δ-MnO2的制备及其对水中Cd2+的吸附

利用溶液中MnSO4与KMnO4之间的氧化还原反应制备了δ-MnO2。用透射电镜和BET法对δ-MnO2进行了表征。实验结果表明：δ-MnO2比表面积为324.58m^2/g,孔体积为0.39cm^3/g,孔径为4.82nm。对Cd2＋的吸附实验结果表明：δ-MnO2对Cd2＋具有很强的吸附能力,吸附作用强烈依赖体系的pH,吸附边界pH为2.50;pH为6.05时Cd2＋的吸附率为98.5%。宏观的吸附-解吸热力学实验证明：当pH为3.30时,为可逆吸附;当pH为6.05时,吸附过程存在固体浓度效应,为不可逆吸附。吸附过程主要为一价阳离子的交换吸附。     

浮游植物群落及粒径结构对光吸收特性的影响

浮游植物吸收及比吸收等光学特性表征浮游植物对光的吸收能力,很大程度上决定了其光合作用效率和碳固定量,是浮游植物生态学、水体光学和水色遥感领域研究热点和前沿问题.本研究基于2013年天目湖7个固定采样点逐月观测数据,分析了浮游植物生物量、群落结构、吸收以及比吸收系数等生物-光学参数的季节变化特征,构建了浮游植物生物量、群...     

Physicochemical characteristics of carbonaceous adsorbent for dioxin-like polychlorinated biphenyl adsorption

It has been known that dioxin-like polychlorinated biphenyls (DL-PCBs) are present in almost all types of environments worldwide. Activated carbon treatment has been expected for the removal of DL-PCBs because it is a simple and low-cost removal technology. In the present study, the physicochemical properties of activated carbon were investigated to identify the characteristics of 16 different types of activated carbon on adsorption properties for DL-PCBs. To accomplish this, micropore volume, and pore diameter were calculated by t-plot analysis and the mesopore volume was analyzed by the Barrett-Joyner-Halenda (BJH) method. In addition, the Brunauer-Emmett-Teller (BET) surface area, pH, metal elements, and surface acid functional groups were analyzed. Then, adsorption experiments using DL-PCB in hexane solution were conducted, and the relationship between adsorption and physicochemical properties of activated carbon was investigated. The results showed that activated carbons having a surface area of 700-1200 m² g⁻¹ and micropores with diameters of about 0.7-0.8 nm exhibited high activity for the adsorption of PCBs. The results also clearly showed that the mesopore volume of activated carbon influenced the adsorption rate and the equilibrium adsorption.     

路堑施工中的爆破设计及安全对策

路堑施工中的爆破在我国目前的工程爆破中占很大的比例,施工中存在很多安全隐患,一旦发生事故,将会导致人员伤亡和财产损失.针对具体的路堑工程,选择合理的爆破设计参数,设计爆破网络,进行爆破施工的设计,然后确定爆破方案,进行安全校核,并运用安全评价的方法辨识施工中存在的危险有害因素,提出适当的合理的安全对策措施.     

多层采空区条件下的高速公路路堑边坡稳定性数值分析

高速公路建设过程中常穿越各种矿山采空区,采空区对路堑边坡的稳定性产生较大的影响。基于有限差分分析的快速拉格朗算法FLAC3D程序,由于具有强大的数值模拟分析功能,可以模拟多种结构形式的地质体,因而广泛应用于各种岩土工程问题。本文结合国家某重点交通项目,采用快速拉格朗算法FLAC3D程序对多层采空区条件下的某路堑边坡稳定性进行了评价,主要包括开挖、注浆和锚固等工况下路堑边坡的应力和位移分析。分析结果表明,采空区经过处理后的路堑边坡是稳定的,FLAC3D应用于多层采空区条件下的路堑边坡稳定性评价是可行的。     

