碳酸根对磷酸钙沉淀反应回收磷的影响简

以模拟的厌氧消化液为处理对象，通过小试实验，考察不同初始磷浓度C_P、Ca/P物质的量比、pH和温度下，碳酸根（CO₃^2-）对磷酸钙沉淀反应回收磷的影响；利用扫描电镜（SEM）、X射线衍射仪（XRD）和傅里叶变换红外光谱（FTIR）对沉淀产物进行表征。结果表明，高浓度的CO₃^2-对以磷酸钙沉淀反应去除和回收磷的效率影响较大；C_P相同时，CO₃^2-浓度（C_CO3^2-）越大，P的去除率越低，低C_P（20 mg/L）时尤为显著；当C_CO3^2-相同时，随着C_P的增大，反应速率加快，P的去除率逐渐升高，但升高幅度越来越小；增大Ca/P比和pH能提高P的去除率，降低CO₃^2-对磷酸钙沉淀反应的抑制作用，综合考虑实际效果，应选择Ca/P比为3.33，pH为9.0作为适宜的反应条件；升高温度对降低CO₃^2-对磷酸钙沉淀反应的抑制作用贡献不大。在C_P为60 mg/L，Ca/P比为1.67，pH为9.0，温度为20℃的条件下，当C _CO3^2-为0时，得到的沉淀产物主要为羟基磷灰石HAP；当C _CO3^2-为30 mmol/L时，得到的沉淀产物为磷酸钙和碳酸合磷灰石的混合物。     

The Fallacies of Concurrent Climate Policy Efforts

Climate policy has assumed an extreme degree of urgency in the international debate in recent years. This article begins by taking a critical look at the scientific underpinnings of the efforts to stabilize the climate. It points to several serious question marks on the purported relationship between greenhouse gas emissions and global warming, and expresses distrust about claims of impending catastrophes related to rising sea levels, hurricanes, and spread of infectious disease. It then reviews the concurrent climate policy efforts and concludes that they are incoherent, misguided and unduly costly, and that they have so far had no perceptible impact on anthropogenic greenhouse gas emissions. The exceedingly ambitious policy plans currently under preparation suffer from similar fallacies. For these reasons, but also because of the remaining scientific doubts and the exorbitant costs that have to be incurred, skepticism is expressed about the preparedness to implement the climate policy plans currently on the table.     

旅游相关企业松散型纵向一体化战略联盟研究

我国旅游产业发展水平不高,其深层次的原因是旅游产业链中存在着严重的纵向外部性问题。在借助演化博弈思想对旅游产业链中经济主体的决策行为进行深入分析后,认为纵向一体化战略联盟能有效提升旅游产业链和相关主体利益,在传统的纵向一体化联盟基础上提出了一种界于市场和企业,但又不同于完全一体化的"混合"组织形式——松散型纵向一体化战略联盟,并初步描绘了这一联盟模式的构建过程。     

Enantioselectivity of racemic metolachlor and S-metolachlor in maize seedlings

Chiral herbicides may have enantioselective effects on plants. In this study, we assessed and compared the enantioselectivity of the chiral herbicides rac-metolachlor and S-metolachlor to maize seedlings. The superoxide dismutase activity (SOD) activity of roots and stem leaves treated by rac-metolachlor was 1.38 and 1.99 times that of roots and stem leaves treated by S-metolachlor. The peroxidase activity (POD) activity of roots and stem leaves was 1.48 and 2.79 times that of roots and stem leaves treated by S-metolachlor, respectively, while the catalase activity (CAT) activity was 4.77 and 8.37 times greater, respectively. The Hill reaction activity of leaves treated by rac-metolachlor were 1.45, 1.33, and 1.14 times those treated by S-metolachlor with treatments of 18.6, 37.2, and 74.4 μM. The differences observed between treatments of rac- and S-metolachlor were significant. Significant differences in maize seedling morphology were also observed between rac- and S-metolachlor treatments. The degradation rate of S-metolachlor in roots was greater than that of rac-metolachlor. The half-lives of rac- and S-metolachlor were 80.6 and 60.3 h at 18.6 μM; 119.5 and 90 h at 37.2 μM; and 169 and 164.8 h at 74.4 μM, respectively. Using the liquid chromatography-mass spectrometry method, hydroxymetolachlor, deschlorometolachlor and deschlorometolachlor propanol were considered to be possible metabolites. We determined the enantioselective toxicity of rac- and S-metolachlor to maize and speculated on the proposed metabolic pathway of metolachlor in maize roots. These results will help to develop an understanding of the proper application of rac- and S-metolachlor in crops, and give some information for environmental safety evaluation of rac- and S-metolachlor.     

