Shi Gang Xin

Application of ICP-AES to the Detection of Heavy Metals in Cordyceps militaris from Shenyang

The microwave digestion-ICP-AES was used to detect the Cr, Cd, Pb, As, Hg and Ni in cordycepsmilitaris from Shenyang. The method accuracy was proved by the national standard method. The result shows the sequence of heavy metals was Pb>Ni >As > Cd> Cr, and Hg was not detected, as was detected in few sample. All the data showed that cordycepsmilitaris accords with the national standards. The method average recovery is 94.07%-107.58%, and RSD is 0.84%-3.25%. It is a promising analysis method on detection of heavy metals in cordycepsmilitaris.

Corrosion Behavior of Conducting Polymer PANI in Simulating PEMFC Conditions

Polyaniline (PANI) polymer coating was electrochemically synthetised by cyclic voltammetry (CV) method on stainless steel bipolar plates of proton exchange membrane fuel cell (PEMFC). Structure and morphology of PANI polymer coating were characterized by means of fourier transform infrared reflection (FTIR) spectrum and scanning electron microscopy (SEM). The corrosion behavior of the coating was evaluated by polarization curve and electrochemical impedance spectroscopy (EIS) in the medium of 1M H2SO4 and 2ppM NaF at 70°C to simulate the corrosive condition of PEMFC. It was found that the optimal conditions for PANI polymer coating synthesis could be 10-15 circles when the voltage ranged from-1.2V to +1.2V(Vs.SCE) with a scan rate of 50 mV/s. SEM observation results indicated that the polymer coating presented with uniform and dense feature. FTIR results illustrated that the coating were composed of PANI. Corrosion current densities of 316L SS and PANI-coated steel were 10-5 and 10-6 A/cm2 respectively. Corrosion potential of the coated SS shifted towards more positive values compared to the uncoated plate. EIS results indicated that the radius of the capacity impedance for PANI increased obviously.

Determination of N-Heptyl Pyridine Tetrafluoroborate in Ethanol

N-heptyl-pyridine tetrafluoroborate is prepared by the double decomposition reaction of HEPB and NaBF4. The ionic liquid at room temperature used in the experiment has a significant absorption determined by UV spectrum within the range of 200-400nm, the maximum absorption wavelength of HEP-BF4 ionic liquid in ethanol is 244nm. The standard working curve of HEP-BF4 ionic liquid is y=0.00441+0.01563x (R=0.99912). The linear range of HEP-BF4 ionic liquids in the ethanol is 1-75 mg/L. The recovery rate of HEP-BF4 ionic liquid which is between 96.6% and 102%, is measured by standard addition method in ethanol.

Detection and Evaluation of Heavy Metal in Edible Fungi of Liaoning Province

Adopting microwave digestion and ICP-AES method while detecting Ni, Cr, Pb, Cd, As and Hg in edible fungus of Liaoning province, results show that the acceptance rate of heavy metal in lentinus edodes, oyster mushrooms, pleurotus eryngium, agrocybe cylindracea, agaricus bisporus, black fungus, coprinus comatus, cordyceps militaris was above 90%, Hg was not checked out, only in exceptional sampals Pb, Cd, Cr have checked out but not exceed, Ni and As out of limits, but the superscale was very small, the lentinus edodes in Liaoning province in a great measrue was safty.

Detection of Phthalate Esters from Plastic Packaging Materials into Edible Oil by Gas Chromatography-Mass

A method for the simultaneous determination of 15 kinds of phthalate esters in edible oil by gas chromatography-mass spectrometer (GC-MS) was firstly established. The calibration curves showed good linearity in the range of 0.001~1mg /L and the correlation coefficients (r) were more than 0.999. The limits of quantification were in the range of 0.001~ 2.000 μg/L (S/N = 10). The recovery of three level ranged from 70.50% to 112.00%, at spiked levels of 0.1mg/L, 1.0mg/L and 10mg/L with the relative standard deviations (n = 6) of 0.59% ~ 7.54%. On the basis of the above method, the three edible oils under different storage temperatures were detected and the results showed that DIBP, DBP and DEHP were detected in two samples. This method possesses high sensitivity and low detection limit and can be used for quantitative analysis PAEs in edible oils.

