In-situ Mineralization Dyeing And Mineralized Residual Liquids Cyclic Utilization Dyeing Technology With Reactive Dyes For Cotton

When the cellulose fiber products is dyed by reactive dyes,there are waste dye inside the residual bath and the fiber after the dyeing process.In order to ensure the color fastness of the dyed samples,post-treatments such as multiple washing,pickling and high-temperature soaping should be carried out.This leads to a large water consumption and sewage discharge.In addition,the inorganic salts used in dyeing cannot be effectively treated in the sewage treatment process,and the discharge of salty water leads to the salinization of water and land.In view of the above problems,this topic proposed in-situ mineralization dyeing and mineralized residual liquids cyclic utilization dyeing technology with reactive dyes.In the dyeing stage of cotton knitwear with reactive dyes,the new alkaline agent XGB was used as a fixing alkali agent.After fixation,a series of self-made auxiliaries for in-situ mineralization were added to treate the bath under the condition of co-presence of fixing residue and fiber.The organic pollutants in the dye residue were decomposed into colorless small molecules,CO₂ and H₂O,so that the post-treatment process was simplified and the water consumption and pollution discharge were reduced.The mineralized residual liquid were simply disposed and then used for subsequent dyeing process to achieve the recycling of salt.A clean dyeing process of cotton knitted fabrics can be realized through the implemention of the in-situ mineralization dyeing and the mineralized residual liquid recycle dyeing technology of reactive dyes.In this investigation,the thermodynamics and kinetics of reactive dyeing had been explored,the best in-situ mineralization dyeing process parameters were determined:in the dyeing stage,when the dosage of dye was 2.6%（owf）⁵.0%（owf）,the amount of sodium sulfate was 80 g/L¹00g/L,the pH value of the fixation bath was adjusted to about 11.0by alkali agent XGB,and keep it at 60℃for 60min;in the in-situ mineralization stage,the pH value was about 3.0,and the dosage of coupling agent XBC was 1.0%（owf）),of coupling agent XYS was 3.0%（owf）⁵.0%（owf）,mineralization treatment was at 60℃for 30 min;in the mineralization residue recycling stage,the pH value of the residual liquid was adjusted to about 10.0 firstly and then to neutral after a standing and a filtering,then the filtrate can be reused for subsequent dyeing.The adsorption isotherms of in-situ mineralization dyeing and mineralized residual liquids cyclic utilization dyeing technology with reactive dyes are consistent with the traditional dyeing process,that is Freindliche type adsorption isotherm.And the dyeing kinetic behavior of it had not change.The mineralization treatment reduced the absorbance of the dye residue by more than 99%,and the COD_Crr value by 55%⁶0%.The colorless and clarified mineralized residual made it a foundation for the cyclic utilization.The application of in-situ mineralization dyeing and its residual liquid recycling technology in the dyeing of cotton fabric with reactive dyes could save the water consumption about37.5%,and the the emission reduction of inorganic salts could be reduced about 62%through the recycling of mineralized residual liquid.The K/S value and color fastness of the in-situ mineralization and its residual liquid recycling dyeing samples were basically the same as those of the traditional process.The color difference of the dyed products among them was small,the bursting strength of the in-situ mineralization dyed samples were about 8%lower than of the traditional process,but it was within control.The test results of scanning electron miCroscopy,infrared spectroscopy,X-ray diffraction showed that the in-situ mineralization dyeing and the mineralized residual liquid recycle dyeing technology made no adverse effects on the appearance and internal miCrostructure of cotton fibers.The research of this subject provided a new way for energy-saving and emission reduction dyeing processing of cotton with reactive dyes.The paper contains Figure 26,Table 33,and Reference 77.