scholarly journals The Production of Biogenic Silica from Different South African Agricultural Residues through a Thermo-Chemical Treatment Method

2021 ◽  
Vol 13 (2) ◽  
pp. 577
Author(s):  
Ncamisile Nondumiso Maseko ◽  
Denise Schneider ◽  
Susan Wassersleben ◽  
Dirk Enke ◽  
Samuel Ayodele Iwarere ◽  
...  
Keyword(s):  
Citric Acid ◽  
South African ◽  
Elemental Analysis ◽  
Chemical Treatment ◽  
Biogenic Silica ◽  
Textural Properties ◽  
Treatment Method ◽  
Attractive Alternative ◽  
Average Pore ◽  
X Ray

A thermo-chemical treatment method was used to produce biogenic amorphous silica from South African sugarcane and maize residues. Different fractions of South African sugarcane (leaves, pith, and fiber) were processed for silica production. The biomass samples were leached with either 7 wt% citric acid or 7 wt% sulfuric acid at 353 K for 2 h prior to being rinsed, dried and combusted using a four-step program ranging from room temperature to 873 K in a furnace. The characterization of the pre-treated biomass samples was conducted using thermogravimetric analysis (TG/DTA), X-ray fluorescence analysis (XRF) and elemental analysis (CHN), while the final products were characterized by XRF, X-ray diffraction (XRD), elemental analysis, nitrogen physisorption and scanning electron microscopy (SEM). Citric acid pre-treatment proved to be an attractive alternative to mineral acids. Amorphous biogenic silica was produced from sugarcane leaves in good quality (0.1 wt% residual carbon and up to 99.3 wt% silica content). The produced biogenic silica also had great textural properties such as a surface area of up to 323 m2 g−1, average pore diameter of 5.0 nm, and a pore volume of 0.41 cm3 g−1.

Synthesis of N/Al Doped TiO2 Mesoporous Nanomaterials with Pyridine as a Template

2013 ◽  
Vol 634-638 ◽  
pp. 1143-1151
Author(s):  
Chen Yan Luo ◽  
Shao You Liu ◽  
Qing Ge Feng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Anatase Phase ◽  
Textural Properties ◽  
Average Pore ◽  
Doped Tio2 ◽  
X Ray ◽  
Co Doping ◽  
Tio2 Lattice ◽  
Isomorphous Replacement ◽  
Chloride Hexahydrate

With tetrabutyl orthotitanate, hydrazine hydrate and aluminum chloride hexahydrate as original materials and pyridine as a template reagent, N/Al doped TiO2 (N-TiO2, Al-TiO2, Al-N-TiO2) mesoporous nanomaterials were successfully synthesized through a simple and environmentally friendly solid state reaction route. The textural properties of the samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), ultraviolet visible light spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS), Raman spectroscope and N2 adsorption-desorption at 77K. Moreover, the formation mechanism of the N/Al-doped TiO2 mesoporous material was proposed in presence of pyridine. It clearly shows that the microscopic structure of Al-N-TiO2 nanomaterial with crystal anatase phase is an irregular shape nanoparticle with size of 5~20 nm. N atoms as N3- states have been incorporated into the lattice of TiO2 or have been entered into the interstice of TiO2 lattice. Al ions occupy the sites of Ti in crystal lattices by isomorphous replacement. Either the doping of N or Al, or the co-doping of N and Al, it can effectively embarrass the crystal growth of TiO2. The specific surface area and the average pore diameter are the 138.4 m2/g and 1.9 nm, respectively. Interestingly, the UV-vis spectra display that the adsorption intensity of N-Al-TiO2 nanomaterial decreases in the order of N-Al-TiO2＞N-TiO2＞Al-TiO2.

scholarly journals Protein Adsorption onto Modified Porous Silica by Single and Binary Human Serum Protein Solutions

2021 ◽  
Vol 22 (17) ◽  
pp. 9164
Author(s):  
Diego R. Gondim ◽  
Juan A. Cecilia ◽  
Thaina N. B. Rodrigues ◽  
Enrique Vilarrasa-García ◽  
Enrique Rodríguez-Castellón ◽  
...  
Keyword(s):  
Human Serum ◽  
Photoelectron Spectroscopy ◽  
Serum Proteins ◽  
Porous Silica ◽  
Textural Properties ◽  
Molar Ratio ◽  
Maximum Adsorption Capacity ◽  
Average Pore ◽  
X Ray ◽  
Human Serum Protein

