Deodorization of Ethyl Mercaptan by Cotton Fabrics Mordant Dyed with a Direct Dye and Copper Sulfate

Six cotton samples obtained from appropriate market sources were dyed with C. I. Direct Blue 200, a copper complex direct dye, and pre-and post-mordanted with Cu(II) sulfate. Dye and copper ion uptake, carboxylic acid contents and deodorization of ethyl mercaptan were measured for the samples appropriately treated. The uptake of the dye by four differently mordant-dyed specimens from a single cotton sample was the same to within ± 10%: the uptake by respective specimens was in the range 10—15 mg/g, except for that of a scoured and mercerized sample, which had uptake in the range of 20 mg/g. The copper ion uptake by pre-mordanted specimens was found not to be correlated with the carboxylic acid contents. It was inferred that the differences in the nature and the scouring treatment of the cotton sample were responsible for the unexpected copper ion uptake. The uptake was most enhanced by the successive pre-mordanting, dyeing, and post-mordanting treatment for all the six cotton samples. The uptake of dyed and post-mordanted samples came next and the rest of the treatments showed that uptake varied within three times the copper ion uptake. The deodorizing abilities of ethyl mercaptan by the dyed and mordanted cotton specimens were compared. It was found that the deodorization rates can be classified into three groups, one group almost null, the second one intermediate and the third one fast in comparison with activated carbon. All the deodorization effects plotted against the copper ion uptakes were found to increase quadratically with the copper ion uptake, regardless of the dyeing and mordanting conditions.