基于三维荧光光谱特征峰的水体有机污染物综合指标检测

对来源不同一的32个水样进行三维荧光光谱的测定,并用5种典型有机物的荧光特征峰A(腐殖酸类)、C(腐殖酸类)、B(络氨酸类)、T1(色氨酸类)、T2(色氨酸类)进行了单一和组合式建模,发现对于来源不同一的水体的总有机含碳量(TOC)、化学耗氧量(COD)的检测采用这种提取特征峰建模的效果并不理想.该研究说明,依据典型特...     

诺氟沙星水溶液的湿式氧化分解及其产物的生成途径

以诺氟沙星(NOR)水溶液作为抗生素废水的代表,在湿式氧化的环境中考察其分解规律与产物生成途径,为含抗生素废水的湿式氧化处理提供方法基础.在温度为473～513 K,压力为3 MPa,NOR初始浓度约为500 mg/L,H2O2投加量为0和32 200 mg左右以及停留时间为10～60 s的条件下进行湿式氧化实验,以诺...     

缩聚-Fenton-A/O生物流化床组合工艺处理酚醛废水的工程案例分析

以广州某公司生产酚醛树脂时产生的酚醛废水为研究对象,针对其高浓度、生物毒性强、可生化性差及难降解等特点,设计缩聚-Fenton-A/O生物流化床联合工艺进行处理。此工艺的工程实践中,在总HRT低于75 h的操作条件下,当进水COD、苯酚及甲醛浓度分别为1.0×105～1.2×105 mg/L、2.2×104～2.5×1...     

Thermal Degradation and Kinetics of Alginate Polyurethane Hybrid Material Prepared from Alginic Acid as a Polyol

Alginate polyurethane hybrid materials are prepared by varying mole ratio of 2, 4-TDI as a di-isocyanate and alginic acid as a polyol in presence of dimethyl sulfoxide (DMSO) as a solvent. FT-IR and ¹³C one-dimensional (1D) solid state NMR (SSNMR) spectroscopy indicates that alginic acid is converted into alginate-polyurethane hybrid material via urethane linkage. Surface morphology of alginate-polyurethane hybrids changes by varying alginic acid: TDI ratio. The peak at near 221 °C in DSC thermogram of alginic acid (Alg) is shifted to higher temperature in alginate-polyurethane hybrid (Algpu1 and Algpu2). TGA study shows that alginate-polyurethane hybrid prepared using alginic acid: TDI = 1:1 (Algpu2) is more stable than alginic acid: TDI = 1:0.5 (Algpu1) at 300 °C. Kinetic analysis was performed to fit with TGA data, where the entire degradation process has been considered as three consecutive 1st order reactions. This study shows that thermal stability of alginate-polyurethane hybrid material was increased by adjusting mole ratio of 2, 4-TDI and alginic acid.     

Study on the Effect of Dicumyl Peroxide on Structure and Properties of Poly(Lactic Acid)/Natural Rubber Blend

In attempt to enhance the compatibility of NR in PLA matrix, and furthermore to enhance mechanical properties of PLA, PLA/NR blends with strong interaction were prepared in Haake internal mixer, using dicumyl peroxide (DCP) as cross-linker. The effects of dicumyl peroxide on morphology, thermal properties, mechanical properties and rheological properties of PLA and PLA/NR blends were studied. The results indicated that dicumyl peroxide could increase the compatibility of poly(lactic acid) and natural rubber. With small amount of dicumyl peroxide, the effect on NR toughening PLA was enhanced and the tensile toughness of PLA/NR blends was improved. When the DCP content was up to 0.2 wt%, the PLA/NR blend reached the maximum elongation at break (26.21 %) which was 2.5 times of that of neat PLA (the elongation at break of neat PLA was 10.7 %). Meanwhile, with introducing 2 wt% DCP into PLA/NR blend, the maximum Charpy impact strength (7.36 kJ/m²) could be achieved which was 1.8 times of that of neat PLA (4.18 kJ/m²). Moreover, adding adequate amount of DCP could improve the processing properties of blends: the viscosity of PLA/NR blend decreased significantly and the lowest viscosity of the blends could be achieved when the DCP content was 0.5 wt%.     

