Electrochemical degradation of p-nitrophenol with different processes

The electrochemical degradation of p-nitrophenol (PNP) under di erent conditions was investigated. The electrochemical behavior of PNP and its reduction product p-aminophenol (PAP) on stainless steel cathode and Ti/Pt anode through cyclic voltammetry were observed. Electrochemical degradation process was performed in an undivided cell and 92% PNP was removed corresponding to a 22% total organic carbon removal. A divided cell was also used and it was found that PNP degradation was mainly attributed to cathodic reduction, while anodic oxidation was responsible for PNP removal due to the reaction with hydroxyl radicals and surface oxide generated on the anode. The sequential electrolytic processes, reduction-oxidation and oxidation-reduction, were compared in the divided cell. In the case of reduction-oxidation process, the total organic carbon removal reached 40%, but PNP removal was the same with the undivided cell. A black deposit was found in the e uent and identified by Fourier transform infrared spectroscopy as a polymer of PAP produced by the 1,4-addition reaction of quinoneimine. Intermediates left in the solution such as hydroquinone, p-benzoquinone and PAP were determined by high performance liquid chromatography. Whereas, the oxidation-reduction process proved unsatisfying.     

Fe3+、Ce3+掺杂TiO2光催化降解气相二苯并呋喃

以气相二苯并呋喃为研究对象,考察了在TiO2、Ce3+/TiO2和Fe3+/TiO2 3种不同光催化剂作用下,反应物初始浓度、湿度、气体循环速率和光强等因素对间歇式光催化反应速率的影响,并建立了估算和测定二苯并呋喃光催化反应常数和Langmuir吸附常数的数学模型和方法.结果表明,Fe3+和Ce3+掺杂修饰TiO2光催化剂后,提高了对二苯并呋喃的光催化降解活性,其中Fe3+/TiO2光催化活性最高;随着二苯并呋喃初始浓度的增大,其光催化降解速率也随之增大;适量的水蒸气存在可以促进二苯并呋喃的降解,但当水蒸气过量后,反而阻碍二苯并呋喃光催化降解;随着气体循环速率加快和光强的增大,二苯并呋喃光催化降解初始速率也随之增大;TiO2、Ce3+/TiO2和Fe3+/TiO2光催化降解二苯并呋喃反应速率常数k分别为34.54×10-5、36.23×10-5和37.95×10-4mg.(min.m2)-1.     

东海西湖凹陷区溢油行为数值模拟

研究东中国海中日共同开发区附近海域溢油污染的问题,在模拟水动力场的基础上模拟了海上溢油漂移扩散情况。在表层流场和风场的作用下漂移,而油膜的扩展则通过油粒子的随机走动来实现。本文以东海西湖凹陷原油为溢油油种,通过模拟分析不同季节和不同风况下的溢油事故,对溢油油膜的扫海范围进行了分析。     

工业园区固体废物生命周期管理边界模型的构建

工业园区内企业众多,副产品和固体废物排放量犬,生产过程也复杂,采用生命周期对固体废物进行管理显得也复杂很多。该文从构建工业园区固体废物生命周期管理边界模型出发,并以电子信息产业园区为例,试着将固体废物与不同的企业或生产过程紧密耦合,构建可行的较稳定的生命周期管理边界模型。     

污水处理市场化改革与运营监管探析——以深圳市龙岗区为例

运营监管是污水处理市场化改革中的重要问题。文章在分析污水处理市场运营监管必要性的基础上,围绕监管制度建设问题,通过对深圳市龙岗区污水处理市场化进程、监管体系的建立和运营监管措施的实证分析,总结经验及不足,并从中得出建立健全污水处理市场化运营监管体制机制的相应思路和建议。     

洞庭湖水质及富营养状态评价

根据2009年洞庭湖水质监测数据,参照GB3838-2002中Ⅲ类水质标准,采用单因子评价法、综合污染指数法和综合营养指数法对洞庭湖水质及富营养状况进行评价。单因子法结果表明,在总氮、总磷不参与评价的情况下,2009年洞庭湖湖体水质整体为优;湖水中总氮、总磷污染严重,监测断面总磷浓度均劣于Ⅲ类水质要求。综合营养指数评价结果表明,洞庭湖水质处于中营养和轻度富营养水平;综合污染指数评价进一步表明,洞庭湖湖体水质劣于入湖口水质,入湖口水质劣于出湖口水质的分布特征。     

应用高密度电法探测北京南口-孙河隐伏断裂

举例说明了高密度电法在北京南口-孙河活隐伏活动断层勘测中的应用,展现高密度电法在断层定位中的广阔应用前景。简单介绍了高密度电法的基本原理。视电阻率异常剖面揭示南口-孙河断裂为正断层,北东盘上升,南西盘下降,推测断裂倾角60°～68°。视电阻率异常剖面与钻孔资料对应较好,并与钻探资料分析的断裂活动特性基本吻合。     

