固定化啤酒废酵母对Cr(Ⅵ)的吸附

用2%海藻酸钠与1%明胶混合作为包埋剂固定啤酒废酵母,研究固定化啤酒废酵母对Cr(Ⅵ) 的吸附特性。结果表明,固定化啤酒废酵母吸附Cr(Ⅵ) 受吸附时间、起始pH 、固定化菌体浓度、Cr(Ⅵ) 起始浓度及共存离子等因素的影响。确定固定化啤酒废酵母对Cr(Ⅵ) 最佳吸附条件为：pH 2,Cr(Ⅵ) 起始浓度100 mg/L ,固定化菌体浓度2 g/L,吸附90 min 。此条件下Cr(Ⅵ) 的吸附率可达96.8%。Pd²⁺等并存离子可抑制固定化啤酒废酵母对Cr(Ⅵ) 的吸附。用1 mol/L盐酸洗脱固定化啤酒废酵母所吸附的Cr(Ⅵ) 3 h,解吸率为93.6%。     

活性炭负载水合氧化铁对草甘膦吸附性能的研究

利用活性炭制备了水合氧化铁负载活性炭AC-Fe,并通过静态吸附实验研究了该材料对水溶液中草甘膦的吸附性能。研究结果表明,该负载方法可以在活性炭上嫁接72 mg/g的铁,AC-Fe对草甘膦的最大吸附容量可以达到120 mg/g;AC-Fe对草甘膦的吸附量随pH的升高而降低;磷酸根对AC-Fe的吸附性能具有明显的抑制作用,原因在于它能和铁离子形成内层络合物,与草甘膦竞争材料表面的吸附位点。     

单质硫改性介孔炭对水溶液中汞的吸附性能研究

对介孔炭CMK-3进行单质硫改性得到OMC-S,并通过静态吸附实验研究了该材料对水溶液中汞的吸附性能。研究结果表明：单质硫改性可以在介孔炭上负载12.33%的硫,从而使得介孔炭对汞的吸附容量从185 mg/g提高到476 mg/g;OMC-S具有较广的适用pH值范围,在pH 3～11.5范围内其对汞的吸附去除率均达到92%以上;氯离子对OMC-S的吸附性能具有一定的抑制作用,原因在于它能和汞离子络合形成一系列吸附性能较差的Hg-Cl络合物,而腐殖酸在所研究的范围内对OMC-S的吸附性能无明显影响。     

省域入境旅游经济的区域差异及发展模式

通过经济空间差异分析方法ESDA技术,对1997-2007年我国省域入境旅游经济的时空演化格局进行研究,探究省际差异,分析差异成因.分析发现:①省域总体空间差异缓慢扩大;②至2007年我国省域入境旅游经济已形成"三阶梯、两顶峰"的空间发展格局;③三阶梯间的入境旅游收入之比为一:二:三=13:1.5:1,可见阶梯间的界限非常明显,由此印证了阶梯划分的合理性;④从入境旅游经济对国民经济总体的贡献率来看,旅游业对处于第三阶梯的西藏具有重要意义;⑤省域间明显表现为一种"先进带动后进"的发展模式;⑥各阶梯处于不同的发展阶段,并由于主导作用的不同而表现为不同的发展趋势;⑦产生此种格局的根本原因在于,省域间旅游发展基础条件的差异和省际间的相互作用.     

Polycyclic aromatic hydrocarbon emission from straw burning and the influence of combustion parameters

A simulated burning experiment was conducted in a tubular furnace system to examine the emission of polycyclic aromatic hydrocarbons (PAHs) from the burning of rice and bean straw, and the influence of combustion parameters was investigated. Total emission amounts of 16 PAHs (∑PAHs) from the burning of rice and bean straw ranged from 9.29 to 23.6 μg g^?1 and from 3.13 to 49.9 μg g^?1, respectively, which increased with the increase of temperatures from 200 to 700 °C. The contribution of combustion to individual PAH yields was about 80.6–100%, which was generally increased with the increase of burning temperature. Moisture content in straw had a negative effect on PAH formation, especially on PAHs with low molecular weight. ∑PAHs emission amounts decreased by 78.2% for bean straw with a moisture content of 30% in comparison with that for dried straw. In addition, PAH emission amounts increased with the increase of O₂ content in supplied air and then decreased, which showed a maximum emission at O₂ content of 40%. The source fingerprint of PAHs in emission from straw burning was established, which showed that naphthalene accounted for 35.0 ± 7.4% of ∑PAHs. Based on the experimental data, emission amounts of ∑PAHs from the burning of rice and bean straw were estimated to be 320–357 and 32.5–76.0 tons to ambient air per year in China, respectively.     

