Synthesis of α-Fe2O3 nanofibers for applications in removal and recovery of Cr(VI) from wastewater

Purpose

Nanomaterials such as iron oxides and ferrites have been intensively investigated for water treatment and environmental remediation applications. The purpose of this work is to synthesize α-Fe₂O₃ nanofibers for potential applications in removal and recovery of noxious Cr(VI) from wastewater.

Methods

α-Fe₂O₃ nanofibers were synthesized via a simple hydrothermal route followed by calcination. The crystallographic structure and the morphology of the as-prepared α-Fe₂O₃ nanofibers were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope. Batch adsorption experiments were conducted, and Fourier transform infrared spectra were recorded before and after adsorption to investigate the Cr(VI) removal performance and adsorption mechanism. Langmuir and Freundlich modes were employed to analyze the adsorption behavior of Cr(VI) on the α-Fe₂O₃ nanofibers.

Results

Very thin and porous α-Fe₂O₃ nanofibers have been successfully synthesized for investigation of Cr(VI) removal capability from synthetic wastewater. Batch experiments revealed that the as-prepared α-Fe₂O₃ nanofibers exhibited excellent Cr(VI) removal performance with a maximum adsorption capacity of 16.17 mg g^?1. Furthermore, the adsorption capacity almost kept unchanged after recycling and reusing. The Cr(VI) adsorption process was found to follow the pseudo-second-order kinetics model, and the corresponding thermodynamic parameters ΔG°, ΔH°, and ΔS° at 298 K were calculated to be ?26.60 kJ?mol^?1, ?3.32 kJ?mol^?1, and 78.12 J?mol^?1 K^?1, respectively.

Conclusions

The as-prepared α-Fe₂O₃ nanofibers can be utilized as efficient low-cost nano-absorbents for removal and recovery of Cr(VI) from wastewater.     

Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China, and its components, which include ultrafine particles (UFPs), volatile organic compounds (VOCs), and other reactive gases, such as NH₃ and NO_x, are the most harmful to human health. China has released various regulations and standards to address pollution from mobile and stationary sources. Thus, it is urgent to develop online monitoring technology for atmospheric pollution source emissions. This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years. These instruments have been applied to monitor emissions from motor vehicles, ships, airports, the chemical industry, and electric power generation. Not only has the level of atmospheric environment monitoring technology and equipment been improving, but relevant regulations and standards have also been constantly updated. Meanwhile, the developed instruments can provide scientific assistance for the successful implementation of regulations. According to the potential problem areas in atmospheric pollution in China, some research hotspots and future trends of atmospheric online monitoring technology are summarized. Furthermore, more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.     

亚洲季风变迁与全球气候的联系

通过研究冰期-间冰期至百年尺度亚洲季风的演变特征,阐明了季风变化同南北半球冰量、太阳辐射、大洋环流、热带辐合带等气候系统内外部因子的动力联系。在海-陆-气相互作用的框架下提出了"冰期-间冰期印度季风变化动力学"新理论,揭示大西洋经向环流对东亚季风突变事件的影响和动力过程,探讨了全新世亚洲季风变化的时空特征和控制因素。该项成果以亚洲季风变迁历史和机理为主线,从地球系统科学的视角,将亚洲古季风研究拓展为多尺度与多动力因子、区域与全球相结合的集成研究,推动了与季风相关的过去全球变化科学的发展。     

四川地区高含硫化氨气田钻完井风险因素分析

通过对川东北地区钻完井事故资料的统计,分析了影响高含硫化氢气田钻完井安全的主要风险因素。     

人水和谐理念下城市河涌整治的环境社会学思考

导致城市河涌污染和不健康的因素众多,不仅具有生态学的根源,而且还具有社会学的根源。河涌整治已经成为许多城市环境治理的重点。文章依据环境社会学的理论和人水和谐的理念,分析当前河涌整治的模式及优缺点,重点探讨政府、企业、市民、传媒等利益相关者在城市水环境污染与治理中的角色、作用以及相互之间的互动与整合,为城市河涌综合整治建立长效社会机制提供依据。     

基于灰色理论的民航燃油消耗量预测模型及应用

民航运输中燃油消耗量的精确预测对能源需求的科学规划和决策具有重要参考价值,针对民航燃油消耗量历史数据少的特点,通过灰色系统建模、关联度分析以及残差辨识,建立了民航燃油消耗量的灰色预测模型,以均方差比值和小误差概率两项评级指标,将预测结果与精度检验等级的对比分析表明灰色预测民航燃油消耗量的拟合精度高,预测结果较为可靠。     

Research on Public Participation and Information Publicity in Strategic Environmental Assessment

Abstract

It has been generally recognized that strategic environmental assessment integrates environment and development into decision-making and becomes an important decision-making tool for implementing sustainable development. This paper firstly introduces the relationships of SEA, public participation(PP)and information publicity(IP), then discusses the key parts in enforcing the effective process of PP: They are the methods for how to make sufficient information open (What), when to implement PP (When), who will determinate the public (Who), and how to make the models of PP (How). Six cases are compared and analyzed. At last, ways to improve the effectiveness of PP in China is also presented.     

Index System and Influence of Drought in Northwest China

Abstract

In this paper, the index systems of the agricultural drought and decrease percentage of grain crop are established. The trend and influence of drought in the region is analyzed based on the 50 years (1951–2000) statistical data of precipitation and 52 years (1951–2002) agricultural drought of the region, including five provinces: Shaanxi, Gansu, Ningxia, Qinghai and Xinjiang. The result shows that the drought disaster is increasing and the most serious were in the 1970s and 1990s, and main agricultural drought is a great disaster incident. The regression prediction equation of drought and flood grades and agricultural drought areas grades are set up by the harmonic wave method, and forecasting the drought will lighten during the first ten years of the 21st century.     

Investigation on oxygen-controlled sewage sludge carbonization with low temperature: from thermal behavior to three-phase product properties

Environmental Science and Pollution Research - A comprehensive study was conducted on the characteristics of oxygen-controlled carbonization process of sewage sludge (SS) using thermogravimetric...     

辽宁本溪大气颗粒物浓度特征

利用本溪大气成分监测站2008年3月至2009年2月大气颗粒物监测仪GRIMM180的连续监测资料,对该地区大气颗粒物的质量浓度变化、谱分布特征以及大气颗粒物与气象因素的关系进行分析研究.结果表明,本溪PM10和PM2.5平均质量浓度分别为0.086 mg.m-3和0.058 mg.m-3,其日平均质量浓度变化幅度较大;冬季和夏季质量浓度日变化均呈现明显的双峰双谷特征;数浓度谱分布较好地符合Junge分布;PM10日平均值超标率为8.7%,且大气颗粒物主要是以细粒子的形式存在;随风速的增大大气颗粒物质量浓度基本呈现逐渐减小的趋势,当风速〉0.6 m.s-1时,大气颗粒物质量浓度随风速增大下降明显,风速〉3.0 m.s-1时,下降的趋势减缓;降水过程对大气颗粒物有清除作用,其中对粗粒子的清除效果非常明显.