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751.
将复合微生物制剂(HBH-Ⅱ)与生物膜法相结合,以重庆市某垃圾填埋场的渗滤液为研究对象,探讨了HBH-Ⅱ制剂在3种不同条件下对渗滤液的处理效果.结果表明,HBH-Ⅱ对垃圾渗滤液COD和NH3-N的去除有明显影响.反应72 h、低流量间歇曝气36 h、接种量1/10 000(HBH-Ⅱ与水的体积比)、进水pH=8.5条件下,处理效果最佳.HBH-Ⅱ中的复合微生物具有生物增强剂的作用,能明显促进污染物的降解.采用HBH-Ⅱ制剂时克服了以往处理工艺中气味恶臭的弊端,还具有产泥量小、色度去除效果好等优点.与单独使用HBH-Ⅱ处理渗滤液相比,以陶粒为填料的HBH-Ⅱ生物膜系统能够为HBH-Ⅱ的生长繁殖提供良好环境.挂膜成功运行5 d后,COD和NH3-N的去除率分别达到70.58%和72.99%. 相似文献
752.
This study was intended to determine the background levels of PCDD/PCDFs and PCBs in the Taiwanese population and to investigate factors potentially related to PCDD/PCDF and PCB levels. The levels of seventeen PCDD/PCDFs in the 251 serum samples collected from the general population in Taiwan ranged from 4.92 to 26.7 pg WHO(1998)-TEQ/g lipid (median: 11.5) and those of the twelve dioxin-like PCBs ranged between 1.74 and 21.6 pg WHO(1998)-TEQ/g lipid (median: 6.14). Five factors, age, gender, region of residence, dietary status, and smoking status, showed statistically significant association with the TEQ level of PCDD/PCDFs. The TEQ level of PCBs was statistically associated with age only, but not with the other four factors. The trends observed between age and the levels of PCDD/PCDFs and PCBs were not parallel in young subjects (<30 years old) and old subjects (>30 years old). The levels of PCDD/PCDFs and PCBs increased by 0.16 and 0.03 WHO(1998)-TEQ/g lipid per year for subjects above the age of 30, but there was no evidence of any association between age and the levels for subjects below the age of 30 years. These factors should be considered when investigating relationships between background serum levels of persistent organic pollutants and parameters associated with exposure sources or health outcomes. 相似文献
753.
Multivariate analysis of trace element concentrations in atmospheric deposition in the Yangtze River Delta,East China 总被引:1,自引:0,他引:1
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756.
稻壳基活性炭的制备及其对亚甲基蓝吸附的研究 总被引:8,自引:3,他引:5
以稻壳为原料,采用K2CO3活化法和H3P04活化法制备了比表面积为1312m^2/g和682m^2/g的活性炭,通过扫描电子显微镜(SEM)、X-射线衍射仪(XRD)对样品进行了表征,并将孔隙发达的活性炭样品用于对亚甲基蓝的吸附,结果表明,K2CO3活化法制备的活性炭样品具有更多的微孔结构;随着亚甲基蓝溶液初始浓度的增加、活性炭吸附时间的延长,亚甲基蓝的去除率呈现逐渐降低和逐渐增大的变化规律,当pH值为6时,活性炭对亚甲基蓝的吸附效果最佳;稻壳基活性炭对亚甲基蓝的吸附等温线符合Langmuir模型,Qm最高可达476.2mg/g;热力学参数△G^0△H^0和△S^0均为负值,表明稻壳基活性炭对亚甲基蓝的吸附是一个自发的放热反应。 相似文献
757.
Xu L Wu F Wan G Liao H Zhao X Xing B 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3462-3467
This report demonstrates that organic matter was an important factor in lake sediment 210Pbex dating. Sediment cores from lakes in central and western China with different-trophic levels were collected, and the 210Pbex activity and total organic carbon (TOC) were measured. The Rock-Eval pyrolysis technique was used to deconvolute TOC into free hydrocarbons (S1), thermally less-stable macromolecular organic matter (S2a), kerogen (S2b), and residual carbon (RC). The results show significant correlations between TOC and 210Pbex, particularly between S2a and 210Pbex, in all the sediment cores. This indicated that the algal-derived organic component S2a may play the most important role in controlling the distribution of 210Pbex. Scavenging by algal-derived organic matter may be the main mechanism. As chronology is the key to the understanding of pollution reconstruction and early diagenesis in sediments, more attention should be paid to the influence of organic matter on 210Pbex. 相似文献
758.
Yu Z Liao R Li H Mo L Zeng X Sheng G Fu J 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2982-2988
In present study, atmospheric particles from Shanghai, the biggest city and the most important industrial base in China, were analyzed for polybrominated diphenyl ethers (PBDEs) and Dechlorane Plus (DP). Concentrations of ∑(20)PBDEs and DP both exhibited the changing trend of industrial area > urban areas. Jiading District had the highest levels of particulate PBDEs and DP with values of 744 ± 152 pg/m(3) and 5.48 ± 1.28 pg/m(3), respectively. Compared with similar data in other areas of the world, PBDEs in Shanghai were at medium pollution level, while DP was at lower level, which reflected their different production and use in Shanghai. The results from multiple linear regression analysis suggested that deca-BDE mixture was the most important contributor of particulate PBDEs in Shanghai. The fractions of anti-DP showed no significant differences to those of the technical mixtures (p > 0.05), which suggested that no obviously stereoselective process occurred in ambient air around Shanghai. 相似文献
759.
Catalytic hydrogenation of polycyclic aromatic hydrocarbons (PAHs) with up to four fused benzene rings over high-density-polyethylene-stabilized palladium nanoparticles in supercritical carbon dioxide via in situ UV/Vis spectroscopy is presented. PAHs can be efficiently converted to saturated polycyclic hydrocarbons using this green technique under mild conditions at 20 MPa of CO2 containing 1 MPa of H2 at 40-50 °C. Kinetic studies based on in situ UV/Vis spectra of the CO2 phase reveal that the initial hydrogenation of a given PAH and the subsequent hydrogenations of its intermediates are pseudo-first-order. The hydrogenation rate of the latter is always much smaller than that of the former probably due to increasing steric hindrance introduced by the hydrogenated benzene rings of PAHs which impedes the adsorption process and hydrogen access to PAHs on catalyst surfaces. 相似文献
760.
It has been speculated that maternal phthalate exposure may affect reproductive development in human newborns. However, the mechanism awaits further investigation. The aim is to evaluate the association between maternal phthalate exposure and cord sex steroid hormones in pregnant women and their newborns from the general population. A total of 155 maternal and infant pair were recruited and analyzed. Levels of urinary phthalate metabolites and sex steroid hormones were determined using liquid chromatography/electrospray tandem mass spectrometry (LC-ESI-MS/MS) and radioimmunoassay (RIA), respectively. No significant correlation was found between each steroid hormones and phthalate metabolites for male newborns, except MMP was marginally significantly correlated with E2. After adjusting for maternal age, estradiol (E2) levels in cord serum from male newborns were not correlated with maternal urinary phthalate metabolites. In female newborns, the maternal urinary levels of mono-(2-ethylhexyl) phthalate (MEHP) and mono-(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP) were negatively correlated with the free testosterone (fT) and fT/E2 levels in cord serum with Pearson correlation coefficients ranging between −0.24 and −0.29 (p < 0.05). Additionally, after gestational age was adjusted, the maternal urinary level of DEHP was negatively correlated with the free testosterone (fT) and fT/E2 levels in cord serum. We suggest that maternal exposure to phthalates may affect sex steroid hormones status in fetal and newborn stage. 相似文献