有机碳含量对土壤剖面中多环芳烃纵向迁移的影响

为探索有机碳含量对土壤剖面中多环芳烃(PAHs)纵向迁移的影响,选取北京地区3条有机碳(TOC)含量明显不同的土壤剖面进行了土柱淋滤实验研究.结果表明,通过30 d(相当于北京地区3年的淋滤水量)的淋滤实验后,不同剖面中PAHs均存在不同程度的迁移现象,但剖面中残留的PAHs仍然主要富集在土柱表层0～30 cm土壤中,且中高环数PAHs的残留率明显高于低环数PAHs.TOC含量与PAHs的残留总量之间具有显著的正相关性,TOC含量越高,PAHs残留量越高.此外,TOC对不同环数PAHs迁移的影响程度存在差别,高环数PAHs受TOC变化的影响高于低环数PAHs.     

Removal and recycling of copper from aqueous solutions using treated Indian barks

Removal of copper from aqueous solutions containing 100–1000 ppm, using different Indian bark species, was performed on laboratory scale. The percentage removal of metal ions depends on the solution pH, bark species and time. The efficiency of copper removal by the used raw barks increases with a rise of solution pH and reaches a maximum of about 65–78% around pH 4–5. However, the decontaminated aqueous solutions were colored due to the dissolution of soluble organic compounds contained in the raw bark. This increases the biological and chemical oxygen demand (BOD and COD) of the solutions as well as the total organic carbon content (TOC). For this reason, raw bark should be treated either by chemical or biological means. Such treatment will allow the extraction of the soluble organic compounds and increase the chelating capacity and efficiency of the treated bark. Depending on the pH value, the chelating efficiency of treated barks is about 1.2–2.2 times that of the raw ones. Moreover, the retention capacity of the Indian treated bark varies from about 42–51 mg/g of dry bark. It is equal to or higher than that of common European species. About 1.8 mols of H₃O⁺ are released, by the treated barks, for every mol of chelated copper ions. Moreover, scanning electron microscopy (SEM) observations show uniform distribution of metal ions throughout the copper saturated bark. Infra red (IR) spectra suggest that the copper ions are chelated to hydroxyl and/or carboxyl functional groups of organic compounds contained in the treated bark. It seems that the interaction of the copper ions with the bark follows a cation exchange mechanism. This hypothesis is supported by elution experiments that allow recovery of about 99% of the contained copper. The retention capacity of the treated bark is almost constant after five cycles of chelation–elution, suggesting that the ‘life time cycle' is sufficiently long for continuous industrial application. The spent copper loaded barks can either be incinerated or pyrolysed. It generates solids containing either ≈80% of CuO or ≈14% of Cu°, respectively. Such materials can be used either in the secondary or primary copper production, thus offering a friendly environmental solution of effluents' treatment. The suggested process can be used as an alternative to the classical technologies for effluent decontamination. It is also efficient for polishing effluents treated by other methods.     

1020型总有机碳水质分析仪校准方法

总有机碳水质分析仪需定期进行检定,制定合理可行的校准方法,并根据标准方法对仪器进行检定,校准结果为重复性1.69%,零点漂移0.045%,直线性1.98%,相关系数0.9984,绝缘阻抗＞20MΩ,满足校准方法技术要求,根据检定结果,该仪器出具数据准确可靠.     

基于呼吸强度和总有机碳综合评价存量生活垃圾好氧稳定化程度的方法研究

设计固定床好氧稳定化实验装置，在恒温、通风、含水量适宜条件下运行，研究东莞、厦门等地开采后的存量生活垃圾以及食堂餐厨垃圾样品稳定化过程中总有机碳（TOC）和4日呼吸强度（AT₄）随时间的变化规律以及两者变化趋势的相关性.优化了TOC和AT₄的检测方法，证明仪器法测定TOC结果更加合理；研究表明采用四分法取样、从迟滞期结束后开始计算得到的AT₄更有参考价值；4种垃圾样品TOC和AT₄之间具有良好的相关性，两者导数之间也具有良好的相关性，且相关系数均大于0.99（R²>0.99），证明了TOC和AT₄变化趋势的同步响应规律，说明可以利用能快速测定的TOC指标的变化趋势反映不能快速测定的AT₄指标的变化趋势，从而提出一种通过TOC的变化趋势和AT₄的数值综合评价存量垃圾好氧稳定化程度的新方法，既缩短了检测周期，又提高了好氧稳定性评价的客观性，为存量垃圾稳定化评价提供了新思路.     

