CF-TiO2的制备及其在模拟太阳光下的光催化性能

以十六烷基三甲基溴化铵(CTAB)和氟化钠分别为碳源和氟源,采用溶胶-凝胶法制备了CF-TiO2光催化剂,并对其进行了SEM、XRD、N2吸附、XPS、UV-visDRS和PL表征。研究了CF-TiO2在模拟太阳光下光催化降解亚甲基蓝溶液的活性,并讨论了氟掺杂量以及CTAB加入量对催化性能的影响。结果表明,CF-TiO2为锐钛矿型,孔结构丰富、比表面积大,氟碳共掺后使TiO2光催化剂的禁带宽度变窄为2.40 eV,在可见光区吸收增强,有效提高TiO2在模拟太阳光下的光催化活性,而且当n(F/Ti)(氟钛摩尔比)为0.1,加入碳源CTAB量为2 g时,其光催化活性最好。     

混合液回流比对改良A~2O工艺效果的调控作用

考察了不同混合液回流比(Ri)条件下,改良A2O工艺的效果。COD去除率受Ri的影响较小,Ri=200%、300%和400%时的COD去除率分别为83.3%、79.9%和84.3%。氮的去除率受其影响明显。不同Ri所引起的缺氧池硝态氮负荷以及实际水力停留时间的变化,使得TN和NH3-N的去除率呈现相互制约的关系。此外,硝酸盐作为反硝化除磷过程的电子受体,Ri为200%和300%时,其浓度较高,对应的TP平均去处率可分别高达73.3%和85.3%;而缺氧池硝酸盐浓度相对较低时(Ri=400%),TP平均去处率仅为54.4%。应对不同进水水质情况对系统脱氮除磷效率提出的要求,可选择适当的Ri,协调工艺对TN、NH3-N以及TP的去除能力,同时,满足较高出水标准的要求。     

空速和二氧化碳对沼气脱硫剂硫容确定的影响

为了弄清空速与二氧化碳含量对氧化铁脱硫剂硫容确定的影响,分别在实验气源为纯硫化氢,空速为40、80、120和160 h-1以及实验气源为二氧化碳含量分别在0%、20%、40%和80%,其余为硫化氢,空速为80 h-1条件下,对T502(粗脱硫剂)和HXT-2(精脱硫剂)2种氧化铁脱硫剂进行了不同测试条件对氧化铁硫容确定影响的研究。研究结果表明,T502和HXT-2氧化铁脱硫剂硫容测试结果随着空速和二氧化碳含量增加而减少,结果显示了在空速较低条件下(120h-1),二氧化碳含量在40%以下时对氧化铁脱硫剂硫容测试结果影响不大,但二氧化碳含量在40%以上时,对氧化铁脱硫剂硫容测试结果影响显著。     

含油浮渣制备含碳吸附剂并用于含油污水的处理

以含油浮渣为原料制备含碳吸附剂,并用于含油污水的处理。用比表面分析仪和SEM技术对吸附剂进行表征。通过正交实验和单因素实验考察吸附剂加入量、吸附时间及温度、污水pH对污水处理效果的影响。表征结果显示,含碳吸附剂碳元素含量高达90%(w)以上,表面粗糙,孔径分布以中孔为主,比表面积477.5 m2/g,碘吸附值376.48 mg/g。实验结果表明:在吸附温度30℃及时间60 min、含碳吸附剂加入量20 g/L、污水pH为7的最佳实验条件下,处理初始COD为502.12 mg/L、石油类质量浓度45.31 mg/L.的含油污水,COD和石油类的去除率分别为91.51%和87.1%,处理后的COD和石油类质量浓度分别为42.62 mg/L和5.83 mg/1,达到GB 8978—1996《污水综合排放标准》中的二级排放标准;含碳吸附剂的污水处理效果优于术质活性炭。     

三种供需关系论

本文提出在人与自然组成的环境－社会系统中存在着三种有决定性意义的供需关系,分析了这三者的异同与联系,剖析了它们在人类社会运行、发展中和及在人类社会可持续发展中的地位。     

西北地区可持续发展应注意的主要问题与对策

本文在分析西北地区社会、经济及自然状况的基础上 ,着重从资源与环境方面指出该地区可持续发展应注意的主要问题 ,并针对这些问题 ,提出以可持续发展为目标的资源、环境策略。     

长江中游水沙灾害形成机理研究

对长江中游泥沙输移规律进行了综合分析,建立了螺山至汉口河段和洞庭湖区泥沙淤积比霽与三口分沙比λS之间的定量关系.通过分析得知.洞庭湖区和螺山至汉口河段各时期多年平均泥沙淤积总量基本保持在180×106t,分沙比的减小调整了上述河段与洞庭湖区之间的淤积关系,使洞庭湖区减少淤积的泥沙转移到上述河段淤积.在此基础上对长江中游泥沙淤积与该区域水位抬高进行了计算分析.文章指出,长江中游防洪的核心是如何正确处理宜昌每年多来的180×106t泥沙淤积问题.     

The Cost of Co-viability in the Australian Northern Prawn Fishery

Fisheries management must address multiple, often conflicting objectives in a highly uncertain context. In particular, while the bio-economic performance of trawl fisheries is subject to high levels of biological and economic uncertainty, the impact of trawling on broader biodiversity is also a major concern for their management. The purpose of this study is to propose an analytical framework to formally assess the trade-offs associated with balancing biological, economic and non-target species conservation objectives. We use the Australian Northern Prawn Fishery (NPF), which is one of the most valuable federally managed commercial fisheries in Australia, as a case study. We develop a stochastic co-viability assessment of the fishery under multiple management objectives. Results show that, due to the variability in the interactions between the fishery and the ecosystem, current management strategies are characterized by biological and economic risks. Results highlight the trade-offs between respecting biological, economic and non-target species conservation constraints at each point in time with a high probability and maximizing the net present value of the fishery.     

Perfluorooctane sulfonate (PFOS) distribution and effect factors in the water and sediment of the Yellow River Estuary, China

The distribution of perfluorooctane sulfonate (PFOS) was investigated in a total of 15 water and sediment samples from the Yellow River Estuary, China in April 2011. The results indicated that the concentrations of PFOS in the water and sediment samples averaged 157.5 ng/L and 198.8 ng/g and ranged from 82.30 to 261.8 ng/L and 75.48 to 457.0 ng/g, respectively. The concentrations of PFOS in the sediment column increased from 45.32 to 379.98 ng/g with the decrease of the sampling depth, which showed that the increased PFOS pollution in the sediment appeared in this region in over recent years. The distribution coefficient (K _d) of PFOS between water and sediment linearly increased from 0.37 to 4.80 L/g as the salinity (S‰) increased from 0.18 to 4.47. Correlation analysis revealed that K _d was significantly and positively correlated to the contents of total organic carbon and clay of the sediment, and salinity. Therefore, salinity was an important parameter in controlling the sediment–water interactions and the fate or transport of PFOS in the aquatic environment. The results of this study showed that the estuary was an important sink for PFOS and suggested that PFOS might be carried with the river water and transported for long distances before it reached to the sea and largely scavenged to the sediment in the estuaries due to the change in salinity.