Advanced Materials Research Vols. 726-731

Abstract: Radioactive isotopes (such as Th4+ Sr2+) on the surface of material such as Stainless steel can be absorbed by modified KGM film and assisting by mixed liquor consist of surfactant and complexing agent, tripolyphosphate and water. The adsorption behaviors for the radioactive isotopes such as Th4+ and Sr2+ were studied and the effects of various parameters including concentration of Th4+ and Sr2+, temperature and the time of film formation were evaluated. Detection of FTIR show that ester group of modified KGM is pivotal to the absorption of pollution source . The results also reveal that the average removal rate of modified KGM film to Th4+ and Sr2+ is 95.6% and 93.8%. And the best dose of film formation solution is Solute (NKGM acetic ester) : solvent (glacial acetic acid) is 10%. The most suited temperature and time separately is 30°Cand 3hours.

Abstract: Combined with the sample monitoring of our research and the previous studies of algae growth kinetics,the total algae biomass of Xinyun Lake that can been gathered and removed was fast estimated as 1218800m³/a. Based on the research work about the result of organic fertilizer from algae paste, the internal pollution load reductions of COD, NH₄-N and available phosphorus were estimated as 13163.04t, 1018.91t and 146.26t, respectively, in 2012. At last, the environmental benefit, economic benefit and social benefit of organic fertilizer from algae were analyzed, and all of them were very significant.

Abstract: In this thesis, on the basis of detailed survey and actual measurement of the emissions of fine particulate matters (PM2.5) and PM2.5 precursors (SO₂, NOx and VOC) in Chengdu City, the source composition of PM2.5 in the atmospheric air of Chengdu City is simulated by taking the mode of Community Multiscale Air Quality (CMAQ); meanwhile, with reference to the source analysis results of the other units, the key objects of dust haze (PM2.5) pollution, namely fugitive dust, industrial pollution sources and motor vehicle exhaust, can be controlled. Therefore, four main measures for controlling the dust haze (PM2.5) pollution are put forward: the first is to deeply control the particulate matters emitted by the industrial enterprises and install the desulfurization and denitrification devices to reduce the emissions of PM2.5 primary particulate matters and precursors; the second is to reduce the emissions of motor vehicle exhaust, nitrogen oxides and VOC; the third is to strengthen the control of fugitive dust; and the fourth is to implement joint prevention and joint control system among the cities.

Abstract: The aim of this study is to investigate the characteristics of size distribution and chemical composition of ambient particulates inside a tunnel. Inside the tunnel, the average concentration of PM_2.5 and PM_2.5-10 was 479 and 444 μg/m³ respectively. The average mass-size distribution showed a trimodal distribution (25-30, 4.0-5.0, and 2.5, PM_2.5-10, and PM_>10 were 25%, 40%, and 35% of the total suspended particulates. Because of the poor air ventilation inside the tunnel, the particulates accumulate inside the tunnel. The dominated species of PM_2.5 were EC (average concentration 122.91 μg/m³, 25.78%), OC (47.68 μg/m³, 10.53%), SO₄^2- (37.42 μg/m³, 8.24%), and NO₃^- (35.01 μg/m³, 7.95%), and were EC ( 131.77 μg/m³, 29.87%), OC (53.74 μg/m³, 12.15%), SO₄^2- (31.35 μg/m³, 7.11%), and NO₃^- (28.10 μg/m³, 6.42%) for PM_2.5-10. Results from this study showed that the concentrations of coarse particulate matter and several metals are apparently dominated by re-suspended matter rather than emissions from vehicles, e.g., Al, Ca, and Fe. Therefore, ambient particulate matter is caused by not only vehicle exhaust emission but also dusty roads and traffic-generated dust.

Abstract: In this paper, we present the data regarding the thermal decomposition of PCDD/Fs during the manufacturing process of ceramisite from MSWI fly ash, and the efficiency of bag filter with activated carbon injection technology to reduce the gas emission of PCDD/Fs. The distribution of seventeen 2,3,7,8-chlorinated dioxins and furans in MSWI fly ash, ceramisite product, bag filter ash and emission gases were analyzed, and the international toxic equivalents (I-TEQ as 2,3,7,8-tetraCDD) values were calculated by using international-toxicity equivalency factor (I-TEF). The total I-TEQ value of PCDD/Fs in MSWI fly ash reached up to 904.944 ng/kg. After high temperature calcining, only 1.250 ng I-TEQ/kg of PCDD/Fs is left in the ceramisite product. The concentrations of PCDD/Fs in two kinds of bag filter ashes, with activated carbon injection (AC) and without activated carbon injection (NAC), were 324.723 ng I-TEQ/kg and 217.066 ng I-TEQ/kg, respectively. The distribution patterns of seventeen 2,3,7,8-chlorinated dioxins and furans in MSWI fly ash, ceramisite product and bag filter ashes are alike, which suggested that the secondary formation of PCDD/Fs did not significantly occur during the thermal process of manufacturing ceramisite from MSWI fly ash. When no activated carbon was injected, the gas emission of PCDD/Fs was 0.373 ng I-TEQ/Nm³, but 100 mg/Nm³ of activated carbon injection, the gas emission of PCDD/Fs was declined to 0.081 ng I-TEQ/Nm³, which is lower than the gas emission limit established by the European Union Directive of 0.1 ng I-TEQ/Nm³. Therefor, we can recommend that the manufacturing ceramisite from MSWI fly ash using the developed rotary kiln system is an effective measure to safely dispose the MSWI fly ash on the aspect of dioxin emission control.