Typical porous silica (SBA-15) has been modified with pore expander agent (1,3,5-trimethylbenzene) and fluoride-species to diminish the length of the channels to obtain materials with different textural properties, varying the Si/Zr molar ratio between 20 and 5. These porous materials were characterized by X-ray Diffraction (XRD), N2 adsorption/desorption isotherms at −196 °C and X-ray Photoelectron Spectroscopy (XPS), obtaining adsorbent with a surface area between 420–337 m2 g−1 and an average pore diameter with a maximum between 20–25 nm. These materials were studied in the adsorption of human blood serum proteins (human serum albumin—HSA and immunoglobulin G—IgG). Generally, the incorporation of small proportions was favorable for proteins adsorption. The adsorption data revealed that the maximum adsorption capacity was reached close to the pI. The batch purification experiments in binary human serum solutions showed that Si sample has considerable adsorption for IgG while HSA adsorption is relatively low, so it is possible its separation.

scholarly journals Extraction and Characterization of Biogenic Silica Obtained from Selected Agro-Waste in Africa

2021 ◽  
Vol 11 (21) ◽  
pp. 10363
Author(s):  
Clement Owusu Prempeh ◽  
Steffi Formann ◽  
Thomas Schliermann ◽  
Hossein Beidaghy Dizaji ◽  
Michael Nelles
Keyword(s):  
Citric Acid ◽  
Biogenic Silica ◽  
Food Production ◽  
Value Added ◽  
Emission Spectrometry ◽  
Biomass Fuels ◽  
X Ray ◽  
Biomass Residues ◽  
Pre Treatment

Increased amounts of available biomass residues from agricultural food production are present widely around the globe. These biomass residues can find essential applications as bioenergy feedstock and precursors to produce value-added materials. This study assessed the production of biogenic silica (SiO2) from different biomass residues in Africa, including cornhusk, corncob, yam peelings, cassava peelings and coconut husks. Two processes were performed to synthesize the biogenic silica. First, the biomass fuels were chemically pre-treated with 1 and 5% w/v citric acid solutions. In the second stage, combustion at 600 °C for 2 h in a muffle oven was applied. The characterization of the untreated biomasses was conducted using Inductively coupled plasma—optical emission spectrometry (ICP-OES), thermal analysis (TG-DTA) and Fourier-transform infrared spectroscopy (FTIR). The resulting ashes from the combustion step were subjected to ICP, nitrogen physisorption, Energy dispersive X-ray spectroscopy (EDX) as well as X-Ray diffraction (XRD). ICP results revealed that the SiO2 content in the ashes varies between 42.2 to 81.5 wt.% db and 53.4 to 90.8 wt.% db after acidic pre-treatment with 1 and 5 w/v% acid, respectively. The relative reductions of K2O by the citric acid in yam peel was the lowest (79 wt.% db) in comparison to 92, 97, 98 and 97 wt.% db calculated for corncob, cassava peel, coconut husk and cornhusk, respectively. XRD analysis revealed dominant crystalline phases of arcanite (K2SO4), sylvite (KCl) and calcite (CaCO3) in ashes of the biomass fuels pre-treated with 1 w/v% citric acid due to potassium and calcium ions present. In comparison, the 5 w/v% citric acid pre-treatment produced amorphous, biogenic silica with specific surface areas of up to 91 m2/g and pore volumes up to 0.21 cm3/g. The examined biomass residues are common wastes from food production in Africa without competition in usage with focus application. Our studies have highlighted a significant end-value to these wastes by the extraction of high quality, amorphous silica, which can be considered in applications such as catalyst support, construction material, concrete and backing material.

scholarly journals Preparation of silicon and alumosilicic aerogels based on the decomposition of nepheline with an alcoholic solution of sulfuric acid

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 54-59
Author(s):  
Yu. O. Velyaev ◽  
◽  
D. V. Maiorov ◽  
I. B. Kometiani ◽  
◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Specific Surface ◽  
Elemental Analysis ◽  
Pore Volume ◽  
Average Pore Size ◽  
Alcoholic Solution ◽  
Average Pore ◽  
Skeletal Density ◽  
X Ray ◽  
Chemical Purity

