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911.
912.
913.
采用恒温振荡平衡法研究了乐山市某一水田土壤和未种植过的土壤对铜离子的吸附特性。结果表明:溶液的pH值越大,土壤对铜离子的吸附量越大;铜标准溶液的初始浓度越大,土壤对铜离子的吸附量越大;土壤含腐殖酸越多,对铜离子的吸附能力越强;水田土壤比未种植过的土壤对铜离子的吸附能力更强;用Freundlish方程来描述各种土壤对铜离子的吸附特性均得到了较好的相关性。 相似文献
914.
915.
Yanhui Zhan Jianwei Lin Yanling Qiu Naiyun Gao Zhiliang Zhu 《Frontiers of Environmental Science & Engineering in China》2011,5(1):65-75
Surfactant-modified natural zeolites (SMNZ) with different coverage types were prepared by loading hexadecyltrimethyl ammonium
bromide (HTAB) onto the surface of a natural zeolite. The adsorption behavior of humic acid (HA) on SMNZ was investigated.
Results indicate that the adsorbent SMNZ exhibited a higher affinity toward HA than the natural zeolite. HA removal efficiency
by SMNZ increased with HTAB loading. Coexisting Ca2+ in solution favored HA adsorption onto SMNZ. Adsorption capacity decreased with an increasing solution pH. For typical SMNZ
with bilayer HTAB coverage, HA adsorption process is well described by a pseudo-second-order kinetic model. The experimental
isotherm data fitted well with the Langmuir model. Calculated maximum HA adsorption capacities for SMNZ with bilayer HTAB
coverage at pH 5.5 and 7.5 were 63 and 41 mg·g−1, respectively. E2/E3 (absorbance at 250 nm to that at 365 nm) and E4/E6 (absorbance at 465 nm to that at 665 nm) ratios of
the residual HA in solution were lower than that of the original HA solution. This indicates that the HA fractions with high
polar functional groups, low molecular weight (MW), and aromaticity had a stronger tendency for adsorption onto SMNZ with
bilayer HTAB coverage. Results show that HTAB-modified natural zeolite is a promising adsorbent for removal of HA from aqueous
solution. 相似文献
916.
Zhaoxing Han Zhenyao Shen Yongwei Gong Qian Hong 《Frontiers of Environmental Science & Engineering in China》2011,5(1):119-129
Emission trading is one of the most effective alternatives to controlling water pollution. Water environmental functional
zone (WEFZ) is used to determine the water quality standard and identify the zone boundary for each river or reach. In this
study, a new emission trading scheme was addressed based on WEFZ, accounting for both the temporal dimension and water quality
control. A temporal factor of emission trading was proposed based on variations in the environmental capacity within a year
by dividing the year into three periods, including high, normal, and low periods of environmental capacity. During each period,
emission trading was implemented exclusively. A water quality-control scheme was suggested based on the water quality requirement
in the water functional zone, in which the water quality at the downstream boundary of the zone was required to meet the water
standard following auto-purification in the stream. Two methods of calculating water quality control are addressed for point-source
pollution and non-point-source pollution. The calculated temporal dimension and water quality control were located in Dongxi
River of the Daning Watershed in the Three Gorges Watershed. The high period was during June, July, and August, the normal
period was during April, May, September, and October, and the low period was during January, February, March, November, and
December. The results from the water quality calculation demonstrated that the discharge of point-source and non-point-source
pollutions led to an excess of common contaminants at the downstream boundary of WEFZ. The temporal and spatial factors above
should be incorporated into the emission trading scheme based on WEFZ. 相似文献
917.
Jiarui Han Qian Ye Zhongwei Yan Meiyan Jiao Jiangjiang Xia 《Frontiers of Environmental Science & Engineering in China》2011,5(4):533-542
The purpose of improving weather forecast is to enhance the accuracy in weather prediction. An ideal forecasting system would
incorporate user-end information. In recent years, the meteorological community has begun to realize that while general improvements
to the physical characteristics of weather forecasting systems are becoming asymptotically limited, the improvement from the
user end still has potential. The weather forecasting system should include user interaction because user needs may change
with different weather. A study was conducted on the conceptual forecasting system that included a dynamic, user-oriented
interactive component. This research took advantage of the recently implemented TIGGE (THORPEX interactive grand global ensemble)
project in China, a case study that was conducted to test the new forecasting system with reservoir managers in Linyi City,
Shandong Province, a region rich in rivers and reservoirs in eastern China. A self-improving forecast system was developed
involving user feedback throughout a flood season, changing thresholds for flood-inducing rainfall that were responsive to
previous weather and hydrological conditions, and dynamic user-oriented assessments of the skill and uncertainty inherent
in weather prediction. This paper discusses ideas for developing interactive, user-oriented forecast systems. 相似文献
918.
919.
为了实施总量控制,在大气环境质量未达标区制定大气污染物排放削减量优化分配方案。得出污染源年度削减限量;在空气质量达标区.依照允许的地面浓度增量,将大气污染物允许排放指标合理地分配到源,以保证经济的持续发展;在大气环境管理中逐步建立起计算机辅助决策支持系统和完善的监测系统。 相似文献
920.
杭州西湖底泥释磷及其对富营养化的影响 总被引:11,自引:1,他引:10
杭州西湖是一个小型浅水湖泊,其底泥由上部藻骸腐泥和下部泥炭层构成。西湖底泥的显著特点是有机碳含量特别高,氮和磷含量也相当高。通过实验室和现场模拟研究,考察了pH、温度、溶解氧、氧化还原电位及上复水种类等环境因素对底泥释磷量和释磷速率的影响。上复水pH值在6.5—7.0范围内底泥释磷量最低;在较高或较低pH值时,底泥释磷量倍增。升高水温或降低上复水溶解氧浓度均能加速磷释放。实验室模拟西湖底泥最大释磷量为0.368μg/g。夏季现场模拟平均释磷速率为1.02mg/m~2·d;估算西湖底泥释磷量达1.346t/y,相当于年平均外部入湖磷负荷的36.4%。底泥释磷对西湖富营养化有着不容忽视的影响。 相似文献