Use of polymeric sub-micron ion-exchange resins for removal of lead, copper, zinc, and nickel from natural waters

This research investigated the removal capacity of polymeric sub-micron ion-exchange resins(SMR) for removal of lead, copper, zinc, and nickel from natural waters in competition with natural organic matter(NOM). Polymeric SMR particles were created and tested to ensure that they were adequately dispersed in the solution. They removed little NOM(10%or less) from river water and wastewater, indicating that competition from NOM was not a major concern. SMR were able to remove 82% ± 0.2% of lead, 46% ± 0.6% of copper, 55% ±20% of zinc, and 17% ± 2% of nickel from river water spiked with 500 μg/L of each. Similarly,in wastewater, they were able to remove 86% ± 0.1% of lead, 38% ± 0.8% of copper, 28% ± 1%of zinc, and 11% ± 1% of nickel.     

地膜覆盖和施氮对菜地CO2通量的影响

为了探讨地膜覆盖和不同施氮处理对菜地生态系统CO₂净交换通量（Net CO₂ Ecosystem Exchange,简称NEE）、生态系统呼吸通量（Ecosystem Respiration,简称ER）及总初级生产力（Gross Primary Productivity,简称GPP）的影响,以辣椒-萝卜轮作菜地为研究对象,采用静态明/暗箱-气相色谱法,进行了为期1 a（2014年5月-2015年4月）的田间原位观测.试验设置8个处理,分别为常规无氮（CN0）、覆膜无氮（MN0）、常规低氮（CN1）、覆膜低氮（MN1）、常规中氮（CN2）、覆膜中氮（MN2）、常规高氮（CN3）、覆膜高氮（MN3）.结果表明,辣椒季累积NEE最大值分别为CN3和MN3处理下的-30.96和-29.83 t·hm^-2,累积ER排放量最大值分别为CN1和MN1处理下的40.18和39.16 t·hm^-2,累积GPP最大值分别为CN3和MN3处理下的70.60和68.61 t·hm^-2;萝卜季累积NEE最大值分别为CN3和MN3处理下的-22.25和-24.88 t·hm^-2,累积ER排放量最大值分别为CN2和MN2处理下的17.00和19.43 t·hm^-2,累积GPP最大值分别为CN3和MN3处理下的37.92和43.80 t·hm^-2.在两个生长季中,覆膜及覆膜和施氮的交互作用只对辣椒季中ER有显著影响,对于NEE和GPP均无显著影响（p>0.05）;施氮显著提高了菜地生态系统NEE和GPP而降低了辣椒季ER（p<0.05）,并且这种增加或降低效应随着施氮量的提高而逐渐增强.本研究中菜地呈现碳汇并随着施氮水平的提高碳汇逐渐增强,而覆膜对CO₂固定无显著影响,表明常规高氮的农田管理措施能够提高西南地区代表性的辣椒-萝卜轮作菜地的固碳潜力,对该地区农田生态系统碳的源/汇功能具有一定的参考意义.     

基于TBL模型的闽江口围垦养虾塘水-大气界面CO2扩散通量估算

扩散模型是估算水生生态系统水-大气界面二氧化碳(CO_2)交换通量的重要手段.选取多种参数化方法对闽江口围垦养虾塘水-大气界面CO_2气体交换速率(k_x)及CO_2扩散通量进行估算,探讨闽江口围垦养虾塘k_x及CO_2扩散通量的变化特征及影响因素.结果表明:①养殖期水-大气界面CO_2气体交换速率及其扩散通量均呈现显著的时间变化特征,分别表现为10月 9月 11月 7月 8月和11月 7月 8月 9月 10月的变化趋势;②风速、pH、水体CO_2、DOC和叶绿素a(Chl-a)浓度是影响CO_2扩散通量时间变化特征的重要因素;③不同参数化方法计算得出的闽江口养虾塘水-大气界面CO_2扩散通量存在显著差异(P 0. 01),表明模型方法估算养殖塘CO_2扩散通量具有一定不确定性,综合分析认为模型RC01和CW03是估算闽江口围垦养虾塘水-大气界面CO_2扩散通量较为合适的方法.     

