Zhong-Wen Liu

Particles from bird feather: a novel application of an ionic liquid and waste resource.

The dissolution and regeneration of the waste chicken feathers in an ionic liquid of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) were demonstrated for preparing chicken feather based particles. The structure and properties of the regenerated chicken feathers were investigated by FT-IR, XRD, SEM, BET and water contact angle. The crystallinity of the regenerated chicken feathers was decreased, and the content of beta-sheet was 31.71%, which was clearly lower than the raw feather (47.19%). The surface property of chicken feather changed from hydrophobicity to hydrophilicity after regenerated from [BMIM]Cl as indicated by the change of the water contact angle from 138 to 76 degrees . The chicken feather particles regenerated from [BMIM]Cl showed an excellent efficiency (63.5-87.7%) for removing Cr(VI) ions in wastewater at the concentrations from 2 to 80 ppm. The Freundlich constant (k(F)) for the adsorption of Cr(VI) ion by the particles of the regenerated chicken feather was four times larger than that of the raw chicken feather, the possible reason is the hydrophilic groups such as amino and carboxyl groups were tend to self-assemble towards surface when the dissolved CF were regenerated by water, amino group will partly hydrate to cationic amino and Cr(VI) ion occurs as an anion in the aqueous phase, so the cationic amino will adsorb the anionic Cr(VI) ion onto the RCF particles through electrostatic attraction. This work demonstrated a new application of the ionic liquid for dissolving chicken feather and a renewable application of waste chicken feather for removing Cr(VI) ion in water.

V2O5/Ce0.6Zr0.4O2-Al2O3 as an efficient catalyst for the oxidative dehydrogenation of ethylbenzene with carbon dioxide.

Vanadium has been widely used in catalysis because metaloxide-supported vanadia can catalyze many industrially important reactions, such as oxidation reactions. 2] The activity of the supported vanadia is highly dependent on the specific oxide support as a result of the so-called strong metal oxide–support effect. Although many researchers have attempted to gain insight into the catalytic mechanism, by using theoretic calculations and various characterization techniques, it is not yet fully understood. Thus, the design of a high-performance supported vanadia catalyst, especially one with a high degree of stability, is still a challenge. The oxidative dehydrogenation of hydrocarbons (ODH) to alkenes is industrially important for various large-volume synthetic polymers. Because ODH with molecular oxygen as oxidant is a promising solution, many efforts have been reported. Based on the concepts of dehydrogenation and selective catalytic oxidation of hydrogen, the commercial SMART process for the oxidative dehydrogenation of ethylbenzene was developed. This process co-feeds oxygen and steam in seriesreactor system. b] To overcome safety problems that result from mixing oxygen and light hydrocarbons, a novel idea to remove the dehydrogenation product of hydrogen by using reducible lattice oxygen was proposed, and a high-performance catalyst for the selective combustion of hydrogen in the presence of light hydrocarbons has been developed. Alternatively, ODH using CO2, being a soft oxidant without the problem of deep oxidation, is very attractive because it may open up new directions for oxidation reactions, and create a new route for ODH. Thus, oxidative dehydrogenation of ethylbenzene with CO2 (CO2-ODEB) has been extensively investigated as an efficient, energy-saving, and environmentally benign process. 7] Although the supported vanadia catalyst shows high activity towards CO2-ODEB, [7a–f] which proceeds via the Mars–van Krevelen redox mechanism, 2] it still suffers from severe catalyst deactivation. Being an excellent redox material, ceria stabilized with zirconia has found widespread use as catalyst or catalyst support. 8] Moreover, defect-site-enriched ceria (with the nature of the defects determined by the applied preparation method) has been reported to promote ODEB with N2O. [9] Thus, the combination of CeZrO2 with vanadia may create a unique ODH catalyst, provided that a very well dispersed oxide can be achieved. In this case, CO2-ODEB may proceed according to the redox cycle illustrated in Scheme 1. The oxidation of Ce to Ce by CO2 and the reduction of V 5+ to lower oxidation states (possibly V) by ethylbenzene are directly involved in CO2ODEB. Subsequently, V is oxidized to V with the reduction of Ce to Ce to complete the full cycle.

