Measurement of Ozone Concentrations in Ambient Air Using a Badge-Type Passive Monitor

Abstract

A badge-type passive monitor was used to evaluate the effectiveness of four ozone trapping reagents for measuring O₃ concentrations in the air. These were sodium nitrite (NaNO₂), 3-methyl-2-benzothiazolinone acetone azine (MBTH), p-acetamidophenol (p-ATP), and indigo carmine. Experiments in an exposure chamber showed that only NaNO₂ and MBTH monitors gave sensitive and linear responses over realistic ranges of O₃ concentrations. When tested in ambient air, NaNO₂ and MBTH monitors with a single-layer diffusion barrier overestimated O₃ concentrations by a significant amount. This was largely canceled out in the NaNO₂ monitor by using a multi-layered diffusion barrier to combat wind turbulence effects. However it had almost no effect on the MBTH monitor, and it was found that NO₂ was a source of serious interference. We concluded that using the NaNO₂ monitor with an effective diffusion barrier can measure O₃ in ambient air with an accuracy of ±16%.     

废旧手机电池的回收现状分析及对策一以泸州市为例

网络信息时代的快速发展，以移动电话手机为代表的通讯设备迅猛发展，人们换手机的频率也越来越快，因此产生了大量的废旧手机电池。为了解废旧手机电池的回收利用情况，本研究主要通过对居民就废旧手机电池的处理方式进行了调查和统计，针对泸州市废旧手机电池的处理现状，提出相应的管理措施和回收利用的对策。     

新形势下我国环境管理与改革取向

在"十三五"我国经济新常态的大逻辑下,环境管理机遇和挑战并存。污染欠账多、污染随着产业转移、政策执行走样、排污收费覆盖面窄、收取率低等,制约环境管理和环保产业的发展。对环境污染的严重性和复杂性、生态环境形势的十分严峻性,以及对污染治理的艰巨性和长期性,应当有一个清醒认识。扭转环境保护与经济发展不协调、不可持续状况,满足城乡居民日益高涨的环境诉求,必须调整环境管理思路,加快改革步伐,扭转环境保护"弱势"格局,厘清环境管理、环境事业和环境市场之间的关系,形成以排污许可证为依据的管理主线、以环境标准为准绳的倒逼机制,以环境司法裁定为常态的终身责任追究制度,创造一个人人守法、企业自觉治理污染和保护环境的社会氛围。     

电沉积处理含镉废水的性能研究

电沉积含镉废水考察溶液的不同初始p H、镉的不同初始浓度、电流密度及金属配合物对电沉积效果的影响,利用SEM和XRD对沉积物的表面形貌和物相成分进行分析,研究沉积物金属的存在形式。实验结果表明,p H在1.5~3.5时,溶液中镉的去除效果达到99.3%;一级动力学常数随着初始镉溶液浓度增加而变大;当电流密度为4.46 m A/cm2进行90 min电沉积时反应速率较快且沉积量最大;氨水与镉形成的配合物可以促进电沉积镉的反应速率;对电沉积后的沉积物进行扫描电镜(SEM)和X-射线衍射(XRD)测试。SEM表明,沉积物呈现树枝状的纳米结构。XRD表明,沉积物主要成分为氢氧化镉和镉。     

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hypereutrophic lake: Lake Taihu, China

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP = 18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary.     

Bioreduction of vanadium (V) in groundwater by autohydrogentrophic bacteria: Mechanisms and microorganisms

As one of the transition metals, vanadium (V) (V(V)) in trace amounts represents an essential element for normal cell growth, but becomes toxic when its concentration is above 1 mg/L. V(V) can alter cellular differentiation, gene expression, and other biochemical and metabolic phenomena. A feasible method to detoxify V(V) is to reduce it to V(IV), which precipitates and can be readily removed from the water. The bioreduction of V(V) in a contaminated groundwater was investigated using autohydrogentrophic bacteria and hydrogen gas as the electron donor. Compared with the previous organic donors, H₂ shows the advantages as an ideal electron donor, including nontoxicity and less production of excess biomass. V(V) was 95.5% removed by biochemical reduction when autohydrogentrophic bacteria and hydrogen were both present, and the reduced V(IV) precipitated, leading to total-V removal. Reduction kinetics could be described by a first-order model and were sensitive to pH and temperature, with the optimum ranges of pH 7.5–8.0 and 35–40°C, respectively. Phylogenetic analysis by clone library showed that the dominant species in the experiments with V(V) bioreduction belonged to the β-Proteobacteria. Previously known V(V)-reducing species were absent, suggesting that V(V) reduction was carried out by novel species. Their selective enrichment during V(V) bioreduction suggests that Rhodocyclus, a denitrifying bacterium, and Clostridium, a fermenter known to carry out metal reduction, were responsible for V(V) bioreduction.