Zhi-hua Liu

Hydrolysis of corncob catalyzed by self-derived carbonaceous solid acid

ABSTRACT Carbonaceous solid acid (CSA) catalysts with –SO3H, –COOH, and phenolic –OH functional groups were prepared by hydrothermal carbonization and sulfuric acid impregnation methods. A maximum furfural (FF) yield of 19.66% from corncob degradation remained stable at 10 runs at 180°C for 170 min while the concentration of sulfuric acid was employed from 2.0 to 0.5 mol/L. The sulfur in CSA catalyst exists in two forms, namely SO42− and –SO3H. The free sulfuric acid and carbon together with –SO3H created good physical contact between the lignocellulose substrate and the solid catalyst in the reaction, and drastically improved the depolymerization rate of hemicelluloses and cellulose to soluble polysaccharide.

Electrocatalytic degradation of rice straw lignin in alkaline solution through oxidation on a Ti/SnO2–Sb2O3/α-PbO2/β-PbO2 anode and reduction on an iron or tin doped titanium cathode

A novel procedure for selective production of biomass-based compounds by electrochemical conversion has been developed in this work. At ambient pressure and mild temperature, rice straw lignin dissolved in sodium hydroxide solution was directly electro-oxidized on the surface of a Ti/SnO2–Sb2O3/α-PbO2/β-PbO2 anode, and subsequently, electro-reduction by the electro-generated chemisorbed hydrogen on the titanium-based (iron or tin doped titanium) cathodes proceeded. The electro-catalysis could effectively break the chemical linkages among phenylpropyl units in rice straw lignin, and more than 16 kinds of aromatic compounds containing phenols, aromatic hydrocarbon, aromatic ester, aromatic ketone, aromatic acid and aromatic aldehyde (e.g. guaiacol, syringol, dihydroeugenol, vanillin, p-coumaric acid, ferulic acid, etc.) were generated and identified utilizing GC-MS measurement. The operation conditions for the enhancement of the product yield including the current density, lignin concentration, temperature and reaction time were optimized. The results indicate that the properties of the cathode materials, current density and reaction time play important roles in the electrocatalytic hydrogenation of rice straw lignin.

Electrocatalytic Degradation of Cellulose Using Lead Dioxide Anode

A novel method of cellulose degradation is investigated in this paper. In this work, a three-electrode system, which contains a Pb/PbO2 anode, two copper cathodes and a reference saturated calomel electrode (SCE), is applied to electrocatalytic degradation of cellulose. The composition of the products in filtrate is characterized by phenol-sulfuric acid method, NMR and GC-MS. In addition, the solid sample is analyzed via Ubbelohde capillary viscometer and FT-IR spectra. The results suggest that it is effective to convert cellulose to soluble sugar, 5-hydroxymethylfurfural (5-HMF) and other products by electrocatalytic method. The reaction mechanism of cellulose degradation is also discussed.