Influence of pore structure on biologically activated carbon performance and biofilm microbial characteristics

• Pore structure affects biologically activated carbon performance. • Pore structure determines organic matter (OM) removal mechanism. • Microbial community structure is related to pore structure and OM removal. Optimizing the characteristics of granular activated carbon (GAC) can improve the performance of biologically activated carbon (BAC) filters, and iodine value has always been the principal index for GAC selection. However, in this study, among three types of GAC treating the same humic acid-contaminated water, one had an iodine value 35% lower than the other two, but the dissolved organic carbon removal efficiency of its BAC was less than 5% away from the others. Iodine value was found to influence the removal of different organic fractions instead of the total removal efficiency. Based on the removal and biological characteristics, two possible mechanisms of organic matter removal during steady-state were suggested. For GAC with poor micropore volume and iodine value, high molecular weight substances (3500–9000 Da) were removed mainly through degradation by microorganisms, and the biodegraded organics (soluble microbial by-products,<3500 Da) were released because of the low adsorption capacity of activated carbon. For GAC with higher micropore volume and iodine value, organics with low molecular weight (<3500 Da) were more easily removed, first being adsorbed by micropores and then biodegraded by the biofilm. The biomass was determined by the pore volume with pore diameters greater than 100 μm, but did not correspond to the removal efficiency. Nevertheless, the microbial community structure was coordinate with both the pore structure and the organic removal characteristics. The findings provide a theoretical basis for selecting GAC for the BAC process based on its pore structure.     

不同类型活性炭处理废水中重金属离子的研究进展

重金属对人体的显著毒性和难降解的特性,使重金属水体污染成为全球性关注的环境问题。本文综述了重金属废水的危害、来源及常用处理方法,比较了不同类型活性炭处理废水中重金属离子的差异,阐述了不同类型活性炭处理技术的优势和特点,并对今后的重金属废水处理技术研究方向进行了展望。     

循环经济产业园规划与产业政策和相关规划的协调性分析

循环经济产业园规划与相关规划的协调性分析是论证循环经济产业园规划合理性的关键环节之一。以武汉市千子山循环经济产业园为例,通过对该产业园规划与产业政策和相关规划的协调性分析,论证了千子山循环经济产业园规划的合理性,为国内同类产业园规划提供参考。     

The passion bug: How and when do leaders inspire work passion?

Drawing from signaling theory, we propose a work passion transfer model where leaders' passion is transmitted to employees through the former's leadership style and is contingent on employees' perceived importance of performance to self-esteem (IPSE). Data from 201 supervisor–employee dyads from the health-care industry show that leaders' harmonious passion led to employees' harmonious passion through charismatic leadership, whereas contingent reward leadership accounted for the transfer of obsessive passion; IPSE did not play a moderating role for either form of passion. Results from a supplementary study further reveal that the link between leadership and employee passion operated through employees' perception of leader passion and that employees' IPSE accentuated for the relationship between perceived leader obsessive passion and employees' obsessive passion. This study advances research in work passion, leadership, and signaling theory and provides important implications for managerial practice.     

On the search for mimetic patterns in environmental disclosure: an international perspective

In this paper, we assert and test the proposition that environmental disclosure (ED) is structured by institutionalised myths and that is why ED is decoupled from environmental performance and media pressures. Focusing on firms from Canada, France and Germany, findings show that ED mimetic isomorphism for different topics varies among countries and by industry sensitiveness to the environment. The results corroborate the institutional presumption that institutionalised myths vary among different contexts. Our findings also suggest that institutionalised ED structures may not reflect environmental performance, mimetic patterns being affected by environmental performance. However, the decoupling between ED mimetic isomorphism and environmental performance decrease when firms’ ED credibility is questioned by the media.     

微波强化CWPO工艺CuO_x-CeO_2/GAC催化剂的制备及其对二甲亚砜的降解

以颗粒活性炭(GAC)为载体、铜为活性组分、铈为助剂组分、草酸钠为沉淀剂,采用浸渍焙烧法制得CuO_x-CeO_2/GAC催化剂。以H_2O_2为氧化剂,微波强化催化湿式过氧化氢氧化(CWPO)处理二甲亚砜(DMSO)初始质量浓度为1 000 mg/L的废水,处理3 min后DMSO去除率达93.8%。催化剂第7次使用时DMSO去除率仍保持在75%以上。初始废水pH在3~9范围内,DMSO去除率均在85%以上。助剂Ce的加入提高了催化剂表面活性组分的分散性和稳定性,使催化剂的活性稳定性和使用寿命显著提高。     

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction

Objective: The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures.

Methods: For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures.

Results: Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance.

Conclusions: The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.     

三维电极电Fenton氧化法处理染料废水

采用三维电极电Fenton氧化法处理实际染料废水,探究了染料废水处理效果的影响因素。实验结果表明：以钌铱镀层钛电极为阳极、不锈钢板为阴极、粉末活性炭为颗粒电极,在粉末活性炭投加量为2.0 g/L、电流密度为0.5 mA/mm²、极板间距为3 cm、pH为2.0、硫酸亚铁投加量为0.50 g/L的最优工艺条件下,反应2 h后COD、TOC、氨氮、色度的去除率达到最大,分别为62.80%、41.15%、42.48%和95.00%;粉末活性炭作为颗粒电极可使染料废水COD去除率提高18个百分点;重复使用10次的处理效果与第2次基本持平。     

Review: recent advances in biogas purifying technologies

Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainable society. This paper presents a comprehensive list of biogas upgrading technologies focused on carbon dioxide removal as well as recent advances reported by researcher with wide expertise in this topic. Additionally, an extensive costs–performance comparison among the technologies studied is discussed. Among the different alternatives, chemical scrubbing stood out to achieve high biomethane purities while cryogenic technologies proved to be effective against methane losses. Regarding the different costs, water scrubbing and membrane separation seem to be the most affordable techniques.     

Cumulative carbon emissions and economic policy: In search of general principles

We exploit recent advances in climate science to develop a physically consistent, yet surprisingly simple, model of climate policy. It seems that key economic models have greatly overestimated the delay between carbon emissions and warming, and ignored the saturation of carbon sinks that takes place when the atmospheric concentration of carbon dioxide rises. This has important implications for climate policy. If carbon emissions are abated, damages are avoided almost immediately. Therefore it is optimal to reduce emissions significantly in the near term and bring about a slow transition to optimal peak warming, even if optimal steady-state/peak warming is high. The optimal carbon price should start relatively high and grow relatively fast.