Production of Microporous Carbon Adsorbents by Thermochemical Activation of Coniferous Sawdust with Orthophosphoric Acid Pre-Processing at the Prepyrolysis Stage

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UDС

661.183.2

DOI:

10.17238/issn0536-1036.2015.3.104

Abstract

Today, virtually the entire planet and, especially, areas of mass human habitation is the subject to the serious environmental threats. Because of physical and chemical properties active carbons are unique and ideal sorption materials for chemical and biological human security, environment and infrastructure. The huge range of adsorbents can be obtained on the basis of large capacity waste of chemical and mechanical processing of wood. The purpose of the work was to carry out the experimental studies on the development of pyrolysis technology of coniferous sawdust in a mode of chemical activation by sodium hydroxide for carbon adsorbents production. The object was to establish a process of pyrolysis, to fit it into the structure of existing enterprises and get adsorbents with minimal expenses and with a wide range of application. Two series of experiments were realized. The first series was carried out with the use of 2 % orthophosphoric acid at a stage of preparation for thermochemical activation (OXM series). The second series of the experiments was implemented without the use of orthophosphoric acid (HRP series). The received coal was washed, dried up, pulverized and analyzed. To evaluate the adsorptive properties of the adsorbents the standard adsorbates were used: iodine, methylene blue and hexane. These substances are widely used in the active carbon testing. As a result of the research the selection of the optimal regime parameters for adsorbents with rather high rate of iodine adsorption and methylene blue clarifying ability, which values significantly exceed the indicators of industrially available acti vated carbon, was carried out. Experimentally it has been found that the activated carbon with a maximum absorbing capacity can be obtained at the following operating parameters: prepyrolysis temperature – 350 °C, thermochemical activation temperature – 650 °C, an alkali dosage – 150 %. The widespread use of activated carbon is dictated by availability of raw materials for its production, low cost, flexibility, and the ability to repeated regeneration.

Authors

A.I. Bubnova, Postgraduate Student N.I. Bogdanovich, Doctor of Engineering, Professor

Affiliation

Northern (Arctic) Federal University named after M.V. Lomonosov, Naberezhnaya Severnoy Dviny, 17, Arkhangelsk, 163002, Russia; е-mail: a.bubnova@narfu.ru

Keywords

adsorbent, active carbon, thermochemical activation, pyrolysis, adsorptive

References

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