醋酸乙烯生产过程废触媒的资源化回收

采用正交实验研究了微波、超声波条件对废触媒解吸效果的影响，对比实验结果表明，1次微波2次超声波联用技术锌的洗脱率较高，回收的活性炭超过了林业局粉状活性炭二级品指标。用洗脱的醋酸锌溶液制备的磷酸锌符合防锈颜料要求。最终的废液采用电石废渣中和后达到国家废水处理三级排放标准。实现了废触媒的综合回收利用。     

The effects of different carbon sources on microbial mediation of arsenic in arsenic-contaminated sediment

Changes in speciation and mobility of As by indigenous bacteria in As-contaminated sediments (339 mg/kg) from an abandoned Au–Ag mine area in Korea were investigated after biostimulation with a variety of carbon sources, including acetate, lactate and glucose in batch experiments. Sequential extraction analysis designed to determine the form of As occurrence revealed that 40 and 47% of As were present in the sediment as Fe-associated and residual fractions, respectively. After 22-day incubation with acetate and lactate, the presence of indigenous bacteria increased the amount of total dissolved As from both Fe-associated and residual fractions in the sediment. More than 99% of dissolved As existed as As(V) in biotic slurries in contrast to sterile controls (less than 50% of total dissolved As), which indicated that indigenous bacteria transformed some dissolved As(III) to As(V). In real environments, depending on the pH, microbially-produced aqueous As(V) may be either immobilized through adsorption or reduced to As(III) after migration to the anoxic subsurface.     

Influence of atmospheric stability on the mass concentration and chemical composition of atmospheric particles: a case study in Rome, Italy

PM(10) concentration and chemical composition (ions and carbon compounds) at three sampling stations in Rome and in its surroundings was determined daily during a one-month field study, carried out during December 2003. PM concentration at the traffic station was considerably higher than at the urban background and semi-rural stations; elemental carbon was detected as one of the chemical components responsible for this increase. The difference in the concentration of sulphate and ammonium was negligible, as it was expected for secondary pollutants. A negative artefact in the determination of ammonium nitrate by means of heated automatic monitors was highlighted. The dilution properties of the lower atmosphere were traced by means of a natural radioactivity monitor. This parameter has been found to play an essential role in pollution buildup. A considerable increase in PM concentration was observed to coincide with periods of atmospheric stability. The main difference in PM composition between periods of high concentration and periods of "clean" air was found to be in the increase of ammonium nitrate concentration.     

A synomone imparting distinct sex pheromone communication channels for Choristoneura rosaceana (Harris) and Pandemis limitata (Robinson) (Lepidoptera: Tortricidae)

Summary. Male obliquebanded leafrollers, Choristoneura rosaceana (Harris), were induced to respond to a pheromone source tainted with a behavioural antagonist, Z9-tetradecenyl acetate, when a source releasing the antagonist was placed 10 cm upwind of the tainted source in a wind tunnel. However, placement of the antagonist upwind of an attractive pheromone source did not interrupt pheromone-mediated responses. Placement of a source releasing Z9-tetradecenyl acetate, a minor pheromone component of the sympatric species, the threelined leafroller, Pandemis limitata (Robinson), upwind of a calling P. limitata female, reduced conspecific male pheromone-mediated response but resulted in upwind flight by male C. rosaceana and contact with heterospecific females. Male P. limitata locked on and flew upwind to but did not contact heterospecific females when a source releasing Z9-tetradecenyl acetate was positioned upwind of a calling C. rosaceana female. In the field, adaptation or habituation to Z9-tetradecenyl acetate caused by atmospheric treatment with this compound apparently resulted in reciprocal heterospecific pheromone responses. More C. rosaceana males were captured in traps baited with their pheromone and the behavioural antagonist in small field plots treated atmospherically with Z9-tetradecenyl acetate than in nontreated control plots. Fewer male P. limitata were captured in traps baited with their own pheromone, or with C. rosaceana pheromone tainted with Z9-tetradecenyl acetate in plots treated atmospherically with Z9-tetradecenyl acetate than in nontreated control plots. We argue that Z9-tetradecenyl acetate is an important synomone which assists in partitioning the sexual chemical communication channels of C. rosaceana and P. limitata. Received 9 February 1999; accepted 22 March 1999.     

