TITLE:
Propyl-Sulfonic Acid Functionalized Nanoparticles as Catalyst for Pretreatment of Corn Stover
AUTHORS:
Leidy Peña, Feng Xu, Keith L. Hohn, Jun Li, Donghai Wang
KEYWORDS:
Acid Functionalized Nanoparticles; Catalyst; Biomass Pretreatment; Hydrolysis
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.5 No.1,
January
10,
2014
ABSTRACT:
Propyl-sulfonic (PS) acid-functionalized nanoparticles were
synthesized, characterized and evaluated as catalysts for pretreatment of corn
stover. Silica coated nanoparticles were functionalized with 0.5%
mercaptopropyltrimethoxysilane
(MPTMS) at neutral pH in a mixture of water and ethanol. Sulfur contents of the
acid functionalized nanoparticles,
measured in a CHNS analyzer, varied from 6%-10%, and the acid load ranged from 0.040 to 0.066
mmol H+/g. A Box-Behnken design
was employed to calculate the minimum number experiments required to obtain an
estimate of the surface response for temperature, catalyst load, and %S content
of the catalyst. Pretreatment of corn stover was carried out at three
temperature levels 160, 180, and 200°C for 1 h. Three levels of catalyst load
were used 0.1, 0.2, and 0.3 g of catalyst per gram of biomass. Hydro-thermolysis
controls were carried at each temperature level. The catalyst load did not have
an effect on the glucose yield at 160°C, and the average glucose yield obtained
at this temperature was 59.0%. The glucose yield was linearly correlated to the
catalyst load during pretreatment at 180°C, and a maximum glucose yield of 90%
was reached when using 0.2 g of PS nanoparticles that had a total sulfur
content of 6.1%. Complete hydrolysis of glucose was reached at 200°C but the
average xylose yield was 4.6%, and about 20.2% of the combined glucose and
xylose were lost as hydroxymethylfurfural and furfural. Results showed that
acid-functionalized nanoparticles can be potential catalysts for the
pretreatment of biomass for its later conversion to ethanol.