Recycling sewage sludge into ceramic materials: A review

Environmental Chemistry Letters - Huge amounts of unwanted sewage sludge are generated in the process of wastewater treatment, calling for methods to recycle sewage sludges into value-added...     

A combined radical and non-radical oxidation processes for efficient degradation of Acid Orange 7 in the homogeneous Cu(II)/PMS system: important role of chloride

Environmental Science and Pollution Research - Trace copper ion (Cu(II)) in water and wastewater can trigger peroxymonosulfate (PMS) activation to oxidize organic compounds, but it only works under...     

An asymmetric analysis of the impacts of energy use on carbon dioxide emissions in the G7 countries

Environmental Science and Pollution Research - The foremost theme of the paper is to explore the asymmetric/symmetric impact of energy consumption on the carbon dioxide emission of G7 countries...     

Understanding and addressing the environmental risk of microplastics

Over the past decades, the plastic production has been dramatically increased. Indeed, a category of small plastic particles mainly with the shapes of fragments, fibers, or spheres, called microplastics (particles smaller than 5 mm) and nanoplastics (particles smaller than 1 μm) have attracted particular attention. Because of its wide distribution in the environment and potential adverse effects to animal and human, microplastic pollution has been reported as a serious environment problem receiving increased attention in recent years. As one of the commonly detected emerging contaminants in the environment, recent evidence indicates that the concentration of microplastics show an increasing trend, for the reason that up to 12.7 million metric tons of plastic litter is released into aquatic environment from land-based sources each year. Furthermore, microplastic exposure levels of model organisms in laboratory studies are usually several orders of magnitude higher than those found in environment, and the microplastics exposure conditions are also different with those observed in the environment. Additionally, the detection of microplastics in feces indicates that they can be excreted out of the bodies of animal and human. Hence, great uncertainties might exist in microplastics exposure and health risk assessment based on current studies, which might be exaggerated. Policies reduce microplastic emission sources and hence minimize their environmental risks are determined. To promote the above policies, we must first overcome the technical obstacles of detecting microplastics in various samples.     

氨废水资源化利用的折流式超重力床集成技术

利用折流式超重力床将氨废水处理的精馏和吸收过程集成在一台设备中,开发出一种设备小型化、流程紧凑的氨废水资源化利用集成技术。与传统技术相比,该技术在大幅节省占地面积和空间的同时,还可大幅节约设备建设所用钢材。工业规模试验结果表明,不同浓度的氨废水经该技术处理后可转化为氨质量分数大于22%的氨水资源,处理出水中氨氮质量浓度低于8.2 mg/L,尾气中未检测到氨,处理结果优于GB 31573—2015《无机化学工业污染物排放标准》。     

地铁区间隧道烟气层化现象研究

以重庆某一地铁区间隧道为原型,搭建了1∶15小尺寸隧道试验台,通过小尺寸试验与FDS 6.5.2数值模拟开展隧道顶部烟气温度分布及分层规律研究。基于Newman提出的烟气层分区条件,研究了不同纵向风速下的烟气分层现象,提出了烟气稳定层化长度的概念,并分析了火源热释放速率及断面型式对烟气层化长度的影响。试验证明了Newman提出的烟气分层计算方法是可信的。结果表明:纵向风速较小时,火源下游能呈现烟气分层现象;烟气稳定层化长度受火源热释放速率影响较大,随热释放速率增大而增大;隧道高度的变化对烟气稳定层化长度的影响较小。     

基于微型无人机遥感数据的城市水环境信息提取初探

近年来,黑臭水体整治已经成为各级政府的重要工作内容。为更好地开展黑臭水体筛查和监管工作,提出基于多旋翼无人机搭载多光谱相机的遥感监测方案,尝试采用影像特征变换结合面向对象分类方法提取黑臭水体的遥感信息。结果表明:(1)无人机影像上地物具有更加丰富的色彩和纹理;(2)与主成分变换和纹理分析方法相比,光谱指数对典型地物具有较好的判别能力;(3)采用标准最邻近分类法提取城市水环境信息,能够获得较高分类精度。     

Carbon Emission from the Surface of Coarse Woody Debris in Korean Pine Forests of Southern Primorye

Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO₂ emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO₂ emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature (R² = 0.65–0.75).     

Heat dissipation characteristic in the intake grille and radiator of a fuel cell vehicle

ABSTRACT

In this study, a three-dimension (3D) computational model was proposed to investigate the flow and heat transfer characteristics of the intake grilles of two different fuel cell vehicles. The models of the intake grilles were constructed according to the actual sizes of two vehicles, namely, Roewe 950 and Toyota Mirai, considering the heat dissipation unit to simplify the heat transfer model of the vehicle. The results showed that relative to Roewe 950, Mirai intake air flow rate was approximately 10% higher, the heat transfer capacity was approximately 7% higher, and the intake grille area was larger. The coolant outlet temperature of Mirai was lower than that of Roewe 950, which was beneficial for the long term and stable operation of a fuel cell. This comparative study provided guidance for the intake grille and radiator design of fuel cell vehicles. The only difference between fuel cell vehicles on the market and conventional vehicles was that in the former, the internal combustion engine was replaced with a fuel cell stack, which had insufficient heat transfer capacity because of the reducing temperature difference. Increasing the intake grille area and the heat exchange capacity of the radiator were the key issues for the development of fuel cell vehicles. In this study, an optimal window opening angle of the radiator fin of 23° provided a maximal heat transfer coefficient.     

磷酸改性生物炭-LDHs(Mg-Al-NO3)复合材料对双酚A的吸附

本研究选取油菜秸秆为原料,在600℃下热解得到生物炭和磷酸改性生物炭,并用共沉淀法制备3种改性生物炭-LDHs(Mg-Al-NO_3)复合材料.采用批量吸附法研究不同pH、吸附时间和不同生物炭/LDHs配比条件下复合材料对双酚A的吸附特性,借助XRD、FTIR和BET等测试手段探究了复合材料吸附双酚A的机制.结果表明,改性生物炭-LDHs(Mg-Al-NO_3)复合材料吸附双酚A的吸附平衡时间为4 h,符合准二级动力学方程(R~20.99);复合材料对双酚A的吸附效果稍逊于改性生物炭,改性生物炭在复合材料中所占比重越大,吸附效果越好.当pH值在5.0—9.0范围内变化时,改性生物炭-LDHs(Mg-Al-NO_3)复合材料对双酚A的吸附量呈下降趋势,且在pH=9.0时达到最小值.等温吸附模型数据表明,复合材料用Freundlich等温吸附模型效果更好.通过XRD、BET、FTIR测试研究发现,由于LDHs占据了生物炭表面的活性位点,致使生物炭与双酚A之间的相互作用减弱,降低了复合物的吸附能力.本研究结果初步阐释了改性生物炭-LDHs(Mg-Al-NO_3)复合材料吸附双酚A的机理,为生物炭-LDHs复合材料处理水体中有机污染物的应用提供了借鉴和参考.