scholarly journals STUDY OF SORPTION OF Ni AND Cd IONS ON NEW CARBON SORBENTS FROM KAZAKHSTAN RAW MATERIALS

2021 ◽  
Vol 57 (2) ◽  
pp. 106-113
Author(s):  
A.Zh. Yerman ◽  
◽  
A.A. Atchabarovа ◽  
K.K. Kishibaev ◽  
◽  
...  

This article presents the optimal results of new sorbents for the sorption separation of nickel and cadmium ions based on waste of plant raw materials of the Republic of Kazakhstan - pine sawdust. To obtain activated carbon, pine sawdust based on plant waste was subjected to thermal treatment by carbonization methods at a temperature of 600-800 ° C and hydrothermal 220-260 ° C. Further, to increase the specific surface area, the samples after heat treatment were activated with hot water vapor at a temperature of 800-850 ° C for 1 hour. As a result of steam-gas activation, combustion of unstructured carbon and an increase in pores on the surface of activated carbon occur. In addition, the main physicochemical characteristics, sorption properties of the obtained activated carbon (specific surface area, m2 /g, fraction of pore volume, cm3 /g, average pore size, nm, sorption capacity by the amount of iodine,%) are considered. Also, the obtained sorption materials were studied in the process of sorption of nickel and cadmium ions from model solutions in a static mode. The optimal parameters of the sorption process were determined, at which the highest degree of extraction of nickel and cadmium ions is achieved: pH, phase contact time, ratio of solid and liquid phases. The recovery rate of cadmium and nickel ions in the static regime was more than 95% for cadmium and nickel. Keywords: activated carbon, sorbent, sorption, plant waste, nickel ion, cadmium ion

2011 ◽  
Vol 480-481 ◽  
pp. 6-10
Author(s):  
Yan Feng Yang ◽  
Xue Jun Zhang ◽  
Hai Yan Li

General purpose pitch-based carbon fiber (PCF) was pretreated with steam to develop pores on the surface of fiber. After immersed in cobalt salt solution, PCF was used as raw materials to prepare activated carbon fiber (ACF) through steam activation process. The effect of pretreatment of carbon fiber on specific surface area, mesopore volume and pore size distribution was investigated by N2 adsorption, and morphology of the resultant ACF was observed with scanning electron microscope(SEM). The results show that pretreatment of PCF enlarges specific surface area and mesopore ratio of ACF remarkably. The best ACF obtained in experiment is the one with specific surface area of 2670 m2/g and mesoporosity of 61.8%. Cobalt has evident catalysis in preparing ACF from activation of PCF, while specific surface area and pore size of ACF get smaller with cobalt salt immersion when pretreatment is too strong.


2019 ◽  
Vol 5 (12) ◽  
pp. 26-36
Author(s):  
Yu. Lugovoy ◽  
N. Antonov ◽  
K. Chalov ◽  
A. Stepacheva ◽  
Yu. Kosivtsov ◽  
...  

Describes the processes of thermal conversion of soft– and hardwood waste to obtain gaseous, liquid and solid products. During the initial stage of the work, the thermogravimetric study of initial samples of birch and pine sawdust was performed in the temperature range from 35 to 1000 °C. On the basis of the thermal analysis data obtained, a method of pyrolysis process of wood waste in the temperature range of 400–500 °C in an inert environment was developed. As a result of experiments on pyrolysis of wood waste, the dependence of the conversion of selected samples into final products, the properties of the resulting gaseous and solid carbon-containing products depending on the conditions of the process, the size of the fraction and the type of wood were obtained. It was found that the optimal temperature of the pyrolysis process in the studied range of system parameters is 450 °C, and the particle size of wood waste is 1–2 mm. Data on the molecular mass distribution of volatile pyrolysis products and kinetic parameters of the pyrolysis process were obtained. The activation energies of the pyrolysis process for pine and birch sawdust samples were 119.3 and 128.2, respectively. The specific surface area of the initial samples of birch and pine wood waste was 9.3 and 8.5 m2/g, respectively. The specific surface area of coal pyrolysis residues for hardwoods increased by 2.4 times and for conifers by 2.1 times, respectively, and assumed values of 22.3 and 17.9 m2/g. Therefore, the coal residues of pyrolysis of wood waste can potentially be used as raw materials for the production of activated carbons and carbon sorbents of various applications.


BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 7935-7942
Author(s):  
Bing Wang ◽  
Huiyuan Chen ◽  
Yonggang Li ◽  
Hongyu Si ◽  
Haomin Wei ◽  
...  

