掺固硫灰AC-13型沥青混合料配合比设计

固硫灰是循环流化床锅炉燃煤固硫产生的废弃物,具有自硬性、火山灰活性和膨胀性等特性,若以其替代矿粉制备沥青混合料并用于道路工程建设中,将有望为固硫灰处理处置提供新途径。选用固硫灰做填料等量替代普通矿粉,通过马歇尔实验研究固硫灰不同替代量(0%、25%、50%、75%、100%)对AC-13型沥青混合料性能的影响,并对机理进行了分析。结果表明,掺固硫灰沥青混合料在一定油石比范围内均能满足现行规范要求,与普通矿粉沥青混合料相比,掺固硫灰沥青混合料水稳定性良好,压实度相同时,掺固硫灰沥青混合料具有更好的抗车辙性。     

北京城市地表河流硝酸盐氮来源的氮氧同位素示踪研究

为了有效防治城市地表河流硝酸盐氮的污染并进行针对性水体治理,利用δ15N和δ18O双同位素示踪技术,对北京城区地表河流硝酸盐污染进行了溯源。选取北京9条河流的10个监测点,分析了硝酸盐氮污染的浓度分布特征,并运用MAT253氮氧双同位素技术解析了硝酸盐的各种来源。研究结果表明,北京城区地表河流硝酸盐氮污染自上游至下游逐渐加重,上游8个监测点的硝酸盐氮平均浓度在0.7～3.4 mg/L之间,下游东护城河和通惠河2处硝酸盐氮的浓度均值分别达7.6 mg/L和7.0 mg/L。利用同位素质谱MAT253分析,得知北京城区地表河流δ15N值总体分布范围为-1.2‰～+28.88‰,δ18O值分布范围为+0.09‰～+6.62‰,依据δ15N和δ18O的特征范围,得出北京城区地表河流硝酸盐来源主要是粪肥和污水。     

原位帽封材料对水体中Pb(Ⅱ)与Cd(Ⅱ)静态吸附

用无纺布包裹珊瑚和丙烯酸树脂制成帽封材料,将底泥中重金属离子原位固定的同时吸附水体中的重金属离子pb2和Cd2.通过红外光谱,电镜扫描和火焰原子吸收仪器来分析该帽封材料的吸附性能.通过改变pH值,吸附剂投放量来检测其吸附效果.结果表明,该帽封材料在pH等于5的时候,Cd2最大吸附量达到434.67 mg/g,pb2+最大吸附量达到524.27 mg/g.pH和吸附剂量保持不变,随着底物浓度增加吸附量也增加;电镜扫描图和红外光谱图表明,该材料能很好地吸附重金属离子.     

不同利用方式土壤中磷的吸附与解吸特性

研究不同利用方式土壤对磷的吸附解吸特性及其影响因素。采用室内恒温培养法研究了湖南典型土壤(红壤、潮土和紫色土)的不同利用方式(旱地、水田)土壤对P的吸附和解吸过程。土壤对磷的吸附解吸过程是分阶段进行的,用Langmuir方程拟合程度比Freundlich方程高,相关系数均在0.90(P<0.05)以上;从最大吸附量(Qm)、吸附反应常数(K)和最大缓冲容量(MBC)3项吸附参数综合考虑,旱地对P的吸附无论在强度还是容量方面均大于同母质的水田土壤;解吸率随着吸附量的增加而增大,其大小为旱地<水田。Qm与<0.002 mm粘粒及无定形铁含量呈正相关,相关系数分别为0.95和0.94(P<0.05)。不同利用方式土壤P吸附解吸特性差别较大,针对不同土壤应采取不同的磷素管理措施以实现作物增产和保护环境的双重效益。     

反渗透膜系统污染物的形貌及组成分析

采用SEM、能谱分析(EDS)、FTIR以及GC-ICP-MS等方法对被污染反渗透膜表面的无机污染物、有机污染物和微生物进行了识别和分析。研究结果表明:反渗透膜表面的无机污染物主要为CaCO3、CaSO4、MgSO4、Ca3(PO4)2、SiO2胶体和Al(OH)3胶体物质;有机污染物主要为石油类和环烷类有机物(如亚甲基环戊烷)等;被污染反渗透膜表面的微生物含量为5.3×109CFU/m2。     

