Advanced Materials Research Vols. 955-959

Abstract: Taking anthraquinone dye reactive brilliant blue KN-R as a target pollutant, this paper studied KN-R degradation rates and electric generation performances in the system of Fe²⁺/PDS and Fe²⁺/PDS-MFC. The Fe²⁺/PDS system is that persulfate (PDS) is activated by ferrous iron (Fe²⁺) ,while Fe²⁺/PDS-MFC system is using Fe²⁺/PDS system as the cathode of microbial fuel cells (MFC) .The results showed that in the two systems, the KN-R degradation rate was increased and then decreased with the increase of initial Fe²⁺ dosage. With the increase of pH, the KN-R degradation rapid declines. In the two systems, both of the KN-R degradation reaction was divided into two stages. In addition, the process of reaction conforms to the first-order kinetic equation. Compared with Fe²⁺/PDS system, the Fe²⁺/PDS-MFC system’s ability to degrade pollutants have little change, the main advantage of Fe²⁺/PDS-MFC system is able to obtain higher and more stable power. Under an optimal condition, the maximum power density achieved 294.07 mW/m², the KN-R degradation rate was 96.90%.

Abstract: In order to reduce the emission of CO₂ and control the global greenhouse effect, the paper introduces and compares two new technologies named chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU) that are both high-efficient and clean. Through comparative analysis, CLC has been widely studied because of its direct separation of CO₂, reduction loss of the heat, improvement of energy efficiency and avoiding of the generation of fuel type NO_x in the combustion process. Besides the current research for metal oxygen carrier, there are some scholars find various non-metal oxygen carriers that have the better performance in CLC. But the study on reactors of CLC is still not mature, especially the solid fuel reactor, which is different from CLOU. In a certain sense, CLOU is an improved technology based CLC, besides the bove advantages, it also can react with coal directly. Many scholars use coal as fuel in the fluidized bed by the technology of CLOU, and the results of them are feasible. So from this perspective, CLOU technology has more broad prospects than CLC in the China.

Abstract: Ba0.6Mg0.4TiO3 (BMT) particles with different morphologies were synthesized through hydrothermal method and their optical and photocatalytic properties were investigated. Their crystal structure and microstructures were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). XRD patterns demonstrate that the as-prepared samples are tetragonal structure. FESEM shows that BMT crystals can be fabricated in different morphologies by simply manipulating the reaction parameters of hydrothermal process. The UV-visible diffuse reflectance spectra (UV-vis DRS) reveal that the band gaps of BMT photocatalysts are about 2.37 - 2.51 eV. The as-prepared BMT photocatalysts exhibite higher photocatalytic activities in the degradation of methyl orange (MO) under visible light irradiation (λ > 420 nm) compared with traditional N-doped TiO2 (N-TiO2) and pure BaTiO3 (BTO). The high photocatalytic performance of BMT photocatalysts could be attributed to the recombination restraint of the e-/h+ pairs resulting from doping of Mg2+ ions. The influence of morphologies upon the photocatalytic properties of BMT was studied. Furthermore, BMT nanowires reveal the highest photocatalytic activity. Up to 94.0% MO is decolorized after visible light irradiation for 360 min.

Abstract: This paper, through the analysis of the serious problems of jiao River such as the deterioration of water environment and water pollution, puts forwards the water protection measures, on the basis of which we appeal to the governments at all levels to attach great importance to jiao River pollution management and actively improve jiao River water environment. At the same time, the paper hopes all of our citizens could contribute to the improvement of jiao River environment.

Abstract: In this study, the distribution and enrichment characters of heavy metals were explored. And the potential ecological risk levels of heavy metals were evaluated by geo-accumulation index method and potential ecological risk index method. The concentrations of heavy metals in sediments of Harbin section of Songhua River are: Zn>Pb>Cr>Cu>Ni>Cd. The enrichment degree of Zn is the highest, while Cd is the lowest. The potential ecological risk indexes of heavy metals in the sediments of section of Songhua River in Harbin are: Cd>Pb>Cu>Zn>Ni>Cr. The main heavy metals pollution is Cd, which has low content but considerable potential ecological risk and contributes most to RI. The ecological risk level of heavy metals in the sediments of the section of Songhua River in Harbin is moderate.

Abstract: In groundwater, the lack of carbon source is a key problem of in-situ denitrification. It is very important to choose appropriate solid carbon-source materials. In this work, wheatstraw and sawdust were selected as potential carbon sources to evaluate the performance for in-situ biological denitrification in groundwater by column experiments. The results showed that sawdust was a suitable corbon source with less release of nitrogen compounds and relatively stable release of organic carbon, compared with wheatstraw, and was applicable for further use as a filling material in in-situ ground water bioremediation.

Abstract: A laboratory-scale electrolytic cell with a Ti/RuO₂-Pt anode and a Ti cathode was developed to treat high concentration cyanide-contained wastewater. The effects of the different electrode distances, concentration of chlorine anion and current densities, on the CN^- removal were investigated. The results shown the too short and long electrode distance resulted in high energy consumption and low current, the appropriate electrode distance was essential. The CN^- removal was very significant at the electrode distance was 9 cm, and the removal efficiency reached 99.2%. The removal CN^- electrochemical oxidation was mainly attributed the success to in direct oxidation effect of chlorine /hypo-chlorite produced during the electrochemical reaction process. The CN^- removal efficiency increased with increasing the concentration of chloride ion and operating current density. The optimum experimental condition was set at the electrode distance of 9 cm, NaCl dosage of 0.5 g/L, the current density of 10 mA/cm², and pH of 12. At the optimum experimental condition, the CN^- concentration in the solution decreased from 150.33 mg/L to 1.20 mg/L, and the CN^- removal efficiency reached 99.2%.

Abstract: The RO concentrate containing non-degradation organic pollutants was treated by electro-Fenton process. The high voltage pulse generator was used as discharge power. The effects of pulsed electric field parameters, aeration rate and pH on COD removal rate was investigated. The results indicate that the COD removal rate is up to 80.71% when pulsed voltage, pulsed frequency, treatment time, aeration rate and pH are 30000 V, 5 Hz, 240 s, 1.0 m3/h and 10, respectively.

Abstract: In this paper, use homemade experimental platform to experimental study on removal of NO using H₂O₂/UV system. The factors include concentration of H₂O₂, initial concentration of NO, concentration of O₂, temperature of H₂O₂ solution, concentration of a metalic catalyst, gas flow. Carrying on orthogonal test with the above 6 factors, determining the optimal value range of the various influencing factors and the optimal technical conditions are determined. When concentration of H₂O₂ is 8%, concentration of O₂ is 5%, gas flow is 850ml/min, initial concentration of NO is 650mg/m³, temperature of H₂O₂ solution is 55°C, the mole ratio of Fe²⁺ is 1:300, then the NO removal is 88.6%. Based on this discussion and analysis, the H₂O₂/UV system of NO Removal system has certain technical popularization.

Abstract: The absorption rates of CO₂ in diethanolamine (DEA) promoted N-methyldiethanolamine (MDEA) aqueous solution were measured at normal pressure with temperatures ranging from 303.15-323.15K. The influence of temperature and the mass fraction of DEA on the absorption rate of CO₂ was illustrated.