耐镉浮萍筛选、鉴定及其对镉的富集效果

近年来,水体镉污染日益严峻,筛选超富集植物用于其治理具有重要意义。本研究以90个浮萍株系为实验材料,采用30 mg·L^-1的镉处理7 d,获得7个镉耐受优势株系。通过Blast比对和构建系统发育树鉴定该7个浮萍株系的种属,确定为Spirodela polyrhiza、Lemna japonica、Lemna minor和Landoltia punctata。通过低质量浓度(0.5 mg·L^-1)和高质量浓度(10 mg·L^-1)镉处理7 d,进一步比较和研究了7个优势株系对镉的富集效果。结果表明,低浓度镉处理后,5个株系的镉富集量超过100 mg·kg^-1;高浓度镉处理后,7个浮萍株系的镉富集量超过1 200 mg·kg^-1,生物富集系数大于120,对水体中镉的去除率高于70%。其中,4号株系(L. japonica)为本次筛选出的最佳株系,其镉富集量、生物富集系数和对水体中镉的去除率分别达到2 834.30 mg·kg^-1、283.43和82.50%。     

La0.5Ca0.5Ni0.5Fe0.5O3催化剂的制备及其对生物质热解特性的影响

采用共沉淀法制备了La0.5Ca0.5Ni0.5Fe0.5O3纳米粉体,并通过XRD、SEM、TG-DTA等手段对所合成的样品进行了分析和表征.结果表明,采用碳酸铵作为共沉淀剂、聚乙二醇为分散剂,在600℃下煅烧6h可作为实验制备该催化剂粉体的最优条件.用实验室自制热解催化炉验证其对生物质热解的效果,实验结果表明,采用La0.5Ca0.5Ni0.5Fe0.5O3催化剂,生物质热解过程中焦油产量降低了12.4%,气体产率提高了14.0%,气体产物中一氧化碳、甲烷含量分别从33.8%和15.1%提高到了38.5%和18.4%,燃气的品质大大提升.     

空气特性对工业炉炉膛辐射换热的分析计算

首先进行天然气的燃烧计算,根据炉膛热平衡得到理论燃烧温度计算式,给出了空气特性变化对理论燃烧温度的影响;然后根据炉内辐射换热原理,计算出工业炉炉膛的辐射换热系数C,给出更加适合工业炉炉膛辐射传热计算的公式,最后结合实例具体计算了空气特性对炉内辐射换热大小的影响,为工业炉炉膛的优化设计提供参考依据。     

Environmental biogeochemical behaviors of rare earth elements in soil–plant systems

With the continual increase in the utilization of rare earth elements (REEs) for industrial and agricultural purposes in China, the research into the environmental biogeochemical behavior of REEs has become a pressing issue. The REEs’ content in soil and various parts of wheat under different conditions in soil–plant systems were measured by INAA and ICP-MS. The results showed four aspects. (1) The mean value of total REEs in soil of China was 176.8 mg kg⁻¹. The mean ratio of ΣLREE/ΣHREE in soils was 8.0 and cerium accounts for 42% of the total REEs. The content of REEs in wheat seed ranged between 10⁻¹¹ and 10⁻⁸ g g⁻¹, 3–4 orders of magnitude lower than that in soil. (2) The REEs contents in ryegrass, especially in roots, were significantly related to that of soil. The bioavailability of REEs in soil mainly depended on the exchangeable fraction of REEs, which was strongly affected by the physico–chemical properties of the soil. (3) Long-term foliage-dressing with Changle microfertilizer of REEs did not affect the contents and distribution patterns of REEs in soil. At the maturing stage of spring wheat, the REEs content was in the order of root > leaf >stem and crust. Compared with the control, foliage-dressing has a higher accumulation of REEs in root and leaf. However, no significant difference was found in stem and crust between the two treatments. (4) There was no significant accumulation with the soil-dressing method. When comparing controls in both foliage- and soil-dressing methods, no distinct residue of REEs in grains was found.     

