Optimization of exhaustion and fixation maximization of reactive dyes

摘要

Large quantities of Sodium Chloride (NaCl) or Sodium Sulfate / Glauber's salt (Na2S 0 4) are used in the exhaustdyeing of cotton fabric with reactive dyes.Many conventional reactive dyeing processes require 50-100 g/L of thesalts to promote adequate exhaustion.Even with the large quantities of water required for rinsing the dyed fabric,theeffluent still averages 2000-3000ppm NaCl when it is used.This level exceeds the current toxicity limit for NaClestablished by the Environmental Protection Agency,and many dyers are discharging at or above this level.Recentattempts to lower the levels of NaCl or Na2S ()4in waste water effluent have involved the selection of dyes with higheraffinity for cotton and dyeing at lower liquor ratios.Also,many dyestuff manufacturers have developed a line of fiberreactive dyes that require less salt to promote exhaustion.Neither of these efforts has proven to be totally satisfactory.In this project we study the optimisation of concentration of salt as exhausting agent for reactive dyeing of cottonfabric that results in washing fastness and color strength,Which is obtained after dosing of reduced salt concentrationfor 1%,3% and 4% dye shade in comparison with the actual and conventional process which is currently used inindustry in soft-flow dyeing machine for complete exhaustion of dye on cotton terry towel.To optimize the chemical used in the process and at same time reduce the effluent load in the entire process.The project aim is to produce green technology with chemical left over in the nature and chemical utdlizatdon,andidentify which is the best exhausting agent for dyeing of reactive dye.