Modification Of Juncus Effuses Fiber And Its Application In Polyester Alcohol-discoloration

Textile as the first place of "food,clothing,housing,and transportation",the consumption of resources is huge,and polyester fiber composition occupies a large proportion.Dihydroxyethyl terephthalate(BHET)is the raw material of many important chemical products,but BHET is limited by the color and purity of waste polyester.Therefore,the current situation of the recycling of colored waste polyester is limited,and the decolorization of the alcoholysis solution of colored waste polyester is the most critical step in its recycling.In this study,natural porous cellulose materials Juncus effuses(JEs),were selected to study the physicochemical properties of JEs under the conditions of acid,alkali,oxidation,and reduction.Secondly,it was chemically modified by resin FA to prepare the adsorbent FA-JEs for the adsorption of Disperse Red 3B dye.Finally combining with practical application conditions,the prepared disperse dye adsorbent FA-JEs was applied to the color decoloring process of polyester glycol alcoholysis liquid,and cellulose sorbents FA-JEs and industry commonly used on decoloring agent activated carbon decoloring effect was compared.The effect of cellulose-based adsorbent on decolorization of polyester alcoholysis solution was verified in practice.First of all,the natural porous cellulose material JEs were selected,which is a three-dimensional network structure and internal interconnection pipe structure.The effects of different concentrations of acid,base,oxidant,and reducing agent on the physicochemical properties of JEs were discussed.The results showed that the surface morphology of JEs treated with acid changed little,and the composition of JEs changed greatly;secondly,the surface morphology and composition of JEs treated with alkali changed greatly,and the composition lost of JEs treated with alkali,lignin and hemicellulose dissolved in alkali solution,and the surface morphology became rough.The resistance of JEs to oxidants and reducing agents was relatively high,and the surface morphology of JEs was basically intact.After etherified 2D resin FA was used to cross-link JEs,the macromolecular alkane groups in the resin FA were introduced into the JEs to get the modified JEs(FA-JEs).The adsorption effect of JEs on Disperse Red 3B dye in water was studied.It was found that the adsorption process was not affected by the pH of the solution,and the removal rate of dye with the same concentration would increase with the increase of contact time.Under certain conditions,the removal rate of FA-JEs for Disperse Red 3B dye reached 99%,and the maximum adsorption capacity reached 105.32g/g.The maximum theoretical adsorption capacity reached 103.95g/g by using the Langmuir adsorption model equation.The adsorption process conforms to the pseudo-second-order kinetic model.Combined with kinetic and thermodynamic analysis,the adsorption mechanism is that the non-polar groups on the adsorbent and the long-chain molecules grafted on the adsorbent provide more adsorption space and opportunities for the Disperse Red 3B dye.Finally,the decolorization efficiency of FA-JEs in the alcoholysis solution of colored polyester was compared with the activated carbon.The results showed that the decolorization efficiency of FA-JEs on the alcoholysis solution of colored polyester showed higher adsorption efficiency at the beginning of the adsorption period,and the decolorization rate was faster than that of activated carbon in the beginning of the adsorption period.FITR,DSC and TG tests were carried out on the BHET crystals before and after FA-JEs decolorization.The results showed that the infrared characteristic absorption peak,melting point and DTG weight loss peak of the samples after decolorization were consistent with those before the decolorization,which indicated that the decolorization of FA-JEs would not cause other irreversible effects on the BHET and met the actual production requirements.