Study On Preparation Of Xylose From Triarrhena Lutarioriparia Hemicellulose

Xylose is a pentose sugar that can be extracted from natural plants and is generally found in plant hemicellulose in the form of glycan.As one of the important carbohydrates,D-xylose is widely used in food,medicine and materials due to its unique physiological and biological characteristics.Triarrhena lutarioriparia is a kind of high quality fiber biomass resource,with the content of hemicellulose at about 20%.The preparation of xylose from Triarrhena lutarioriparia as the raw material can open a new way for Triarrhena lutarioriparia is deep processing,and is also conducive to the realization of the biological refining of lignocellulosic in Triarrhena lutarioriparia.In industry,inorganic acid hydrolysis method is often used to prepare xylose,but this method has some shortcomings,such as serious corrosion of equipment,environmental pollution and high cost of neutralizing inorganic acid.Therefore,it is of great significance to study a new green and efficient method for the preparation of xylose to realize the high value utilization of the whole components of argyra amida.In the present study,Triarrhena lutarioriparia was used as a raw material,and an environmentally friendly and cost-efficient approach was established to separate the three components of Triarrhena lutarioriparia and prepare high-purity xylose.First,we identified a better process for separating formazan components from formic acid,and then a preliminary decolorization and purification process was performed using the crude xylose extract.Finally,a deacidification and purification study was carried out on the xylose solution,and the composition of xylose solution was analyzed.The main work procedures and conclusions were as follows:(1)The chemical constituents of Triarrhena lutarioriparia were analyzed,the formic acid method was used to separate the lignocellulosic components of Triarrhena lutarioriparia,the influences of different conditions on the separation of Triarrhena lutarioriparia were studied,and its structure was characterized.The results showed that the optimal parameters were as follows: formic acid mass fraction of 88%,reaction time of 3 h,water bath temperature of 100 ℃,and material-liquid ratio of 1:10.Under these above-mentioned conditions,the recoveries of cellulose,hemicellulose and lignin were 91.7%,80.2% and 85.3%,respectively,and the purity of cellulose and lignin was 83.6% and 86.8%,respectively.GM-CS sugar analysis showed that xylose was the main component in hemicellulose sugar solution,and its content was 89.8%.FT-IR,XRD,and TGA analyses showed that the cellulose and lignin obtained from formic acid separation underwent considerable formylation,the basic structure of cellulose remained intact,the relative crystallinity was significantly increased,and the structure of lignin benzene ring remained intact and showed high thermal stability.(2)An activated carbon pretreatment method was established,and the decolorization of xylose extract was studied by using such activated carbon pretreatment method.Through single-factor and orthogonal experiments,the process conditions for decolorization of xylose solution were determined as follows: addition amount of 30 g/L,decolorization temperature of 70 ℃,and decolorization time of 70 min.Under these optimized conditions,the decolorization rate of the xylose solution was 92.33%,and the retention rate of the xylose was 88.58%.(3)The most suitable ion exchange resin for the purification of xylose from formic acid was selected using the static adsorption test.The effects of adsorption temperature and injection speed on dynamic adsorption as well as the effects of elution speed and analytical temperature on dynamic analysis were investigated.The process conditions for deacidification and purification of xylose solution were also determined as follows:adsorption temperature of 30 ℃,injection speed of 1mL/min,the injection volume is 20 mL,elution flow rate of 1.5 mL/min,and analytical temperature of 55 ℃.More than 99% of formic acid could be removed under these conditions,and the purity of xylose could reach 86.34%.In addition,most of the salt ions in the xylose solution were also removed by the above-mentioned procedure,leading to the desalination rate and light transmittance of 87.02% and 97.61%,respectively.Dowex resin was used for dynamic elution and separation of xylose and arabinose in xylose solution.The effects of several parameters,such as elution temperature,elution flow rate and resin filling height,on sugar separation were investigated.The results showed that the optimal conditions of separation and purification of the xylose solution were as follows:the elution temperature of 40 °C,elution flow rates of 1.5 mL/min,and filling height of 40 cm.Under these optimized conditions,a large amount of impurities were eliminated,and a xylose solution containing more than 95% xylose was obtained.