微波催化燃烧技术处理印刷包装行业VOCs

微波催化燃烧技术将微波辐照与吸波型催化剂相结合,可用于对挥发性有机化合物(VOCs)进行催化燃烧处置.研制了 Pt/CuMnCeOx/堇青石和Pt/CuMnCeOx/纳米陶瓷整体式蜂窝状催化剂,并开发了微波催化燃烧VOCs的装置,将其应用于印刷包装行业的VOCs治理.通过操作条件的优化,考察了微波催化燃烧技术对VOCs...     

Factors Determining the Choice of Hunting and Trading Bushmeat in the Kilombero Valley,Tanzania

Regulation of illegal bushmeat trade is a major conservation challenge in Africa. We investigated what factors are most likely to induce actors in the bushmeat trade to shift to an alternative occupation by conducting a choice experiment with 325 actors in the bushmeat trade in the Kilombero Valley, Tanzania. Specifically, we asked respondents to choose between hunting or trading bushmeat and alternative salary‐paying work, in a set of hypothetical scenarios where the attributes of these alternatives were varied and included measures of command and control, price of substitute meat, daily salary in the work option, and whether or not cows were donated to the respondent. We modeled the choice contingent on socioeconomic characteristics. The magnitude of fines and patrolling frequency had a significant but very low negative effect on the probability of choosing to engage in hunting or trading bushmeat compared with the salary of an alternative occupation. Donation of livestock and the price of substitute meats in the local market both affected the choice significantly in a negative and a positive direction, respectively. The wealthier a household was the more likely the respondent was to choose to continue hunting or trading bushmeat. On the margin, our results suggest that given current conditions in the Kilombero Valley on any given day 90% of the respondents would choose salary work at US$3.37/day over their activities in the bushmeat trade, all else equal. Factores que Determinan la Elección de Cazar y Vender Carne de Caza en el Valle Kilombero, Tanzania     

基于复合LSTM模型的PM2.5浓度预测

在对淄博市19个空气质量监测站点监测数据进行分析后,提出了一种基于机器学习的复合模型——灰色关联度分析(GRA)-改进的完备总体经验模态分解(ICEEMD)-长短期记忆网络(LSTM)模型。通过分析淄博市2019年大气污染物和气象数据,选用LSTM模型预测PM_2.5浓度。由于传统单一模块机器学习模型具有训练时间较长和预测精度较低的问题,提出了复合LSTM模型。该模型由3部分组成：GRA,用于PM_2.5浓度影响因素变量筛选;ICEEMD,用于PM_2.5分解、分量筛选和原始大气污染物及气象数据处理;LSTM,用于PM_2.5浓度预测。预测结果表明：淄博市中部丘陵地带PM_2.5浓度高于南部山区和北部平原,东部高于西部;淄博市逐月PM_2.5浓度呈“U”形分布,1月最高,8月最低;淄博市PM_2.5浓度受PM₁₀和CO影响较大,受湿度和温度影响较小。对比单一LSTM模型和GRA-LSTM模型,GRA-ICEEMD-LSTM模型...     

Seasonal variation and partition of trace metals (Fe, Zn, Cu, Mn, Cr, Cd and Pb) in surface sediments: relationship with physico-chemical variables of water from the Calabar River, South Eastern Nigeria

The seasonal variation and partition of trace metals (Fe, Cu, Zn, Mn, Cd, Cr and Pb) in the surface sediments of the Calabar River are reported. Chemical partition of the metals in the sediments reveals that 2–30% of the total metal load was contributed by the non-detrital (acid-soluble) fraction, while fine-grained host minerals/compounds are the main carriers of the detrital (acid-insoluble) fraction (70–98%). Using multivariate statistical analysis, the seasonal fluctuations in the distribution of some of the metals show significant influence by physio-chemical changes (dissolved oxygen, pH, salinity and conductivity) in the water column. Fe–Mn oxide grain coatings and sulphide materials have been identified as scavengers of some of the non-detrital and detrital trace metals in the sediments. On the basis of index of geoaccumulation (I-geo) and comparison with previous studies, the Calabar River surface sediments have been classified as unpolluted.     

