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Deep shades on cotton using fiber-reactive dyes require high concentrations of dye, electrolyte and alkali, yet produce high concentrations of dye in effluent. The goal of this research was to develop an optimized pre-treatment method for cotton that enables conventional reactive dyes to exhibit high substantivity toward the fiber at high dye concentrations. Cotton fabrics were cationized with 3-chloro-2-hydroxypropyl trimethylammonium chloride using a cold-pad batch method. At equivalent depths of shades to conventional dyeing, substantially less dye and zero electrolyte were required when cotton was cationized, especially when mercerized cotton was cationized. Other advantages of cationized cotton for dyeing include an almost clear effluent and excellent washfastness under optimized conditions. Also, optimized dyeing requires 75% less alkali for equivalent colorfastness properties. While the dyeing process of cationized cotton was shown to be environmentally more benign than conventional methods, a full life cycle assessment is required to assess the environmental impact of all the wet processing stages, including the pre-treatments. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare the adsorption capacity of Remazol Brilliant Blue R (RBBR) onto three different coal-based adsorbents namely, untreated bottom ash (BA), H2O2-treated BA and physical-activated BA. The removal of RBBR was determined over a concentration range of 50–500 ppm using batch adsorption experiment at room temperature. The percentage removal of RBBR was decreased with the increase of initial concentration. The comparison of percentage removal of RBBR onto the various adsorbents followed the trend: physical-activated BA > H2O2-treated BA > untreated BA. In addition, the adsorption isotherm constant reveals that physical-activated BA gives the highest adsorption capacity of RBBR. Result shows that the adsorption mechanisms of RBBR onto the adsorbents studied are well presented by both Langmuir and Freundlich isotherms. [ABSTRACT FROM PUBLISHER]

Activated carbon was prepared from Rubber Wood, an illimitable indigenous source obtained from Kerala by chemical activation using phosphoric acid as all activating reagent. The carbon was prepared by changing the parameters like activation time, particle size and concentration of the impregnating reagent. The parameters were changed in order to prepare the good quality carbon. The prepared carbon was characterised by its Iodine and Methylene Blue Number. The obtained Iodine and Methylene Blue Number illustrates that the carbon obtained is in the meso-macropore range and its suitability in liquid phase applications. The optimised carbon was used for the removal of Remazol Red (5B) dye. The parameters like contact time, pH, and carbon dosage were studied in order to study the influence of these parameters during adsorption. Adsorption isotherms were studied by varying the particle sizes and was analysed by Langmuir and Freundlich models. Adsorption studies show favourable adsorption and was found that resulting carbon is well suitable for removal of colour from effluents. [ABSTRACT FROM AUTHOR]