Separation And Modification Of Lignin Generated From Sporl-Pretreated Bioconversion Of Wheat Straw To Ethanol

Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) was recently developed and is new to the biomass research community. High enzymatic hydrolysis glucose yield, high removal of hemicellulose as well as lignin, and low amounts of fermentation inhibitors can be achieved in the SPORL pretreatment. Furthermore, the existing mature equipment, technology, and infrastructure that have long been used in the pulp and paper industry can be fully used during SPORL treatment and therefore it has bright commercial prospects.In the second part of paper, the first object is to find a compromising way between soluble lignin precipitation and fermentable sugars conservation in the SPORL liquid by Ca(OH)2treatment in order to utilize lignin resource. Therefore, SPORL liquid was treated by Ca(0H)2, to investigate the influence of Ca(OH)2treatment on the content of lignin, glucose and xylose in the SPORL liquid. The result indicated that increasing Ca(OH)2charge, duration, temperature, and SPORL liquor concentration tend to favor precipitation of lignosulphonates, but hurt fermentable sugars conservation. Taking both lignosulphonates precipitation and fermentable sugars conservation into account, application of Ca(OH)220g·L-1to the liquor phase without enrichment at30℃for90minutes could be an optimal condition. Under this process condition,25.95%(percentage of initial concentration) lignosulphonates were precipitated, while nearly all glucose and60.25%xylose (percentage of initial concentration) were conserved for further saccharification and fermentation.In this paper, the lignosulfonate water reducing agent was prepared via oxidation and sulfomethylation of enzymatic hydrolysis lignin. The results indicated that increased reaction temperature, duration and charge of oxidizer and sulphonating agent would improve solubility and dispersity of modified production. The optimum reaction conditions were decided as follow, for oxidation conditions:charge of H2O215%, Na2CO330%, pH value about9, oxidation temperature was70℃, duration60min; for sulphomethylation conditions:dosage of HCHO6%, Na2SO325%, sulfomethylation temperature90℃, duration180min. The solubility and dispersity of enzymatic hydrolysis lignin was improved obviously after modification. Under above condition, the soluble solid of modified production was69.6%, which was46.41%higher than control sample. The fluidity of cement paste can reach187mm at0.35%charge of water reducing agent, which were63mm higher than control sample.