Advanced Materials Research Vols. 518-523

Abstract: The activated carbon fiber (ACF) was treated by different concentration nitric acid (HNO₃) and hydrogen peroxide (H₂O₂) oxidization to enhance its adsorption capacity to hexavalent chromium (Cr⁶⁺) ion. The adsorption amount and adsorption kinetics of Cr⁶⁺ ion on ACFs, and the surface chemical groups were investigated. The results showed that the modified ACFs with 1% HNO₃ and 10% H²O² had a better adsorption capacity, respectively. The adsorption amount of ACFs was affected strongly solution pH value, and decreased significantly with increasing of the pH value. The adsorption kinetics indicated that the adsorption rates of Cr6+ ion on different modified ACFs were well fitted with the pseudo-second-order kinetic model. After 1% HNO₃ and 10% H₂O₂ modification, respectively, the total acidic oxygen-containing groups on ACFs surface had an increase obviously, which might be enhance the adsorption amount of Cr⁶⁺ ion on ACFs.

Abstract: Integrated with the project performance research development in the world, this article structures a performance evaluation system which accords with the urban rivers pollution characteristics and the treatment project performance in the south city of China. With an empirical study on the treatment project of the Panlongjiang River in Nanba Village of Kunming City, this article evaluates the treatment projects from the aspects of social economic profit, ecological benefit and the social benefit for people’s livelihood. The evaluation result shows that the treatment project on the part of Panlongjiang River in Nanba Village of Kunming City works effectively. The investment and income, the benefit of projects and the river environmental quality belong to the level of very efficient. The pollution emission reduction benefit, the ecological quality of riparian zone landscape, aquatic environment condition, and the development of basic establishment belong to the level of efficient. The environmental protection and management performance belongs to the level of ordinary. The practice demonstrates that this evaluation index system has certain serviceability and can reflect the process and the real achievements of treatment projects of black color and odor urban rivers.

Abstract: Using sampling survey data from 20 representative villages, this paper analyzes the status of environmental pollution in mountainous and hilly rural area of Sichuan Province in China, and makes comprehensive analysis of environmental pollution factors of the research area based on BP neural network model. The result shows that there are about 60% of the villages investigated displaying environmental pollution of varying degrees. It also indicates that environment renovation measures conducted by government and labor out-migration are conducive to environmental protection in mountainous and hilly rural area of Sichuan, while the concentration of population and development of rural enterprise have negative impact on local environment. The influence degree of each factor in descending order is labor out-migration, environment renovation measures, concentration of population, rural enterprise development.

Abstract: Basing on water quality and aquatic ecological data of 142 lakes in eastern region of China, the article selected causal variable (TN, TP, COD_Mn) and response variable (Chl-a, SD), used Comprehensive Trophic Level Indexes (TLI) classification method and got the eutrophication control standards of five factors. The result showed that the eutrophication control standards were in excess of values of III water standard in GB3838-2002. The result could provide scientific conference for lake eutrophication control standard.

Abstract: Total of 40 soil samples were collected in vegetable garden soil in the urban-rural area of Fushun city. Heavy metal elements were evaluated including Cu, Zn, Pb, Cd , Cr, Ni, As and Hg. Soil environmental quality was evaluated by a combination of the single quality index method and the complex quality index method. Meantime, the soil potential ecological hazard was evaluated by Hakanson method. It will provide scientific basis for regional agricultural production, environmental protection and industry structural adjustment. The study showed that eight samples were contaminated by Ni, exceeding rate of 20.0%, and seven samples were contaminated by Cu, exceeding rate of 17.5%. In comprehensive study, light polluted accounted for 12.5%; warning and safety level accounted for 87.5%. At the same time, the order of the potential ecological risk of single-factor was Cd>Hg>Cu>Ni>As>Pb>Zn>Cr. Integrated potential ecological hazard was slight with the number of 25.48. Statistical analysis, correlation analysis and factor analysis all suggested that concentration of Cu, Ni, Zn and Hg were mainly affected by human activities, Pb, Cd, Cr and As were mainly controlled by parent rocks.

