Porosity of carbons obtained by chemical activation: effect of the nature of the alkaline carbonates

Carbon ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1140-1143 ◽  
Author(s):  
A Addoun ◽  
J Dentzer ◽  
P Ehrburger
2014 ◽  
Vol 699 ◽  
pp. 87-92 ◽  
Author(s):  
Abdul Rahim Yacob ◽  
Adlina Azmi ◽  
Mohd Khairul Asyraf Amat Mustajab

The characteristics and quality of activated carbons prepared depending on the chemical and physical properties of the starting materials and the activation method used. In this study, activated carbon prepared using pineapple waste. Three parts of pineapple waste which comprises of peel, crown and leaf were studied. For comparison activated carbon were prepared by both physical and chemical activation respectively. Three types of chemicals were used, phosphoric acid (H3PO4), sulphuric acid (H2SO4), and potassium hydroxide (KOH). The preparation includes carbonization at 200°C and activation at the 400°C using muffle furnace. The chemical characterization of the activated carbon was carried out using Thermogravimetric analysis (TGA), Nitrogen gas adsorption analysis and Fourier transform infrared (FTIR). The highest BET surface area was achieved when the pineapple peel soaked in 20% phosphoric acid with a surface area of 1115 m2g-1. FTIR analysis indicates that the reacted pineapple waste successfully converted into activated carbons.


2013 ◽  
Vol 634-638 ◽  
pp. 1398-1403
Author(s):  
Jun Han Li ◽  
Shao Li Yang ◽  
Ning Sun ◽  
Lan Ma

The impact of activator varieties on the activation effect in preparing activated carbon with corncob adopting chemical activation process were researched in this paper, the results showed that phosphoric acid as the activator was much better than potassium hydroxide and zinc chloride. It was deduced from the orthogonal experiment results that the impact of activation temperature on the activation effect is the greatest, impregnation ratio takes the second place, and the activator concentration the least. Suitable parameters of activation process were obtained: when the activator concentration is 50%, activation temperature 500°C, impregnation ratio 2.7:1, the iodine value of activated carbon is 822.08mg/g.


2021 ◽  
Vol 11 (22) ◽  
pp. 10647
Author(s):  
Evgenii M. Shcherban’ ◽  
Sergey A. Stel’makh ◽  
Alexey Beskopylny ◽  
Levon R. Mailyan ◽  
Besarion Meskhi

One of the crucial problems in current construction is energy, resource, and material efficient technologies in both industrial and civil engineering, associated with new material manufacturing and building construction. This article is devoted to developing comprehensive technology for activation effects on concrete made by various production techniques: vibration, centrifugation, and vibro-centrifugation. The possibility of a significant improvement in the microstructure of concrete and obtaining materials with increased specified characteristics, depending on its manufacturing technology, were studied during the complex activation effect exposed to this concrete and its components. Chemical activation of water and mechanical activation of cement were considered. The urgency and prospects of double, complex mechanochemical activation of concrete mixture components were substantiated. It was proven that the complex mechanochemical activation of the concrete mixture components gives a synergistic effect in obtaining concrete composition with an improved structure and improved characteristics. Furthermore, the relationship between concrete production technology and the technology of activation of its components was established. It was revealed that the most effective is the complex mechanochemical activation of vibro-centrifuged concrete, which gives an increase in strength up to 30%. The study results indicate a further direction of development associated with an increase in variatropic characteristics using both prescription and technological factors.