A Novel Chemical Degumming Process for Ramie Bast Fiber

A novel chemical degumming process for ramie fiber was developed, using sodium carbonate solution with poly(vinyl alcohol) (PVA) as an auxiliary surfactant and sodium triphosphate. Optimum performance for the degumming of ramie fiber was obtained with sodium carbonate concentration 30 g·L —1, PVA concentration 2.2 g·L— 1, sodium triphosphate concentration 6.0 g·L— 1 and temperature 90 °C. The tensile properties of the ramie fibers degummed using Na2CO3 are comparable with fibers degummed using sodium hydroxide. This new mild, rapid degumming technique for ramie fiber has a potential application in industry, and is less environmentally polluting than the traditional method. The ramie fibers before and after degumming were characterized by FT-IR, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy.

Preparation and application of cellulose triacetate microspheres.

Cellulose triacetate was prepared via reacting of a mixture of acetic anhydride and acetic acid containing sulfuric acid as catalyst with ramie fiber obtained from a biomass of ramie. The cellulose triacetate with a degree of substitution (DS) 2.93 of the ramie fiber was obtained. The honeycomb-like cellulose triacetate microspheres with an average diameter of 14 microm were made from the cellulose triacetate solution. The optimum conditions for preparing the microspheres were determined as cellulose triacetate/dichloromethane ratio 1:7 (w/w), and 0.75% sodium dodecylsulfonate. The cellulose triacetate microspheres were characterized using FT-IR, NMR, XRD, and SEM. Application of the microspheres as an adsorbent for removing disperse dyes in water was investigated under the temperatures from 15 to 50 degrees C, pHs from 4 to 9, and the weight of cellulose triacetate microspheres from 0.03 to 0.09 g. The cellulose triacetate microspheres exhibited a 16.5mg/g capability to remove DR dye from water at 50 degrees C and pH 7.

Poly(vinyl alcohol) Functionalized β-Cyclodextrin as an Inclusion Complex

Hydrophilic poly(vinyl alcohol) functionalized β -cyclodextrin polymers were synthesized by copolymerization through a mixture of β -cyclodextrin (β -CD) and epichlorohydrin (Epi) in the presence of poly(vinyl alcohol) (PVA). The water soluble or hydrogel polymers were obtained depending on the β -CD/Epi molar ratios used in the polymerization. The structures of polymers were characterized by FT-IR, 1H-NMR, 13C-NMR, XRD, TGA, and DSC, respectively. The results demonstrated that the copolymerization between PVA and β -CD indeed occurred. The number of cyclodextrin units grafted on PVA chain calculated from 1H-NMR spectra are 37, 41 and 73 mole β -CD per 1000 mole PVA units in PVA-β -CD1, PVA-β -CD2 and PVA-β -CD3 polymers, respectively. The contents of β -CD in polymers increased with the increase of Epi/β -CD molar ratio in the reactions. In vitro release of aspirin (Asp) suggested that all polymers performed sustained-release of Asp, especially, PVA-β -CD3 showed nearly linear release of Asp for 24 h. The half lifetime of an Asp tablet made from PVA-β -CD 1∼ 5 is 13, 7, 13, 8, and 8 h, respectively. The 3-hydroxy-2-naphthoic acid (3H2NA) was used to study the interaction between drug and polymers. Fluorescence emission spectra analysis demonstrated that cyclodextrin units grafted on polymers keep the ability of forming inclusion complex with 3H2NA by supermolecular interactions. The regression of experimental data showed that 1:1 stoichiometry for the inclusion complex between β -CD and 3H2NA, and the association constant for PVA-β -CD1, PVA-β -CD2 and PVA-β -CD3 are 305, 97 and 354 mL· g−1, respectively, which increased with the increase of the content of β -CD in PVA-β -CD polymers.

