Advanced Materials Research Vols. 233-235

Abstract: Two novel types of metallo-deuteroporphyrins bearing the disulphide bond were employed to investigate their catalytic activity in oxidation of cyclohexane with molecular oxygen (air) to cyclohexanol and cyclohexanone without the use of sacrificial co-reductant. The catalytic activity of metallo-deuteroporphyrin disulphide derivatives was obvious difference when different metals were incorporated into the porphyrin. However, the same metal cobalt porphyrin complexes exhibited the different catalytic efficiency due to the effect of substituents. Co(II)deuteroporphyrin disulphide derivative is more active than other metallo-porphyrin complexes. On the basis of the obtained results the new reaction process is discussed.

Abstract: Novel membrane contactors offer a number of important advantages over conventional dispersed phase contactors, including absence of emulsions, no flooding at high flow rates, no unloading at low flow rates, no density difference between fluids required, and surprisingly high interfacial area. Based on the former work of our group, this paper provides a general review of recent progress in the application of hollow fiber membrane contactors in liquid/liquid and gas/liquid separation and in the environmental waste treatment including VOC_s and CO₂ separation, metal ion recovery, and alcohol purification.

Abstract: The membrane integrated process including nanofiltration (NF) and reverse osmosis (RO) had more advantages in recycling the electroplating effluent than conventional physical and chemical methods. Separation experiments with different kinds of membranes were carried out in pilot scale installation using industrial effluents for more effective desalination. The selective rejection of different ions in NF and RO process was investigated with the Donnan effects and solution-diffusion theory to check its consistence. Although NF membranes had a higher permeate flux and better ion selectivity even under a relatively low operating pressure, RO membranes prevailed in rejection of toxic heavy metal ions and COD and would approach a higher potential for producing feed water of industrial cooling system.

Abstract: The sorption of eosin by peanut husk, which was chemically modified by formaldehyde in acidic medium was studied with variation in the parameters of contact time, pH, initial eosin concentration and temperature. They were used for equilibrium sorption uptake studies with eosin. The results indicate that sorption equilibrium could be well described by the Freundlich isotherm equation. The sorption followed the pseudo-second order model. The mass transfer model as intraparticle diffusion was applied to the experimental data to examine the mechanisms of the rate controlling step. It was found that the intraparticle diffusion is becoming the significant controlling step under the experimental conditions. The thermodynamic constants of the sorption process were also evaluated, which suggest an endothermic physical sorption process which runs spontaneously.

Abstract: Electrocoagulation (EC) has been proven by a substantial number of studies to be an efficient technology to remove organic pollutants from wastewater. Nevertheless, the high energy consumption of this technology inhibits its extensive application. The objective of this work is to investigate the feasibility of electrical energy conservation and high efficiency by using Pulse Electrocoagulation (PE). PE, a combination of a pulsing technique and EC, was proposed in an attempt to treat the dye wastewater. The results demonstrated that PE, as compared with DCE (direct current electrocoagulation), resulted in up to 51.66% energy conservation by using two iron electrodes as anode and cathode. Moreover, this high energy conservation was obtained during a high level of treatment efficiency: 99.62% of color removal and 91.15% of COD removal for 1000 mg L^-1 4BS solution in a short electrolyzing time of 15 mins.

Abstract: A new method of solid phase extraction (SPE), using crosslinked carboxymethyl starch as adsorbent, combined with direct slurry sampling graphite furnace atomic absorption spectrometry (ss-GFAAS) has been developed for the high sensitive determination of lead in water samples. The SPE adsorbent loaded with the analyte was made in to slurry with the assistance of Triton X-100. The slurry was directly injected into the graphite furnace for the determination of lead. Variables such as the pH, sample volume, and amount of Crosslinked Carboxymethyl Starch (CCMS) were investigated. The detection limit (3σ) was 0.082 μg L^-1 and the RSD was 4.9% (n = 11, c = 1.0 mg L^-1) for Pb(II). The enrichment factor was 100 at a sample volume of 100 mL. The proposed method has been applied to the determination of lead in environmental water reference materials and two water samples with satisfied results.

Abstract: The evaporation loss is one of the long-term serious problems to the storage and transit of the fuel oil, as well as the environment protection. Therefore, it is necessary to develop an economic, low investment, simple and convenient maintenance technology to reduce the evaporation loss, which can be applied to different kinds of condition. To perform this task the surface-fluorinated polymer hollow spheres are designed as the surface-covering layer of the fuel oil to restrict evaporation. A comparison of fuel oil evaporation loss from both surface-fluorinated polymer hollow sphere surface and free fuel oil surface has been done. Experiments show that this technique can reduce about 62.2% of the rate of evaporation loss from fuel oil. It is considered has a wide application perspective, as well as in the efficient use of water in agriculture, industry and drought areas.

Abstract: The relation between isotopic compositions of precipitation and surface air temperature provides an unique tool for paleoclimate studies. Ananysis was conducted of monthly and annual mean d¹⁸O content of precipitation and surface air temperature for spatial and a fixed location by using the the data of China (1985~2002) in Global Network of Isotopes in Precipitation (GNIP) Database.This study shows that there is a positive correlation between d¹⁸O of precipitation and surface air temperature for those stations whose latitude is higher than 34°~36°N. The seasonal d¹⁸O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.34‰°C^-1. The d¹⁸O-temperature gradient, however, derived from the longterm annual mean data of 13 stations,, is about 0.52‰°C ^-1 which is substantially larger than the seasonal gradient. This longterm annual d¹⁸O-temperature gradient could be used as the isotope thermometer for palaeoclimate reconstruction in mid- and high-latitude regions in China.

Abstract: The photocatalytic degradation of pyrene (PYRE) and benzo[a]pyrene (BaP) on soil surfaces in the presence of Fe₂O₃ using ultraviolet (UV) light source was investigated in a photo chamber, in which the temperature was maintained 30 . The effects of UV irradiation intensity and UV wavelength on the degradation performance of polycyclic aromatic hydrocarbons (PAHs) were studied. The results show that with the intensity of UV irradiation being enhanced, the photocatalytic degradation rates of PAHs were increased. Photocatalytic degradation rates of PYRE and BaP on soil surfaces with 5% Fe₂O₃ were different at UV irradiation wavelengths of 254, 310 and 365 nm, respectively.

Abstract: It is important to separate the nonmagnetic metals from shredded automobiles scraps efficiently. The research relates in general to the separation of non-magnetic metals automatically on the basis of the different density of the magnetic fluids in a magnetic field. A water-based magnetic fluid was prepared with a chemical coprecipitation method by using ultrasonic in dispersing process. The magnetic field system was design and simulated by a finite element analysis software package, ANSYS 8.1. Separation tests were performed on the mixtures of aluminum, zinc, copper and lead with various scrap size and shape using the water-based magnetic fluids.