Mining Scince ◽  
2020 ◽  
Vol 27 ◽  
Author(s):  
Djelloul Ladjel ◽  
Moncef Zairi ◽  
Larbi Belagraa

2017 ◽  
Vol 6 (1) ◽  
pp. 39-44
Author(s):  
Khalimatus Sa'diyah ◽  
Muchamad Syarwani ◽  
Sigit Hadiantoro

This research has been carried out to produce adsorbent from Lapindo mud through various activation process, to adsorb nickel from nickel sulfate solution. Several investigations were performed in this research such as characterization of Lapindo mud before and after activation, effect of physical, chemical and chemico-physical activation to Si/Al ratio and determine the most effective method to produce adsorbent with high adsorption rate. Lapindo mud in this research was prepared through several methods such as without activation, calcination at 500 C for 3 hours, chemical activation with 6 N HCl under reflux for 6 hours, chemical activation with 6 N NaOH under reflux for 6 hours, chemical activation with 6 N HCl under reflux followed by calcination process and the last treatment is chemical activation with 6 N NaOH under reflux followed by calcination process. The object of this research is the Lapindo mud adsorbent ability to adsorb Ni from NiSO4 solution. While activation methods and nickel concentration in this become independent variable. The reduction of nickel concentration efficiency is determined by the nickel concentration before and after adsorption process. The Si/Al ratio of Lapindo mud before activation process was 3.01 and it increase as the mud is activated. The highest Si/Al ratio was found at activation using HCl which is 7.85. Chemical activation using NaOH was found to be the best method to create the adsorbent with adsorption capacity 98.3%.


2018 ◽  
Vol 926 ◽  
pp. 134-139 ◽  
Author(s):  
Wen Juan Yao ◽  
Lei Fan ◽  
Guang Yan Liu

The hydration products, microstructure and development principle of intensity of cement-glass powder cementitious materials acted in alkali and activation effect of chemical activation on waste glass powder were investigated. The principle of intensity and effect of curing time was analyzed by changing alkali type, content of alkali, incorporation of glass powder, incorporation method of activators and other factor. The result shows that: sodium carbonate and sodium silicate can single stimulate activity of glass powder under a certain condition, the activated effect of combined admixture is superior to the effect on single-doped activator, under the action of an excitation agent, surface hydrolysis of glass powder takes place on the glass body first and the hydration products occurs, The pozzolanic reactivity of glass powder increases gradually and generated a larger amount of hydration products,which has lapped and interlocked growth between each other,and form the compact hardened matrix. In addiation, the shorting of curing time is used by activator, the result may be lead to initial curing and against in engineering construction.


2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Hongying Xia ◽  
Song Cheng ◽  
Libo Zhang ◽  
Jinhui Peng

AbstractThe present work attempts to convert walnut shell into a high surface area activated carbon by microwave heating and chemical activation. Different activation agents such as KOH, NaOH, K


Author(s):  
Takuma Saito ◽  
Toshihiro Takizawa

Cells and tissues live on a number of dynamic metabolic pathways, which are made up of sequential enzymatic cascades.Recent biochemical and physiological studies of vision research showed the importance of cGMP metabolism in the rod outer segment of visual cell, indicat ing that the photon activated rhodopsin exerts activation effect on the GTP binding protein, transducin, and this act ivated transducin further activates phosphodiesterase (PDEase) to result in a rapid drop in cGMP concentration in the cytoplasm of rod outer segment. This rapid drop of cGMP concentration exerts to close the ion channel on the plasma membrane and to stop of inward current brings hyperpolarization and evokes an action potential.These sequential change of enzyme activities, known as cGMP cascade, proceeds quite rapidly within msec order. Such a rapid change of enzyme activities, such as PDEase in rod outer segment, was not a matter of conventional histochemical invest igations.


2019 ◽  
Author(s):  
Chem Int

Activated carbon was prepared from molasses, which are natural precursors of vegetable origin resulting from the sugar industry. A simple elaboration process, based on chemical activation with phosphoric acid, was proposed. The final product, prepared by activation of molasses/phosphoric acid mixture in air at 500°C, presented high surface area (more than 1400 m2/g) and important maximum adsorption capacity for methylene blue (625 mg/g) and iodine (1660 mg/g). The activated carbon (MP2(500)) showed a good potential for the adsorption of Cr(VI), Cu(II) and Pb(II) from aqueous solutions. The affinity for the three ions was observed in the following order Cu2+ Cr6+ Pb2+. The process is governed by monolayer adsorption following the Langmuir model, with a correlation coefficient close to unity.


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