Major Energy Plants and Their Potential for Bioenergy Development in China

China is rich in energy plant resources. In this article, 64 plant species are identified as potential energy plants in China. The energy plant species include 38 oilseed crops, 5 starch-producing crops, 3 sugar-producing crops and 18 species for lignocellulosic biomass. The species were evaluated on the basis of their production capacity and their resistance to salt, drought, and/or low temperature stress. Ten plant species have high production and/or stress resistance and can be potentially developed as the candidate energy plants. Of these, four species could be the primary energy plants in China: Barbados nut (Jatropha curcas L.), Jerusalem artichoke (Helianthus tuberosus L.), sweet sorghum (Sorghum bicolor L.) and Chinese silvergrass (Miscanthus sinensis Anderss.). We discuss the use of biotechnological techniques such as genome sequencing, molecular markers, and genetic transformation to improve energy plants. These techniques are being used to develop new cultivars and to analyze and manipulate genetic variation to improve attributes of energy plants in China.     

低pH生物滤池处理甲苯废气

采用低pH生物滤池处理甲苯废气。实验结果表明,低pH生物滤池对甲苯有较好的去除效果,当甲苯废气进气流量为420L/h、进气甲苯质量浓度为200~700mg/m3时,稳定运行阶段,甲苯平均去除效率在98%以上,出气甲苯质量浓度为0~30mg/m3。低pH生物滤池中,CO2的产生量与甲苯降解量的比(物质的量比)为2.60,小于理论值3.35。经过长时间运行,低pH生物滤池内的优势微生物由刚开始接种时的以异养细菌为主演变为真菌为主,优势真菌菌株分别属于白地霉(Geotrichum candidum)、产黄青霉(Penicillium chrysogenum)和黑曲霉(As-pergillus niger)。优势异养细菌为恶臭假单胞菌(Pseudomonas putida)。     

Removal of PCDD/Fs from contaminated sediment and released effluent gas by charcoal in a proposed cost-effective thermal treatment process

A novel cost-effective thermal treatment technology has been proposed for the removal of PCDD/Fs from contaminated sediment and released effluent gas using charcoal as both an adsorbent and a thermal source. When a reactor was used for thermal treatment, the PCDD/Fs removal efficiency exceeded 98% from the sediment at the three different air superficial velocities employed in this study. The total PCDD/F international toxic equivalent (I-TEQ) contents, both in the treated sediments and effluent gas, were below the Japanese emission standard limit. Analysis of the PCDD/F contents in different fractions showed that large quantities of PCDDs but not PCDFs were evaporated from the sediment and adsorbed in the moist sediment column. This difference was attributed to the formation of PCDDs from pentachlorophenol (PCP) during the cooling process following the thermal treatment process in the reactor. This proposed thermal process provides a promising alternative to the conventional methods.     

Capability of novel ZnFe₂O₄ nanotube arrays for visible-light induced degradation of 4-chlorophenol

Highly ordered ZnFe₂O₄ nanotube arrays were successfully prepared by anodic aluminum oxide templates from sol-gel solution. The results from environmental scanning electron microscopy and X-ray photoemission spectroscopy indicated that the as-prepared samples were vertically aligned spinel ZnFe₂O₄ nanotube arrays, and the nanotubes were uniform along the axial direction with an average diameter of approximately 200 nm. The absorption edge of ZnFe₂O₄ nanotube arrays shifted to a higher energy in the UV-Vis absorption spectrum compared with that of ZnFe₂O₄ nanoparticles film. The synthesized ZnFe₂O₄ nanotube arrays exhibited excellent photocatalytic capability for degradation of 4-chlorophenol under visible-light irradiation. The main intermediate degradation species of 4-chlorophenol identified by liquid chromatography-mass technique were benzoquinone, hydroquinone, hydroxybenzoquinone and 2-peroxy-o-dihydroxybenzene. The degradation pathways of 4-chlorophenol under visible-light irradiation was derived and discussed by interpreting the observations of the intermediate species in the photocatalytic reactions.