Abstract: A pilot study was carried out to evaluate the application of aerobic submerged MBR in treating polyester wastewater and a full scale system in which MBR was adopted as the key aspect was put forward to treat the polyester wastewater of Zhuhai Yuhua Polyester co., Ltd., China. The pilot study revealed that HRT could be affected by the influent COD, and a HRT larger than 36h was proposed for treating polyester wastewater by MBR. Volumetric loading rate and sludge loading rate ranged in 0.7-2.0 kgCOD/m3•d and 0.09~0.24 kgCOD/ kgMLSS•d respectively were of small influence on the COD removal. DO in the range of 2.5-4.0 mg/L seemed to be optimal for avoiding limitations due to oxygen concentration and creating an effective turbulence. The modified full scale system which includes anaerobic digesting tank and MBR followed by a stabilization pond was verified to be effective to treat the polyester wastewater in the latest two years. The results illustrated that the effluent water quality could meet the discharge limits of water pollutants (DB 44/26-2001) which was established in Guangdong, China. Observed sludge yield of the system fluctuated between 0.10-0.18 gMLSS/gCOD and averaged at 0.137 gMLSS/gCOD. The membrane permeate at around 10 L/m2h, TMP of less than 0.7bar, and total mixed liquor suspended solids (MLSS) between 6-7g/L were suitable to operate the MBR.

Abstract: This paper presents the results of reduction of nitric oxide, NO, by metallic iron in a one-dimensional electrically heated ceramic tubular reactor in the temperature range of 300 °C to 1200 °C with simulated flue gas of 0.05% NO in N2 base. Several sizes of iron mesh rolls were used as iron samples and were placed in the centre of the reactor. The effect of CO on NO reduction was examined by introducing 0.1% CO into the flue gas. Effluent NO was measured as a function of temperature by online gas analyzer. The chemical changes of the iron samples after the reaction were analyzed by X-ray diffraction (XRD) methods. Results showed that iron mesh roll was very effective to reduce NO to N2. When the temperature was higher than 900°C, the NO reduction efficiency was observed to exceed 90% for all the mesh rolls used. Fe2O3 was formed at the surface of the iron mesh. The presence of CO increased the NO reduction efficiency by reducing the iron oxide, mainly Fe2O3, to metallic iron.

Abstract: In this paper, the characteristics of SO₂ and NO release during combustion of lean coal with different coal rank were experimentally studied in the one-dimensional furnace for pulverized coal combustion. The results showed: The coal property and proportion of the component coals have great influence on the characteristics of SO₂ and NO release. The releasing concentration of SO₂ and NO distributing along the furnace height is generally between that of component coals, and the releasing characteristics of SO₂ and NO would be more near to that of the larger proportion coal. The measuring value of the formation concentration of SO₂ and NO are different from the calculating value based on the weighted means of the component coals to a certain extent. While the different coal are added to lean coal, the time corresponding with peak value releasing concentration of SO₂ and NO is different.

Abstract: A full-field investigation was conducted of far-infrared thermal desorption of sandy soil polluted by r-Hexachlorocyclohexane (RH). The effects of thermal desorption time, temperature, vacuum and water content on the thermal desorption efficiency (C_E) were determined. C_E of RH is increasing with the increasing of thermal desorption_{Subscript text} time, temperature, vacuum. The optimum thermal desorption conditions for sandy soil are as follows: thermal desorption time 10 minutes, thermal desorption temperature 200°C, vacuum 0.05MPa and water content 15%.The material balance was basically realized, and most RH lies in condensed liquid.

Abstract: The paper introduce the main measures to reduce NOx emission in boiler combustion progress, the principles of several low NOx combustion technologies at home and abroad and the application in power plant boiler. Analysis are made to these traditional measures of their limitations. The development of NOx control in combustion progress and the prospect forecast of low NOx combustion technologies is also discussed.