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661.
Dengqiang FU Ying TENG Yuanyuan SHEN Mingming SUN Chen TU Yongming LUO Zhengao LI Peter CHRISTIE 《Frontiers of Environmental Science & Engineering》2012,6(3):330-335
Dissipation and plant uptake of polycyclic aromatic hydrocarbons (PAHs) in contaminated agricultural soil planted with perennial ryegrass were investigated in a field experiment. After two seasons of grass cultivation the mean concentration of 12 PAHs in soil decreased by 23.4% compared with the initial soil. The 3-, 4-, 5-, and 6-ring PAHs were dissipated by 30.9%, 25.5%, 21.2%, and 16.3% from the soil, respectively. Ryegrass shoots accumulated about 280 μg·kg-1, shoot dry matter biomass reached 2.48 × 104 kg·ha-1, and plant uptake accounted for about 0.99% of the decrease in PAHs in the soil. Significantly higher soil enzyme activities and microbial community functional diversity were observed in planted soil than that in the unplanted control. The results suggest that planting ryegrass may promote the dissipation of PAHs in long-term contaminated agricultural soil, and plant-promoted microbial degradation may be a main mechanism of phytoremediation. 相似文献
662.
采用实验室压滤装置对胜利油田某联合站罐底清罐油泥进行压滤脱水研究,采用单独添加助滤剂G、絮凝剂PAM或PAC均可改善过滤效果,提高滤速,降低过滤比阻。但仅使用助滤剂G时滤速的提高尚不够理想,单独使用絮凝剂PAM或PAC时,滤饼含水率偏高,滤饼不易从滤布上剥离;絮凝剂PAM 0.1%与助滤剂G 3.0%复配,滤饼比阻由空白样的18.7×1012 m/kg降低到0.05×1012 m/kg,3 min即可使滤饼含水率降到74.16%,滤液澄清,滤饼成形性好,较仅添加絮凝剂PAM时,更容易从滤布上剥离。 相似文献
663.
Wei Gao Ritsu Dobashi Toshio Mogi Jinhua Sun Xiaobo Shen 《Journal of Loss Prevention in the Process Industries》2012,25(6):993-999
To reveal the effects of particle characteristics on the mechanisms of flame propagation during organic dust explosions clearly, three long chain monobasic alcohols which are solids at room temperature and have similar physical–chemical properties were chosen to carry out experiments in a half-closed small chamber. A high-speed video camera was used to record the flame propagation process and to obtain the direct light emission photographs. Flame temperature was detected by a fine thermocouple. Based on the experimental results above, analysis was conducted on flame propagation characteristics and temperature profiles of organic particle cloud. As a result, it was found that the particle materials, especially volatility, strongly affected the flame propagation behavior. Particle concentration also affects the combustion zone propagation process significantly. With increasing the particle concentration, the maximum temperature of the combustion zone increases at the lower concentration, reaches a maximum value, and then decreases at the higher concentration. The propagation velocity of the combustion zone has a linear relationship with the maximum temperature, which implies conductive heat transfer is dominant in the flame propagation process of the three different volatile dusts. 相似文献
664.
Honghong Chang Longhui Cui Xing Li Jun Shen Wenlong Wei Ziming Kou 《Journal of Loss Prevention in the Process Industries》2012,25(6):1028-1032
In order to avoid existing shortcomings of chlorine leakage treatment, we developed a new chlorine scavenger. The main composition of the chlorine scavenger was calcium hydroxide. The chlorine scavenger was prepared by wet process with water as solvent through adding surface active agent and silicone oil, etc. The influence of surfactant on modified powder was investigated, which included the sodium dodecyl benzene sulfonate, the sodium stearate, the water-soluble silicone oil, the emulsifying silicon oil and the amino silicone oil, and the effect of modification of judgment were illustrated, which mainly involved the sifting rate, the bulk density, the contact angle, on this basis, also the author analyzed the powder of modification by using SEM analysis and size distribution, The modified powder had the following characteristics: high absorptivity, anti-caking, good air permeability and so on. The results showed that overall performance of modified powder was better than the performance of unmodified powder. The adding amount of sodium stearate was preferably 2% while the optimum amount of emulsifying silicon oil and amino silicone oil was 3%. The comprehensive performance of powder modified with compound modifiers was better than the performance of the powder modified with a single modifier. The property of powder modified with sodium stearate and amino silicone oil had a good performance analyzed from the uniformity of particle size distribution of the powder and anti-caking. The powder modified with sodium stearate and emulsifying silicon oil had a good absorption rate of chlorine. 相似文献
665.