不同类型机动车尾气中的多环芳烃含量分析

采用底盘测功机模拟汽车的加速、减速、匀速和怠速过程,采集了机动车排放的尾气,并对尾气中颗粒态物质和气态物质的多环芳烃含量进行了分析,结果表明,柴油车和汽油车无论在何种工况下,尾气中低环多环芳烃在气态物质中的含量都要高于在颗粒态物质中的含量;中环多环芳烃在气态物质中和颗粒态物质中的含量相接近;高环多环芳烃在颗粒态物质中的含量要高于气态物质中的含量.机动车尾气中PAHs的苯并[a]芘等效致癌浓度(BaPE)在0.558～5,684之间,BaPE/BaP比值在2.029～8.413之间.即BaP以外的多环芳烃贡献了相当于103%～741%BaP浓度的等效致癌毒性;尾气中气态物质和颗粒态物质的PAHs总量和苯并[a]芘含量的回归分析表明两者之间存在着较好的线性关系,其可决系数分别为0.8343和0.7158.     

ZnIn2S4/g-C3N4光催化降解水中痕量药物卡马西平

本文采用水热合成法制备ZnIn₂S₄/g-C₃N₄复合催化剂应用于水中痕量药物卡马西平（CBZ）的太阳光催化降解,探究实际河水中固体颗粒（SS）,无机盐（IS）和溶解性有机物（DOM）对催化剂活性的影响以及ZnIn₂S₄/g-C₃N₄/浮石负载型催化剂光催化CBZ效果.结果表明,质量比为20：1 ZnIn₂S₄/g-C₃N₄的光催化活性高于ZnIn₂S₄,ZnIn₂S₄与g-C₃N₄异质结构加速了电子-空穴对的分离并抑制其复合、ZnIn₂S₄/g-C₃N₄中孔的增多和比表面积的增加有效提高了催化剂活性.水质参数对催化剂活性的影响顺序为DOM>IS>SS,过滤后河水中CBZ的光催化速率常数比原水提高了13倍;125mg/L催化剂投加量和太阳光照射240min后,100μg/L的CBZ被完全降解.动态试验中CBZ的光催化效率随水流速度的增大而下降;流速5mL/min下循环4次,ZnIn₂S₄/g-C₃N₄/浮石光催化降解与矿化CBZ的效率分别为86.4%和43.9%.     

美国环保局对除尘器滤料性能的认证

本文介绍了美国环保局(EPA)环境技术认证(ETV)项目中对袋式除尘器滤料性能的检测方法和结果,可为国内外广大除尘设备用户在选择滤料时提供参考.     

基于图像感兴趣区域融合特征的PM2.5浓度预测方法

通过图像预测PM_2.5浓度的准确性,在很大程度上取决于模型所选用的特征参数。为丰富特征参数的表达,设计了一种基于图像传统特征与深度特征充分融合的PM_2.5浓度预测方法。首先,根据不同PM_2.5浓度下的成像差异,选定图像感兴趣区域,解决图像尺寸过大导致的模型运算效率较低问题。然后,针对所选取的局部图像,利用传统图像处理方法手动设计并提取图像浅表视觉特征,同时利用卷积神经网络自动提取图像深层语义特征。最后,将两种特征融合,交由卷积神经网络的全连接层实现对PM_2.5浓度的回归预测。预测误差比对结果显示,相比使用单种特征,使用融合特征能够有效提高模型的预测性能。     

茂名滨海新区环境保护政策法制创新探析

茂名滨海新区在有关环境保护的管理体制、立法、司法、执法保障机制等方面,还没有成熟的做法,理论研究亦存在空白。论文在借鉴国内其他新区发展经验的基础上,对茂名滨海新区生态环境保护的政策创新与法制保障问题给予了特别关注,提出了滨海新区创新发展的方向,这对茂名未来的经济发展与环境保护都具有重要的现实意义。     

微波加热下苯的催化氧化性能研究

研究考察了微波加热与传统电炉加热两种不同加热方式下苯的催化氧化性能,同时考察了微波加热下铜锰质量比,铈掺杂量及焙烧温度变化对铜-锰-铈/分子筛催化剂催化氧化苯性能的影响,并对催化剂进行了SEM和XRD表征.结果表明,微波加热下苯的催化氧化性能优于电炉加热,微波的"局部热点"效应、偶极极化作用与稳定的床层反应温度保证了苯的高效催化氧化;铜∶锰∶铈质量比1∶1∶0.33和焙烧温度500℃下催化剂的活性最高,苯的起燃温度与完全燃烧温度分别为165℃和230℃.催化剂表征分析可知,铜、锰氧化物及铜锰尖晶石固溶物等活性相的存在保证了催化剂的高活性;稀土元素铈的掺杂促进了活性组分在催化剂表面的分散与规整化;高温焙烧可导致催化剂表面的烧结与活性组分的团聚,从而降低其催化氧化苯的活性.