Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more...Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more favorable than heterogeneous particles,thanks to their faster reaction rate,more storage capacity,and higher stability.Foaming,however,could not be avoided during hydrate dissociation with the presence of SDS.This paper investigated the ability of five fluorinated surfactants:potassium perfluorobutane sulfonate(PBS),potassium perfluorohexyl sulfonate(PHS),potassium perfluorooctane sulfonate(POS),ammonium perfluorooctane sulfonate(AOS),and tetraethylammonium perfluorooctyl sulfonate(TOS)to promote methane hydrate formation.It was found that both PBS and PHS achieve a storage capacity of 150(V/V,the volume of methane that can be stored by one volume of water)within 30 min,more than that of SDS.Cationic ions and the carbon chain length were then discussed on their effects during the formation.It was concluded that PBS,PHS,and POS produced no foam during hydrate dissociation,making them promising promoters in large-scale application.展开更多
Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthra...Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthraquinone(AQ)+sodium lignosulfonate(SLS)),and then enzymatically hydrolyzed with an enzyme cocktail(cellulase(Celluclast 1.5L),β-glucosidase(Novozyme 188)and xylanase(from thermomyceslanuginosus))in the pH range of 4.0-6.5.It was found that the suitable pH for the enzymatic saccharification process to achieve a high glucan yield was between 4.2 and 5.7,while the appropriate pH to obtain a high xylan yield was in the range of 4.0-4.7.The best pH for the enzymatic saccharification process was found to be 4.4 in terms of the final total sugar yield,as xylanase worked most efficiently in the pH range of 4.0-4.7,under the conditions in the study.The addition of xylanase in the enzymatic saccharification process could hydrolyze xylan in the substrates and reduce the nonspecific binding of cellulase,thus improving the total sugar yields.展开更多
基金This work was financially supported by the Key R&D Project of Shandong Province(No.2017GSF16106)DICP&QIBEBT Unite Fund(No.:DICP&QIBEBT UN201807)Strategic Priority Research Program of the Chinese Academy of Science(No.XDA 21060400).
文摘Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more favorable than heterogeneous particles,thanks to their faster reaction rate,more storage capacity,and higher stability.Foaming,however,could not be avoided during hydrate dissociation with the presence of SDS.This paper investigated the ability of five fluorinated surfactants:potassium perfluorobutane sulfonate(PBS),potassium perfluorohexyl sulfonate(PHS),potassium perfluorooctane sulfonate(POS),ammonium perfluorooctane sulfonate(AOS),and tetraethylammonium perfluorooctyl sulfonate(TOS)to promote methane hydrate formation.It was found that both PBS and PHS achieve a storage capacity of 150(V/V,the volume of methane that can be stored by one volume of water)within 30 min,more than that of SDS.Cationic ions and the carbon chain length were then discussed on their effects during the formation.It was concluded that PBS,PHS,and POS produced no foam during hydrate dissociation,making them promising promoters in large-scale application.
基金The authors are grateful for the great support of research funding from Procter and Gamble Co.This work was also partially supported by the National Natural Science Foundation of China(Grant No.31370582,Grant No.21306216,and Grant No.31470609)Shandong Provincial Natural Science Foundation for Distinguished Young Scholar(China)(Grant No.JQ201305)as well as the National High Technology Research and Development Program(“863”program)of China(Grant No.2012AA022301).
文摘Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthraquinone(AQ)+sodium lignosulfonate(SLS)),and then enzymatically hydrolyzed with an enzyme cocktail(cellulase(Celluclast 1.5L),β-glucosidase(Novozyme 188)and xylanase(from thermomyceslanuginosus))in the pH range of 4.0-6.5.It was found that the suitable pH for the enzymatic saccharification process to achieve a high glucan yield was between 4.2 and 5.7,while the appropriate pH to obtain a high xylan yield was in the range of 4.0-4.7.The best pH for the enzymatic saccharification process was found to be 4.4 in terms of the final total sugar yield,as xylanase worked most efficiently in the pH range of 4.0-4.7,under the conditions in the study.The addition of xylanase in the enzymatic saccharification process could hydrolyze xylan in the substrates and reduce the nonspecific binding of cellulase,thus improving the total sugar yields.