Preparation and catalytic performance of biomass-based solid acid catalyst from Pennisetum sinense for cellulose hydrolysis.

As a kind of lignocellulosic biomass, Pennisetum sinense (P. sinense) is commonly used as animal feed, fertilizer or papermaking raw materials. Based on the high carbon content and renewability of P. sinense, we explored the possibility and feasibility of using it as catalyst matrix. The catalyst was produced by sulfonation of char obtained from the carbonization of P. sinense at 550 °C. The structure of the catalyst was characterized by SEM, BET, XRD, FT-IR, XPS and TGA, and its catalytic performance for the hydrolysis of cellulose was investigated in detail. The highest acidity of the catalyst was 3.79 mmol/g and the maximum glucose yield of 59.92% was achieved under optimized conditions. The catalyst also showed a promising reusability. The glucose yield was 53.01% after 5 cycles and as high as 55.92% when using the regenerated catalyst.

Preparation and heavy metal ions biosorption of graft copolymers from enzymatic hydrolysis lignin and amino acids.

Novel biosorbents, graft copolymers, were prepared via Mannich reaction from enzymatic hydrolysis lignin with glycine and cystine, respectively. The element content, FT-IR and fluorescence spectra, relative viscosity, and particle size of the copolymers were systematically investigated. Furthermore, effects of initial pH, ionic strength, temperature, contact time and initial metal ion concentration on the biosorption capacities of Cu(II) and Co(II) ions onto the copolymers were studied using batch sorption technique. It was found that the copolymers exhibited excellent biosorption characteristics for Cu(II) and Co(II) ions. The sorption kinetic data can be described well with a pseudo-second-order model, and the equilibrium data can be fitted well to the Langmuir and Freundlich isotherm for Cu(II) and Co(II) biosorption process, respectively. Surface complexation and ion-exchange modeling were performed to elucidate the biosorption mechanism involved because surfaces of the copolymers contained three main types of acid/base sites from the amino acid grafted copolymer units.

Liquefaction of lignin by polyethyleneglycol and glycerol.

Enzymatic hydrolysis lignin (EHL), isolated from the enzymatic hydrolysis residues of the biomass, was liquefied using the mixed solvents of polyethyleneglycol (PEG) and glycerol at the temperature of 130-170°C with sulfuric acid as a catalyst. The influences of liquefaction parameters, such as the molecular weight of PEG, mass ratio of sulfuric acid to EHL, liquefaction temperature and time, and mass ratio of liquid (liquefying cosolvent) to solid (EHL) on the residue content and hydroxyl number were discussed. The FT-IR spectrum result showed that the liquefaction product of EHL was polyether polyol. The hydroxyl number of the liquefaction product was 80-120 mgKOH/g higher than that of PEG.

Synthesis of lignin-base cationic flocculant and its application in removing anionic azo-dyes from simulated wastewater.

In this paper the Mannich reaction product of dimethylamine, acetone and formaldehyde was grafted onto hydroxymethylated lignin to form a lignin-base cationic polyelectrolyte (L-DAF). L-DAF samples with different cationic strengths and molecular weights were synthesized and characterized. Their performance as a cationic flocculant in removing three anionic azo-dyes (Acid Black, Reactive Red and Direct Red) from simulated dye wastewater was evaluated. The removal of anionic dyes by L-DAF was ascribed to two simultaneous mechanisms, which included coagulation by charge neutralization and flocculation by bridging. There was a different optimum dose of flocculant for each dye wastewater, at which dye removal can reach above 95%. Furthermore, a longer settling time and a lower solution pH increased the efficiency of the decolorization process. During the treatment, more than 89% of chemical oxygen demand (COD) reduction was achieved with sludge production being less than 5.4%.

Preparation and characterization of phenol-formaldehyde adhesives modified with enzymatic hydrolysis lignin.

Phenol-formaldehyde (PF) adhesives modified with enzymatic hydrolysis lignin (EHL) were synthesized by a one-step process. The phenol component of the PF adhesives was partially substituted by EHL extracted from the residues of cornstalks used to produce bio-ethanol. The EHL-PF adhesives were used to prepare plywoods by hot-pressing. The pH value, viscosity, solid content, free phenol content, free formaldehyde content and brominable substance content of EHL-PF resins were investigated. The bonding strengths of the plywoods were determined, and the influences of the replacement percentage of phenol by EHL (a) and the NaOH content (b) on the properties of the adhesives were investigated. The results showed that the performance of the modified adhesives and the plywoods glued with them almost met the Chinese National Standard (GB/T 14732-2006) for first grade plywood when 20 wt% of the phenol was replaced by EHL.

[Spectra and structural analysis of high boiling solvent lignin from Bagasse].

Bagasse high boiling solvent lignin is a polymer prepared by high boiling solvent pulping process. In the IR spectra, the absorbance of HBS lignin at 1700 and 1 328 cm(-1) is present. It is showed that the nonconjugated carbonyl existed. The strong absorbance of UV spectra of HBS lignin is about 201 nm for n-->pi electron transition, which indicates that the HBS lignin is an unsaturated polymer. Judged from the 1H NMR, the syringyl and guaiacyl group in the lignin is present. The element composition and the content of OCH3 group were investigated. The empirical C9-formula of the lignin is C9H9.79O2.58(OCH)0.75 according to dealing with the experiment data. The weight-average molecular weight of the HBS lignin is 2674 g x mol(-1).