离子交换树脂在污泥处理中的应用及展望

离子交换树脂(IER)因其不溶性以及可循环利用性被广泛用于废水处理,但目前仍缺乏其对污泥应用研究的综述。本文汇总了污泥中常见IER类型(阳离子交换树脂、阴离子交换树脂以及螯合树脂),并介绍了树脂的基本特性以及适用的污泥方向,其中阳离子交换树脂,尤其是强酸性苯乙烯系阳离子交换树脂,适用范围最广。IER在污泥中的应用归为4类,分别为去除/回收重金属、回收磷、胞外聚合物提取以及调理污泥,并阐述了基本应用机理以及优缺点。针对IER在污泥中应用的不足,提出未来的研究方向,包括改性或开发新型IER去除/回收污泥中的重金属,优化IER直接回收污泥中磷的方法,改进IER调理污泥的方式以及开发新型分离IER与污泥的手段。本文有助于研究人员更好的了解IER在污水厂污泥中的应用现状,优化IER处理污泥的应用方式以及开发应用于污泥处理的新型IER。     

Conservation practitioners’ understanding of how to manage evolutionary processes

Both academics and practitioners consider a lack of knowledge about evolutionary theory to be a general barrier to effectively managing genetic diversity. However, it is challenging to judge practitioners’ level of understanding and how this influences their management decisions. Knowledge built through experience may be difficult for practitioners to articulate, but could nonetheless result in appropriate management strategies. To date, researchers have assessed only the explicit (formal) knowledge practitioners have of evolutionary concepts. To explore practitioners’ understanding of evolutionary concepts, it is necessary to consider how they might apply explicit and implicit knowledge to their management decisions. Using an online survey, we asked Australian practitioners to respond to 2 common management scenarios in which there is strong evidence that managing genetic diversity can improve outcomes: managing small, isolated populations and sourcing seeds for restoration projects. In describing their approach to these scenarios, practitioners demonstrated a stronger understanding of the effective management of genetic diversity than the definitions of the relevant concepts. However, their management of genetic diversity within small populations was closer to best practice than for restoration projects. Moreover, the risks practitioners described in implementing best practice management were more likely to affect their approach to restoration than translocation projects. These findings provide evidence that strategies to build the capacity of practitioners to manage genetic diversity should focus on realistic management scenarios. Given that practitioners recognize the importance of adapting their practices and the strong evidence for the benefits of actively managing genetic diversity, there is hope that better engagement by evolutionary biologists with practitioners could facilitate significant shifts toward evolutionarily enlightened management.     

Impact of authentic leadership on performance: Role of followers' positive psychological capital and relational processes

Authentic leadership has received considerable attention and research support over the past decade. Now the time has come to refine and better understand how it impacts performance. This study investigates the moderating role followers' positive psychological capital (PsyCap) and the mediating role that leader–member exchange (LMX) may play in influencing the relationship between authentic leadership and followers' performance. Specifically, we tested this mediated moderation model with matched data from 794 followers and their immediate leaders. We found that authentic leadership is positively related to LMX and consequently followers' performance, and to a larger degree, among followers who have low rather than high levels of PsyCap. Our discussion highlights the benefits of understanding the roles of relational processes and followers' positive psychological resources involved in the effectiveness of authentic leadership and how they can be practically implemented. Copyright © 2012 John Wiley & Sons, Ltd.     

Preparation of a novel anion exchange group modified hyper-crosslinked resin for the effective adsorption of both tetracycline and humic acid