滇池沉积物有机磷形态分级特征

考察沉积物磷对湖泊富营养化贡献时,大量研究涉足无机磷,对有机磷的研究十分薄弱.针对滇池的33个沉积物样品,采用有机磷分级提取方法,将沉积物有机磷分为活性磷、中等活性磷、非活性磷等三种具有不同稳定性的有机磷.结果表明:排除滇池西北部外源污染严重的样品后,沉积物有机磷与总磷有自北向南逐渐降低的变化趋势,有机质与总磷、活性有机磷、中等活性有机磷以及非活性有机磷都表现出了显著相关关系.沉积物活性有机磷和中等活性有机磷与NaHCO3提取无机磷均显著相关,说明二者具有潜在的生物有效性.     

几种氯代苯甲酸的生物可降解性及其动力学

2 ,4-二氯苯甲酸、4-氯苯甲酸、3-氯苯甲酸、2 -氯苯甲酸经过污泥的驯化作用可以达到降解 ,但是不同的接种污泥对相同的底物达到同样的降解效果所需的驯化时间不同 ,经 9d驯化的膜生物反应器中的污泥即具有经 2 8d驯化的一般活性污泥相当的降解活性 ,但 4种氯代苯甲酸的生物可降解性次序是一定的 :2 ,4-二氯苯甲酸 >4-氯苯甲酸 >3-氯苯甲酸 >2 -氯苯甲酸 ,不随污泥的驯化期及接种污泥而改变 .降解动力学研究表明 ,这 4种氯代苯甲酸在不同的污泥驯化期其降解动力学模式不同 ,在驯化初期底物的降解符合零级反应 ,在驯化后期符合一级反应 .     

E型树脂装置清洁生产审计介绍

对岳阳石化总厂环氧树脂厂的清洁生产审计方案的实施过程及情况进行介绍，为实现节能、降耗、减污的目的积累了经验，并取得了显著的环境和经济效益。     

Vertical distribution of polycyclic aromatic hydrocarbons in atmospheric boundary layer of Beijing in winter

Air samples were collected using active samplers at various heights of 8, 15, 32, 47, 65, 80, 102, 120, 140, 160, 180, 200, 240, 280 and 320 m on a meteorological tower in an urban area of Beijing in two campaigns in winter 2006. Altitudinal distributions of polycyclic aromatic hydrocarbons (PAHs) in atmospheric boundary layer of Beijing in winter season were investigated. Meteorological conditions during the studied period were characterized by online measurements of four meteorological parameters as well as trajectory calculation. The mean total concentrations of 15 PAHs except naphthalene of gaseous and particulate phase were 667±450 and 331±144 ng m⁻³ in January and 61±19 and 29±6 ng m⁻³ in March, respectively. Domestic coal combustion and vehicle emission were the dominant PAH sources in winter. Although the composition profiles derived from the two campaigns were similar, the concentrations were different by one order of magnitude. The higher concentrations in January were partly caused by higher emission due to colder weather than March. Moreover, weak wind, passing through the city center before the sampling site, picked up more contaminants on the way and provided unfavorable dispersion condition in January. For both campaigns, PAH concentrations decreased with heights because of ground-level emission and unfavorable dispersion conditions in winter. The concentration ratio of PAHs in gas versus solid phases was temperature dependent and negatively correlated to their octanol–air partition coefficients.     

膜分离活性污泥法的研究

提高生物难降解有机污染物的去除率，改善处理水的水质和达标率，缩小装置的占地面积，节省动力消耗是活性污泥法工艺的发展方向。本试验以膜分离单元代替普通活性污泥法的二沉池，开发了一种新的废水处理工艺。试验结果表明：膜分离活性污泥法对有机物和ＮＨ＿３－Ｎ的去除率比普通活性污泥法高，二级处理可以获得三级处理的效果。根据不同水质和工艺要求，膜孔径应小于２０μｍ，采用水反冲和药液清洗可以确保膜分离装置长期稳定的运行。