Positively charged microporous ceramic membrane for the removal of Titan Yellow through electrostatic adsorption

To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane.The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y_2O_3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421 L/(m~2·hr) under the trans-membrane pressure of 0.03 bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10 mg/L between pH 3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater.     

Influences and mechanisms of nanoparticles on pentachloronitrobenzene accumulation by earthworms

Environmental Science and Pollution Research - Pesticides and nanoparticles may coexist in soil; however, influences of nanoparticles on accumulation of pesticides in terrestrial organisms are...     

税收竞争对环境污染的影响及传导机制分析

在中国经济高增长的背后,环境污染问题愈发凸显,不利于经济的可持续增长。税收竞争是影响环境污染的主要因素之一,但是学术界研究税收竞争对环境污染的影响及其作用机制的较少。本文按照污染物属性将其划分为外溢性污染物和非外溢性污染物,通过构建一个包含生产者、消费者、地方政府及中央政府的一般均衡模型,刻画了在税收竞争的背景下,地方政府的税收征管效率对不同属性污染物的影响及其传导机制。结果发现当污染物具有外溢性属性时,税收征管效率对该地环境污染的影响通过改变本地及周边地区资本存量渠道实现;当污染物具有非外溢性属性时,降低税收征管效率通过增加该地区资本存量而提高了环境污染。文章首先使用随机前沿模型测算了2007—2014年中国28个省份企业所得税的税收征管效率,并将其作为税收竞争的衡量指标,然后运用系统GMM法证实了所提的假说。研究显示:地方政府的税收竞争增加了本地区的资本存量;税收竞争是将本地资本存量作为其推高外溢性污染物(二氧化硫)及非外溢性污染物(固体废弃物)排放量的一个主要渠道,邻近地区资本存量则是推高外溢性污染物(二氧化硫)的次要渠道。这意味着,要想改善环境质量,中央政府应规范地方政府的税收竞争行为,尽快建立一套科学、有效的绿色GDP评价体系;完善地方转移支付制度;应针对各个地区的污染及经济发展情况利用财政激励手段引入环保、绿色的资本项目;地方政府应减少不利于环境改善的地方财政支出,增加环保投入比重。     

Investigation of declared seating preference and measured cognitive performance in a sunlit room

Current daylighting standards are not sufficient to guarantee a high-quality daylighting experience as they fail to take the behavior of building occupants into consideration. The way that a daylit room is appreciated and used has not been fully explored, especially under sunlighting conditions. This research is the first of its kind to assess how the distance between a subject and a sun patch on the floor is related to a broad range of behavioral responses, including conclusive preference and measured cognitive performance. One hundred subjects participated in a controlled experiment in a work setting. Investigations of the declared preferences of seating area and subjects' cognitive performances indicated that people are not always aware of the environmental factors that influence their behavior. Subjects were generally attracted to sunlight and outdoor views, but they did not necessarily perform best in these preferred areas. Privacy and a sense of control were two hidden factors that greatly affected subjects' decisions and performances. Current daylighting literature and design practice do not pay adequate attention to such factors as sense of visual control or privacy in the design of rooms. On the other hand, the perceived problem of visual glare caused by sunlight penetration did not affect performance as much as subjects believed it would. An additional result suggested that individual behaviors were more affected by environmental elements than were group activities.     

热水解-厌氧消化工艺中污泥的触变性分析

采用触变动力学系数作为评价指标,通过流变试验研究了热水解-厌氧消化联合工艺中污泥标准化黏度和触变性的变化规律,并探讨了屈服应力和触变性二者间的联系,从触变性角度为热水解-厌氧消化污泥的处理处置提供参考依据。结果表明:与滞后环相比,用触变动力学系数K更适合表征污泥的触变性;调配污泥、热水解污泥和厌氧消化污泥的标准化黏度均随时间增大逐渐减小;3种污泥的触变性随TSS质量分数增大而减小,经热水解-厌氧消化后污泥的触变性增大,流动性增强;污泥屈服应力越大,触变性越小,稳定性越强。     

珠江三角洲农业土壤重金属含量特征研究

调查研究了珠江三角洲农业土壤中重金属的分布规律,在研究区域采集了212个表层土壤样品,分析了其中8种重金属元素(Cu,Pb,Zn,Cr,Ni,Cd,As和Hg)的全量与有效态含量.结果表明:在珠江三角洲农业土壤中,8种重金属元素的含量均有超标现象,其中以Zn,Cd和Hg的超标率较高;在所有重金属元素中,Cd的有效态占全量的比率最高,平均为45.58%;而Hg所占的比率最低,平均仅为0.41%.重金属的有效态含量与全量存在正相关关系.交通、污水灌溉、工业污染、垃圾和城市污泥是造成珠江三角洲土壤重金属污染的主要原因.      

