Wyniki wyszukiwania - BazTech

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Efektywność usuwania chromu(VI) z roztworów wodnych w procesie wymiany jonowej

Puszkarewicz A., Kaleta J., Papciak D.

Przemysł Chemiczny

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2013

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T. 92, nr 6

1083--1086

2

Removal of chromium from aqueous solutions using Derris indica wood based activated carbon. Adsorption batch studies

Ulaganathan S., Govindan V.

Environment Protection Engineering

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2013

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Vol. 39, nr 3

21--29

EN

Adsorption efficiency in removal of chromium from waste water has been studied using Derris indica based activated carbon by conducting batch adsorption tests. Adsorption kinetics of chromium removal by Derris indica was examined by varying factors such as pH and concentration of synthetic solution and dosage of activated carbon. It has been found that the Derris indica based activated carbon is able to remove 80 mg/dm3 of chromium from aqueous solution by dosage of 0.8 g/150 cm3 with optimum contact time of 15 min. The isotherm data confirms with both Langmuir and Freundlich isotherm forms.

3

Niektóre warunki stosowania żelaza(II) do usuwania chromu ze ścieków

Dylewski R., Lipińska M.

Chemik

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2003

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Vol. LVI, nr 2

48-50

PL

Omówiono szkodliwe działanie chromu na organizm człowieka oraz główne źródła przedostawania się związków chromu(III) i (VI) do środowiska naturalnego. Przedstawiono najważniejsze metody wydzielania chromu ze ścieków. Na podstawie wybranych kryteriów, jakie powinny spełniać takie metody, wybrano do rozważań metodę redukcji chromu(VI) za pomocą żelaza(II), połączoną z koagulacją i łącznym oddzielaniem mieszaniny Fe(OH)3 + Cr(OH)3. Porównano wariant chemiczny tej metody, polegający na stosowaniu soli żelaza (II), z wariantem elektrochemicznym, w którym źródłem Fe(OH)2 jest roztwarzalna anoda żelazna. Zaproponowano zakresy stosowania tych wariantów.

EN

Discused are harmful effects of chromium on the human body and main sources of penetrating Cr(III) and Cr(VI) into the environment. The most important methods used to precipitate chromium from effluents are presented. On the basis of the criteria selected to be met by such methods, the reduction of Cr(VI) by using Fe(II) combined with the coagulation and separation of Fe(OH)3 + Cr(OH)3 mixture is selected to consider. A chemical alternative of this reduction method depending on the use of iron(II) salts is compared with the electrochemical variant, where a digestable iron anode is used as the source for Fe(OH)2. Application anges of the two alternatives are suggested.

4

Usuwanie chromu (VI) na węglu aktywnym regenerowanym węglanem sodu

Lach J., Dębowski Z., Ociepa E.

Ochrona Środowiska

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2000

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nr 3

3-6

EN

Investigated was the potentiality of using sodium carbonate for the regeneration of activated carbons spent in the course of chromate onion desorption. The experiments were carried out on WD-extra carbon treated with muriatic acid for partial removal of ash particles. The regeneration procedure involved sodium carbonate and was conducted in a through-flow system. The desorption and sorption effects were related to three values of Na2CO3 concentration (2,5 and 10%) and two values of flow velocity (2 and 4 m/h). The best sorption effects were achieved on carbon regenerated with the 2% Na2CO3 solution. When use was made of increased (5% or 10%) sodium carbonate concentrations, consecutive sorptions were less effective. This finding, however, cannot be explained by the amount of the desorbed chromium. The sorption effects following the regeneration procedure were found to be adversely influenced by the local increase of pH in the micropores of the activated carbon. Of importance was also the overall number of the regeneration procedures performed. Each successive procedure reduced noticeably the adsorbing capacity of the carbon with respect to chromate onion. The contribution of flow velocity to the sorption effect was less distinct. However, the flow velocity of the Na2CO3 solution contributed markedly to the duration of the regenerating procedure and to the quantity of the reagent to be used. Thus, at the flow velocity of 2 m/h, the length of regeneration increased, whereas the quantity of the sodium carbonate used decreased.