A novel hyper-crosslinked resin (MENQ) modified with an anion exchange group was prepared using divinylbenzene (DVB) and methyl acrylate (MA) as comonomers via four steps: suspension polymerization, post-crosslinking, ammonolysis and alkylation reactions. The obtained resin had both a high specific surface area (793.34 m²·g^-1) and a large exchange capacity (strong base anion exchange capacity, SEC: 0.74 mmol·g^-1, weak base anion exchange capacity, WEC: 0.45 mmol·g^-1). XAD-4 was selected as an adsorbent for comparison to investigate the adsorption behavior of tetracycline (TC) and humic acid (HA) onto the adsorbents. The results revealed that MENQ could effectively remove both TC and HA. The adsorption capacity of XAD-4 for TC was similar to that of MENQ, but XAD-4 exhibited poor performance for the adsorption of HA. The adsorption isotherms of TC and HA were well-fitted with the Freundlich model, which indicated the existence of heterogeneous adsorption through cation-π bonding and π–π interactions. The optimal solution condition for the adsorption of TC was at a pH of 5–6, whereas the adsorption of HA was enhanced with increasing pH of the solution.     

锰氧化物-阳离子交换树脂复合材料的制备及其对水中重金属的吸附性能

采用原位沉淀-空气氧化法将锰氧化物负载于大孔强酸性阳离子交换树脂D001上,制备出一种新型锰氧化物-阳离子交换树脂复合材料Mn-D001,并对该材料吸附水中Pb2+、Cd2+、Cu2+的性能进行了深入研究.TEM、XRD以及XPS的分析结果表明,负载的锰氧化物以MnO2的形态存在.基于单一金属离子静态吸附的一元体系实验表明,Mn-D001比D001对Pb2+、Cd2+、Cu2+具有更高的吸附选择性,在高浓度竞争离子Ca2+、Mg2+、Na+共存的情况下,仍能保持较高的重金属去除率;Mn-D001对Pb2+、Cd2+、Cu2+的吸附行为符合准一级动力学模型(R2>0.99)和Langmuir吸附等温线模型(R2>0.99).在温度为303 K时,Mn-D001对3种重金属的饱和吸附容量可分别达到476.19 mg.g-1、243.90 mg.g-1及196.08 mg.g-1,优于原有树脂D001.基于复合重金属离子竞争吸附的二元、三元体系的实验表明,Mn-D001对3种重金属的吸附能力顺序为Pb2+>Cu2+>Cd2+,吸附能力由原有树脂D001以及负载的锰氧化物的性质共同决定.     

脉冲滤筒除尘器对超细粉体净化的实验研究

随着工业的快速发展,空气中颗粒污染物的含量和种类越来越多,不仅对人体健康造成危害,颗粒污染还对能见度、气候、动植物均有影响,寻找合适的除尘设备,提高对微细粉尘的除尘效率,对安全和环境保护有着重要而深远的意义。该文利用脉冲滤筒除尘器对粒径分布为0.5-5μm的超细粉体进行净化实验。测试了除尘器净化效率、除尘器阻力及过滤风速等主要性能参数。实验结果说明:脉冲滤筒除尘器对于粒径为0.5-5μm超细粉体,在过滤风速为0.8-1.25m/min时,除尘器阻力小于300Pa,净化效率达99.9999%。得到结论:滤筒除尘器具有高除尘效率,低阻力损失,节约除尘系统的动力消耗的优点,有利于在超细粉体净化工艺中的应用。     

The supervisor POS–LMX–subordinate POS chain: Moderation by reciprocation wariness and supervisor's organizational embodiment

We present three studies providing an increased understanding of the interdependence between perceived organizational support (POS) and leader–member exchange (LMX). Using employees from a social service agency and new hires from a variety of organizations, we report evidence for a relational chain leading from supervisors' perceptions of support by the organization (supervisor POS) to the formation of high‐quality LMX relationships with their subordinates (first link), who interpret high‐quality LMX as support from the organization (subordinate POS, second link) and, ultimately, repay the organization with increased dedication and effort (examined here in terms of reduced withdrawal behavior). The relationship between supervisor POS and LMX with subordinates was strongly moderated by supervisor fear of exploitation in exchange relationships (reciprocation wariness), holding only for supervisors with low reciprocation wariness. Consistent with the view that employees perceive the organization as partly responsible for treatment received from supervisors, LMX was found to be more strongly related to POS when employees highly identified their supervisors with the organization (supervisor's organizational embodiment), and this interaction extended to reduced withdrawal behavior. Copyright © 2013 John Wiley & Sons, Ltd.