Release of volatile organic compounds during bio-drying of municipal solid waste

Three treatments were tested to investigate the release concentrations of volatile organic compounds (VOCs) during the bio-drying of municipal solid waste (MSW) by the aerobic and combined hydrolytic-aerobic processes. Results showed that VOCs were largely released in the first 4 days of bio-drying and the dominant components were: dimethyl disulfide, dimethyl sulfide, benzene, 2-butanone, limonene and methylene chloride. Thus, the combined hydrolytic-aerobic process was suggested for MSW bio-drying due to fewer aeration quantities in this phase when compared with the aerobic process, and the treatment strategies should base on the key properties of these prominent components. Malodorous sulfur compounds and terpenes were mainly released in the early phase of bio-drying, whereas, two peaks of release concentrations appeared for aromatics and ketones during bio-drying. Notably, for the combined hydrolytic-aerobic processes there were also high concentrations of released aromatics in the shift from hydrolytic to aerobic stages. High concentrations of released chlorinateds were observed in the later phase. For the VOCs produced during MSW bio-drying, i.e., malodorous sulfur compounds, terpenes and chlorinateds, their release concentrations were mainly determined by production rates; for the VOCs presented initially in MSW, such as aromatics, their transfer and transport in MSW mainly determined the release concentrations.     

Thermodynamic study of adsorption of phenolic compounds onto Amberlite XAD-4 polymeric adsorbents and its acetylized derivative MX-4

Adsorption equilibrium isotherms of phenolic compounds, phenol, p-cresol, p-chlorophenol and p-nitrophenol, from aqueous solutions by Amberlite XAD-4 polymeric adsorbent and its acetyhzed derivative MX-4- within temperature range of 283-323K were obtained and fitted to the Freundlich isotherms. The capacities of equilibrium adsorption for all four phenolic compounds from their aqueous solutions increased around 20% on the acetylized resin, which may be contributed to the specific surface area and the partial polarity on the network.Estimations of the isosteric enlhalDV, free energy, and entropy for the adsorption process were reported.     

铬污染及其生态效应

阐述了环境中铬及其化合物的产生、存在形态和转化,对铬及其化合物的危害机理和生态效应进行探讨。     

环境中磷化氢的含量差异及其影响因素

分析测定了不同环境来源的 12个样品的磷化氢含量 ,结果表明不同来源的样品其磷化氢含量差别很大 ,最高的是污水处理厂的污泥 ,其磷化氢含量可达 2 130 7 4ng·kg-1,远远高于目前文献报道的湖泊、稻田、垃圾场、海洋沉积物等来源样品的含量 ,磷化氢的产生在污水除磷处理中有一定的作用 ;其次是稻田土壤的磷化氢含量 ;最低的是太湖底泥样品 .进一步分析了样品中与微生物生命活动相关的因素 ,如微生物数量、总氮、氨氮、硝态氮、总磷、有机磷化合物、无机磷化合物、总碳、还原糖等 ,结果发现磷化氢与还原糖、厌氧微生物、总碳、有机磷化合物的关系最为密切 ,呈现显著的正相关性 ,其相关性系数R2 分别为 0 99、0 92 (厌氧微生物数量的对数 )、0 90和 0 81.磷化氢含量与其它环境因素的关系不大     

红枫湖流域表层沉积物中全氟化合物的污染特征

PFCs(perfluorinated compounds, 全氟化合物)因具有持久性、生物富集效应和毒性而受到环境科学领域的普遍关注. 采用超高效液相色谱-串联质谱联用仪(UPLC-MS/MS)并结合固相萃取的方法,对贵阳市主要饮用水水源地——红枫湖主要入湖支流及湖区表层沉积物中10种PFCs的质量分数进行了检测,分析了其污染水平、空间分布及组成特征. 结果表明,各采样点w(∑PFCs)(10种PFCs的总质量分数)为0.27~1.65 ng/g,其中PFBA(全氟丁酸)、PFPeA(全氟戊酸)、PFOA(全氟辛酸)、PFBS(全氟丁烷磺酸)、PFOS(全氟辛烷磺酸)及PFHxA(全氟己酸)不仅检出率高,而且对各采样点w(∑PFCs)的贡献较大,是红枫湖表层沉积物中主要的PFCs;受湖区水文水动力条件及沉积物有机质的影响,北湖表层沉积物中w(∑PFCs)高于南湖,并且全湖w(∑PFCs)的最高值位于出湖口处,达到1.65 ng/g;红枫湖流域表层沉积物中的w(PFOA)和w(PFOS)分别为0.07~0.51和nd(未检出)~0.16 ng/g,与国内外其他流域相比处于较低水平;大气沉降可能是红枫湖流域PFCs的主要来源.      

