Dyeing And Printing Chemical Substitution Research Based On Chemical Footprint

Textile printing and dyeing industry is one of the industries with high pollution.The discharge of printing and dyeing wastewater causes high ecological toxicity to the freshwater ecosystem,and is seriously harmful to the ecological environment.In order to improve the high toxicity of printing and dyeing wastewater,it is urgent to substitute toxic and harmful chemicals from the source.In the past,the research on the substitution of toxic and harmful printing and dyeing chemicals only remained on the technical feasibility.The potential ecological risks of the use of substitution chemicals were not quantitatively analyzed.Chemical footprint is the volume of fresh water which the chemical substance occupies below the concentration point that does not cause damage to the ecosystem.Chemical footprint index is the proportion of chemical footprint in renewable water resources.Chemical footprint and chemical footprint index can be used to evaluate ecological feasibility of alternative printing and dyeing chemicals.This study is based on chemical footprint,which builds 7 functional kinds of chemicals list,including 15 kinds of dyeing and printing chemicals which need to be substituted and 14 kinds of technically feasible alternative chemicals.The chemical toxicity of this list is compared and analyzed.And the environmental benefits of the alternative chemicals under the dosage of printing and dyeing chemicals scenario is calculated.The ecologically feasibility of the alternative chemicals is demonstrated.The main research results are as follows:(1)Among the 29 chemicals listed in this study,three chemicals with the greatest potential risks to freshwater ecology are all the substitution chemicals of fire retardants and plasticizers.Three chemicals with the least potential risk to freshwater ecology are fungicide substitute,dye solvent substitute and thickener which needs to be substituted.The results showed that some of the alternative chemicals could not be used as substitutes for toxic and harmful chemicals when considering the ecological feasibility.(2)The chemical footprints of the 21 plans composed of the chemicals which need to be substituted under the dosage of printing and dyeing chemicals scenario are from 18.67 km3 to 438.96 km3.The CFIs are from 3.60 to 84.71.The chemical footprints of the 30 plans composed of the alternative chemicals under the dosage of printing and dyeing chemicals scenario are from 8.72?10-2 km3 to 5.66?104 km3.The CFIs are from 0.02 to 10913.66.The chemical footprint of the alternative chemicals with the smallest chemical footprint was 0.56% of the one of the chemicals needed to be substituted with the smallest chemical footprint.The result indicates that using the alternative chemicals with the least ecotoxicity in the printing and dyeing chemicals can significantly reduce the chemical footprint and be more beneficial to the freshwater ecosystem.(3)Seven functionally kinds of chemicals with the least chemical footprint are Acrylic Acid,Sulfuric Acid,C.I.direct black 22,Flexol EPO,(1-Methylethyl)phenol phosphate(3:1),Poly(hexamethylenebiguanide hydrochloride)and Isopropanol.Since the ecotoxicity of C.I.direct black 22 is higher than that of its counterpart-C.I.direct black 38,it is recommended that other eco-friendly alternative chemicals should be developed as soon as possible.According to the research results,some suggestions are put forward for the management of printing and dyeing chemicals.It is possible to improve the ecological toxicity of printing and dyeing wastewater from the source.