Complexes of fulvic acid on the surface of hematite, goethite, and akaganeite: FTIR observation

The present work extended our knowledge on the binding and complexation of a fulvic acid (FA) derived from leonardite and the iron oxides (hematite, goethite and akaganeite) by Fourier transform infrared spectroscopy (FTIR). As a prerequisite, the iron oxides were firstly prepared and characterized by transmission electron micrograph (TEM). All iron phases were single and well-described crystalloid. The FTIR data obtained by two different sampling preparation methods gave the consisting evidences that under our experimental conditions the interaction mechanism was to the ligand-exchange involving carboxylic functional groups of the FA and the surfaces sites of both hematite and goethite, while no complexation can be evidenced in the case of akaganeite, only surface adsorption. In general, the binding affinities of the iron oxides with the FA was in the order of hematite>goethite>akaganeite. The present method, although associated with some uncertainties, provided an opportunity to increase the knowledge in the field of the humic chemistry.     

陕西省ODS使用量分布特征的分析

通过调查陕西省消耗臭氧层物质(ODS)的销售和使用量,分析了陕西省消耗臭氧层物质的行业和地区分布特征。根据各受控物质的特点,计算了这些物质的实际使用量的臭氧消耗潜能(ODP)值。结果表明,2008年陕西省使用的ODS总量约为679.95 t,按照ODP值折算,相当于约132.76 t当量CFC-11。ODS的使用主要集中在清洗行业和制冷行业,区域重点在西安市。     

航站楼旅客群体性事件预警监控系统架构及关键技术

针对航站楼旅客群体性事件的智能化预警问题,在民用机场航站楼内的现有视频监控系统的基础上,提出旅客群体性事件预警监控系统架构和关键技术。针对航站楼内的视频监控系统的视频数据进行预处理;基于空间聚类算法,从图像中提取人群聚集特征;针对目标监控区域的历史视频和突发事件数据进行统计分析,研究正常和非正常两种情况下的人群分布特征,并建立相应的预警规则库;根据预警规则,在人群聚集特征识别的基础上,对非正常目标密集人群进行识别。该系统可根据航站楼旅客群集性事件的时空特性,针对不同事件、不同时间、不同地点采用不同的规则进行预警,提高了预警的可靠性。     

Enhanced activation of peroxymonosulfate by CNT-TiO2 under UV-light assistance for efficient degradation of organic pollutants

CNT-TiO₂ composite is used to activate PMS under UV-light assistance. Superior performance is due to the enhanced electron-transfer ability of CNT. SO₄•⁻, •OH and ¹O₂ play key roles in the degradation of organic pollutants. In this work, a UV-light assisted peroxymonosulfate (PMS) activation system was constructed with the composite catalyst of multi-walled carbon nanotubes (CNT) - titanium dioxide (TiO₂). Under the UV light irradiation, the photoinduced electrons generated from TiO₂ could be continuously transferred to CNT for the activation of PMS to improve the catalytic performance of organic pollutant degradation. Meanwhile, the separation of photoinduced electron-hole pairs could enhance the photocatalysis efficiency. The electron spin resonance spectroscopy (EPR) and quenching experiments confirmed the generation of sulfate radical (SO₄•⁻), hydroxyl radical (•OH) and singlet oxygen (¹O₂) in the UV/PMS/20%CNT-TiO₂ system. Almost 100% phenol degradation was observed within 20 min UV-light irradiation. The kinetic reaction rate constant of the UV/PMS/20%CNT-TiO₂ system (0.18 min⁻¹) was 23.7 times higher than that of the PMS/Co₃O₄ system (0.0076 min⁻¹). This higher catalytic performance was ascribed to the introduction of photoinduced electrons, which could enhance the activation of PMS by the transfer of electrons in the UV/PMS/CNT-TiO₂ system.     

Comparison of CNT-PVA membrane and commercial polymeric membranes in treatment of emulsified oily wastewater

CNT-PVA membrane was fabricated and compared with polymeric membranes. The separation performance was evaluated by homemade and cutting fluid emulsions. The three membranes show similar oil retention rates. CNT-PVA membranes have higher permeation fluxes compared with polymeric membranes. CNT-PVA membrane shows higher fouling resistance. Membrane separation is an attractive technique for removal of emulsified oily wastewater. However, polymeric membranes which dominate the current market usually suffer from severe membrane fouling. Therefore, membranes with high fouling resistance are imperative to treat emulsified oily wastewater. In this study, carbon nanotube-polyvinyl alcohol (CNT-PVA) membrane was fabricated. And its separation performance for emulsified oily wastewater was compared with two commercial polymeric membranes (PVDF membrane and PES membrane) by filtration of two homemade emulsions and one cutting fluid emulsion. The results show that these membranes have similar oil retention efficiencies for the three emulsions. Whereas, the permeation flux of CNT-PVA membrane is 1.60 to 3.09 times of PVDF membrane and 1.41 to 11.4 times of PES membrane, respectively. Moreover, after five consecutive operation circles of filtration process and back flush, CNT-PVA membrane can recover 62.3% to 72.9% of its initial pure water flux. However, the pure water flux recovery rates are only 24.1% to 35.3% for PVDF membrane and 6.0% to 26.3% for PES membrane, respectively. Therefore, CNT-PVA membrane are more resistant to oil fouling compared with the two polymeric membranes, showing superior potential in treatment of emulsified oily wastewater.     