Aquatic ecological health assessment of Shaying River Basin based on indices of physico-chemistry and aquatic organisms北大核心CSCD

With a variety of ecosystem services, river ecosystem plays an important role in the process of human society development. On the other hand, health condition of most aquatic ecosystems is seriously threatened by human activities. Restoring and maintaining a healthy ecosystem has already become a vital goal of river management. As a basis of river management, river health assessment is therefore particularly important. Based on indices of physics, chemistry and aquatic organisms, this research tried to establish a comprehensive evaluation system of aquatic ecological health suitable for the situation of Shaying River Basin. The system included 6 factors including riparian zone, river morphology, nutrients, oxygen balance, periphyton and benthic macroinvertebrates, which were defined into 19 indices reflecting the aquatic ecological health from different aspects. The assessment results indicated that the health condition of overall basin was normal, varying among different parts of the region, with Shahe River, Lihe River and Beiru River in the upper part sub-healthy, and Jialu River in the same part sub-sick. The middle region was generally in normal or sub-sick level; the health condition of the lower part was comparatively better due to a good condition. Within the indices, the nutrients and benthic macroinvertebrates were the major constraining factors to the health condition of Shaying River Basin for their poor health condition. The health conditions showed significant differences among the rivers (P < 0.01), with Jialu River being the worst. The result indicated that the aquatic ecological health of Shaying River Basin is affected by many factors, with urban and industrial sewage being the main ones, And that different protective measures should be employed for rivers of different conditions. The result can provide theoretical basis for the ecological restoration of Shaying River Basin and reasonable exploitation and conservation of the water resource of the whole Huaihe River Basin.     

Removal of tetracycline from aqueous solution by a Fe3O4 incorporated PAN electrospun nanofiber mat

Pollution of antibiotics, a type of emerging contaminant, has become an issue of concern, due to their overuse in human and veterinary application, persistence in environment and great potential risk to human and animal health even at trace level. In this work, a novel adsorbent, Fe₃O₄ incorporated polyacrylonitrile nanofiber mat (Fe-NFM), was successfully fabricated via electrospinning and solvothermal method, targeting to remove tetracycline (TC), a typical class of antibiotics, from aqueous solution. Field emission scanning electron microscopy and X-ray diffraction spectroscopy were used to characterize the surface morphology and crystal structure of the Fe-NFM, and demonstrated that Fe-NFM was composed of continuous, randomly distributed uniform nanofibers with surface coating of Fe₃O₄ nanoparticles. A series of adsorption experiments were carried out to evaluate the removal efficiency of TC by the Fe-NFM. The pseudo-second-order kinetics model fitted better with the experimental data. The highest adsorption capacity was observed at initial solution pH 4 while relative high adsorption performance was obtained from initial solution pH 4 to 10. The adsorption of TC on Fe-NFM was a combination effect of both electrostatic interaction and complexation between TC and Fe-NFM. Freundlich isotherm model could better describe the adsorption isotherm. The maximum adsorption capacity calculated from Langmuir isotherm model was 315.31 mg/g. Compared to conventional nanoparticle adsorbents which have difficulties in downstream separation, the novel nanofiber mat can be simply installed as a modular compartment and easily separated from the aqueous medium, promising its huge potential in drinking and wastewater treatment for micro-pollutant removal.     

Removal of tetracycline from aqueous solution by a Fe3O4 incorporated PAN electrospun nanofiber mat

Pollution of antibiotics, a type of emerging contaminant, has become an issue of concern,due to their overuse in human and veterinary application, persistence in environment and great potential risk to human and animal health even at trace level. In this work, a novel adsorbent, Fe3O4 incorporated polyacrylonitrile nanofiber mat(Fe-NFM), was successfully fabricated via electrospinning and solvothermal method, targeting to remove tetracycline(TC), a typical class of antibiotics, from aqueous solution. Field emission scanning electron microscopy and X-ray diffraction spectroscopy were used to characterize the surface morphology and crystal structure of the Fe-NFM, and demonstrated that Fe-NFM was composed of continuous, randomly distributed uniform nanofibers with surface coating of Fe3O4 nanoparticles. A series of adsorption experiments were carried out to evaluate the removal efficiency of TC by the Fe-NFM. The pseudo-second-order kinetics model fitted better with the experimental data. The highest adsorption capacity was observed at initial solution p H 4 while relative high adsorption performance was obtained from initial solution p H 4 to 10. The adsorption of TC on Fe-NFM was a combination effect of both electrostatic interaction and complexation between TC and Fe-NFM. Freundlich isotherm model could better describe the adsorption isotherm. The maximum adsorption capacity calculated from Langmuir isotherm model was 315.31 mg/g. Compared to conventional nanoparticle adsorbents which have difficulties in downstream separation, the novel nanofiber mat can be simply installed as a modular compartment and easily separated from the aqueous medium, promising its huge potential in drinking and wastewater treatment for micro-pollutant removal.