Fengxian Qiu

Heterogeneous solid base nanocatalyst: Preparation, characterization and application in biodiesel production

A solid base nanocatalyst was prepared by ZrO(2) loaded with C(4)H(4)O(6)HK and investigated for transesterification of soybean oil with methanol to biodiesel. The obtained nanocatalyst was characterized by means of XRD, FTIR, TEM, TGA, N(2) adsorption-desorption measurements and the Hammett indicator method. TEM photograph showed that the nanocatalyst had granular and porous structures with particle sizes of 10-40 nm. The nanocatalyst had longer lifetime and maintained sustained activity after being used for five cycles. The separate effects of the molar ratio of methanol to oil, reaction temperature, nanocatalyst amount and reaction time were investigated. The experimental results showed that a 16:1M ratio of methanol to oil, 6.0% catalyst, 60°C reaction temperature and 2.0 h reaction time gave the best results and the biodiesel yield of 98.03% was achieved. Production of biodiesel has positive impact on the utilization of agricultural and forestry products.

Coupling with a narrow-band-gap semiconductor for enhancement of visible-light photocatalytic activity: preparation of Bi2S3/g-C3N4 and application for degradation of RhB

A coupled system for the photodegradation of Rhodamine B dye was realized using a Bi2S3/g-C3N4 composite as a photocatalyst under visible light irradiation. The Bi2S3/g-C3N4 composite was prepared by a hydrothermal method and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with pure g-C3N4, the Bi2S3/g-C3N4 sample exhibits an enhanced photocatalytic activity and the best photocatalytic efficiency is 3.68 times more than that of pure g-C3N4. The obtained results indicate that a coupled system of Bi2S3 and g-C3N4 could overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and a narrow photoresponse range. On the basis of the corresponding energy band positions, the mechanism of photocatalytic activity enhancement was proposed.

Optimization of biodiesel production process from soybean oil using the sodium potassium tartrate doped zirconia catalyst under Microwave Chemical Reactor

A solid base catalyst was prepared by the sodium potassium tartrate doped zirconia and microwave assisted transesterification of soybean oil was carried out for the production of biodiesel. It was found that the catalyst of 2.0(n(Na)/n(Zr)) and calcined at 600°C showed the optimum activity. The base strength of the catalysts was tested by the Hammett indicator method, and the results showed that the fatty acid methyl ester (FAME) yield was related to their total basicity. The catalyst was also characterized by FTIR, TGA, XRD and TEM. The experimental results showed that a 2.0:1 volume ratio of methanol to oil, 65°C reaction temperature, 30 min reaction time and 10 wt.% catalyst amount gave the highest the yield of biodiesel. Compared to conventional method, the reaction time of the way of microwave assisted transesterification was shorter. The catalyst had longer lifetime and maintained sustained activity after being used for four cycles.

Recent advances in non-enzymatic electrochemical glucose sensors based on non-precious transition metal materials: opportunities and challenges

With the booming requirements for diabetes management, food quality control, and bioprocess inspection, monitoring of glucose in various matrices has drawn unprecedented interest of both academic and industrial researchers recently. As a relatively new class of glucose sensors, enzyme-free detection of the target is capable of providing several fascinating characters such as ultra-high sensitivity, excellent stability, and simple fabrication. Considering the rapid expansion of the glucose determination field without using any biological enzymes, here we focus our attention on updating the latest advances in non-enzymatic electrochemical glucose sensors based on non-noble transition metal materials achieved in the past few years. In this minireview, both the superiorities and the intrinsic drawbacks of detecting glucose by employing non-precious materials including Ni, Cu, Co, Mn, and Fe are intensively highlighted, followed by a systematic discussion on the important progress harvested for enzymeless glucose sensing. Finally, the potential opportunities of non-noble transition metal materials in fabricating high-performance enzyme-free glucose sensors are given, and the current challenges for their practical applications are also summarized.

Adsorption Behavior of Azo Dye Eriochrome Black T from Aqueous Solution by β-Cyclodextrins/Polyurethane Foam Material

β-cyclodextrin/polyurethane (β-CD/PU) materials were prepared by foaming technique. The adsorption behavior of EBT on β-CD/PU material and the influences on the adsorption efficiency were investigated. Under the optimal experimental conditions, the maximum adsorption efficiency of EBT was 93.14%. The kinetics characteristic and thermodynamic parameters were analyzed. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations and the results indicated that the Langmuir isotherm showed a better fit for EBT adsorption. The experimental results suggest that the β-CD/PU foam materials have potential application for the wastewater treatment containing EBT dye.