不同培养温度对大曲微生物群落结构、酶活及挥发性化合物的影响

为分析不同发酵温度对大曲品质的影响,以同一批制曲原料进行中温和高温发酵,将两类成品大曲作为研究对象,全面比较微生物群落结构、酶活及挥发性化合物差异.利用高通量测序技术测定大曲细菌和真菌群落结构,并利用顶空固相微萃取(HS-SPME)结合气相色谱质谱(GC-MS)测定大曲挥发性化合物.结果表明,发酵温度对大曲细菌群落影响...     

固相萃取-超高效液相色谱-串联质谱法测定污水中16种全氟和多氟烷基化合物

建立了以固相萃取-超高效液相色谱-串联质谱同时测定污水中16种全氟和多氟烷基化合物(PFASs)的方法.样品经固相萃取柱富集浓缩,采用BEH-C18色谱柱(2.1 mm×100 mm,1.7μm),以甲醇和5 mmol·L-1乙酸铵溶液(pH=9)为流动相梯度淋洗,负离子多反应监测模式进行定性和定量分析,内标法定量.1...     

黄河水体氨氮超标原因探讨

根据黄河水体氮污染物的种类、浓度和来源以及黄河特有的泥沙和水化学条件,结合实验结果,从生物和化学的角度讨论黄河氨氮超标的可能原因.结果表明,水体悬浮颗粒物对硝化过程有明显的促进作用,氨氮的超标不是因为泥沙对硝化作用的影响所导致.氮污染物的不断输入是黄河水体氨氮超标的根本原因,高浓度氨氮和有机氮对硝化过程有抑制作用,当NH⁺₄-N初始浓度分别为10.1,18.4,28.2 mg/L时,初始的硝化效率分别为17.4％,13.0％,2.5％,当有机氮初始浓度分别为5.5,8.6 mg/L时,其降解所产生的氨氮最高浓度分别为0.47,1.69 mg/L,在水体中滞留的时间分别为2 d和6 d.水体中耗氧有机物和有毒物质对硝化细菌活性的影响间接导致了氨氮在水体中的滞留.黄河水体高pH值导致非离子氨浓度较高,进一步对硝化细菌产生抑制作用.水量较小、颗粒物含量较低和微生物的活性降低是枯水期氨氮污染加重的原因.     

安捷伦7890/5975C GC/MSD显著缩短EPA8270方法中的分析时间

美国EPA方法8270用于同时检测70-100种半挥发性酸、碱和中性化合物,实验室为提高分析效率希望将分析时间减少到25-60min.安捷伦7890A/5975C GC/MSD通过应用较小内径的色谱柱、快速降温和反吹技术来满足这种需求,在1-200mg·l-1校正范围内,应用质控样品连续校正样品进行标定.     

高效液相色谱三元梯度分离法测定大气中11种醛酮类化合物分析方法的研究

研究建立了高效液相色谱三元梯度分离法测定11种醛酮类化合物的最佳色谱分离条件,醛酮类化合物的最小检测量从0.45到2.04ng,各化合物保留时间的相对标准偏差RSD≤0.38%,在所测定的含量范围内具有很好的线性关系,每种化合物的相关系数均大于0.999;并研究了涂敷2,4-二硝基苯肼硅胶吸附采样夹的制作方法,且应用于大气环境中醛酮类化合物的分析,方法简单、快速,11种醛酮类化合物的平均解吸效率在98.3%～105%之间,结果令人满意.