S. K. Smolin

Biosorption removal of nitrophenols by activated carbon

The article has investigated the efficiency of biofiltration of solutions 2,4-dinitrophenol and 2-nitriphenol through activated carbon of the grade KAU—usual and modified by iron oxide. It has been shown that both sorbents are characterized by a high selective adsorption for substances being investigated. The impact of modification of carbon by iron oxides when removing nitrophenols is manifested in an increase of active life of biofilter operation and activization of the biofilm development.

Structural and sorption properties of activated carbon modified with iron oxides

The structural and sorption characteristics of activated carbon modified with iron oxides were investigated and static exchange capacity of its surface functional groups of basic and acidic nature was determined. The modification of carbon with iron oxides was found to result in insignificant (7–13%) reduction of micropore and mesopore volume and in basification increase of the sorbent surface. The modified activated carbon is highly efficient in removing phenolic compounds from water.

Biosorption of procaine on biologically active carbon

The article has studied the dynamics of biosorption purification of water of procaine adapted by biomass of active sludge immobilized on activated carbon. The greatest constant of the rate of biodestruction of procaine (0.151 h–1) suspended by adapted biomass is observed at the concentration of the matter 100 mg/dm3. At biosorption removal of procaine on activated carbon under conditions of stirring the constants of the rates of biodestruction increase two–five times compared with suspended biomass. The adapted biofilm noticeably extend the service life of carbon compared with the spontaneously emerging biofilm at the sake of higher destruction activity.

Removal of aromatic compounds from water on biologically activated carbon

We have carried out an assessment of the content of aromatic compounds (o-nitrophenol, o-aminobenzoic acid) in grains of activated carbon of a biofilter at the stage of stationary water treatment. It was found that the removal degree of aromatic compounds by the biofilm of biologically activated carbon in great measure is determined by the value of the decreasing of Gibbs free energy of adsorption (−ΔGa). It is shown that due to the competing action of the biofilm part of the accessible surface of activated carbon is not used for adsorption of organic matter.

The impact of aromatic compounds on the efficiency of biofiltration through activated carbon

The article has investigated the sorption process on activated carbon of aromatic compounds with different functional groups (o- nitrophenol, o-aminophenol, aniline). We have showed the possibility of assessing the efficiency of biofiltration depending on such factors as the variation of the Gibbs free energy of adsorption of sorbates and the value of the specific load of an organic substance on activated carbon. For determining a contribution of the biological component to the total efficiency of the process we used the value of the ratio between the specific dynamic adsorption to the specific equilibrium adsorption at uniform loads in terms of the organic matter on biologically activated carbon.

Impact of characteristic of activated carbons on the efficiency of removal from water of pharmaceutical preparations of various chemical nature

The article has investigated regularities of adsorption of sulfanilamide, sulfathiazole, levamizole and procaine on activated carbons KAU and Filtrasorb F400. Within the interval of concentrations 0.1–1 mol/dm3 the series of adsorption affinity of substances under research on both carbons coincide. Adsorption values decrease in the following sequence: sulfanilamide > sulfathiazole > procaine > levamizole. It has been shown that for the removal from water of the mixture of pharmaceutical preparations with different physicochemical properties it is expedient that the combination of mainly microporous carbon sorbents have different surface chemistry.

Biofiltration of the chlorophenol aqueous solution through the activated carbon bed

The efficiency of biofiltering the o-chlorophenol solution through the KAU-grade activated carbon is common and modified with iron oxide—was studied. Both sorbents showed high selective adsorption ability for the compound investigated. The activated carbon modified with iron oxides was found to have a positive effect on the adsorption of o-chlorophenol at low equilibrium concentrations and continuous filtration.

Features of biosorption filtration of aromatic compounds in water treatment

The paper has studied features of biosorption filtration of phenol, o-nitrophenol, and o-aminobenzoic acid through activated carbon. The study has shown antibate relationship between the value of the variation of free energy of Gibbs adsorption and the removal rate from the water of aromatic compounds by a layer of activated carbon in the mode of biostabilization.

Off-Line Activated Carbon Bioregeneration in Filtration Process of 2-Nitrophenol Solutions

The article shows that purification of water of 2-nitrophenol the term of the effective operation of biological activated carbon is increased by 1–1.5 month in fulfilling periodic offline aeration of the sorbent (4–7 days) with addition of nutrients. In this case 60–80% of restored pores volume was freed of products of vital activities of microorganisms.

Chemical Regeneration of Biological Activated Carbon in Removing Nitrophenol

Investigated are changes of the porous structure of biological activated carbon in filtration and after chemical regeneration. It is shown that 71–84 vol % of recovered pores were blocked by the products of microbe vital activity. Alkaline treatment of the bed of biological activated carbon (during several days) makes it possible to prolong efficient nitrophenols removal from water by 10–11 months.