The Study Of Surfactant Assisted Ultrasound-Ionic Liquid Pretreatment On Lignocellulose

With the economic increasing,the fossil fuel like coal and oil are extensively exploited,a great amount of green house gas was emitted in atmosphere which causes globe warming and rising sea level.In the rapid development of China’s economic,as a huge consumer of fossil energy its emissions ranked first in the world.There are a large mount of waste straw in China which is one of the country which have most abundant of lignocellulose resource.Development of bio-fuel not only meet requirement for national policy,but also maintain the energy security.To take the second generation bio-fuel for example,it is made from lignocellulose which is widely spread,cheap and substantial.The rugged structure of natural lignocellulose prevents the enzyme and bacterium from accessing the polysaccharides which decreases the sugar yield of enzymatic saccharification.Thus,an efficient pretreatment to disrupt the sturdy construction,break down the crystalline cellulose and are required to enhance the efficiency of enzymatic hydrolysis.This study was discussed the effect of Ultrasound/Ionic liquid(US-ILs)pretreatment on enzymatic of water hyacinth.The pretreatment factors include temperature,time,pulse ratio and power.Different concentration of sodium dodecyl sulfate(SDS)was added to the medium which assisted the US-ILs to pretreat water hyacinth in optimal condition to enhance the enzymatic hydrolysis.Moreover,the enhancement and mechanism of added surfactant in USILs pretreatment was verified by component anlysis,scanning electron microscopy(SEM),fourier transform infrared(FTIR),X-ray diffraction(XRD)and atomic force microscope(AFM).The water hyacinth and 1-Butyl-3-methylimidazolium chloride(BMIMCl)were used as lignocellulose material and ILs,respectively.The factors of US-ILs pretreatment was optimized by single factor test.As a result,the optimal condition for enzymatic hydrolysis of water hyacinth were 5%(w/w)solid loading,at 15 s/15 s,120 °C,100 W for 45 min.0.5%(w/w)SDS were added to the US-ILs pretreatment of water hyacinth to enhance saccharification The prodection of reducing sugar,cellulose conversion and delignification were increased by 72.24% 58.79% and 21.01% in 48 h enzymatic hydrolysis,respectively.In the other hand,the CrI% TCI and LOI value were decreased by 6.54%,15.27% and 11.27%,respectively.In conclusion,the SDS could furtherly destroy the crystalline region.Compared with US-ILs pretreated water hyacinth,the added SDS one showed more fragment and removal of hydrophobic lignin.Furthermore,the effect of type and polymerization degree of surfactant on enzymatic hydrolysis and component were investigated in this study with rice straw treated by US-ILs pretreatment assisted surfactants.The FTIR analysis was applied to explore the variation of functional group and crystallinity in different surfactants.This part is aim to provide more data for US-ILs assisted by surfactant which verify the possibility of this method.The rice straw and 1-allyl-3-methylimidazolium chloride(AMIMCl)were used as lignocellulose material and ILs,respectively.The pretreatment condition were 5%(w/w)solid loading,at 15 s/15 s,120 °C,100 W for 45 min.This study investigated the effect of combining different types of surfactants including SDS,Tween20,rhamnolipid and cetyl trimithyl ammonium bromide(CTAB)and different polymerization degree of surfactants including Tween20-80 for enhancement of US-ILs pretreatment.The improvement of sugar yield and removal of lignin were proved by the enzymatic hydrolysis,component analysis and FTIR analysis in US-ILs assisted by SDS and rhamnolipid.The polymerization degree have not significant effect on the efficiency of pretreatment.With the addition of SDS and rhamnolipid,the delignification were increased by 45.02% and 45.20%,cellulose conversion were increased by 35.93% and 31.35%,respectively.While the TCI values were decresed by 38.82% and 7.90%,LOI values were decreased by 19.71% and 18.79%,respectively.Finally,this study also investigated the recyclability of ILs in rice straw treated by SDS assisting US-ILs pretreatment.With 5 times batch pretreatment,the recovery of ILs were above 95%,and 79.6% of the total ILs was retained in fifth batch pretreatment.In contrast to the first batch,the sugar yield in enzymatic hydrolysis,cellulose conversion and delignification of treated rice straw were decreased by 15.52%,13.15% and 24.19%,respectively.While the TCI and LOI were increased by 15.34% and 12.42%,respectively.In conclusion,the efficiency reduced as the batch number increased,especially in the fifth batch.Research results can provide theoretical and practical reference to enhance the lignocellulose pretreatment.