以非贵金属Cu、Fe、Mn和Ce为主要活性成分和TiO2、-γA l2O3为载体,制备了10种用于催化湿式氧化法处理糖蜜酒精废液的催化剂。考察了载体、焙烧温度、成分配比对催化剂催化活性与稳定性的影响,研究了氧气分压、催化剂投加量、反应温度和反应时间对催化湿式氧化过程的影响规律。结果表明:(1)Fe-Mn/-γA l2O3(3∶1∶1)催化剂是催化湿式氧化法处理糖蜜酒精废液的可选催化剂;(2)适宜的氧气供应量为理论需氧量的3.4~4.6倍,催化剂的投加量以10 g/L为佳;在300℃下反应30 m in或在280℃下反应60 m in,处理水可达到污水综合排放标准GB9878-1996的三级标准。 相似文献
In this paper, continuous production of hydrogen through fermentation with liquid swine manure as substrate was researched using a semi-continuously fed fermenter (8 L in total volume and 4 L in working volume). The pH and temperature for the fermenter were controlled at 5.3 +/- 0.1 and 35 +/- 1 degrees C, respectively, throughout the experiment. Three hydraulic retention times (16, 20, and 24 h) were investigated for their impact on the efficiency and performance of the fermenter in terms of hydrogen yields. The results indicate that hydraulic retention time (HRT) has a strong influence on the fermenter performance. An increasing HRT would increase the variation in hydrogen concentration in the offgas. To produce hydrogen with a fairly consistent concentration, the HRT of the fermenter should not exceed 16 h, which, however, did not appear to be short enough to control methanogenesis because the offgas still contained about 5% methane. When methane content in the offgas exceeded 2%, an inverse linear relationship between hydrogen and methane was observed with a correlation coefficient of 0.9699. To increase hydrogen content in the offgas, methane production has to be limited to below 2%. Also, keeping oxygen content in the fermenter below 1.5% would increase the hydrogen concentration to over 15%. The product to substrate ratio was found to be around 50% for the fermenter system studied, evidenced by the observation that for every 6 liters of manure fermented, 3 liters of pure hydrogen were produced, which was significant and encouraging. 相似文献
Quasi-dynamic leaching characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from raw and solidified air pollution control (APC) residues were examined via a nine-time multiple leaching test. The effect of injected activated carbon in the APC residues on the PCDD/F leachability was also evaluated. When humic acid solution was used as a leachant, the leaching concentrations of PCDD/Fs fluctuated between the first and the fifth leaching, followed by a gradual increase and then suddenly reached maximum values at the leaching sequences around seventh and eighth. This significant enhancement in PCDD/F leachability was mainly due to an increase in the release of highly chlorinated PCDD/Fs. Leaching of PCDD/Fs with n-hexane was, in contrast, primarily caused by the partitioning of hydrophobic PCDD/Fs between the APC residue surface and the liquid phase of n-hexane. Consequently, the largest leaching concentrations for n-hexane tests achieved at the first leaching, followed by a decrease and reached plateaus. Solidification/stabilization (S/S) decreased the PCDD/F leachability up to the fifth leaching by the use of humic acid solution. However, S/S increased the PCDD/F leaching concentrations and rates with n-hexane. The activated carbon in APC residues significantly inhibited the release of PCDD/F with n-hexane. The inhibiting effect provided by activated carbon was, however, less significant by the use of humic acid solution. 相似文献
The continuous increase in waste generation warrants global management of waste to reduce the adverse economic, social, and environmental impact of waste while achieving goals for sustainability. The complexity of waste management systems due to different waste management practices renders such systems difficult to analyze. System dynamics (SD) approach aids in conceptualizing and analyzing the structure, interactions, and mode of behavior of the complex systems. The impact of the underlying components can therefore be assessed in an integrated way while the impact of possible policies on the system can be studied to implement appropriate decisions. This review summarizes various applications of SD pertinent to the waste management practices in different countries. Practices may include waste generation, reduction, reuse/recovery, recycling, and disposal. Each study supports regional-demanding targets in environmental, social, and economic scopes such as expanding landfill life span, implementing proper disposal fee, global warming mitigation, energy generation/saving, etc. The interacting variables in the WMS are specifically determined based on the defined problem, ultimate goal, and the type of waste. Generally, population and gross domestic product can increase the waste generation. An increase in waste reduction, source separation, and recycling rate could decrease the environmental impact, but it is not necessarily profitable from an economic perspective. Incentives to separate waste and knowledge about waste management are variables that always have a positive impact on the entire system.