天然和CPB改性沸石对Hg^2＋的吸附特征

通过静态实验研究溴代十六烷基吡啶（CPB）改性沸石和天然沸石对废水中Hg^2＋的吸附特性，探讨了吸附动力学、吸附平衡和吸附热力学机制。研究表明：Langmuir方程能较好地描述2种沸石对Hg^2＋的吸附，CPB改性沸石对Hg^2＋的吸附率得到显著提高。实验条件下，改性沸石对Hg^2＋的吸附率从67．5％提高到98．9％，吸附容量从0．521mg／g提高到3．07mg／g。利用准一级动力学方程、假二级动力学方程、颗粒内扩散模型和Elovich方程分别对动力学过程进行拟合，发现2种沸石对Hg^2＋的吸附均满足假二级动力学方程，且离子的颗粒内扩散对整个吸附过程有影响。动力学拟合、D-R方程拟合和热力学研究综合表明：2种沸石对Hg^2＋的吸附既存在化学吸附又存在物理吸附，吸附吉布斯自由能变（△G^0）、焓变（△H^0）、熵变（△S^0）均小于0，反应为自发的放热反应，低温有利于吸附的进行。     

云南近期3次中强震的天文背景

分析了澄江地震至丘北地震间云南发生的3次中强震时的天体位置、地球自转与太阳活动等天文背景，分析结果表明，尽管这3次地震的震级都较小，但都发生在震中所受引潮力变化较大时刻和太阳活动局部下降时段。     

硝酸盐对反硝化除磷过程的影响分析

在厌氧/缺氧间歇反应器内考察了硝酸盐进水浓度及进水方式对反硝化除磷过程的影响。结果表明：在缺氧阶段，反硝化除磷菌(DPBs)可将硝酸盐转化为亚硝酸盐，当硝酸盐浓度较低时，DPBs以亚硝酸盐为电子受体吸磷。进水COD浓度为220 mg/L，正磷浓度为6.8 mg/L，硝酸盐初始浓度为26 mg/L时，系统达到最佳脱氮除磷效果，期间亚硝酸盐浓度积累至10.71 mg/L。采用连续流投加硝酸盐的方式更利于氮磷的高效去除。     

Closing a Loop: Substance Flow Analysis of Nitrogen and Phosphorus in the Rainbow Trout Production and Domestic Consumption System in Finland

Ongoing eutrophication is changing the Baltic Sea ecosystem. Aquaculture causes relatively small-scale nutrient emissions, but local environmental impact may be considerable. We used substance flow analysis (SFA) to identify and quantify the most significant flows and stocks of nitrogen (N) and phosphorus (P) related to rainbow trout aquaculture in Finland. In 2004–2007, the input of nutrients to the system in the form of fish feed was 829 t N year⁻¹ and 115 t P year⁻¹. Around one-fifth of these nutrients ended up as food for human consumption. Of the primary input, 70% ended up in the Baltic Sea, directly from aquaculture and indirectly through waste management. The nutrient cycle could be closed partially by using local fish instead of imported fish in rainbow trout feed, thus reducing the net load of N and P to a fraction.