Persistence of the herbicide butachlor in soil after repeated applications and its effects on soil microbial functional diversity

Effects of repeated applications of the herbicide butachlor (N-(butoxymethyl)-2-chloro -N-2′,6′-dimethyl acetanilide) in soil on its persistence and soil microbial functional diversity were investigated under laboratory conditions. The degradation half-lives of butachlor at the recommended dosage in soil were calculated to be 12.5, 4.5, and 3.2 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index H′ was observed. However, the Simpson index 1/D and McIntosh index U were significantly reduced (P ≤ 0.05) during the initial 3 days after the first application of butachlor, and thereafter gradually recovered to a similar level to that of the control soil. A similar variation but faster recovery in 1/D and U was observed after the second and third Butachlor applications. Therefore, repeated applications of butachlor led to more rapid degradation of the herbicide, and more rapid recovery of soil microorganisms. It is concluded that repeated butachlor applications in soil had a temporary or short-term inhibitory effect on soil microbial communities.     

Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system

Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume of dust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 μm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.

Implications: VOCs and particles have been of interest both in industrial field and public indoor spaces. In this study, a post cyclone (PoC) that utilizes a residual vortex from the mother cyclone was modified by inserting a flow guide and was applied to capture toluene vapor. The device of modified post-cyclone system can be used effectively in simultaneous treatment of gas-solid flow.     

焦化废水处理过程外排污泥中重金属形态特征及其潜在环境风险

焦化废水处理过程所排放污泥中重金属的含量及化学形态是否构成环境风险将直接影响污泥处置方法的选择,为此,实验采用BCR顺序提取法分析了焦化废水处理站外排污泥中重金属(Cd、Hg、Pb、Cr、As、Ni、Zn、Cu和Mn)的形态特征,并采用地累积指数(Igeo)和潜在生态危害指数(RI)评价了重金属对土壤的潜在环境风险。研究结果表明:除Ni主要以可氧化态存在外,焦化废水外排污泥中其他几种重金属元素主要存在于残渣态,重金属元素的含量低于《城镇污水处理厂污染物排放标准(GB18918—2002)》中的控制限值;与城市污泥相比,焦化废水外排污泥具有低Pb、Cr、Zn、Cu含量,而高Cd、Hg、Mn含量的特点;基于Igeo和RI的评价结果,Cd和Hg是外排污泥中具有一定环境风险的元素,需要考虑其下游去向。焦化废水处理外排污泥中主要存在残渣态重金属成分,不表现为很高的环境风险,其处置应重点考虑其中有机污染物特别是POPs。     

基于生命周期分析的餐厨垃圾肥料化利用环境风险评价研究

餐厨垃圾肥料化利用过程的风险因子主要产生于原料运输与存储、预处理、堆肥、废物填埋和肥料化产品施用5个过程,其风险影响包括地表水和地下水污染、恶臭污染、土壤盐碱化和影响作物生长以及由此引起的人体健康损害.基于生命周期全过程分析,以好氧堆肥为代表的餐厨垃圾肥料化利用的环境风险为研究对象,系统地分析了餐厨垃圾堆肥过程中的潜在风险,归纳并提出风险源项估算以及环境风险影响评价的具体方法和相关参数,通过南京市餐厨垃圾示范性项目案例,说明餐厨垃圾肥料化利用风险评价方法的具体应用.     

松花江水质的多元统计分析

采用主成分分析法、因子分析法对松花江干流11个断面的水质监测数据按照不同水期进行分析,研究了各水质参数的相关性并对污染来源及不同水期内反映水质的重要参数进行了初步探讨.结果表明,水中可生物降解污染物对水体DO有一定的影响,水体温度是控制耗氧性污染物降解的主要因素.枯水期NH3-N与生活污水排放有重要关系,且在TN中占有较高比例.丰水期NH3-N与挥发酚相关性增加,这可能与汛期内煤化工类企业排放不达标有关;平水期,NH3-N与NO3-N相关性增加,可能平水期的污染来源及负荷与其他水期有差别.通过因子分析发现,在不同水期有不同的水质参数影响水质,枯水期大肠杆菌、TP是反映水质的重要参数;丰水期NH3-N、TP、石油类、pH为影响水质的主要水质参数;平水期DO、TN、电导率是反映松花江水质状况的重要水质参数,应当针对不同水期的污染负荷构成制定相应的污染防治方案.