Characterization of Phthalate Plasticizer from Bottled Beverages by GC-MS

A GC/MS method was established for the determination of phthalates plasticizers in bottled beverages. The calibration curves are all linear in the range of 0.01 to 5μg/L with correlation coefficients greater than 0.997. The recoveries are in the range between 97.27% and 105.05% under two levels. The testing data of the samples showed that the five bottled beverages all contained DBP, DIBP and DEHP plasticizers, and DIBP content was obviously higher than the other two.

Preparation and Corrosion Behavior of Environment Friendly Conversion Coating Formed on Zn-5%Al Galvanized Steel

A non-chromate conversion coating was prepared from molybdate based bath on the surface of Zn-5%Al hot dip galvanized steel. The influence of the preparation conditions such as temperature, bath pH and treating time on the corrosion resistance of the obtained conversion coating was investigated. The corrosion performance of the film was researched using electrochemical technique in 3.5%NaCl. The results indicate that the anodic branch of the polarization curves present in passivation character. Electrochemical impedance spectroscopy (EIS) illustrate that the radius of the capacity impedance for conversion coating varies distinctly according to the preparation condition. The surface morphology was observed using scanning electron microscopy (SEM), and the results show that the surface of Zn-5%Al hot dip galvanized steel present in eutectic feature after conversion coating treatment. The chemical composition of the coating was detected by energy dispersive X-ray (EDX), and the results illustrate that the conversion coating is composed of Zn, Al , O, P and Mo.

Effect of Molybdate Bath Service Life on Corrosion Resistance of Conversion Coating Deposited on Hot Dip Galvanized Steel

A conversion coating was obtained in the molybdate based bath on hot dip galvanized steel. The influence of the bath service life and bath component variation on the corrosion resistance of the conversion coating were investigated. Corrosion resistance of the coating was evaluated by electrochemical technique in 3.5%NaCl. It is found that the anodic branch of polarization curves presented in passivation character. Electrochemical impedance spectroscopy (EIS) results confirm that the radius of the capacity impedance for molybdate film decreased with treating area, which reveals that the bath life and bath component variation affected anti-corrosion performance of the coating remarkablely. The bath constituent was analysed by inductively coupled plasma atomic emission spectrometry (ICP), and the results show that the bath will lose the passivation ability after treating 1.16m2 sample area for new prepared treating solution of 500ml. The surface morphologies of the coatings were observed using scanning electron microscopy (SEM), and the element composition of the coatings was detected using energy dispersive X-ray (EDX). The investigation results indicate that uniform and compact film is formed on the surface of the galvanized steel, and the film is composed of zinc,oxygen, phosphor and molybdenum.

A Study on Anaerobic Digestion of Petrochemical Residual Activated Sludge

Abstract In order to study the reducing and reusing of petrochemical residual sludge and solve the technical problem of traditional anaerobic digestion, the contrast research was carried out between the mesophilic (30°C) and thermophilic (60°C) anaerobic digestion. The result showed that the efficiency of thermophilic digestion was twice as big as that of mesophilic digestion. When sludge dosage increased, the concentration of volatile fatty acid rose sharply and pH value decreased correspondingly. When the reaction became stable, the concentration of volatile fatty acid began to drop and the corresponding pH value began to rise gradually. At each sludge dosage, alkalinity dropped first and then increased with the reaction carried on. In a different sludge dosage, the fluctuation of pH, volatile fatty acid, and alkalinity under the thermophilic condition was less than that under the mesophilic condition by a different sludge dosage. Through the experiment of sludge digestions, the optimizing technical conditions are as follows: biochemical reaction of residual sludge input rate: 10%; retention time: 10 days at a high temperature of 60°C by full agitation.

Performance of Polypropylene Composites Filled by Calcium Carbonate Whiskers

Calcium carbonate (CaCO3) whiskers were firstly treated by sodium stearate, and then blended with polypropylene (PP) to prepare the composites by a closely intermeshing co-rotating twin-screw extruder at 200°C. The performance of the composites, such as thermal behavior, microstructure and mechanical properties, were analyzed with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical testing. The results showed that CaCO3 whisker influenced the crystalline behavior of PP phase in the blends because of its intervening. Moreover, thermo-decomposing temperature, tensile and bending strengths of the blends all increased with increasing whisker content. CaCO3 whiskers had good reinforcing and toughening effects on PP.