京密引水中天然有机物的形态

用改进的Ｌｅｅｎｈｅｅｒ分离方法，并引入最新的ＸＡＤ－８，ＸＡＤ－４树脂串联技术，将京密引水中有机物定量分离为悬浮和溶解态两大类。后者又进一步分离为憎水有机物、腐殖酸类，ＸＡＤ－４酸和亲水中性有机物等形成。溶解态有机物含量约为３ｍｇＣ／ｌ，其中一半左右为腐殖酸类。ＸＡＤ－４酸占溶解态有机１５－２０％，非极性憎水有机物所占比例很低。     

Exudation of UV-light absorbing natural products by seedlings ofNuphar lutea

Summary Seedlings ofNuphar lutea (L.) Sm. were raised from seeds and cultivated in a synthetic sterile nutrient solution under physiologically controlled and undisturbed conditions. The extracellular release of carbon compounds from the plants into the surrounding medium was examined by direct carbon estimation, by various specific chemical assays and by HPLC analysis. Direct carbon estimation was not sensitive enough to obtain reliable values; five of six specific chemical assays also failed. Only the Folin-Denis assay indicated there was a production of phenolic compounds, which followed a linear course that took up to six days of incubation. The phenolic compounds ranged between 0.2 and 1.3 µg/h g dry weight. Rp-HPLC with UV detection yielded a major fraction containing at least five highly polar compounds (not retainable on reversed phase), and a minor fraction of at least eight less polar (rp-retainable) compounds. Exudation followed a linear course for some days up to a distinct level of saturation in the surrounding medium. Cultures incubated in light or absolute darkness exhibit the same production rates; however, lower temperatures caused significant reduction in the production rate and on the pattern of exuded compounds as well. After withdrawing the exuded compounds by rinsing the cultures, a new production can be repeatedly induced many times until the potential of the system is seemingly exhausted. Nuphar seedlings procedures are introduced as a new macrophyte system suitable for studying the mechanism of extracellular secretion among aquatic macrophytes.     

总有机碳与生化需氧量相互关系的实验研究

本文通过平行的生化培养试验证实,在“参与耗氧的含碳有机物”这一意义下,TOC和BOD是等价的,两者均服从一阶动力学过程并具有相同的降解速率常数,两者之间通过TOC的耗氧系数α和不可生化量b而存在线性的一般关系:BOD_5=α·(TOC—b)·exp(-5k_1).以在研究中关于BOD_5,与TOC的比值关系只是这一线性关系的特例.     

生物表面活性剂鼠李糖脂对水体中石油烃降解的促进作用

从被含油废水污染的土壤中筛选得到4株能利用柴油为唯一碳源生长的杆菌(X1,X2,X3和X4),经鉴定,这4株菌分别属于沙雷铁氏菌属(Serratiasp.)、不动菌属(Acinetobactersp.)、芽孢杆菌属(Bacillussp.)和氮单胞菌属(Azomonassp.).其中,菌株X4于32℃摇床培养28d后对柴油的降解率达62%,而在相同条件下,添加生物表面活性剂鼠李糖脂后柴油的降解率提高了26%.平板菌落计数结果表明,鼠李糖脂能促进菌的生长,生物量明显增多.对菌株降解反应的动力学研究进一步验证了鼠李糖脂对菌株X4降解石油烃的促进作用,添加了鼠李糖脂的样品组比对照组的半衰期缩短了近1倍.通过设计正交实验,本文研究了培养温度、培养时间、鼠李糖脂的添加量及石油烃的浓度等主要环境因子对水体中石油烃降解的影响.实验结果表明,影响水体中石油烃降解的主导因子是培养时间,其次是培养温度、石油烃的浓度和鼠李糖脂的添加量.图4表2参17     

A novel use of TiO2 fiber for photocatalytic ozonation of 2,4-dichlorophenoxyacetic acid in aqueous solution

More efficient oxidation methods are needed to degrade especially newly emerging recalcitrant organic contaminants at low concentrations in the water environment. Reduced photonic efficiency of immobilized TiO2 is a major challenge in TiO2-assisted advanced oxidation processes (AOP). Mineralization of 2,4-dichllorophenoxyacetic acid (2,4-D) in low aqueous solution by O3/UV/TiO2 using the world's first high-strength TiO2 fiber was investigated and compared with O3, UV/TiO2, and O3/TiO2 in laboratory batch ex...     

红枫湖入库河流沉积物中重金属污染状况分析

采用综合污染指数法和Hakanson生态风险指数法,对红枫湖几条主要入湖河流入湖处以及原后五养殖区沉积物中8种重金属(Cd、Pb、Cu、Co、Ni、Cr、V、Zn)含量进行了分析。研究结果表明桃花源河污染最严重,达到了中等污染水平(P=2.70,RI=171.02);后六河尽管Zn污染较严重,但其生态危害性低;其余河流的污染程度都较低。几条入湖河流的潜在生态危害性由高到低的顺序为:桃花源河>后六河>羊昌河>麻线河。所研究的8种重金属中只有Cd(Eir均≥40)具有较高的潜在生态风险,桃花源河的Cd的Eir最高(Eir=82)。其余重金属由于毒性系数小,尽管部分重金属含量达到了背景值的许多倍,但都无显著的潜在生态风险。但是后六河的Zn含量高过了生态效应必然浓度值(PEL),需引起重视。通过对桃花源河沉积物重金属含量垂向变化的研究发现,在早期成岩过程中沉积物中Cd、Pb、Ni、Co、Cr、Cu、V的沉降主要受有机质的控制;Cr不仅受有机质的影响,还受氧化还原条件的影响;而Zn则明显受粒度的控制。