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291.
292.
Activated carbons derived from oil palm empty-fruit bunches: Application to environmental problems 总被引:1,自引:1,他引:0
Md. Zahangir ALAM Suleyman A. MUYIBI Mariatul F. MANSOR Radziah WAHID 《环境科学学报(英文版)》2007,19(1):103-108
Activated carbons derived from oil palm empty fruit bunches (EFB) were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process, Two types of activation namely; thermal activation at 300, 500 and 800℃and physical activation at 150℃ (boiling treatment) were used for the production of the activated carbons. A control (untreated EFB) was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800℃ showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800℃. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price (USD 0.50/kg of activated carbon) compared the activated carbon from other sources and processes. 相似文献
293.
Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes 总被引:2,自引:0,他引:2
In this study an effort has been made to use plant polyphenol oxidases; potato (Solanum tuberosum) and brinjal (Solanum melongena), for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation. 相似文献
294.
Multi-indicator assessment of water environment in government
environmental auditing 总被引:1,自引:0,他引:1
This study focused on a multi-indicator assessment methodology for governmental environmental auditing of water protection programs. The environmental status of Wuli Lake in China was assessed using the global indicators (driver-status-response) developed by the Commission on Sustainable Development, and four additional indicators proposed by the author: water quality, pollution load, aquatic ecosystem status, and lake sediment deposition. Various hydrological, chemical, biological and environmental parameters were used to estimate the values of the indicators for assessment of environmental status of the lake based on time series data sets for twenty years. The indicators proposed can be customized to meeting the needs for particular assessment of water protection programs. This method can be used to evaluate the performance of national environmental protection programs and provide technical support for environmental auditors. 相似文献
295.
Contribution of additives Cu to its accumulation in pig feces: study in Beijing and Fuxin of China 总被引:13,自引:1,他引:12
Massive amounts of pig manure are produced by intensive pig farm in China, and the composition of pig manure has changed much due to the use of feed additives. However, little is known about the exact Cu (copper) feed as additives or present as contaminants in pig feed and the residues in feces. One hundred and thirty-seven feeds and one hundred and forty-two fecal samples from 48 pig farms were collected in Beijing and Fuxin cities in 1999 and 2005, respectively. The concentrations of Cu were in the range of 6.86-395.19 mg/kg in the feed samples, and the mean values were in the order of weaner〉 grower-finisher〉 sow's feeds. The high concentrations over EU recommendations implied that excessive levels of Cu are fed on many pig farms in Beijing and Fuxin. Cu was also present in high concentrations in feces, and concentrations were highly variable. Cu concentrations in the feces from grower-finisher and weaner pigs were significantly greater than feces of sows. The super-intensive and small-scale farms had higher levels of Cu in feces than the middle farms. Cu concentrations in pig feces were approximately 5-times greater than in pig feeds. Feed management in grower-finisher pigs on super-intensive and small-scale pig farms is needed to reduce high Cu concentrations in feces and risks to soil contamination while feces are land-applied. 相似文献
296.
Anoxic biodegradation of dimethyl phthalate (DMP) by activated sludge cultures under nitrate-reducing conditions 总被引:3,自引:0,他引:3
Worldwide extensive use of plasticized plastics has resulted in phthalates pollution in different environment. Nitrates from industry and agriculture are also widely disseminated in the soils, natural waters and wastewaters. Dimethyl phthalate (DMP) biodegradation by activated sludge cultures under nitrate-reducing conditions was investigated. Under one optimized condition, DMP was biodegraded from 102.20 mg/L to undetectable level in 56 h under anoxic conditions and its reaction fitted well with the first-order kinetics. Using the high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS) analysis, mono-methyl phthalate (MMP) and phthalic acid (PA) were detected as the major intermediates of DMP biodegradation. When combined with the determination of chemical oxygen demand (CODCr) removal capacity and pH, DMP was found to be mineralized completely under anoxic conditions. The biodegradation pathway was proposed as DMP → MMP → PA → … → CO2 H2O.The molar ratio of DMP to nitrate consumed was found to be 9.0:1, which agrees well with the theoretical stoichiometric values of DMP biodegradation by nitrate-reducing bacteria. The results of the non-linear simulation showed that the optimum pH and temperature for the degradation were 7.56 and 31.4℃, respectively. 相似文献
297.
渤海重金属污染历史研究 总被引:14,自引:4,他引:14
1979-1985年用大口径静矸取样器采集了渤海28柱示劝岩心样。采用^210P年代学方法,通过柱样沉积物稳定天然密度资料获得沉积速度,沉积通量和岩心编年, 此提出了渤海车颗粒沉积物中Cu、Pb、Zn、Cd环境背景值,探讨了渤海重点海域和毗邻河口区重金属污染历史。 相似文献
298.
目的 研究某高超声速导弹飞行过程中的振动状态,获得导弹在给定压力载荷下的振动响应特性。方法结合有限元分析、随机振动理论,利用三维软件构建导弹有限元模型,并在Ansys Workbench平台对其进行模态分析及谐响应分析。基于模态分析结果,对导弹进行随机振动响应试验,探究导弹在频域及力学上的振动响应特征。结果 计算得出导弹前六阶固有频率和振型,获得导弹上一检测点在给定振动激励载荷下的加速度响应曲线,并得到导弹整体结构的应力分布云图。结论 导弹模型强度符合要求,导弹在振动激励载荷下的加速度响应峰值均出现在380~400Hz,应力极值出现在导弹尾部区域,在此区域内,导弹更易产生结构性损伤。在飞行器地面环境模拟试验中,应着重考虑此频域及位置的振动条件。 相似文献
299.
三江源地区极端气候事件演变事实及其成因探究 总被引:8,自引:0,他引:8
利用三江源地区14个气象台站1962-2005年逐日气温、降水资料分析了该地区冷暖干湿极端气候事件的演变规律,探讨了其变化成因。研究表明:近44a来三江源地区气温等级由冷向暖转变,极端高温事件频繁发生,而极端低温事件则逐年减少,致使气温不断向着更高的均值状态持续增暖;尽管降水量干湿变化不甚显著,但降水的极端状况即严重干旱或暴雨事件均呈减少趋势,降水量的变化趋于稳定,降水变率减小;地形对极端气温、降水事件频次变幅的空间分布均有着较为显著的影响,且对后者的影响更为显著;高原季风、厄尔尼诺事件及高原积雪等因子的年际振荡是三江源地区极端气候事件发生频次波动的主要原因。 相似文献
300.
石羊河流域经济发展与生态环境协调度评价 总被引:2,自引:1,他引:2
以石羊河流域117个乡(镇)为基本研究单元,借助流域1986、2000和2011年的Landsat TM解译数据和相关社会经济统计数据构建了ESV模型、EEH模型和AGPI模型,依据ESV指数和EEH指数揭示石羊河流域经济发展与生态环境系统的相关关系和演变特征.研究表明:①1986年以来石羊河流域生态系统服务功能价值呈小幅下降趋势,1986—2000年年均损失0.48%,2000—2011年年均损失0.27%.②1986年以来石羊河流域各乡镇经济发展较快,AGPI增长呈现从上游向下游转移的趋势,流域北部增长率明显高于南部.③石羊河流域经济与生态环境协调度在1986—2000年期间保持了原始和自然发展状态,经济发展与生态环境协调度较差.此后2000—2011年期间二者协调度有所改善,但石羊河流域经济与生态环境关系正处于矛盾多发且此消彼长的不稳定阶段,两极分化现象比较明显. 相似文献