汶川地震后四川省安县黄洞子沟泥石流特征

2008年5月12日汶川地震诱发了黄洞子沟流域规模巨大的大光包滑坡,部分滑体前冲堆积于沟道内,直接为后期泥石流的形成提供了丰富的松散固体物质,改变了黄洞子沟泥石流形成条件,使黄洞子沟从一条非泥石流沟演变成了一条高频泥石流沟。震后黄洞子沟几乎每年雨季都会暴发不同规模的泥石流,其中以2013年"7·09"泥石流灾害规模和危害最大。本文着重分析了黄洞子沟泥石流形成特征,并从地形、降水和地质三个方面将黄洞子沟和文家沟进行对比,得出了物源堆积体颗粒粒径与泥石流形成的关系。     

鼓泡式反应器高径比对氨法烟气脱碳性能的影响

以N2和CO2混合气模拟燃烧烟气,研究了鼓泡反应器的高径比以及反应条件对氨法烟气脱碳性能的影响。实验结果表明:在相同高径比的条件下,CO2吸收率随氨水质量分数的增加、反应温度的升高而逐渐增大,随进气CO2体积分数和模拟烟气流量的增加而逐渐减小;CO2吸收率随高径比的增加而增大,在高径比为3.98、氨水质量分数为28%、进气CO2体积分数为10%、模拟烟气流量为1.0L/min、反应温度为40℃的条件下,CO2吸收率最高可达100%。     

Tree and stand growth of mature Norway spruce and European beech under long-term ozone fumigation

In a 50- to 70-year-old mixed stand of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) in Germany, tree cohorts have been exposed to double ambient ozone (2×O₃) from 2000 through 2007 and can be compared with trees in the same stand under the ambient ozone regime (1×O₃). Annual diameter growth, allocation pattern, stem form, and stem volume were quantified at the individual tree and stand level. Ozone fumigation induced a shift in the resource allocation into height growth at the expense of diameter growth. This change in allometry leads to rather cone-shaped stem forms and reduced stem stability in the case of spruce, and even neiloidal stem shapes in the case of beech. Neglect of such ozone-induced changes in stem shape may lead to a flawed estimation of volume growth. On the stand level, 2×O₃ caused, on average, a decrease of 10.2 m³ ha⁻¹ yr⁻¹ in European beech.     

数学模拟好氧颗粒污泥的形成及水力剪切强度对颗粒粒径的影响

以生物膜数学模型和活性污泥数学模型为基础,建立好氧颗粒污泥一维数学模型,并模拟营养物质的去除、颗粒粒径变化、反应器周期表现以及好氧颗粒污泥内DO和菌群分布.模拟有机物SS浓度和出水NH4+-N浓度逐渐降低,在大约50 d左右达到稳定,50 d后模拟出水浓度分别<25 mg.L-1和<1.5 mg.L-1.模拟出水NO3--N浓度随着粒径的增加呈现降低趋势.当颗粒粒径由模拟30 d时的1.1 mm增加到100 d时的2.5 mm,颗粒污泥缺氧区面积相应增加,总氮(TN)的去除率由不到10%增加到91%左右,最终模拟出水NO3--N浓度降低到<3 mg.L-1.在好氧颗粒污泥系统内,由于氧气传质阻力,模拟颗粒污泥外层DO浓度高而内层浓度低,颗粒内可以发生同时硝化反硝化,且好氧颗粒污泥内DO特征随时间而发生变化.在好氧初期,好氧颗粒污泥代谢活性高,模拟DO传质深度大约为100～200μm;而在好氧末期,模拟DO传质深度为800μm.模拟自养菌主要分布在DO浓度高的颗粒外层,异养菌分布在整个颗粒.当水力剪切系数kde由0.25(m.d)-1逐渐增加到5(m.d)-1时,模拟颗粒平衡粒径依次由3.5 mm左右减小到大约1.8 mm.在不同水力剪切强度下模拟颗粒污泥生长特征相似,其平衡状态下粒径随曝气强度的增加而减小,可以通过控制曝气强度来控制好氧颗粒污泥的平衡粒径.