Preparation, characterization and properties of UV-curable waterborne polyurethane acrylate/SiO2 coating

The UV-curable waterborne polyurethane acrylate (UV-WPUA) oligomer was first prepared based on isophorone diisocyanate (IPDI), polyether polyol (NJ-220), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate (HEMA) via an in situ method. With the different content tetraethoxysilane (TEOS) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) as coupling agents, a series of waterborne UV-WPUA/SiO2 oligomers were prepared by the sol–gel process. The physical and mechanical properties of the UV-WPUA and UV-WPUA/SiO2 hybrid coating materials were measured. The UV-WPUA and WPUA/SiO2 hybrid materials were characterized using FTIR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) measuring apparatuses to determine their structures, thermal properties, surface morphologies, etc. The results showed the SiO2 particles of the hybrid materials had wide dispersion, forming a good interfacial bonding layer on surfaces. The tensile strength, water resistance, and thermal properties of the hybrid materials were better than those of the UV-WPUA. The resulting UV-WPUA/SiO2 hybrids are promising for a number of applications, e.g., for high-performance water-based UV-curable coatings.

Preparation, Morphology and Properties of Waterborne-Polyurethane/Silica

A series of waterborne-polyurethane/silica (WPU/SiO2) were prepared from isophoronediisocyanate, polyester polyol, dimethylolpropionic acid, tetraethoxysilane and 3-glycidyloxypropyl trimethoxysilane. The WPU/SiO2 dispersion had narrower particle size distribution than the pure WPU. The mechanical properties of WPU/SiO2 films were improved than the pure WPU. WPU/SiO2 films were characterized by FT-IR spectroscopy, SEM, TEM, AFM, XRD and UV-Vis spectroscopy. The results showed that WPU/ SiO2 hybrid films were found to be smooth morphology, and had good thermal stability and tunable transparence with the silica fraction in the film. Through suitable adjustment of silica content, some thin films have potential applications as the specialty materials.

Preparation and Application of Polymers as Inhibitors for Calcium Carbonate and Calcium Phosphate Scales

The scale inhibitor was prepared based on itaconic acid (IA), styrene p-sulfonic sodium (SSS), maleic anhydride (MA), and acrylamide (AM) as monomers, and ammonium persulfate as an initiator by the free-radical polymerization. The structure of the polymer was characterized by FT-IR and UV-Vis spectroscopy. Using the static experiment method, the scale inhibition efficiency to CaCO3, the effects of some factors (concentration of polymer, time, concentration of Ca2+, pH value, concentration of HCO3 −, and temperature) were investigated. Using the malachite green photometric method, the scale inhibition efficiency to Ca3(PO4)2 and the effects of some factors (concentration of polymer, time, Ca2+, pH, temperature, and the concentration of PO4 3−) were also investigated. The experimental results showed that the polymer had an excellent efficiency of scale inhibition and a resistance rate of calcium carbonate scale up to 96.67%, a resistance rate of calcium phosphate scale up to 92.5%, and could be used in the system of high-temperature and high-hardness water. The polymer had good dispersing ability with respect to iron.

Waterborne Polyurethane-Acrylate Containing Different Polyether Polyols: Preparation and Properties

The waterborne polyurethane–acrylate (PUA) was prepared based on isophorone diisocyanate, polyether polyol, dimethylol propionic acid, hydroxyethyl methyl acrylate, butyl acrylate (BA) and styrene (St). Fourier transform infrared spectrometry (FT-IR), Ultraviolet-visible spectrophotometry (UV-Vis) and Differential scanning calorimetry (DSC) were employed to investigate the structures, optical transparency and thermal properties. Some physical properties of the aqueous dispersions such as viscosity, particle size and surface tension were measured. Some mechanical performances and solvent resistance of films were investigated. When the ratio of the BA/St was 30/70, the films had excellent water and alkali resistances. The obtained PUA composites have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.

One-Pot Anchoring of Pd Nanoparticles on Nitrogen-Doped Carbon through Dopamine Self-Polymerization and Activity in the Electrocatalytic Methanol Oxidation Reaction

Exploration of advanced electrocatalysts to promote the sluggish methanol oxidation reaction (MOR) is of vital importance for developing high efficiency and low-cost direct methanol fuel cells. Highly dispersed palladium nanoparticles (Pd NPs) anchored on a nitrogen-doped carbon support were fabricated using a facile one-pot dopamine self-polymerization mediated redox strategy, in which dopamine not only acted as a moderate reductant to induce the formation of Pd NPs during self-polymerization but was also the precursor of the nitrogen-doped carbon support for Pd. The synthesized hybrid features the following characteristics: 1) High dispersity of Pd NPs, which exposed a high abundance of active surfaces and sites for heterogeneous electrocatalysis; 2) metal-support interactions, which may affect the surface chemistry and electron distribution of active Pd NPs; 3) the Pd NPs were partially imbedded or encapsulated into the support, thus reducing the possible agglomeration of Pd NPs during cyclic measurements. The electrocatalyst with such favorable features provided higher mass activity (2.2 times that of commercial Pd/C) and better durability (reduced loss of activity during simulated frequent startup-shutdown operations) for the MOR in alkaline media.