All Components Conversion Of Poplar Wood Into Ethanol,lactic Acid,and Carbon Electrode Material

The increased uncertainty of continuous oil supply and the negative impact of fossil fuels on the environment,particularly greenhouse gas emissions,have resulted in the extensive exploration of renewable fuel alternatives.All components conversion of poplar into high-value added products is essential for the industrialization of biorefinery.In this study,a new ethanol,lactic acid(LA),and interconnected hierarchical porous nitrogen-doped carbon(HPNC)coproduction process is proposed.Poplar wood was pretreated with white-rot fungi and alkaline hydrogen peroxide.The combined treatments increased the enzymatic digestibility to 89.3%,compared with 10.6%for untreated sample and 12.9%for solely white-rot treated samples.Highest digestibility of cellulose was achieved after 8 weeks of white-rot treatment and alkaline treatment at 120?,whereas sugar yield was highest from sole alkaline treatment at 160?.The efficient conversion can be ascribed to synergistic interaction between white-rot and alkaline treatments,resulting in increased enzymatic accessibility of cellulose.Results from MWL revealed that the cleavage of??-O-4 linkages(from 76.4/100Ar to 31.5/100Ar)and the degradation of ?-? and ?-5 linkages clearly occurred,resulting in a decrease in molecular weight.In addition,G-type lignin was degraded more than S-type lignin,with a slightly elevated S/G ratio from 1.13 to 1.29.Further analyses of lignin degradation compounds confirmed these results by showing a high amount of conjugated and unconjugated C=O functionalities.Furthermore,the degradation product of G-type lignin(vanillin)was detected by 2D HSQC NMR and GC-MS.Pretreatment with 10%H2O2(gH2O2/gwood at 160 0C for 2 h was found to be the optimal condition with remarkably increased ethanol yield.The proposed process resulted in 63.1%of ethanol yield.which,was about five times more than that of the untreated sample.The e addition of concentrated hemicellulose hydrolysate at 48 hours,which resulted in a maximum LA concentration of 22.3 g/L,was the most environment-friendly and cost-effective process.After the improved fermentation,361 mg LA and 132 mg ethanol were produced from 1 g of raw poplar wood.That is,the production of one gallon of ethanol produced $9 worth of LA.Lignin-derived products was prepared HPNC material.The obtained HPNC exhibited favorable features for supercapacitor applications,such as hierarchical bowl-like pore structures,a large specific surface area of 2218 m2/g,a high electronic conductivity of 4.8 S/cm,and a nitrogen doping content of 3.4%.HPNC-based supercapacitors in a 6 M KOH aqueous electrolyte exhibited high-rate performance with a high specific capacitance of 312 F/g at 1 A/g and 81%retention at 80 A/g as well as an excellent cyclic life of 98%initial capacitance after 20 000 cycles at 10 A/g.Moreover,HPNC-based Supercapacitors in the ionic liquid electrolyte of EMI-BF4 displayed an enhanced energy density of 44.7 Wh/kg(remaining 74%of max value)at an ultrahigh power density of 73.1 kW/kg.Through the above approach,we obtained glucose,ethanol,lactic acid and HPNC material.This combined approach was proved an effective method for the promotion of the whole component conversion of poplar.