Synthesis and Application of Bleach Activators Containing Various Cationic Groups and PET Fabric Decolorization using Fenton's Reagent.

摘要

CBAs are quaternary ammonium salts (QAS) that are extensively used in various applications. Although most of the QAS are generally believed to be nontoxic to humans, they will harm aquatic life both animals and plants. CBAs are applied in textile bleaching process and the wastewater after bleaching contains chemicals including bleach activators. Even though wastewater contains CBAs will be treated in a wastewater treatment plant, the treated water still contain these chemicals. The study of acute toxicity and genotoxicity of CBAs to aquatic organisms was conducted in this study. Eight new bleach activators and two bench mark cationic bleach activators were investigated. New invented cationic bleach activator 3- PBBC is 86 times less toxic in the Daphnia sp. Immobilization Test, 18 times less toxic in Algae Toxicity assay and 10 times less mutagenic in the Salmonella/microsome microsuspension assay in comparison with the benchmark product (TBBC). This confirmed that replacing the cationic group in CBAs using low toxicity ammines can reduce the toxicity of CBAs to aquatic organisms.;An effective low temperature and neutral pH bleaching system was developed using CBAs. A comparison life-cycle assessment for conventional and innovational bleaching system was conducted in this study. Their relative environmental performance was analyzed and compared. Based on data from industry, pre-published research, lab-scale experiments and the Ecoinvent database, the life-cycle-inventory (LCI) for both innovative and conventional bleaching process was developed. Seven impact categories from TRACI, USETox and IPCC 2007 were selected to evaluate the impact based on the results of the LCI. The innovative bleaching process has lower environmental impacts than conventional method. It consumes less electricity, steam, water, and process time by modifying the conventional bleaching process.;Polyester (polyethylene terephthalate; PET) fibers now exceed cotton as the largest volume textile substrate in commerce, owing to their economy, strength, and versatility. Unlike cotton, PET fibers are not readily biodegradable, leading to their persistent if placed in a landfill environment following their useful lifetime. The modern-day corporate commitment to product stewardship has led to considerable interest in the recycle/reuse of textiles derived from synthetic fibers such as PET. It is generally recognized that the key step in the recycling process is color removal. Fenton's chemistry was used in the present investigation as an approach to decolorizing PET fabrics containing a variety dye structural types, providing an indication of the versatility of this method. A full factorial design of experiments was used to establish the amount of FeSO4 and H2O2 needed to optimize fabric decolorization. In this study, an optimized method consisting of FeSO4 (0.18 mM), H2O2 (1235 mM), and water: acetone (1:1), at 120 °C, for 15 min was found suitable for color removal from most PET fabrics.;Due to the technique barrier, the used PET garment cannot be recycled as simple as used PET bottles. By developing the method which can be used to remove the dye in the used PET garments, it is possible to recycle used PET garments for PET fiber production. In this study, a life-cycle assessment was used to compare the environmental impacts of fiber production using post-consumer PET fabric and virgin PET fiber production. After analysis, using postconsumer PET fabric to produce fiber will release 5.45% to 44.61% less impacts to the environment compared to virgin PET production. Only emissions, which cause ozone depletion, released by recycled fiber production through chemical recycling process are more than the emissions released by virgin PET production. In order to reduce the environmental impacts of the post-consumer PET fabric to fiber production, the optimizations of PET fabric decolorization process, recycling process and chemical production are necessary. A decolorization process using less chemical and at lower temperature should be developed in the future. A more environmental friendly process for hydrogen peroxide production should be used.