Weizun Li

Separation and recovery of cellulose from Zoysia japonica by 1-allyl-3-methylimidazolium chloride.

We investigated the use of ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AMIMCl) for extracting cellulose from Zoysia japonica by using Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy and thermogravimetric analysis to analyze the IL and its effects on cellulose extraction. After water pretreatment at 121 °C for several minutes, cellulose extraction rate was 71% under optimized conditions, and the yield of cellulose was >99% by AMIMCl. The effectiveness of AMIMCl as an extraction agent can be attributed to the prevalence of intra- and inter-molecular hydrogen bonding in cellulose. By contrast, hemicelluloses were not recovered by AMIMCl because hemicelluloses in plant cell walls are connected to lignin by covalent bonding. Results also showed that the regenerated cellulose was exactly the same as untreated cellulose, except for the degree of crystallinity.

Dissolution of cellulose from AFEX-pretreated Zoysia japonica in AMIMCl with ultrasonic vibration

In this study, 1-allyl-3-methylimidazolium chloride (AMIMCl), an ionic liquid, was synthesized and characterized by a series of test methods. Pretreatment of Zoysia japonica by ammonia fiber expansion (AFEX) was shown to reduce significantly the mass of hemicellulose and lignin in biomass, thereby breaking the lignocellulosic structure. Z. japonica samples pretreated with AFEX showed reasonable solubility in AMIMCl upon ultrasonic treatment. The rate of cellulose regeneration from Z. japonica samples pretreated with AFEX increased with increase in applied power of ultrasonication within a certain power range from 0 to 110 W. The regeneration rate of cellulose from AFEX-pretreated Z. japonica reached a maximum of 97% when the ultrasonic power was 110 W. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses indicated that the regenerated cellulose was similar to microcrystalline cellulose.

Cellulose extraction from Zoysia japonica pretreated by alumina-doped MgO in AMIMCl.

In this study, alumina-doped MgO was produced as a solid alkali for lignocellulose pretreatment. Pretreatment with alumina-doped MgO disrupted the lignocellulose structure and significantly reduced the lignin content of the Z. japonica. After pretreatment, Z. japonica showed significant solubility in 1-allyl-3-methylimidazolium chloride (AMIMCl). The similar high solubility of pretreated Z. japonica samples by original alumina-doped MgO and used alumina-doped MgO also proved that alumina-doped MgO had strong stability, which can be recycled and used repeatedly. The regenerated cellulose was similar to microcrystalline cellulose according to FTIR and NMR analyses. Compared to microcrystalline cellulose, only the crystallinity of the regenerated cellulose decreased.

Rapid production of organic fertilizer by dynamic high-temperature aerobic fermentation (DHAF) of food waste.

Keep composting matrix in continuous collision and friction under a relatively high-temperature can significantly accelerate the progress of composting. A bioreactor was designed according to the novel process. Using this technology, organic fertilizer could be produced within 96h. The electric conductivity (EC) and pH value reached to a stable value of 2.35mS/cm and 7.7 after 96h of fermentation. The total carbon/total nitrogen (TC/TN) and dissolved carbon/dissolved nitrogen (DC/DN) ratio was decrease from 27.3 and 36.2 to 17.4 and 7.6 respectively. In contrast, it needed 24days to achieve the similar result in traditional static composting (TSC). Compost particles with different size were analyzed to explore the rapid degradation mechanism of food waste. The evidence of anaerobic fermentation was firstly discovered in aerobic composting.

Gold nanoparticle-modified TiO2/SBA-15 nanocomposites as active plasmonic photocatalysts for the selective oxidation of aromatic alcohols

The catalytic performance of noble-metal on mesoporous silica hosts has been widely investigated because the effects of surface plasmon resonance can open new avenues for the improvement of catalytic performance under light irradiation. In this study, a series of photoactive Au/TiO2/SBA-15 catalysts were developed for the selective oxidation of alcohols to corresponding aldehydes and ketones. The catalysts thus developed were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), scanning transmission electron microscopy energy-dispersive spectrometry, X-ray photoelectron spectroscopy (XPS), transient photocurrent response and electrochemical impedance spectroscopy (EIS). Au and small TiO2 nanoparticles (NPs) were uniformly anchored into the SBA-15 channels by the microwave-assisted alcohol reduction, resulting in the increase of the interfacial area between gold and titania; this increase in turn results in better catalytic performance of the Au2/TiO2/SBA-15 catalysts toward the selective oxidation of aromatic alcohols to aromatic aldehydes (ketones) as a result of the efficient pore confinement and visible-light absorption by the LSPR effect. A scheme with respect to the enhancement of photooxidation induced by the LSPR effect on the Au NP-decorated TiO2/SBA-15 composite was proposed.

Separation of polysaccharides from rice husk and wheat bran using solvent system consisting of BMIMOAc and DMI

A solvent system consisting of 1,3-dimethyl-2-imidazolidinone (DMI), and ionic liquid 1-butyl-3-methylimidazolium acetate (BMIMOAc) was used to separate polysaccharides from rice husk and wheat bran. The effects of the DMI/BMIMOAc ratios, temperature, and time on the dissolution of rice husk and wheat bran were investigated, and the influence of anti-solvents on the regeneration of polysaccharides-rich material was evaluated. We found that the solvent system is more powerful to dissolve rice husk and wheat bran than pure BMIMOAc, and that polysaccharides-rich material can be effectively separated from the biomass solution. The polysaccharides content of regenerated material from wheat bran can reach as high as 94.4% when ethanol was used as anti-solvents. Under optimized conditions, the extraction rate of polysaccharides for wheat bran can reach as high as 71.8% at merely 50°C. The recycled solvent system exhibited constant ability to separate polysaccharides from rice husk and wheat bran.

Fertilizer production by biodegrading lignocelluloses and process design

Biomass solid wastes containing lignocelluloses become more than 1 billion tons in China, 2010. If biomass solid wastes can be degraded into fertilizer, it would greatly promoted economic and social improvement. On the basis of experiments, aeration, moisture content, particle size, fermentation temperature and pH were the main factors affecting mixing bacterial fermentation. After understanding the microbial characteristics, the process was designed by considering the costs of equipment and production and also the main factors mentioned above.