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Selektywne usuwanie jonów metali ciężkich z wód oraz ścieków przemysłowych poprzez wymianę jonową

Dąbrowski A., Hubicki Z., Podkościelny P., Barczak M.

Przemysł Chemiczny

2006

T. 85, nr 4

232-241

Proces wymiany jonowej umożliwia wymianę jonów niepożądanych na inne jony, które nie przyczyniają się do zanieczyszczenia środowiska. Metoda jest prosta z technologicznego punktu widzenia i wystarczająco skuteczna do usuwania nawet śladowych ilości zanieczyszczeń z roztworów. Zaprezentowano liczne przykłady selektywnego usuwania jonów metali ciężkich za pomocą procesu wymiany jonowej. Szczegółowo omówiono usuwanie Pb(II), Hg(II), Cd(II), Ni(II), V(IV),V(V), Cr(III), Cr(VI), Cu(II) i Zn(II) z wód i ścieków przemysłowych za pomocą różnych, nowoczesnych typów wymieniaczy jonowych.

A review with 95 refs. covering removal of bivalent Pb, Hg, Cd, Ni, Cu, Zn(II), as also V(IV, V) and Cr(III, VI) from contaminated waters.

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Dąbrowski A., Podkościelny P., Hubicki Z., Barczak M., Robens E.

Wiadomości Chemiczne

2005

[Z] 59, 7-8

639--694

Adsorption of phenolic compounds on activated carbons is considered based on survey of abundant literature on it. Phenols belong to a group of common environmental contaminants. Since they are highly toxic and, in general, not amenable to biological degradation, methods of treatment are continuously being modified and developed. Adsorption by activated carbons is the best and most frequently used method to remove phenols from waters. Numerous factors are known to have important influence on this phenomenon: type of carbon, carbon surface functionalities, pH value of the coexisting bulk liquid phase, oxygen availability, etc. In this review, we have tried to discuss the significance of the above-mentioned factors. The first chapter of the review deals with characterization of the activated carbon from the point of view of application for phenols uptake. The selection of precursors of activated carbon as well as generation of porosity and surface chemical composition are taken into account. Adsorption of phenolic compounds has been described critically, showing the development of investigations on the subject and presenting some of the most important results. A special attention is paid to the effect of surface functionalities and pH of solution. These two factors are considered together, because owing to the amphoteric character of a carbon surface its surface properties may be influenced by the pH value of the coexisting liquid bulk phase. The fundamental mechanisms of phenol adsorption have been emphasized i.e. "π-π interactions" and ,.donor-acceptor complex formation", taking into account the influence of the so-called "solvent effect". Energetic heterogeneity of activated carbons is presented on the basis of adsorption energy distribution functions, calculated by using algorithm based on a regularization method. Analysis of these functions provides significant comparative information about their heterogeneity. Problems associated with irreversible adsorption from aqueous solutions of phenols and their surface polymerization are reported in vast paragraph. We concluded that the presence of molecular oxygen and its amount has a significant influence on the adsorption capacity of activated carbon for phenol and its derivatives. Oxidative coupling in the presence of molecular oxygen causes irreversible adsorption (chemisorption). Effects of different substituents of phenols are considered too. Bigger size and/or larger number of groups of an adsorbate lead to a higher heterogeneity for the same surface. It has been stressed that, neither of the substituent groups was involved directly in the interaction with the carbon surface, but they contribute to the electron-acceptor characteristics of the aromatic ring of the solute. The cheap precursors of activated carbons from the waste materials are also described in our review. Finally, some remarks dealing with application of novel adsorbents for phenols adsorption, such as activated carbon fibers are discussed.