Study On Recovery Of Terephthalic Acid From Waste Polyester-cotton Blended Fabrics Under Hydrothermal Conditions

The population of China is the highest in the world,and the production ofnational textile fiber is 5000 wt in 2014, more than 50% of the world’s sum. In the face of growing tension of oil resources and ensuring the red line pressure today, recycle waste textiles is particularly urgent. In terms of the textile fiber, the output of polyester and cotton fiber accounted for more than 70% of all textile fiber production.Thus recycling of polyester-cotton blended fabric has been the key to the recycling of textile fiber.At present, the most commonly used methods of waste polyester/cotton blend fabric is mechanical means or physical method, that is, keep the chemical properties of fabrics on the basis of simple physical changes. These methods are often recycled products of low value, and the used field is limit.In recent years, the use of chemical method to recovery polyester/cotton blended fabric has made some progress, but it is usually the single recovery of polyester or cotton, with the expense of one substance waste.So this recovery is not efficient. Some researches had studied on recycling of polyester and cotton, but because of the great difference in property of polyester and cotton, most of them choice to separate the two fabrics, then recovered.Therefore, the paper used waste polyester and cotton blended fabric as the research subject, using hydrothermal method for processing to recycle polyester and cotton,which is no need to separated.Because of the limit of energy,the paper only make analyses and discussions on the recycling of TPA from waste polyester and cotton blended fabric,and studying the impact of cotton fibers on the TPA recovery. After research and analysis, found that, under hydrothermal conditions, both reaction time and temperature impact on the recycling of TPA from waste polyester fabric. In terms of energy loss and the production efficiency, the optimum hydrolysis conditions of waste polyester fabric under hydrothermal conditions is 250℃,6 h. Cotton could inhibit the generation and promote the decomposition of TPA. The recycling white solid product obtained after react in autoclave waste polyester-cotton blend fabric is TPA. By the comprehensive experimental results concluded that the optimal reaction time is 7 h, the optimal reaction temperature range of 240℃ when recovery TPA from waste polyester/cotton blended fabric under the condition of water heat.