Removal of Colored Wastewater Generated From Hand-Made TextileWeaving Industry


The hand-made textileweaving industry in Thailand produces only a small volume of coloredwastewater. These small industries, however, are scattered throughout the country,crating widespread water resources contamination. For local villagers,conventional treatment technologies are too costly to bear and too complicatedto handle. Consequently, villagers simply pay no attention to the treatment oftheir wastewater products.

A study of thedecolorization of cotton direct dyestuffs (Blue 201, Red 23 and Violet 9) bywood charcoal (WC) and activated wood charcoal (AWC) is presented. Studies ofthe effects of pH, contact time, salt concentration and temperature on the absorptionwere conducted. Equilibrium absorption capacity was studied using Langmuir andFreundlich isotherms.

The absorption of directdyestuffs on both WC and AWC was found to conform to the two isotherms. Theabsorption of Red 23 and Violet 9 on AWC is pH independent over a pH range of4.5 to 11.0, but the absorption of Blue 201 is slightly increased at a lowerpH. The concentration of NaCl up to 10,000 ppm has no effect on the absorptionof all dyes. Temperature has very little effect on the absorption of Blue 201,but the binding of Red 23 and Violet 9 is higher at a higher temperature, whichindicated the endothermic absorption reaction. The absorption capacity of Blue201, Red 23 and Violet 9 by AWC is about 2.3, 1.2 and 1.2 times higher than by WC.

WC, even though it isless effective than AWC, is an effective and inexpensive absorbent for theabsorption of direct dyestuffs. The treatment method (absorption) is easy tohandle and requires no special skills for a person to operate and to maintain.The cheap WC makes regeneration not necessary and it could be burnt.

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Winai Somboon is associated withDepartment of Chemistry, Faculty of Science, King Mongkuts University ofTechnology Thonburi, Bangkok,Thailand.