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CNAA / Theses / 2006 / June /

Specific surface properties of carbonaceous adsorbents


Author: Raisa Nastas
Degree:doctor of chemistry
Speciality: 02.00.04 - Physical chemistry
Year:2006
Scientific adviser: Tudor Lupaşcu
doctor habilitat, professor, Institute of Chemistry, Academy of Sciences of Moldova
Institution:
Scientific council:

Status

The thesis was presented on the 23 June, 2006
Approved by NCAA on the 28 September, 2006

Abstract

Adobe PDF document1.08 Mb / in romanian

Thesis

CZU 661.183.2 + 541.183.5: 628.515 + 615.246.2 + 613

Adobe PDF document 13.11 Mb / in romanian
127 pages


Keywords

active carbons, surface properties, catalytic activity, hydrogen sulfide.

Summary

The thesis includes physicochemical research dealing with synthesis and efficiency of carbons usage, especially emphasizing the study of surface peculiarities, including the catalytic ones of carbonaceous adsorbents, for the purpose of correlating surface chemistry with catalytic abilities of carbonaceous adsorbents to oxidize the species of hydrogen sulfide from underground waters. Detailed studies regarding technique improvement and the procedure of modification of ion exchangers and catalysts obtained from vegetable raw materials such as fruit stones, grape seeds and nutshells have been performed. Chemical and physicochemical methods have been applied, and different agents for activation and oxidation of carbons, procedures for modification of surface chemistry of oxidized carbons due to impregnation with metals have been tested. Surface chemistry of carbons has been investigated using electrometric titration techniques in order to establish the acid-basic properties of adsorbents, and spectral methods using UV-VIS spectra and the Fourier transform infrared spectra (FTIR) to detail the chemistry of functional groups have been utilized. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, surface pH of adsorbents in suspension, and the influence of the type of impregnated metals on removal of hydrogen sulfide species have been researched. The peculiarities of mechanisms and the effects of surface modification of carbonaceous adsorbents towards the catalytic processes of hydrogen sulfide species oxidation were pointed out. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous underground waters.