666.
667.
高压脉冲等离子体降解水中苯酚的实验研究 总被引:6,自引:0,他引:6
对高压脉冲放电等离子体技术降解水中有机污染物苯酚进行了实验研究,观察了脉冲成形电容、脉冲峰值电压、脉冲频率、放电电极直径、放电距离、苯酚的人口质量浓度等因素对苯酚降解率的影响;实验结果表明脉冲成形电容有一最佳值;降解率随脉冲峰值电压、脉冲频率增大而升高,随放电电极直径和放电距离的减小而增大,随苯酚人口质量浓度增大而增大。 相似文献
668.
2005年8月5日中午,“麦莎”台风向上海袭三类的信息传利到金山区山阳镇海业村,吃过中饭, 相似文献
669.
Water samples from 20 locations on rivers in the Tongzhou District of Beijing were collected four times from July 2005 to
March 2006. In addition, sediment samples were collected in July 2005. All samples were analyzed for 16 US Environmental Protection
Agency (EPA) priority pollutants polycyclic aromatic hydrocarbons (PAHs). The concentration, distribution, seasonal variation,
and sources of the 16 PAH compounds identified in the water samples, suspended particles, and surface sediments were then
evaluated. The concentrations of PAHs in the water and suspended particle and surface sediment samples ranged from 87.3 to
1,890 ng l−1, 1,330 to 27,700 ng g−1, and 156 to 8,650 ng g−1, respectively. These results demonstrated that rivers in the Tongzhou District of Beijing had a high level of PAH pollution,
especially in the suspended particles. The highest and lowest concentrations of PAHs in the water samples were observed in
summer and spring. However, the seasonal variations in the concentration of PAHs in the suspended particles were more complicated.
The dominant compounds in the water, suspended particle, and surface sediment samples were two-, three- and four-ring PAH
compounds, respectively. Ratio analysis illustrated that fuel-burning was the primary source of PAHs in the study area. Gasoline,
diesel, coal, and coke oven sources were identified and the contributions of the different fuel-burning sources were then
calculated using factor analysis and multiple linear regression. These analyses revealed that coal combustion, gasoline combustion
plus coke oven emission, and diesel combustion accounted for 38.8%, 38.5%, and 22.7% of the PAHs in suspended particles, respectively. 相似文献
670.
Bingbing Xu Zhonglin Chen Fei Qi Jimin Shen Fengchang Wu 《Frontiers of Environmental Science & Engineering》2009,3(1):91-97
In order to provide basic data for practical application, photodegradation experiment of N-nitrosodimethylamine (NDMA) in aqueous solution was carried out with a low-pressure Hg lamp. Effects of the initial concentration of NDMA, solution pH, dissolved oxygen, and the presence of humic acid on NDMA photodegradation were investigated. NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min, except that at 1.07 mmol/L, NDMA could be photodegraded almost completely in the acidic and neutral solutions, while the removal efficiency decreased remarkably in the alkaline solution. Dissolved oxygen enhanced the NDMA photodegradation, and the presence of humic acid inhibited the degradation of NDMA. Depending on the initial concentration of NDMA, NDMA photodegradation by UV obeyed the pseudo-first-order kinetics. Dimethylamine, nitrite, and nitrate were detected as the photodegradation products of NDMA. 1O2 was found to be the reactive oxygen species present in the NDMA photodegradation process by UV, based on the inhibiting experiments using tert-butanol and sodium azide. 相似文献