The influence of thermal treatment on bioweathering and arsenic sorption capacity of a natural iron (oxyhydr)oxide-based adsorbent

Chemosphere ◽  
2017 ◽  
Vol 188 ◽  
pp. 99-109 ◽  
Author(s):  
Klaudia Debiec ◽  
Grzegorz Rzepa ◽  
Tomasz Bajda ◽  
Lukasz Zych ◽  
Jan Krzysztoforski ◽  
...  
2019 ◽  
Vol 19 (3) ◽  
pp. 219-226
Author(s):  
I. E. Barkovskiy ◽  
A. I. Lysikov ◽  
Zh. V. Veselovskaya ◽  
N. V. Mal’tseva ◽  
A. G. Okunev

Modified carbon materials were synthesized by impregnating activated carbons with an aqueous solution of sodium hydroxide followed by thermal treatment in air at moderate temperature (60–200 °C). The samples were tested for sorption-catalytic cleaning of air from hydrogen sulfide. Particular attention was paid to the influence of temperature of thermal treatment (activation) on sorption capacity of the modified carbons to H2S. The modifying of activated carbons by impregnation with aqueous NaOH followed by their thermal treatment in air at 200 °C was shown to allow the dynamic sorption capacity to H2S to be more than 8 times increased. The results obtained can be used to synthesize new materials based on commercial activated carbons for removal of hydrogen sulfide from air.


2012 ◽  
Vol 15 (1) ◽  
pp. 57 ◽  
Author(s):  
K.K. Kudaybergenov ◽  
E.K. Ongarbayev ◽  
Z.A. Mansurov

Agricultural byproducts or residues are widely produced in Kazakhstan and their utilization as a sorbent material for petroleum spill can be developed as low cost, high tech environmental technology. Rice husk, an agricultural waste, was used as petroleum sorbent material. The present study examines the sorption capacity of thermally treated rice husk for different petroleum products. Results showed that the petroleum sorption capacity of this material prepared at 700 ºC was 15 g/g for heavy crude petroleum. The material obtained by thermal treatment of rice husk has very good buoyancy characteristics, high petroleum sorption capacity and high hydrophobicity. The effects of heating temperature, contact time and petroleum density on the petroleum sorption capacity of thermally treated rice husks were further studied on the basis of phase composition, microstructure and morphology using X-ray diffraction analysis, FTIR spectrometry, optical digital microscopy and scanning electron microscopy (SEM). The results of the SEM and optical microscopy studies strongly indicate that thermal treatment is a suitable method to improve structure of husk particles regarding porosity compared to virgin samples. The research provides the basis for development of a new environmental material with optimal characteristics, providing efficient sorption of petroleum and petroleum products from aqueous medium.


Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.


Author(s):  
X. Qiu ◽  
A. K. Datye ◽  
T. T. Borek ◽  
R. T. Paine

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.


1977 ◽  
Vol 27 (1) ◽  
pp. 93-98
Author(s):  
Naim A. Fadl ◽  
Magdi Z. Sefain ◽  
Mohomed Rakha
Keyword(s):  

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