Efficient production of hydrogen peroxide in microbial reverse-electrodialysis cells coupled with thermolytic solutions

● Appreciable H₂O₂ production rate was achieved in MRCs utilizing NH₄HCO₃ solutions. ● Carbon black outperformed activated carbon as the catalyst for H₂O₂ production. ● The optimum carbon black loading for H₂O₂ production on air-cathode was 10 mg/cm². ● The optimum number of cell pairs was determined to be three. ● A maximum power density of 980 mW/m² was produced by MRCs with 5 cell pairs. H₂O₂ was produced at an appreciable rate in microbial reverse-electrodialysis cells (MRCs) coupled with thermolytic solutions, which can simultaneously capture waste heat as electrical energy. To determine the optimal cathode and membrane stack configurations for H₂O₂ production, different catalysts, catalyst loadings and numbers of membrane cell pairs were tested. Carbon black (CB) outperformed activated carbon (AC) for H₂O₂ production, although AC showed higher catalytic activity for oxygen reduction. The optimum CB loading was 10 mg/cm² in terms of both the H₂O₂ production rate and power production. The optimum number of cell pairs was determined to be three based on a tradeoff between H₂O₂ production and capital costs. A H₂O₂ production rate as high as 0.99 ± 0.10 mmol/(L·h) was achieved with 10 mg/cm² CB loading and 3 cell pairs, where the H₂O₂ recovery efficiency was 52 ± 2% and the maximum power density was 780 ± 37 mW/m². Increasing the number of cell pairs to five resulted in an increase in maximum power density (980 ± 21 mW/m²) but showed limited effects on H₂O₂ production. These results indicated that MRCs can be an efficient method for sustainable H₂O₂ production.     

Anammox: an option for ammonium removal in bioreactor landfills

Experiments carried out in bioreactor landfill simulators demonstrated that more than 40% of the total N was transferred into the liquid and gas phases during the incubation period of 380 days. Ammonium, an end product of protein degradation and important parameter to consider during landfill closure, tends to accumulate up to inhibitory levels in the leachate of landfills especially in landfills with leachate recirculation. Most efforts to remove ammonium from leachate have been focused on ex situ and partial in situ methods such as nitrification, denitrification and chemical precipitation. Besides minimal contributions from other N-removal processes, Anammox (Anaerobic Ammonium Oxidation) bacteria were found to be active within the simulators. Anammox is considered to be an important contributor to remove N from the solid matrix. However, it was unclear how the necessary nitrite for Anammox metabolism was produced. Moreover, little is known about the nature of residual nitrogen in the waste mass and possible mechanisms to remove it. Intrusion of small quantities of O₂ is not only beneficial for the degradation process of municipal solid waste (MSW) in bioreactor landfills but also significant for the development of the Anammox bacteria that contributed to the removal of ammonium. Volatilisation and Anammox activity were the main N removal mechanisms in these pilot-scale simulators. The results of these experiments bring new insights on the behaviour, evolution and fate of nitrogen from solid waste and present the first evidence of the existence of Anammox activity in bioreactor landfill simulators.     

Acid aerosols in the Pittsburgh Metropolitan area

This article presents data on ambient concentrations of selected acidic aerosols at four existing monitoring sites in the Pittsburgh PA metropolitan area. The data were collected by staff of the Allegheny County Health Department, Division of Air Quality during the summer and fall of 1993. The sampling protocol was focused on obtaining 24 h-average ammonia, ammonium, acidic sulfates, and particle strong acids data on a 2 to 3 day cycle. The data were obtained using Harvard University School of Public Health's “Short-HEADS” annular denuder sampling train. The Pittsburgh area is of interest because it is downwind of a major regional source of sulfur and nitrogen emissions from coal-burning power plants: the Ohio River Valley. The data presented here indicate that ground-level concentrations of acidic aerosols in Pittsburgh are highly correlated spatially and that many pollutants are higher on days when ground-level wind direction vectors indicate that wind is coming from the southwest rather than from the Pittsburgh source area itself. The monitoring site that is most upwind of the Pittsburgh source area – South Fayette – has particle strong acid levels about twice those of sites closer in to the Pittsburgh central business district.     

反硝化除磷的影响特性试验

采用SBR反应器(厌氧/缺氧/好氧工艺),分别研究了乙酸盐及硝酸盐浓度变化对反硝化除磷的影响特性。试验结果表明,当进水COD浓度>230mg/L时,乙酸盐浓度的变化对释磷、除磷速率等影响并不显著。在硝酸盐浓度<30mg/L时,硝酸盐浓度越高,缺氧段除磷速率也就越高。在C/P>23,C/N>5条件下,SBR系统对磷、氮去除率在90%以上。     

铝箔复合膜集气袋对有机废气的适用性研究

通过在不同的时间段,测定存放于铝箔复合膜集气袋和玻璃注射器的丙酮,醋酸乙酯,苯,异丙醇标准气的浓度,气体浓度与贮存时间的关系,本次试验结果表明,丙酮,醋酸乙酯,苯,异丙醇在铝箔气袋中的稳定性明显优于在玻璃注射器中,应尽可能在８－２４ｈ内测定。