H3PMo12O40/活性白土UV - H2O2催化氧化降解甲基橙

采用浸渍吸附法制备了H3PMo12O40/活性白土催化剂,并考察了H3 PMo12O40/活性白土对偶氮染料甲基橙的UV-H2O2降解的催化性能.实验结果表明,当H2O2加入量为0.4 mol/L、H3PMo12O40/活性白土加入量为0.30 g/L、溶液初始pH为2、反应温度为70℃、反应时间为1.0h时,甲基橙去...     

微波改性锆-铝柱撑膨润土对水中Cr(Ⅵ)的吸附

以膨润土为原料,通过微波辐射加热法制备锆-铝柱撑膨润土(MZAPB)吸附剂,研究了 MZAPB 加入量、溶液 pH、吸附时间、温度等因素对 Cr(Ⅵ)吸附效果的影响.研究结果表明:当溶液初始 Cr(Ⅵ)质量浓度为 25mg/L、MZAPB 加入量为 10 g/L、溶液 pH 为 5.6、吸附温度 25℃、吸附时间为 6...     

Persistent organic pollutant emissions from medical waste incinerators in China

The huge amount of medical waste (MW) has caused a tough challenge to environmental protection in China because of its serious infectious potential. At present, incineration is the most common technology for MW disposal. Unfortunately, the medical waste incinerator (MWI) is considered one of the major sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study was conducted to investigate the generation and the components of MW; the fingerprint of PCDD/Fs in MWI; and PCDD/F, polychlorinated biphenyl (PCB) and hexachlorobenzene concentrations in residue ash. The estimated annual production of MW was estimated to be 0.97 million tons in China in 2008; in addition, plastic and rubber accounted for 24.5% of MW contents. PCDD/F emissions from MWI could be divided into two main groups according their fingerprints, and the ratio of PCDFs/PCDDs was mostly over 1.5, with a mean value of 3.43. The toxic equivalent of PCDD/Fs was over 30 times that of the value of PCBs in the residue ash, and PCDD/F contents in fly ash accounted for approximately 67% of the total output of PCDD/Fs, which was in line with the UNEP default emission factors for MWI (class 3, 63.7%).     

两段式混合滤料渗滤系统处理模拟废水

两段式混合滤料渗滤系统在土壤渗滤系统的基础之上,加强反硝化反应,进而强化脱氮过程。为强化脱氮,整个系统被分成好氧段和厌氧段。混合滤料的使用可有效防止系统堵塞。厌氧段添加的锯末草灰为反硝化反应提供了足够的碳源,因此运行初期厌氧段内NO3--N去除率可达100%。同时铁屑的添加除强化还原环境外还加强了TP的去除效果。采用模拟废水的研究结果表明:运行稳定后,该系统对COD、NH4+-N、TN和TP的平均去除率分别达到了87.7%、82.6%、81.0%和90.4%。     

A Modal Approach to Vehicular Emissions and Fuel Consumption Model Development

Abstract

This study reports on the analysis of emissions and fuel consumption from motor vehicles using a modal approach. The four standard driving modes are idling, accelerating, cruising, and decelerating. On‐road data were collected using instrumented test vehicles traveling many times through the urban areas of Hong Kong. A model was developed for estimating vehicular fuel consumption and emissions as a function of instantaneous speed and driving mode. Piecewise interpolation functions were proposed for each nonidling driving mode. Idling emission and fuel consumption rates were estimated as negative exponential functions of idling time. Preliminary modeling results showed good agreements for the test vehicles and indicated that the on‐road measurements are feasible for the development of modal emission and fuel consumption models.     

Removal of NOx from Flue Gas with Iron Filings Reduction Following Complex Absorption in Ferrous Chelates Aqueous Solutions

Abstract

A novel process for removal of nitrogen oxides (NO_x) from flue gases with iron filings reduction following complex absorption in iron-ethylenediaminetetraacetic acid aqueous solution is proposed. The reaction mechanism involved in the process is discussed briefly. The parameters influencing the process, including the concentration of ferrous chelates, initial pH, amount of iron filings, temperature, flow rate of the flue gas, and inlet nitric oxide concentration and oxygen content of the flue gas, are researched in detail. The optimal NO_x removal conditions are established. The regeneration and circular utilization of the absorption solution also is studied.     

天然锰砂去除水中的砷

天然锰砂是一种廉价、高效的水处理用材料,但尚未用于水中砷的去除。实验研究了反应时间、砷形态、初始砷浓度、温度、溶液初始pH对吸附过程的影响。结果表明,天然锰砂对As(Ⅲ)的吸附能力大于As(Ⅴ)。25℃时,固液比为10 g/L的条件下,天然锰砂对初始浓度为5.0 mg/L的砷溶液吸附过程经72 h基本达到平衡,平衡时对As(Ⅲ)和As(Ⅴ)的去除率分别达到94.5%和85.9%。吸附过程符合Lagergren准一级反应动力学模型和假二级反应动力学模型。相比之下,假二级动力学模型拟合程度更高。对As(Ⅲ)和As(Ⅴ),45℃时的吸附量均大于25℃时。不同温度下,天然锰砂对As(Ⅲ)和As(Ⅴ)的吸附过程更符合Freundlich等温吸附模型。在溶液初始pH为3～10范围内,锰砂对砷的吸附能力受pH的影响较小。实验结果表明,天然锰砂是一种具有实际应用潜力的除砷材料。     

Characterizing the interactions between polycyclic aromatic hydrocarbons and fulvic acids in water

Polycyclic aromatic hydrocarbons (PAHs) are persistent, bioaccumulative, and toxic chemicals and are listed as priority pollutants by the US EPA. Although they are sparsely soluble in water, their solubility can be increased by binding to dissolved organic matter in natural waters, which will further increase their environmental risk as toxic pollutants. In this study, the interaction between PAHs, exemplified by fluorene and anthracene, and fulvic acid (FA) was studied using fluorescence quenching titration method with fluorescence emission spectra, respectively. The association of FA with the mixture of fluorene and anthracene was also evaluated by excitation–emission matrix (EEM) fluorescence spectrometry combined with parallel factor (PARAFAC) analysis. Results demonstrate that EEM fluorescence spectrometry with PARAFAC analysis was sensitive and reliable to determine the binding properties of PAHs with FA in a mixed aqueous solution. The conditional stability constants and binding capacities show that both PAHs bind to FA tightly.     

稠油废水破乳剂的研究进展

介绍了稠油废水的来源、特点和乳化成因,综述了稠油废水破乳剂的研究进展,分析了不同破乳剂的破乳机理和优缺点,并对破乳剂的发展方向进行了展望和建议。     

光磁耦合废水处理工艺条件的优化研究

以Fe3O4/TiO2作为磁性光催化剂,采用光磁耦合技术处理模拟印染废水。利用统计学方法对光磁耦合废水处理的影响因素进行了探讨和分析,考察了磁场强度、磁性光催化剂投加量、pH值和光照时间对光磁耦合废水处理的影响。通过Design-Expert 7.0.0软件分析得到最佳工艺条件:磁场强度73.95 mT,磁性光催化剂投加量1.13 g/L,模拟废水pH值13,光照时间120 min。在最佳工艺条件下进行实验,脱色率为88.60%。