区域大气污染物总量控制技术与示范研究

分析了我国的大气环境问题和特征,剖析了大气污染的成因;重点介绍了区域大气污染物总量控制技术研究中,大气污染物排放清单的编制技术,多尺度的空气质量模拟技术,基于现代控制理论的大气环境容量优化技术,基于环境容量和排放绩效的总量分配技术,多种总量监控方法,科学有效的总量控制管理机制和规则等的关键技术、技术突破、主要研究与理论创新及成果的应用与示范;紧密结合国家空气环境质量管理和大气污染控制的需要,提出了我国大气环境管理、政策和大气环境科学研究的建议.      

Rapid and long-effective removal of broad-spectrum pollutants from aqueous system by ZVI/oxidants

• The coupling of oxidants with ZVI overcome the impedance of ZVI passive layer. • ZVI/oxidants system achieved fast and long-effective removal of contaminants. • Multiple mechanisms are involved in contaminants removal by ZVI/oxidant system. • ZVI/Oxidants did not change the reducing property of ORP in the fixed-bed system. Zero-valent iron (ZVI) technology has recently gained significant interest in the efficient sequestration of a wide variety of contaminants. However, surface passivation of ZVI because of its intrinsic passive layer would lead to the inferior reactivity of ZVI and its lower efficacy in contaminant removal. Therefore, to activate the ZVI surface cheaply, continuously, and efficiently is an important challenge that ZVI technology must overcome before its wide-scale application. To date, several physical and chemical approaches have been extensively applied to increase the reactivity of the ZVI surface toward the elimination of broad-spectrum pollutants. Nevertheless, these techniques have several limitations such as low efficacy, narrow working pH, eco-toxicity, and high installation cost. The objective of this mini-review paper is to identify the critical role of oxygen in determining the reactivity of ZVI toward contaminant removal. Subsequently, the effect of three typical oxidants (H₂O₂, KMnO₄, and NaClO) on broad-spectrum contaminants removal by ZVI has been documented and discussed. The reaction mechanism and sequestration efficacies of the ZVI/oxidant system were evaluated and reviewed. The technical basis of the ZVI/oxidant approach is based on the half-reaction of the cathodic reduction of the oxidants. The oxidants commonly used in the water treatment industry, i.e., NaClO, O₃, and H₂O₂, can be served as an ideal coupling electron receptor. With the combination of these oxidants, the surface corrosion of ZVI can be continuously driven. The ZVI/oxidants technology has been compared with other conventional technologies and conclusions have been drawn.     

利用粒子群算法确定阶段曝气法设计中的泥龄

确定泥龄(SRT)是成功设计活性污泥法的关键,以往的SRT通常根据经验来估算。给出了确定阶段曝气法设置中SRT的一元无约束优化模型,并应用粒子群算法(PSO)求解该优化问题。数值实例结果表明,PSO能精确、快速地求解SRT,为污水处理厂的设计提供了理论依据。     

Gas/particle partitioning of polycyclic aromatic hydrocarbons in coastal atmosphere of the north Yellow Sea, China

Samples of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected at three sampling stations (Xiaomai Island, Laohutan, and Zhangzi Island) in the north Yellow Sea, China during November 2008 and September 2009 to study their atmospheric transport potential and the gas/particle distributions. The composition of PAHs was dominated by gaseous compounds. The percentages of the particle-phase PAHs to the total concentrations were found to be higher during the heating period than the non-heating period. The ratios of naphthalene and acenaphthene to phenanthrene, chrysene and dibenzo(a,h)anthracene showed an increasing trend from Xiaomai Island to Zhangzi Island, which can be called as the local atmospheric distillation of PAHs. Gas/particle partitioning coefficients (K _p) and their relationship with the sub-cooled liquid vapor pressures (pº_L) of PAHs were investigated. The regressions of logK _p versus logpº_L gave significant correlations for all samples of the three sites with r ² values in the range 0.56–0.66 (p?<?0.01). Both Junge–Pankow adsorption model and octanol–air partition coefficient absorption model tended to underestimate the sorption for most PAHs, but the absorption model appeared to be more suitable for predicting the particle fraction of PAHs than the Junge–Pankow model.