Abstract: Through designing orthogonal tests, the influence mechanism of iron to the growth of fresh water algae was studied. The results indicated that the initial Fe concentration of 0.3mg/L or above can lead to high algae relative growth rate while the initial Fe concentration under 0.3mg/L can only generate low algae relative growth rate. The consumption of iron in Group LNLP under low initial Fe concentration and Group HNHP under high initial Fe concentration was in synchronism with the consumption of nitrogen and phosphorus. However, in Group HNHP under low initial Fe concentration and Group LNLP under high initial Fe concentration the concentration of iron decreased with the increase of algal biomass before reaching the peak value of algal biomass and it increased after reaching the peak value in contrary. Among all those 25 groups the order of the peak value of algal biomass from big to small is as follows:All-rich Group>Nitrogen-lacked Group>Phosphorus-lacked Group>Iron-lacked Group>All-lacked Group. The lack of Fe content will restrain the growth of algae. In certain concentration rage algal biomass increased with the increasing of Fe content while Fe content will restrain the growth of algae in contrary if beyond the concentration rage.

Abstract: Microbial biofilm plays a major role in aquatic ecosystems by acting as an important food source for fish and other aquatic creatures as well as a refuge for microorganisms. With this in mind, promoting bacterial biofilm formation on a matrix or a carrier is an important low cost strategy in keeping water ecosystem balance. In industrial wastewater processes, many biofilm carriers are built according to the microbial biofilm principle with the homophylic carrier used to treat the contaminative nature water bodies being absent. So we developed a novel biofilm carrier made from high polymer for in situ biofilm technology to improve natural water bodies and named the new carrier device as Artificial Aquatic Mats (AAMs). An investigation to research such device was performed in order to determine the influence of this novel photoautotrophic biofilms carrier on the changes of water quality and phosphorus (P) forms in sediments and to compare the effects of AAMs and carbon fiber carriers (CFC) treatment. Transparency of water appears to possibly be enhanced by the treatments of AAMs and CFC by inhibiting the harmful algae growth for allelopathy. Experimental results revealed, in a same projective area, the transparency cleaned by AAMs increased faster than that of CFC. Both devices had a certain positive effect on decreasing total phosphorus (TP) of water. In the control, there was a persistent large variationnot only the occurrence of algae blooms but also in the changes of both total P (TP) and P form concentrations in the sediments. TP concentrations in sediments of AAMs treatment remained higher than the CFC treatments throughout the experiment. With the exception of the Labile-P, the change in trend lines of all of the P forms in the two treatments did not deviate from one another. Organic matter (OM) was the most important P sink because the contributions of OM were well correlated with the TP and Labile-P. Statistical analysis in Ca-P and Residual-P showed that the AAMs-treatment could more prevent phosphorus from releasing from sediment into water column than that of CFC-treatment.

Abstract: Activated carbon prepared from grapefruit peel, an agricultural solid waste by-product, has been used for the adsorption of Cr(VI) from aqueous solution. The effects of adsorbent dosage, pH and temperature on adsorption of Cr(VI) were investigated. The maximum adsorption yield was obtained at the initial pH of 3. The dynamical data fit very well with the pseudo-second-order kinetic model and the calculated adsorption capacities (23.98, 24.33 and 24.81 mg/g) were in good agreement with experiment results at 20°C, 30°C and 40 °C for the 100 mg/L Cr(VI) solution. The Freundlich model (R² values were 0.9198-0.9871) fitted adsorption data better than the Langmuir model. The calculated parameters confirmed the favorable adsorption of Cr(VI) on the activated carbon prepared from grapefruit peel.

Abstract: The removal of strontium from aqueous solution with collagen fiber immobilized tannins was studied. The effects of several experimental parameters such as pH, dosage, temperature, contact time and initial concentration of strontium on removal efficiency of strontium were investigated to determine the optimum conditions of strontium sorption process. The adsorbent was characterized by SEM and FTIR analysis. The results of regression analysis indicated that temperature parameters were not individually statistically significant for Sr²⁺ adsorption. However, the efficiency of strontium adsorption increased with the increase in pH and dosage. The adsorption capacity was increased with increasing initial concentration of Sr²⁺. The removal efficiency of Sr²⁺ was 49% at optimum pH of 6 and initial concentration of 20mg/L. Moreover, the absorption data were fitted well to the Langmuir sorption isotherm model.

Abstract: Waste beer yeast was utilized as adsorbent to remove Th⁴⁺ from simulated radioactive wastewater. Effects of various parameters including pH value, temperature, absorbent dosage, and absorption time on adsorption of Th⁴⁺ by waste beer yeast were studied. Beer yeast before and after adsorption was characterized by IR and SEM. The results show that the removal efficiency could be reached 95% at the optimized conditions. The adsorption kinetics was described well by the pseudo second-order equation.