore and beach environments.Strata in the study area display a range of fold styles, mostly showing northward vergence. Low angle thrust faults dip south and some thrusts dip north. In general, the orientation of fore-thrusts and folds in the study area indicate a northward-directed compression event during the Late Palaeozoic. This pattern conforms to the structural development in other parts of the Cape Fold Belt in the Eastern Cape. South-dipping normal faults and strike-slip faults post-date thrust faulting, and formed during the breakup of Gondwana, during the Mesozoic, transecting all other structures in the study area. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Role of ceria in CO 2 adsorption on NaZSM-5 synthesized using rice husk ash

Ceria (3, 5, 7, 11, 19 wt%) impregnated NaZSM-5 was synthesized and studied for adsorption of CO 2. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), CO 2-temperature programmed desorption (CO 2-TPD) and Brunauer–Emmett–Teller (BET) techniques. The heat of the reaction (Δ H r) derived from differential scanning calorimetry (DSC) analysis was 490 Btu/lb. XRD analysis showed a decrease in the intensity of patterns with the increase in the ceria loading but crystallization of ceria to larger size was clearly evident for 11 and 19% loading. The surface area decreased for 3 and 5% loading, but increased for 7, 11 and 19% loading illustrating difference in dispersion. The maximum adsorption capacity of CeO 2(5%)/NaZSM-5 was 130 mg/g of sorbent. Extraction of silica from the agricultural waste, rice husk, and its use in the zeolite synthesis was an advantage in this study. Hence, from the study it was concluded that ceria impregnated NaZSM-5 could be treated as a novel material for CO 2 adsorption, as they were regenerable and recyclable. This study can also be applied to all other zeolites.

Genomic DNA extraction protocols for bone samples: The comparison of Qiagen and Zymo Research spin columns

The aim of this study was to develop an extraction protocol for bone samples based on ZR Genomic DNA Tissue MicroPrep kit and perform a quantitative comparison with the existing silica extraction protocol based on Qiagen columns and evaluate the effect of demineralization on the quantity of extracted DNA.

Thermogravimetry applied to characterization of fly ash-based MCM-41 mesoporous materials

The thermogravimetry (TG) was used for characterization of the fly ash (FA)-based MCM-41 mesoporous materials. MCM-41 mesoporous materials were synthesized using silica extracts from different FA. The synthesis of MCM-41 from FA was carried out by the hydrothermal method using the supernatants of coal FA (in the form of sodium silicate) and cationic cetyltrimethylammonium bromide (CTAB) surfactants as the structure-directing agents. On the basis of the data obtained from the TG analysis, thermal behaviour of FA-based MCM-41 mesoporous materials was assessed. This study has established the range of temperatures corresponding to the desorption of water, decomposition of the surfactant and condensation of silanol, thereby making the overall quality assessment of FA-based MCM-41 mesoporous materials.

Determination of ricin by nano liquid chromatography/mass spectrometry after extraction using lactose‐immobilized monolithic silica spin column

Ricin is a glycosylated proteinous toxin that is registered as toxic substance by Chemical Weapons convention. Current detection methods can result in false negatives and/or positives, and their criteria are not based on the identification of the protein amino acid sequences. In this study, lactose-immobilized monolithic silica extraction followed by tryptic digestion and liquid chromatography/mass spectrometry (LC/MS) was developed as a method for rapid and accurate determination of ricin. Lactose, which was immobilized on monolithic silica, was used as a capture ligand for ricin extraction from the sample solution, and the silica was supported in a disk-packed spin column. Recovery of ricin was more than 40%. After extraction, the extract was digested with trypsin and analyzed by LC/MS. The accurate masses of molecular ions and MS/MS spectra of the separated peptide peaks were measured by Fourier transform-MS and linear iontrap-MS, respectively. Six peptides, which were derived from the ricin A-(m/z 537.8, 448.8 and 586.8) and B-chains (m/z 701.3, 647.8 and 616.8), were chosen as marker peptides for the identification of ricin. Among these marker peptides, two peptides were ricin-specific. This method was applied to the determination of ricin from crude samples. The monolithic silica extraction removed most contaminant peaks from the total ion chromatogram of the sample, and the six marker peptides were clearly detected by LC/MS. It takes about 5 h for detection and identification of more than 8 ng/ml of ricin through the whole handling, and this procedure will be able to deal with the terrorism using chemical weapon.

Synthesis of Pure Zeolite X from Palygorskite Clay Using a Two-Stage Method

A natural mineral, palygorskite clay, was used to synthesize pure zeolite X via a two-stage method. The synthetic parameters, such as calcination, crystallization time, and SiO2/Al2O3molar ratio, were investigated. The results indicated that calcination enhanced the extraction of silica from palygorskite clay and was beneficial for the formation of zeolite X. Micro-sized pure zeolite X with the particle size of 1-4 μm was obtained in the gel with the SiO2/Al2O3molar ratio range of 1.93 to 3 after hydrothermal treatment at 80 °C for 5 h. The synthetic zeolite X showed high specific surface area (487 m2/g) and low Si/Al ratio (1.17).

Treatment of iron ore slime for value addition

Typical Indian iron ore slime in a steel plant contains 56% iron, 6.78% Al 2O 3 and 5.8% SiO 2. Value addition to this reject / waste material has been investigated using chemical treatment and electrowinning. Two alternate chemical treatment routes have been explored: (i) acid extraction of iron followed by alkali treatment and (ii) alkali extraction of aluminum oxide and silica from iron ore slime. Alkali extraction improved iron content up to 65% w/w. Acid extraction could improve the same up to 63% w/w. Electrowinning of iron from oxalic acid solution using steel cathode and a lead anode, surrounded by a synthetic cloth diaphragm, produces high purity iron deposits on the cathode surface. Chemically treated iron ore slime is suitable for iron production using blast furnace whereas the elemental iron produced by electrowinning can be used directly for steelmaking. Along with the process details, a preliminary calculation of the economics of the two processes has been presented.