Carbon nanotubes-incorporated MIL-88B-Fe as highly efficient Fenton-like catalyst for degradation of organic pollutants

CNTs were incorporated into MIL-88B-Fe to get a new Fenton-like catalyst (C@M). Fe(II) was introduced in C@M to get a fast initiation of Fenton-like reaction. Fe(II) content in C@M was related with oxygen-containing functional groups on CNTs. C@M shows efficient catalytic degradation of pollutants over a wide pH range. Iron-based metal organic frameworks have been verified to be efficient heterogeneous Fenton catalysts due to their open pore channels and highly uniform distribution of metallic centers. In these catalysts, however, the iron element is mainly in the form of Fe(III), which results in a process required to reduce Fe(III) to Fe(II) to initiate Fenton reaction. To address this problem, carbon nanotubes (CNTs) with electron-rich oxygen-functional groups on the surface were incorporated into the metal organic frameworks (MIL-88B-Fe) to improve Fe(II) content for an enhanced Fenton-like performance. The prepared CNT@MIL-88B-Fe (C@M) showed much stronger catalytic ability toward H₂O₂ than MIL-88B-Fe. The pseudo-first-order kinetic constant for phenol degradation by C@M (0.32 min^–1) was about 7 times that of MIL-88B-Fe, and even higher than or comparable to the values of reported heterogeneous Fenton-like catalysts. Moreover, the Fenton-like system could effectively degrade various kinds of refractory organic pollutants and exhibited excellent catalytic activity over a wide pH range (4–9). XPS analysis confirmed that Fe(II) content of the catalyst gradually increased with CNT loadings. Electron spin resonance analysis showed that the signal intensity (•OH) of C@M was much higher than MIL-88B-Fe, which was consistent with the degradation efficiency of pollutants. Furthermore, the Fe(II) content of the catalyst gradually increased along with the oxygen-functional group content of CNTs. The result demonstrated that oxygen-containing functional groups of CNTs have a significant impact on the enhanced catalytic performance of C@M. This study provides a new insight to enhance Fenton reaction by using nanocarbon materials.     

Changes in the heavy metals and petroleum hydrocarbon contents in seawater and surface sediment in the year following artificial reef construction in the Pearl River Estuary,China

Environmental Science and Pollution Research - Marine pollution is an important driver of ocean biodiversity loss, which can be mitigated by the construction of artificial reefs (ARs). Many studies...     

哌嗪氨基二硫代甲酸型螯合树脂的合成及其吸附性能

用哌嗪和二硫化碳反应合成氨基二硫代甲酸中间体，再与二卤代烃反应得到1，4-双(二硫代酯基)哌嗪聚合物，考察了中间体和螯合树脂对Ag^ ，Cu^2 ，Zn^2 ，Ni^2 ，CO^2 ，Pb^2 ，Pd^2 ，Cr^3 的静态吸附性能，结果表明，两者均可以吸附金属离子，缩聚后的螯合树脂具有更强的吸附能力。     

王哥庄湾陆源硝酸盐氮输送通量研究

以汇水区域相对独立的崂山王哥庄地区为例 ,通过研究该区的水文地质条件、分析地表水和地下水中的硝酸盐氮 (NO3 N) ,采用流量法和断面法分别对河流和地下水向王哥庄湾的NO3 N输送量进行了计算。结果表明 ,1999年 5月下旬地下水向海洋输送的NO3 N占整个陆源输入量的 30 .0 6 % ,说明地下水向海洋的营养盐输送量是海洋环境评估的重要边界条件。     

影响郑州市大气TSP浓度诸因素的灰色关联分析与弹性分析

根据郑州市大气TSP浓度的监测数据以及相关影响因素数据，运用灰色系统理论的关联分析方法，得出了影响TSP浓度的主要因素，并通过建立灰色GM（1，N）模型，运用弹性分析理论分析了各影因素对TSP浓度的贡献大小。经过两者分析，提出了控制和治理TSP污染的对策。