The results of studies on the production of silicon and aluminum-silicon aerogels from nepheline are presented. The morphology of the obtained samples was studied. Their chemical purity was proved by the method of X-ray elemental analysis. The structural and surface properties of the resulting aerogel are presented, such as: specific surface area (843.62 и 503.99 m2/g) and pore volume (0.396 и 0.237 cm3/g), average pore size (1.870 nm). Data on the skeletal density of the obtained samples are given

Signal/Noise Ratio and Elemental Detectivity by Eels

1982 ◽  
Vol 40 ◽  
pp. 488-489
Author(s):  
R. F. Egerton
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Elemental Analysis ◽  
Electron Energy Loss Spectroscopy ◽  
Emission Spectroscopy ◽  
X Ray ◽  
Signal Noise ◽  
Characteristic Signal ◽  
Noise Ratio ◽  
Electron Energy Loss

An important parameter governing the sensitivity and accuracy of elemental analysis by electron energy-loss spectroscopy (EELS) or by X-ray emission spectroscopy is the signal/noise ratio of the characteristic signal.

Effect of Chemical Treatment with Citric Acid or Ozonated Water on Microbial Growth and Polyphenoloxidase Activity in Lettuce and Cabbage

2004 ◽  
Vol 9 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Hyoung-Jun Youm ◽  
Jae-Won Jang ◽  
Kyu-Ri Kim ◽  
Hyo--Jjung Kim ◽  
Eun-Hee Jeon ◽  
...  
Keyword(s):  
Citric Acid ◽  
Chemical Treatment ◽  
Microbial Growth ◽  
Ozonated Water

scholarly journals Non-Thermal Plasma-Modified Ru-Sn-Ti Catalyst for Chlorinated Volatile Organic Compound Degradation

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Surface Oxidation ◽  
Treatment Method ◽  
X Ray ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Doped Titania

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.

scholarly journals Efficient Adsorption of Methylene Blue by Porous Biochar Derived from Soybean Dreg Using a One-Pot Synthesis Method

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 661
Author(s):  
Zhiwei Ying ◽  
Xinwei Chen ◽  
He Li ◽  
Xinqi Liu ◽  
Chi Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
Urban Pollution ◽  
Maximum Adsorption Capacity ◽  
One Pot ◽  
Average Pore ◽  
X Ray ◽  
Isotherm Equation

Soybean dreg is a by-product of soybean products production, with a large consumption in China. Low utilization value leads to random discarding, which is one of the important sources of urban pollution. In this work, porous biochar was synthesized using a one-pot method and potassium bicarbonate (KHCO3) with low-cost soybean dreg (SD) powder as the carbon precursor to investigating the adsorption of methylene blue (MB). The prepared samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analyzer (EA), Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), Raman spectroscopy (Raman), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The obtained SDB-K-3 showed a high specific surface area of 1620 m2 g−1, a large pore volume of 0.7509 cm3 g−1, and an average pore diameter of 1.859 nm. The results indicated that the maximum adsorption capacity of SDB-K-3 to MB could reach 1273.51 mg g−1 at 318 K. The kinetic data were most consistent with the pseudo-second-order model and the adsorption behavior was more suitable for the Langmuir isotherm equation. This study demonstrated that the porous biochar adsorbent can be prepared from soybean dreg by high value utilization, and it could hold significant potential for dye wastewater treatment in the future.

scholarly journals 4-vinylpyridine derivatives: Protonation, methylation and silver(I) coordination chemistry

2021 ◽  
pp. 174751982198965
Author(s):  
Guoqi Zhang
Keyword(s):  
Mass Spectrometry ◽  
Schiff Base ◽  
Coordination Chemistry ◽  
Elemental Analysis ◽  
Silver Complex ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
X Ray Crystallography ◽  
Pyridine Moiety ◽  
New Compounds

( E)-4-[2-(Pyridin-4-yl)vinyl]benzaldehyde, containing both a 4-vinylpyridine and an aldehyde functionality, is utilized to develop new, highly conjugated chalcone compounds and a bis-Schiff base azine compound. The chalcone-containing compounds are further explored for their protonation, methylation and silver(I) coordination chemistry using the pyridine moiety. In parallel, a cyano-containing analogue, ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile is also synthesized and studied for its silver(I) coordination chemistry. These new compounds are fully characterized by mass spectrometry, elemental analysis and spectroscopic techniques. The methylated product of ( E)-1-(9-anthryl)-3-{4-[2-(pyridin-4-yl)vinyl]phenyl}prop-2-en-1-one and a silver complex of ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile are structurally determined by X-ray crystallography.

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