Advanced Materials Research Vols. 838-841

Abstract: Alginate-diatomite immobilized microspheres were prepared through immobilized biosorption of diatomite and Aspergillus niger by sodium alginate. Three major factors such as alginate concentration, diatomite content and embedding capacity on physical properties and microbial activity of Alginate-diatomite immobilized microspheres were investigated, and the optimal preparation conditions of Alginate-diatomite immobilized microspheres were determined as 2% of alginate, 1% of diatomite, 10% of Embedding capacity. Keywords: Embedded immobilization;Degradation; Acephate; Alginate; Aspergillus niger

Abstract: The potentials of three plant species, rape, alfalfa and white clover, separately or jointly on the degradation of polycyclic aromatic hydrocarbons (PAHs) in soils were estimated by pots experiments. Results showed that the presence of vegetation apparently enhanced the dissipation of PAHs at initial concentrations ranging from 20.05 to 322.06 mg·kg^-1, but the efficacy enhanced varied greatly among plant species and cropping patterns. Within 70-day experiment, alfalfa and white clover showed higher efficiencies for the removal of PAHs than those of rape, and mixed cropping greatly enhanced the dissipation of PAHs as compared to single cropping. On average 74.87% of phenanthrene or 62.81% of pyrene were removed from soils with mixed cropping of rape and alfalfa, and 72.01% of phenanthren or 68.44% of pyrene removed by mixed cropping of rape and white clover. Under similar pollution level, PAHs accumulated in plant, irrespective of root and shoot, was much lower in mutli-planted treatments than in mono-planted ones. Results suggested a feasibility of the establishment of multispecies remediation for enforcing the dissipation of PAHs, which may also decrease the accumulations of PAHs in plant and thus reduce their risks to humans.

Abstract: Continuous treating process by iron-carbon micro-electrolytic technology treating actual dyeing wastewater was studied, performance of the micro-electrolysis reactor (MER) assembled homemade iron-carbon micro-electrolysis materials (MEM) and the process of alkaline addition, the properties of iron mud (flocculation precipitation produced from alkaline addition) were also investigated. The results shows that:(1) COD removal rate of MER was stable at around 60%, and the chroma could reached less than 40 times at stable stage of 60 days operation; (2) According to 30 days of continuous operation test, 7.6 kg of iron mud was produced when one ton wastewater was treated in this system; it was also found that iron mud can be recycled as raw materials for the synthesis of MEM by EDS analysis; (3)Effluent reflux (reflux ratio 1~1.5) could effectively reduce the dosage of alkali in practical process.

Abstract: Alginate-diatomite immobilized microspheres were prepared through immobilized biosorption of diatomite and Mucor sp. by sodium alginate, which were employed to adsorb acephate and Hg²⁺ in wastewater. Several major factors were investigated. Results showed that initial concentration of acephate and Hg²⁺ were both 300ug/l, percent of adding immobilized microspheres full of Mucor sp.was 6%(m:m), rotating speed 160~200r/min. Keywords: Adsorption; Acephate; Hg²⁺; Mucor sp.

Abstract: Three-phase slurry bubble column reactor owns a wide application area. This review focuses on the hydrodynamics of the reactor from the findings of published studies, which includes the flow regimes, gas holdup, bubble size and distribution and mass transfer coefficients. The factors affecting each parameter and the status of the research are discussed, and the development of slurry bubble column reactor has also been prospected. At present, the experimental data that can be used in the industrial application is not accurate, an enlargement of the reactor is still a difficult problem, it remains to be further exploring in close to real environment.

Abstract: It has been generally agreed that methyl orange (MO) can be effectively decolorized in KIO₄ homogeneous reaction system under UV irradiation. The knowledge on the kinetics of the system possesses both practical and theoretical values. Decolorization efficiency of MO increases as the loading of KIO₄ increases and has no an optimal amount of KIO₄ in this case. The decolorization reaction manifests the first order with lower concentration and the zero order with higher concentration. As the initial concentration goes up, the order of the reaction is reduced from 1 to 0.

Abstract: We used methods such as microorganism cultivation and PCR-DGGE to examine the influence of glyphosate, paraquat, and xiao suo (used exclusively in China) on biodiversity. Two weeks after herbicide application, the strongest herbicidal effect was observed from paraquat, followed by glyphosate and then xiao suo. Although weed suppression was maintained over the effective period of each herbicide, surface vegetation gradually recovered after one month. Levels of soil bacteria and fungi were noticeably altered by exposure to herbicide. Actinomycetes were unaffected, however. Bacterial genetic diversity obviously changed, with some DGGE bands disappearing. Although several DGGE bands were lost, fungal genetic diversity remained constant. Actinomycetes remained constant. Overall, glyphosate and paraquat had stronger culling effects on surface plants than xiao suo, whereas glyphosate and xiao suo had stronger effects on soil microorganisms than paraquat. The results have implications for agriculture production, and provide information related to soil ecological stability and recovery for use in ecological management of economic forests.

Abstract: In order to study the characteristic of soil seed band (SSB) in different urbanized regions of Tianjin, the research selected typical samples along urban districts, suburban districts, outer suburbs. After the germination tests, the results show that: from outer suburbs to urban districts,the density of SSB show an increasing trend, Sorensen Similarity Index show an increasing trend, but the specie richness show a decreasing trend. Suburban districts have the lowest Shannon-Wiener Index, Ecological Dominance Index, Pielou Evenness Index. Compared with outer suburbs, the species richness in urban districts and suburban districts have decreased 66.67% and 45.23%, urbanization promotes the homogenisation of species. Suburban districts have the highest density and species richness, the germinated seeds have large numbers of woody seedlings, so it can be considered for vegetation recovery.

Abstract: Dust pollution has become one of the major problems that impact unban environment. While urban vegetation plays an important role in improving the urban atmospheric environment. This study conducted a preliminary research on the dust-retention ability of 20 greening tree species, by field sampling investigating and laboratory analyzing. The 20 greening tree species in Tianjin Airport Economic Area, a new industrial zone of Tianjin, were taken as research object. The results of the study show that: (1) the dust-retention ability of shrubs is bigger than arbors; (2) the dust-retention ability per unit area of different tree species varies; (3) Among Arbors, the order of the dust-retention ability is Populus tomentosa> Sophora japonica> Paulownia tomentosa> Firmiana simplex> Platanus orientalis> Robinia pseudoacacia> Koelreuteria paniculata> Salix matsudana > Fraxinus chinensis; (4) Among shrubs, the order is Syzygium aromaticum> Kerria japonica> Sorbaria sorbifolia> Ligustrum obtusifolium> Malus micromalus> Prunus cistena> Hibiscus syriacus> Prunus cerasifera var. pissardi> Prunus cistena> Lonicera maackii (Rupr.)Maxim.> Sambucus racemosa> Cercis chinensis. The research provides a theoretical basis for choosing the tree species in reducing the atmospheric particulate matter in Tianjin Airport Economic Area and the new industrial zone of northern China. In addition, the greening activity will be in favor of improving the ecological environment of the region.

Abstract: In order to explore the and biological reference frame to suit to development in the large river of songliao basin and to meet the need of water quality standards of basin institutions, the study on methods of biological assessment of deep type river at home and abroad were referred, combined with the methods of determining the specified aquatic organisms and provided the necessary technical support for conventional biological monitoring and evaluation water quality programs of river basin.