A combined model–observation approach to estimate historic gridded fields of PM2.5 mass and species concentrations

This paper introduces a methodology for estimating gridded fields of total and speciated fine particulate matter (PM_2.5) concentrations for time periods and regions not covered by observational data. The methodology is based on performing long-term regional scale meteorological and air quality simulations and then integrating these simulations with available observational data. To illustrate this methodology, we present an application in which year-round simulations with a meteorological model (the National Center for Atmospheric Research/Penn State Mesoscale Model, hereafter referred to as MM5) and a photochemical air quality model (the Community Multiscale Air Quality Model, hereafter referred to as CMAQ) have been performed over the northeastern United States for 1988–2005. Model evaluation results for total PM_2.5 mass and individual species for the time period from 2000 to 2005 show that model performance varies by species, season, and location. Therefore, an approach is developed to adjust CMAQ output with factors based on these three variables. The adjusted model values for total PM_2.5 mass for 2000–2005 are compared against independent measurements not utilized for the adjustment approach. This comparison reveals that the adjusted model values have a lower root mean square error (RMSE) and higher correlation coefficients than the original model values. Furthermore, the PM_2.5 estimates from these adjusted model values are compared against an alternate method for estimating historic PM_2.5 values that is based on PM_2.5/PM₁₀ ratios calculated at co-located monitors. Results reveal that both methods yield estimates of historic PM_2.5 mass that are broadly consistent; however, the adjusted CMAQ values provide greater spatial coverage and information for PM_2.5 species in addition to total PM_2.5 mass. Finally, strengths and limitations of the proposed approach are discussed in the context of potential uses of this method.     

时间因素在安全评价中的作用

安全评价的主要作用是为生产经营单位和监管部门准确反映系统的安全状态,为安全生产管理和监管提供决策依据,但目前的评价结果只能反映某一特定时刻的系统情况,而对未来一段时间系统安全状况的变化情况不能做出预判,如果能有效考虑时间因素,安全评价的结果将更加完善.     

氯乙烯储罐安全性分析

氯乙烯是被列入高毒物品的易燃易爆气体物质,液化氯乙烯由于其常温储存下蒸气压力高于大气压而在发生泄漏时容易引起火灾、爆炸、中毒等事故.氯乙烯储罐往往因为储存的物质量大而成为重大危险源.从国内现阶段法律法规、标准要求入手,分析了对氯乙烯储罐的安全要求,并以一具体储罐及其安全设施为实例,研究分析了储罐安全阀发生排放和储罐BLEVE等事故后果.并以此为基础,提出了本实例条件下保证储罐安全的具体要求.     

系统安全评价方法对比研究

安全评价是衡量风险,实现安全生产的重要途径。为了不同的评价目标开发出来的各种安全评价方法都有其针对性和局限性。认清这些方法的优点和缺点有助于系统地运用安全评价方法衡境目标的风险。安全评价软件有助于弥补安全评价方法的不足,并提高安全评价的效率和可靠性。     

近年胶州湾陆源SGD及其营养盐输送

根据青岛市胶州湾周边的水文地质条件及地下水位、水质动态特征,运用断面法计算了2001～2003年该区地下水及其N、P、Si无机营养盐向海湾的输送量.研究表明近年该区地下水向海湾的输送量分别为(1.87～2.41)×106m3,其中白沙河平原输送量占95%以上.地下水向海湾的NO 2、NH 4、PO3-4输送量较少,而NO 3和可溶性SiO2的输送量较大,分别达(4.3～6.6)×106 mol/a、(0.6～1.1)×106 mol/a,分别占河流输送量的20%和1.3%,白沙河平原地下水NO 3输送量占研究区地下水总输送量的99%.