Effects of rapid cooling following pyrolysis were studied relative to the properties of activated carbon using different biomass as the raw materials. Coconut shell-based activated carbon (CSAC), bamboo-based activated carbon (BAC), and straw-based activated carbon (WSAC) were activated via high temperature and subsequently rapidly cooled to below minus 150 °C. The results showed that rapid cooling effectively increased the specific surface area, pore volume, and yield of activated carbons. Compared to natural cooling, rapid cooling increased the specific surface area of CSAC from 1076 m2/g to 1484 m2/g, increased the pore volume from 1.46 mL/g to 1.57 mL/g, decreased the average pore size from 2.25 nm to 2.13 nm, and increased the yield from 27.1% to 31.5%. The variation of the properties of activated carbon after rapid cooling using different raw materials and process conditions were studied using orthogonal experiments.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3811
Author(s):  
Zhongbao Liu ◽  
Jiayang Gao ◽  
Xin Qi ◽  
Zhi Zhao ◽  
Han Sun

In this study, the hydrothermal method was used to synthesize MIL-101(Cr), and activated carbon (AC) with different content was incorporated in to MIL-101(Cr), thereby obtaining AC-MIL-101(Cr) composite material with a huge specific surface area. The physical properties of MIL-101(Cr) and AC-MIL-101(Cr) were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), nitrogen adsorption and desorption and specific surface area testing, and ethanol vapor adsorption performance testing. The results show that with the increase of activated carbon content, the thermal stability of AC-MIL-101(Cr) is improved. Compared with the pure sample, the BET specific surface area and pore volume of AC-MIL-101(Cr) have increased; In the relative pressure range of 0–0.4, the saturated adsorption capacity of AC-MIL-101(Cr) to ethanol vapor decreases slightly. It is lower than MIL-101(Cr), but its adsorption rate is improved. Therefore, AC-MIL-101(Cr)/ethanol vapor has a good application prospect in adsorption refrigeration systems. The exploration of AC-MIL-101(Cr) composite materials in this paper provides a reference for the future application of carbon-based/MOFS composite adsorbent/ethanol vapor working fluid in adsorption refrigeration.


2011 ◽  
Vol 415-417 ◽  
pp. 1265-1272
Author(s):  
Wen Biao Zhang ◽  
Wen Zhu Li ◽  
Bing Song Zheng

Miscanthus is a highly productive, rhizomatous, C4 perennial grass that should be considered as an excellent active carbon precursor. This paper compares the charcoal characterization and chemical composition between M. sinensis and M. floridulus. Species differed in water content, hot water extract, 1% NaOH extract, organic solvent extract, cellulose, lignin and ash. Carbonization temperatures have effects on charcoal yields of Miscanthus, which ranged from 23.5% to 48.0% for M. sinensis and 11.3% to 37.2% for M. floridulus. Water content, charcoal density, pH value, and specific surface area of charcoal characterization varied between two species of Miscanthus. The specific surface area increased with the increase of carbonization temperature. The highest specific surface area of M. sinensis and M. floridulus was 351.74 m2g−1and 352.74 m2g−1, respectively, when the carbonization temperature was 800°C.


2015 ◽  
Vol 749 ◽  
pp. 17-21 ◽  
Author(s):  
Joanna Sreńscek Nazzal ◽  
Karolina Glonek ◽  
Jacek Młodzik ◽  
Urszula Narkiewicz ◽  
Antoni W. Morawski ◽  
...  

Microporous carbons prepared from commercial activated carbon WG12 by KOH and/or ZnCl2 treatment were examined as adsorbents for CO2 capture. The micropore volume and specific surface area of the resulting carbons varied from 0.52 cm3/g (1374 m2/g) to 0.70 cm3/g (1800 m2/g), respectively. The obtained microporous carbon materials showed high CO2 adsorption capacities at 40 bar pressure reaching 16.4 mmol/g.


