| In recent years,with the continuous growth of textile fiber consumption,waste textiles are also increasing.At present,the disposal method is incineration or landfill.This not only causes a waste of resources,but also serious environmental problems.The comprehensive utilization of waste textiles can reduce carbon emissions,lower energy consumption and save water and timber resources.Therefore,the recycling of waste textiles is of great significance.This paper selects the waste polyester-cotton blended fabric as raw materials.A simple separation of cellulose and polyester from their mixed fabrics was accomplished by a two-step process consisting of acid treatment in the first step and mechanical grinding of the fabrics in the second step,by which cellulose was efficiently separated from polyester fabrics as a powder.The key factors related to the sulphuric acid treatment such as the acid concentration,the treatment time and temperature are also investigated to clarify their effects on cotton recovery and polyester recovery.The recovered cotton fiber was pretreated by alkali and then reacting with carbon disulfide to synthesize the cellulose xanthate.The cellulose xanthate was used to adsorb the nickel ions in aqueous solution.The main research contents include:(1)A single factor experiment on the treatment of waste polyester-cotton blended fabric with dilute sulfuric acid was carried out and analyzed the influence of the acid concentration,the treatment time and temperature to make a better recycling.The results showed that the recovery rate was positively correlated with the mentioned three factors.The recovery of polyester increased with the increase of acid treatment condition,and the cotton recovery firstly increased and then decreased.When the acid concentration is 10%,treatment time is 40 min and the temperature is 95?,the recovery of cotton fiber is 93.51% and the recovery of polyester is 98.1%.(2)The effects of treatment temperature,treatment time and acid concentration of sulfuric acid on the length and fineness of cotton fiber were studied.In addition,by testing the recycled cotton and polyester with microscopy,transmission electron microscopy(TEM),FTIR and XRD,the structure and processing properties of recycled polyester and cotton was compared with the untreated raw material,the results shows that with the acid treatment conditions intensifies,the length and fineness of cotton fiber are reduced and the cotton fiber was degraded into powder.The length of cotton fiber mainly distributed in 0-300?m and the length of cotton fiber recovered by the optimal acid treatment was mainly distributed in 0-25?m and the fineness was mainly distributed in 0-20?m.The XRD picture shows that the cellulose crystal type was cellulose ? crystal type,which means the treat process does not damage the crystal structure of cotton fiber.The appearance of the recycled polyester fiber was still smooth and its molecular structure was not changed.(3)Cellulose xanthate was prepared to study its application of absorbing nickel ions.The cotton fiber recovered from the optimum treatment conditions was pretreated by alkali and then reacting with carbon disulfide to synthesize the cellulose xanthate.The influencing factors such as temperature,the dosages of absorbent,contact time,the initial concentration of heavy metals,p H on adsorption were analyzed.The best adsorption condition was obtained: the initial concentration of 0.8g/L,adsorbent dosage 0.4g and contact time is 90 min,the temperature is 40 ?,the p H is 7.Under these conditions,the adsorption rate and adsorption capacity were up to 93.6% and 18.72 mg /g. |
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