• Carbon letters
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• v.11 no.3
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• pp.206-210
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• 2010

Removal of dyes Reactive Blue 221, N Blue RGB and Acid Blue MTR using two different samples of activated carbon by static batch method was studied. Experimental data on optical density of solutions at different concentrations ranging from 10 to 100 mg/L and of solutions after adsorption on activated carbon samples were measured. Calibration curves were plotted and the amount of dye $q_e$ adsorbed was calculated. The data was fitted to Langmuir and Freundlich isotherms for two different carbon samples and different concentration and pH values. Constants were calculated from the slope and intercept values of the isotherms. Coefficient of correlation $R_2$ and Standard Deviation SD were also noted. The data fitted well to the isotherms. Carbon sample $C_1$ showed higher potential to adsorb all the three dyes. Adsorption was higher at lower concentrations. Carbon sample $C_2$ showed better adsorption in acidic pH as compared to in alkaline pH. From the analysis of the data capacity of $C_1$ and $C_2$ to remove the dyes from water have been compared.

• Carbon letters
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• v.8 no.1
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• pp.1-5
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• 2007

The use of low cost and ecofriendly adsorbent has been investigated as an alternative to the current expensive method of removing dyes from wastewater. Cow dung cakes were collected from the nearby village which was burnt in a muffle furnace at $500^{\circ}C$ to obtain the required ash. This paper deals with the removal of Reactive Blue 221, Acidoll Yellow 2GNL and Olive BGL which are mainly used in textile industry, from aqueous solution by cow dung ash without any pretreatment. The adsorption was achieved under different pH, adsorbate concentration and the applicability of Langmuir and Freundlich isotherms were examined.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.221-225
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• 2011

To detect superoxide anion ($O_2{\cdot}^-$) or singlet oxygen ($^1O_2$) in biological systems during gamma irradiation, specific chemical probes, 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron) or 2,2,6,6-tetramethyl-piperidine (TEMP), were evaluated. Tiron or TEMP spin adducts was structurally stable in aqueous solution during gamma irradiation up to 500 or 1,000 Gy, respectively. The signal of Tiron semiquinone radical, a spin adduct of Tiron upon reaction with $O_2{\cdot}^-$, was slightly increased by gamma irradiation. This trend was dose-dependently manifested in $O_2$-saturated aqueous solution using nitro blue tetrazolium (NBT), a common probe for both hydrated electron ($e{^-}_{aq}$) and $O_2{\cdot}^-$. In contrast, a spin adduct of TEMP, was never inducible by gamma irradiation, while its signal was substantially enhanced by photosensitization of riboflavin. These results suggest that Tiron and NBT or TEMP could be utilized to detect $O_2{\cdot}^-$ or $^1O_2$ in biological systems during gamma irradiation, although $O_2{\cdot}^-$ or $^1O_2$ are not the main reactive oxygen species produced by water radiolysis.