Amphiphilic Imbalance and Stabilization of Block Copolymer Micelles on-Demand through Combinational Photo-Cleavage and Photo-Crosslinking

An amphiphilic block copolymer of poly(ethylene oxide)-b-poly((N-methacryloxy phthalimide)-co-(7-(4-vinyl-benzyloxyl)-4-methylcoumarin)) (PEO45 -b-P(MAPI36 -co-VBC4 )) is designed to improve the micellar stability during the photo-triggered release of hydrophobic cargoes. Analysis of absorption and emission spectra, solution transmittance, dynamic light scattering, and transmission electron microscopy supports that polymer micelles of PEO45 -b-P(MAPI36 -co-VBC4 ) upon the combinational irradiation of 365 and 254 nm light can be solubilized through the photolysis of phthalimide esters and simultaneously crosslinked via the partially reversible photo-dimerization of coumarins. The photo-triggered release experiment shows that the leakage of doxorubicin molecules from crosslinked micelles can be predictably regulated by controlling the irradiation time of 365 and 254 nm light.

Light-Triggered Disruption of PAG-Based Amphiphilic Random Copolymer Micelles

The amphiphilic random copolymer of P(NVP-co-NHPSS) with photocleavable N-O sulfonate side groups has been prepared to investigate the light-triggered disruption of copolymer micelles. Methods of absorption and emission spectra, solution transmittance, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied. It was found that P(NVP-co-NHPSS) could form polymeric nanoaggregates in aqueous solution. And the photocleavage of the N-O bond within copolymer micelles upon 365 nm UV light could be conveniently controlled by changing the irradiation intensity, leading to the disruption of copolymer micelles and the photocontrolled release of Nile red encapsulation. And by encapsulating NaLuF4:Gd/Yb/Tm UCNPs inside copolymer micelles, the response of the photocleavable N-O bond to the 980 nm laser was much weaker than the response to 365 nm light; however, the photocontrolled release of Nile red could still be effectively triggered by the NIR light of the 980 nm laser.

The photodimerization characteristics of anthracene pendants within amphiphilic polymer micelles in aqueous solution

An amphiphilic polymer with anthracene pendants of PEO-b-PAM has been applied to comprehensively investigate the photodimerization characteristics of anthracene in aqueous solution upon various selected narrow band of light irradiations in the UV-vis-NIR region.

Insights into the vanadia catalyzed oxidative dehydrogenation of isobutane with CO2

Vanadia-based catalysts were prepared using the sol-gel method and were subjected to the oxidative dehydrogenation of isobutane with CO2. The materials were extensively characterized by using X-ray diffraction, N2 adsorption-desorption, O2-temperature programmed oxidation, temperature programmed surface reaction, and in situ Fourier transform infrared techniques. Catalytic results indicate that a high selectivity toward total C4 olefins over 85% was obtained over all of the catalysts. On the contrary, the highest conversion of isobutane was observed over 12 wt% V2O5/Ce0.6Zr0.4O2(7 wt%)-Al2O3, and a more stable performance was achieved over 6 wt% V2O5-Ce0.6Zr0.4O2(7 wt%)-Al2O3. The catalytic activity for the titled reaction was found to be dependent on the dispersion and crystallinity of the VOx species over the catalyst, and the deposition of the heavier coke over the catalyst was revealed to be the main reason for the catalyst deactivation. Moreover, the benefit of CO2 toward the titled reaction was clearly revealed from TPSR results, and the reaction was confirmed to follow the redox mechanism.

A general method for faithful replication of keratin fibers with metal oxides

An easily controlled two-step surface precipitation approach using an inorganic metal salt as a precursor is developed to faithfully replicate micro-fibrous oxides from keratin fibers in a practical and environmentally benign manner.