Author(s):  
Т.В. САВЕНКОВА ◽  
М.А. ТАЛЕЙСНИК ◽  
Н.А. ЩЕРБАКОВА ◽  
С.Ю. МИСТЕНЕВА ◽  
И.И. МИЗИНЧИКОВА

Описаны и теоретически обоснованы разработанные технологические приемы производства мучных кондитерских изделий при сохранении влаги на всех стадиях производства. В рамках исследования решали следующие задачи: увеличение удельной поверхности частиц дисперсной фазы эмульсии за счет моделирования рецептурного состава; дезагрегирование муки, повышение равномерности распределения дисперсионной среды (эмульсии) с образованием оболочек вокруг максимально возможного количества частиц муки различных фракций. Объектом для моделирования рецептурного состава было сахарное печенье. Установлено, что замена рецептурных компонентов с повышенной влажностью на сырье с высоким содержанием сухих веществ позволяет высвободить влагу и использовать новые виды сырья с повышенными нативными свойствами. Предложенные приемы подготовки сырьевых компонентов: снижение вязкости солодового экстракта, используемого для снижения количества сахара-песка, осмотическое набухание яичного порошка, пластикация жира со стабилизацией его структуры лецитином, инверсия сахарозы в условиях совмещения гидродинамического и акустического кавитационных воздействий при получении инвертного сиропа – обеспечивают благоприятные условия получения эмульсии с повышенной удельной поверхностью. Отличительной особенностью предлагаемой технологии является получение эмульсии в две стадии: приготовление суспензии без жира и собственно получение эмульсии. Раздельная подача сахара в два приема: 40–60% его рецептурного количества вносится на стадии приготовления суспензии, оставшаяся часть – при приготовлении эмульсии – и кавитационная обработка суспензии при температуре 36–38°С и частоте колебаний волновода 24 кГц позволяют повысить частичную концентрацию частиц сахара в 8–12 раз. При приготовлении эмульсии пластицированный жир и лецитин предварительно смешивают с оставшейся частью сахара-песка, а затем с суспензией. Дезагрегированную путем аэрации муку и эмульсию одновременно и параллельно подают в месильную машину для достижения их заданного соотношения до начала процесса тестообразования. Разработанный комплекс технологических приемов позволил создать технологический поток производства сахарного печенья с улучшенными показателями качества – намокаемостью до 230% (по классической технологии 180–200%), сниженной на 20% плотностью, повышенными пористостью и рассыпчатостью и сохраняющего до 92% влажности, что на 18% выше, чем в изделиях, полученных по классической технологии. The developed technological techniques for the production of flour confectionery products while maintaining moisture at all stages of production are described and theoretically justified. The following tasks were solved in the framework of the study: increasing the specific surface area of the particles of the dispersed phase of the emulsion by modeling the recipe composition; disaggregating flour, increasing the uniformity of the distribution of the dispersion medium (emulsion) with the formation of shells around the maximum possible number of flour particles of various fractions. The object for modeling the formulation composition was sugar cookies. It is established that the replacement of prescription components with high humidity with raw materials with a high content of dry substances allows you to release moisture and use new types of raw materials with increased native properties. The proposed methods of preparation of raw materials: reducing the viscosity of malt extract used to reduce the amount of granulated sugar, osmotic swelling of egg powder, fat plasticization with the stabilization of its structure with lecithin, sucrose inversion under conditions of combining hydrodynamic and acoustic cavitation effects in the production of invert syrup – provide favorable conditions for obtaining an emulsion with an increased specific surface area. The production of an emulsion in two stages is a distinctive feature of the proposed technology: the preparation of a suspension without fat and the actual production of the emulsion. Separate supply of sugar in two steps: 40–60% of its prescription amount is introduced at the stage of preparation of the suspension, the remaining part – during the preparation of the emulsion – and cavitation treatment of the suspension at a temperature of 36–38°С and the waveguide oscillation frequency of 24 kHz, it is possible to increase the partial concentration of sugar particles by 8–12 times. When preparing the emulsion, the plasticized fat and lecithin are pre-mixed with the remaining part of the granulated sugar, and then with the suspension. The aeration-disaggregated flour and emulsion are fed simultaneously and in parallel to the kneading machine to achieve their desired ratio before the dough-forming process begins. The developed complex of technological techniques allowed to create a technological flow for the production of sugar cookies with improved quality indicators – wetting up to 230% (according to the classical technology 180–200%), reduced density by 20%, increased porosity and friability, and preserving up to 92% humidity, which is 18% higher than in products obtained by the classical technology.


2021 ◽  
Vol 15 (2) ◽  
pp. 131-144
Author(s):  
Chunjiang Jin ◽  
Huimin Chen ◽  
Luyuan Wang ◽  
Xingxing Cheng ◽  
Donghai An ◽  
...  

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.


2016 ◽  
Vol 18 (2) ◽  
pp. 141 ◽  
Author(s):  
A.A. Atchabarova ◽  
R.R. Tokpayev ◽  
A.T. Kabulov ◽  
S.V. Nechipurenko ◽  
R.A. Nurmanova ◽  
...  

<p>Electrode materials were prepared from activated carbonizates of walnut shell, apricot pits and shungite rock from “Bakyrchik” deposit, East Kazakhstan. Physicochemical characteristics of the obtained samples were studied by the Brunauer-Emett-Taylor method, scanning electron microscopy, Raman spectroscopy and other methods. Electrochemical properties of the obtained materials were studied by the method of cyclic voltammetry. It was found that the samples have an amorphous structure. Samples based on plant raw materials after hydrothermal carbonization at 240 °С during 24 h, have more homogeneous and developed surface. Specific surface area of carbon containing materials based on apricot pits is 1300 m<sup>2</sup>/g, for those on the based on mineral raw material, it is 153 m<sup>2</sup>/g. It was shown that materials after hydrothermal carbonization can be used for catalytic purposes and electrodes after thermal carbonization for analytical and electrocatalytic purposes. Electrode obtained by HTC have electrocatalytic activity. CSC 240 has high background current (slope i/Е is 43 mА V<sup>–1</sup> cm<sup>–2</sup>), low potential of the hydrogen electroreduction (more positive by ~ 0.5 V than samples based on plant raw materials). The reaction of DA determination is more pronounced on the electrodes obtained by HTC 240 °C, 24 h, due to the nature, carbon structure and high specific surface area of obtained samples.</p>


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