Study On Dedradation And Carbonization Of Cotton Fiber Under Hydrotheral Condition

At present,the lifetime of textiles have been shorted and fiber annual consumption has increased significantly,but the supply of textile fiber raw materials is difficult to continue.What's more,thousands of waste textiles are burned or buried every year,but the recycled rate is less than 1%.It caused serious resources waste and environmental pollution.Cotton and cotton fabrics account for more than one-third of abandon textiles.At present,most of the recycling methods for waste cotton textiles are limited to cutting or crushing cotton fibers,then to make some products with low added value,which difficult to promote recycling of waste textiles.Cotton fiber is the biomass material with the highest content of cellulose,which can be used as carbon source to prepared carbon material to receive the high value utilization of waste cotton fiber.The environment-friendly hydrothermal method was chosen in the paper.The waste cotton fiber was carbonized under different hydrothermal conditions,and the structure and properties of the products were characterized and analyzed.In order to obtain a spherical carbon material with excellent structure and performance,phenol,acetic acid and hydrochloric acid were chosen as catalysts.The paper studied the effect of three catalysts on the carbonization of cotton fiber,and the dehydration and carbonization of glucose which is intermediate product of hydrothermal carbonization of cotton fiber.The following conclusions can be obtained:?1?Optimum reaction conditions for hydrothermal carbonization of cotton fibers is 300?³20?,the heat preservation time is 8¹0 h and the concentration of catalysts is 20³0g/L.The graphitization degree of the carbonized products of cotton fiber is low,and there are abundant oxygen functional groups on the product surface,the product morphology is mainly stick or block structure.?2?Phenol promotes hydrolysis of cotton fibers into glucose,and participate in the hydrothermal carbonization reaction of cotton fiber.In addition,Phenol will increase the carbon content and yield of the product and improve the degree of graphitization,but the effect of the product morphology was small.?3?Acetic acid can promote the hydrolysis and carbonization of cotton fibers,the yield of hydrothermal products increased from14.7%to 16.8%.Acetic acid can change the appearance structure of cotton fiber carbonization products.The carbonized morphology is changed from particulate matter to spheroidal particle size of 1?m.But it can destroy the structure of the glucose carbide,the product of hydrothermal carbonization of glucose is bonded,dispersion variation.It is beneficial to the carbonization of cotton fiber when the content of acetic acid is less than 8 wt.%.?4?HCl can obviously promote the carbonization of water heating of cotton fibers,the yield of products and the carbon content of products are both improved,when the content of is 0.8wt.%.The yield of hydrothermal products was 20.52%,and the carbon content was79.20%.And the product has a good topographic structure.In addition,the detailed path of the carbonization reaction of cotton fiber is clarified.The H₃O⁺concentration in solution is an important factor affecting the carbonization of cotton fibers.