scholarly journals The Synthesis of Organoclays Based on Clay Minerals with Different Structural Expansion Capacities

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 707
Author(s):  
Leonid Perelomov ◽  
Saglara Mandzhieva ◽  
Tatiana Minkina ◽  
Yury Atroshchenko ◽  
Irina Perelomova ◽  
...  

An important goal in environmental research for industrial activity and sites is the investigation and development of effective adsorbents for chemical pollutants that are widespread, inexpensive, unharmful to the environment, and have the required adsorption selectivity. Organoclays are adsorption materials that can be obtained by modifying clays and clay minerals with various organic compounds through intercalation and surface grafting. Organoclays have important practical applications as adsorbents of a wide range of organic pollutants and some inorganic contaminants. The traditional raw materials for the synthesis of organoclays are phyllosilicates with the expanding structural cell of the smectite group, such as montmorillonite. Moreover, other phyllosilicates and inosilicates are used to synthesize organoclay to a limited extent. The purpose of this review was to analyze the possibility of using minerals of other groups with different abilities to expand the structure and structural charge for the adsorption of chemical environmental pollutants. The structural characteristics of various groups of phyllosilicates and chain minerals that affect their ability to modify organic surfactants and the adsorption properties of prepared organoclays were reviewed.

2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Liliana Anchidin-Norocel ◽  
Sonia Amariei ◽  
Gheorghe Gutt

The aim of this paper is the development of a sensor for the quantification of nickel ions in food raw materials and foods. It is believed that about 15% of the human population suffers from nickel allergy. In addition to digestive manifestations, food intolerance to nickel may also have systemic manifestations, such as diffuse dermatitis, diffuse itching, fever, rhinitis, headache, altered general condition. Therefore, it is necessary to control this content of nickel ions for the health of the human population by developing a new method that offers the advantages of a fast, not expensive, in situ, and accurate analysis. For this purpose, bismuth oxide-screen-printed electrodes (SPEs) and graphene-modified SPEs were used with a very small amount of dimethylglyoxime and amino acid L-histidine that were deposited. A potentiostat that displays the response in the form of a cyclic voltammogram was used to study the electrochemical properties of nickel standard solution with different concentrations. The results were compared and the most sensitive sensor proved to be bismuth oxide-SPEs with dimethylglyoxime (Bi2O3/C-dmgH2) with a linear response over a wide range (0.1–10 ppm) of nickel concentrations. Furthermore, the sensor shows excellent selectivity in the presence of common interfering species. The Bi2O3/C-dmgH2 sensor showed good viability for nickel analysis in food samples (cocoa, spinach, cabbage, and red wine) and demonstrated significant advancement in sensor technology for practical applications.


2019 ◽  
Vol 8 (1) ◽  
pp. 20-40 ◽  
Author(s):  
Maria Ventura ◽  
Marcelo E. Domine ◽  
Marvin Chávez-Sifontes

Valorization of lignocellulosic biomass becomes a sustainable alternative against the constant depletion and environmental problems of fossil sources necessary for the production of chemicals and fuels. In this context, a wide range of renewable raw materials can be obtained from lignocellulosic biomass in both polymeric (i.e. cellulose, starch, lignin) and monomeric (i.e. sugars, polyols, phenols) forms. Lignin and its derivatives are interesting platform chemicals for industry, although mainly due to its refractory characteristics its use has been less considered compared to other biomass fractions. To take advantage of the potentialities of lignin, it is necessary to isolate it from the cellulose/ hemicellulosic fraction, and then apply depolymerization processes; the overcoming of technical limitations being a current issue of growing interest for many research groups. In this review, significant data related to the structural characteristics of different types of commercial lignins are presented, also including extraction and isolation processes from biomass, and industrial feedstocks obtained as residues from paper industry under different treatments. The review mainly focuses on the different depolymerization processes (hydrolysis, hydrogenolysis, hydrodeoxygenation, pyrolysis) up to now developed and investigated analyzing the different hydrocarbons and aromatic derivatives obtained in each case, as well as the interesting reactions some of them may undergo. Special emphasis is done on the development of new catalysts and catalytic processes for the efficient production of fuels and chemicals from lignin. The possibilities of applications for lignin and its derivatives in new industrial processes and their integration into the biorefinery of the future are also assessed.


2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Yongning Bian ◽  
Qian Yuan ◽  
Guocheng Zhu ◽  
Bozhi Ren ◽  
Andrew Hursthouse ◽  
...  

With the rapidly increasing industrial and agricultural development, a large amount of sludge has been produced from much water treatment. Sludge treatment has become one of the most important environmental issues. Resource utilization of sludge is one of the important efficient methods for solving this issue. Sludge-based activated carbon (SBAC) materials have high adsorption performance and can effectively remove environmental pollutants including typical organic matter and heavy metals through physical and chemical processes. Therefore, developing efficient SBAC materials is important and valuable. At present, preparation, modification, and application of SBAC materials have gained widespread attention. This paper provides a review of the research on SBAC preparation and modification and its utilization in removing environmental pollutants. It included the following topics present in this review: conventional and new methods for preparation of SBAC were clearly present; the effective methods for improving SBAC performance via physical and chemical modification were reviewed; and the correlation of their physic-chemical properties of SBAC with pollutants’ removal efficiencies as well as the removal mechanisms was revealed. SBAC has a better adsorption performance than commercial activated carbon in some aspects. Furthermore, it is a cost-effective technique and has a wide range of raw materials. However, there are still some drawbacks to its research; thus, some suggestions for further research were given in this review.


Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3701 ◽  
Author(s):  
Alyne Lamy-Mendes ◽  
Rafael B. Torres ◽  
João P. Vareda ◽  
David Lopes ◽  
Marco Ferreira ◽  
...  

Serious environmental and health problems arise from the everyday release of industrial wastewater effluents. A wide range of pollutants, such as volatile organic compounds, heavy metals or textile dyes, may be efficiently removed by silica materials advanced solutions such as aerogels. This option is related to their exceptional characteristics that favors the adsorption of different contaminants. The aerogels performance can be selectively tuned by an appropriate chemical or physical modification of the aerogel’s surface. Therefore, the introduction of amine groups enhances the affinity between different organic and inorganic contaminants and the silica aerogels. In this work, different case studies are reported to investigate and better understand the role of these functional groups in the adsorption process, since the properties of the synthesized aerogels were significantly affected, regarding their microstructure and surface area. In general, an improvement of the removal efficiency after functionalization of aerogels with amine groups was found, with removal efficiencies higher than 90% for lead and Rubi Levafix CA. To explain the adsorption mechanism, both Langmuir and Freundlich models were applied; chemisorption is most likely the sorption type taking place in the studied cases.


Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2505 ◽  
Author(s):  
Jarosław Brodny ◽  
Magdalena Tutak

Growing competition in the market for energy raw materials needed for power generation has led to an increasing number of measures being undertaken in the mining sector to reduce the unit costs of mining production. One of the areas that offer considerable savings in this regard is the utilisation of the technical resources owned by mines. This article is therefore focussed on analysing the utilisation effectiveness of these machines, based on the data recorded by industrial automation systems, as well as on measurements from independent surveying and chemical analysis of the excavated material’s quality. For this purpose, a methodology was developed to use the data about the operational parameters of the machines in order to analyse the effectiveness of their utilisation. It was assumed that the reliability of this assessment would depend mainly on the quality of the data used to conduct it. It was also assumed that using independent data sources for the analysis would provide objective and reliable information on the operation of the machines, devoid of any subjective feelings of the personnel or other factors. The developed methodology, based on a modified Overall Equipment Effectiveness (OEE) model, was used to analyse four machines that comprise the automated longwall system. Values were determined for each machine, including their availability, performance and product quality. This, in turn, made it possible to determine a total effectiveness indicator, based on a modified Overall Equipment Effectiveness (OEE) model, for the particular machines and the entire technical systems they form. The obtained results were used to assess the effectiveness of their utilisation and recommend corrective measures aimed at improving this metric. Moreover, the analysis results made it possible to assess the utilisation status of the machines in question. They also served as the basis for determining further lines of research, the purpose of which is to improve the effectiveness of the mining sector. The obtained results indicated that this process requires the wide application of IT tools, especially for data archiving and analysis. These tools, along with the developed model and methodology based on the analysis of large volumes of digital data, are in accord with the activities related to the implementation of Industry 4.0 idea in mining. It is the authors’ opinion that the material at hand should find a wide range of practical applications in supporting the management of technical resources within the mining sector.


1998 ◽  
Vol 20 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Graeme Allinson

Ion mobility spectrometers (IMS) are small, lightweight, extremely robust devices with low power requirements, no moving parts, no absolute requirement for gases or vacuums, that can be operated at ambient temperatures and pressures, and yet are capable of measuring vapour phase concentrations of organic chemicals at very low levels (sub-μg/l). IMS are capable of analysing complex mixtures and producing a simple spectral output. Volatile components produce measurable negative and positive product ions in the spectrometer through chemical ionization. The spectra produced are essentially the vapour phase fingerprints of the target molecules/mixture. Quantitative data can be obtained provided instrument response is within the linear dynamic range of these instruments, but most practical applications of IMS have used the technology in a qualitative manner in situations which require just an above/below threshold or positive/negative response.In the manufacturing industry there are many examples where the aroma/odour of raw materials has safety or product quality implications. IMS was not developed to replace traditional methods of analysis, e.g. GC/MS or sensory panels, but rather to provide a rapid, qualitative response complementary to more established methods. This paper reports on the use of a hand-held ion mobility spectrometer to characterize the vapours produced by volatile organic compounds,fresh herbs and retail spice mixtures at ambient temperature and pressure. The results show that by monitoring in both ion acquisition modes, ion mobility spectrometers are capable of discriminating between a wide range of products.


Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.


Author(s):  
J.M. Cowley

The HB5 STEM instrument at ASU has been modified previously to include an efficient two-dimensional detector incorporating an optical analyser device and also a digital system for the recording of multiple images. The detector system was built to explore a wide range of possibilities including in-line electron holography, the observation and recording of diffraction patterns from very small specimen regions (having diameters as small as 3Å) and the formation of both bright field and dark field images by detection of various portions of the diffraction pattern. Experience in the use of this system has shown that sane of its capabilities are unique and valuable. For other purposes it appears that, while the principles of the operational modes may be verified, the practical applications are limited by the details of the initial design.


Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.


2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.


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