人工回灌过程中胶体对CHCl3形成机制的影响

以揭示回灌过程中CHCl₃耦合胶体效应影响下的二次形成作用为研究目标,通过批实验分析有、无胶体条件下不同水化学条件对CHCl₃生成速率及生成量的影响,并结合切向流超滤技术和原子力电镜扫描（AFM）表征手段分析CHCl₃-SiO₂胶体协同作用模式.结果表明,CHCl₃的生成量随着反应时间的增加而增大,并在特定的反应时间内,高氯/TOC比率、高pH值、低离子强度均会促进CHCl₃的二次形成.SiO₂胶体的存在会影响反应前体物的吸附,使各时刻CHCl₃生成作用均受到抑制,并对水中的CHCl₃有强吸附作用.结果可为人工回灌过程中CHCl₃的二次形成作用提供科学参考.     

Waste control by waste: efficient removal of bisphenol A with steel slag,a novel activator of peroxydisulfate

Activated persulfates are efficient reagents for oxidation of organic contaminants and water treatment. Various compounds are currently used to activate persulfates, but there is a need for cheap and efficient activators. Here, we report the first use of steel slag, an industrial solid waste, as a solid activator for peroxydisulfate activation. We tested this system for bisphenol A degradation. Results indicate that about 70% of bisphenol A can be removed within 1 h. Conditions were 50 μg/L of bisphenol A, 2 g/L of peroxydisulfate, 3 g/L of steel slag and temperature of 298 K. The components and surface morphology of unused and recycled steel slag were analyzed by X-ray diffraction and scanning electron microscopy, whereas the main reactive oxygen species were elucidated by using radical scavengers. Findings show that both base oxides and iron oxides are responsible for peroxydisulfate activation. A redox mechanism involving liquid and solid phases is proposed. Overall, this study reveals the successful recycling of steel slag to activate persulfates for water treatment, following the principle of ‘waste control by waste.’     

Typhoon hazards in the Shanghai area

There are three major typhoon hazards that apply to the Shanghai area. First, galeforce winds can damage buildings and service facilities. The most severe damage from this occurs only when a typhoon strikes Shanghai directly. Second, both the urban and rural sections of Shanghai are liable to flooding during typhoon seasons. These floods occur when typhoon-induced storm surges coincide with high spring tides and meet with high discharges from the river network as a result of the typhoon downpours. Third, typhoon-induced torrential rain has caused waterlog hazards, particularly in the most densely populated parts of Shanghai. The waterlog hazard has been exacerbated by land subsidence and poor management of pumping systems. In order to prevent disasters happening and reduce the scale of damage, the government has issued construction guidelines and invested in flood defences. Further measures are to be brought in including engineering projects, educational programmes and insurance policies.     

农药对陆生生物的生态毒性及风险评估

农药的使用会对非靶标生物造成影响,由此世界各国都采取了风险控制手段以预防农药造成的生态危害。本文综述了欧洲、美国和日本针对农药开展的陆生生态系统风险评估方法,包括陆生非靶标生物、风险评估模型、风险评估的基本方法及生态毒性的评价指标。同时分析了农药登记管理对陆生生生物的生态毒性及风险评估中存在的科学问题,且提出了方法学的发展方向。     

渔阳太守张堪

侯风地动仪的发明者——东汉伟大的科学家张衡,早已广为人知。对于张衡的爷爷,很多读者却比较陌生。《后汉书·张衡传》里也只有7个字: “祖父堪,蜀郡太守。”其实,张堪在《后汉书》里也有传,记载也比较详细:张堪,字君游, 南阳郡宛县(今河南南阳市)人。父母双亡后,张堪将数百万遗产让与侄子, 16岁到长安学习儒学,品行出众,被老     

钢渣在建筑材料中的易磨性和稳定性研究

针对目前钢渣处理和钢渣综合利用中存在的问题,指出对钢渣实施改质处理是提高钢渣资源化率的有效途径。通过高温成分改质、电子束辐照改质钢渣,和对钢渣改质机制的研究,解决钢渣应用中的体积不稳定性、易磨性和活性问题。该技术的研究可为寻求大宗量应用钢渣的途径和开发出高质量的钢渣产品奠定基础。     

Improvement of detection method of Cryptosporidium and Giardia in reclaimed water

Cryptosporidium and Giardia are two typical species of pathogenic protozoans that seriously endanger water quality. Previous works indicated that detection of Cryptosporidium and Giardia with modified United States Environmental Protection Agency (USEPA) method-1623 using a membrane filtration-elution for sample concentration attained better recovery and lower cost compared to the USEPA method-1623. Several improvements of membrane filtration-elution step as well as immunomagnetic separation (IMS) steps were investigated and an optimized method for detection of Cryptosporidium and Giardia in wastewater reclamation system was recommended in this paper. The experimental results show that an overnight soak of the membrane after scraping and vortex agitation before elution could enhance and stabilize the recovery. Increasing turbidity to 4 NTU by adding kaolin clay before filtration could effectively improve the recovery of low-turbidity water. Washing the concentrate after centrifugation and twice acid dissociation both reduced the impact of water quality to protozoan recovery. Protozoans in different water samples were determined by this optimized method, and the recovery of Cryptosporidium and Giardia were above 70% and 80% respectively, much higher than the acceptance of method-1623.     

考虑径向温度效应的能源桩荷载传递分析方法研究

针对能源桩受温度作用影响时的承载特性难以量化,提出考虑径向温度效应的荷载传递法对能源桩热-力耦合作用下的受力特性进行研究,评估温度变化对能源桩的影响,研究桩身轴力、桩侧摩阻力的分布状态,并以昆山能源桩的现场测试为依托,验证了本文方法的可行性。计算结果表明,温度作用对能源桩桩身应力应变状态有显著影响,当桩体受极限荷载与温度作用时,侧阻力发挥的作用几乎不大,在降温作用下能源桩桩顶会产生残余变形,因此在能源桩设计时应以降温作用时的沉降值为标准进行折减,考虑能源桩的设计承载力。     

Q345R在微量小分子有机酸中的腐蚀行为研究

本文通过腐蚀失重试验、腐蚀产物分析和交流阻抗谱研究了Q345R在不用的微量的两种小分子有机酸(甲酸和乙酸)中的常温25℃和液相高温85℃中腐蚀行为.根据试验结果可知,随着浓度的逐渐升高,Q345R在两种小分子有机酸腐蚀速率均有所升高,腐蚀产物逐渐增厚,腐蚀形貌未发生明显变化.根据电化学试验结果,在25℃环境温度下,小分子有机酸对Q345R的腐蚀剧烈程度随时间明显降低,并且表面吸附作用明显减弱.在85℃环境温度下,小分子有机酸对Q345R的腐蚀剧烈程度随时间变化不大,反应行为也未发生明显的变化.这说明在较高的温度下,随着反应激活能提高,扩散条件并非控制腐蚀反应的最主要因素,腐蚀行为也与较低环境温度下产生显著的区别.