[Fouling behavior of sodium alginate during microfiltration at various ionic compositions: XDLVO approach].

The extended Derjaguin-Laudau-Verwey-Overbeek (XDLVO) theory was utilized to quantitatively evaluate short-range interfacial interactions involved in microfiltration (MF) membrane fouling by sodium alginate (SA) at various ionic compositions. Results showed that for hydrophilic membrane surfaces, van der Waals interactions facilitated fouling, whereas acid-base interactions alleviated fouling; for hydrophobic membrane surfaces, however, van der Waals interactions mitigated fouling and acid-base interactions turned out to be favorable for fouling. Electrostatic double layer interactions contributed minimally to fouling when SA molecules came into contact with MF membrane surface. Ionic strength and Ca2+ affected SA fouling of MF membranes mainly through alteration of acid-base interactions between membrane and SA or among SA themselves. Higher ionic strength could make acid-base interaction less repulsive or more attractive, thus aggravating SA fouling of MF membrane. Although Ca2+ accelerated flux decline significantly, Ca2+ could enhance physical cleaning efficiencies. Under all tested ionic compositions, fouling potentials (K) of initial and subsequent stages correlated well with membrane-SA interfacial free energy of adhesion and SA-SA interfacial free energy of cohesion, respectively. This implies that the XDLVO theory is applicable for description of MF membrane fouling by SA at various ionic compositions.

[Characteristics of dioxin-like polychlorinated biphenyls contamination in soils of Gudao Region in Dongying].

To investigate pollution characteristics of dioxin-like polychlorinated biphenyls (DL-PCBs) in Gudao Region, Dongying City, twenty surface soil samples were collected in April, 2011. The DL-PCBs in soil samples were determined by Soxhelt extraction-Florisil purification-Gas Chromatography(GC)-Electron Capture Detector (ECD). The concentration of DL-PCBs in surface soils ranged from 1.4 microg x kg(-1) to 7.4 microg x kg(-1), with the mean concentration of (3.5 +/- 1.7) microg x kg(-1). The total TEQ level was between 1.2 ng x kg(-1) and 31.8 ng x kg(-1), and the mean TEQ was 5.4 ng x kg(-1), which exceeded the Canadian soil environment quality guidelines (4.0 ng x kg(-1)). The congener profiles of DL-PCBs were similar among sites. Tetra-CB and penta-CB were the major homologues in all soil samples, together accounting for more than 80% of the total DL-PCBs. The level of DL-PCBs exhibited a decreasing trend with the increasing distance from the Gudao town to the suburb, which could be attributed to the chemical plants around the town. The correlation analysis showed that the concentration of DL-PCBs was positively correlated with the organic matter content and clay particle content (R2 were 0.732 and 0.687, separately, P < 0.01), but negatively correlated with the sand particle content (R2 = -0.438, P < 0.05).

[Photo-catalytic degradation of gas phase benzene and toluene over multi-composite TiO2 catalyst].

Photo-catalytic degradation of gas-phase benzene and toluene were studied in the condition of no catalyst, pure anatase catalyst, pure rutile catalyst and multi-composite catalyst. The influences of initial concentration of reactants and the catalysts of different composite on photo-catalytic degradation rate of gas-phase benzene and toluene were investigated. The results show that the degradation efficiency of benzene and toluene is improved a lot on anatase catalyst, but improved a little on rutile catalyst in relation to the crystal-structure of anatase and rutile catalyst. In the condition of no catalyst and pure rutile catalyst, toluene is easier to be degradated than benzene, and on anatase catalyst benzene is easier to be done than toluene. The initial concentration of reactant has an effect on the photo-catalytic degradation process. The degradation rates of benzene and toluene are faster in low concentration than in high concentration. A certain amount of rutile doped in anatase catalyst could improve the photo-catalytic activity. The catalyst with 80% anatase and 20% rutile shows the best photo-catalytic activity to benzene, and the catalyst with 90% anatase and 10% rutile gives the best photo-catalytic activity to toluene.

[Ozone pollution, influence factors and their correlation at urban area in summer].

Based on the observational data of near surface O3, NO, NO2, CO and meteorological factors in the urban area of Ji'nan during summer 2003, the 03 concentrations and their temporal variation characteristics were studied. The correlation between O3 and its precursors (NO, NO2, CO) and related meteorological factors (solar radiation, temperature) was analyzed. The results show that O3 pollution during summer was very serious in Ji'nan, and the levels of O3, NO, NO2, NOx and CO were quite high during the observational period. O3 concentrations were well negatively correlated with NO, NO2, NO, and CO during day time. As to the meteorological factors, O3 concentrations correlated well with solar radiations, but showed no obvious correlation with the temperatures. Consequently, based on the above data and results, a regression equation that relates ozone concentrations observed in the day time to its precursors and solar radiation was constructed. The results show that the calculated values were in good agreement with the observed values.

[Ozone and carbon monoxide concentration distribution on Taishan Mountain].

The concentrations of ozone (O3) and carbon monoxide (CO) on the top of Taishan Mountain were monitored, and the variations and correlation were studied. The results show that the frequency of O3 hourly concentrations more than the first-degree of National Ambient Air Quality Standard(GB-3095-1996, NAAQS) was 15.81%, and the frequency of CO concentrations more than the first-degree of NAAQS was zero. The variation of O3 concentrations appears in a narrow scope, which indicates that there is scarcely influenced by the pollution of industry around. The diurnal variation of the concentrations of O3 and that of CO both present two peaks with the peaks of O3 in the behind of CO, which indicates that the concentration variations of O3 and its precursor CO are primarily controlled by local photochemical reaction process. The daily concentrations of O3 correlated well with CO.

[Characteristics of atmospheric ozone in the urban area of Ji'nan].

Based on the observational data of near surface O3 in the urban area of Ji'nan during the latest two years, the O3 concentrations and their temporal variation characteristics were analyzed. The results showed that O3 concentrations fluctuated periodically,and the photochemical pollution in Ji'nan was serious. Diurnal variations of ozone concentrations exhibited with the characteristic of a single peak, and showed the maximum in the afternoon and minimum in the early morning before sunrise. Ozone concentrations in spring and summer were higher than autumn and winter, while the varying scopes of ozone concentrations in summer and autumn were broader than spring and winter. Variations of ozone concentrations in weekend days were different from weekdays, which caused by the temporal regulation of human activities.

[Ozone concentration distribution of urban].

The increase of ozone concentration in urban is one of the most important research topics on environmental science. With the increase of nitrogen oxides and hydrogen-carbon compounds which are exhausted from cars, the ozone concentration in urban is obviously increased on sunlight, and threat of photochemistry smog will be possible. Therefore, it is very important to monitor and study the ozone concentration distribution in urban. The frequency-distribution, diurnal variation and monthly variation of ozone concentration were studied on the campus of Shandong University during six months monitoring. The influence of solar radiation and weather conditions on ozone concentration were discussed. The frequency of ozone concentration less than 200 microg/m3 is 96.88%. The ozone concentration has an obvious diurnal variation. The ozone concentration in the afternoon is higher than in the morning and in the evening. The maximum appears in June, when it is the strong solar radiation and high air-temperature. The weather conditions also influence the ozone concentration. The ozone concentration in clear day is higher than in rainy and cloudy day.