人工湿地植物生物质资源能源化利用潜力评估

通过测定不同人工湿地植物的纤维素组分和热值,并采用NaOH–酶解工艺研究不同人工湿地植物水解液组分,对在人工湿地技术体系中起重要作用的湿地植物能源化利用潜力进行系统评估.结果显示,15种人工湿地植物的纤维素含量在19.78%～36.9%之间,半纤维素含量在4.51%～19.67%之间,木质素含量在10.79%～20.47%之间,具有与玉米秸秆相当的热值,其热值在14.002～17.839 MJ/kg之间.在NaOH–酶解工艺条件下,不同人工湿地植物水解液中存在5种糖类组分,主要为葡萄糖和木糖.研究表明,人工湿地植物是一种较好的生物质资源,可通过生物质固体成型燃料技术、沼气技术和燃料乙醇技术加以利用,进而建立人工湿地植物生物质资源能源化藕联利用模式.图2表2参22     

南宁市相思湖湿地公园生态景观调查与分析

相思湖湿地公园是南宁市打造"中国水城"品牌的重要建设项目,既保护了湿地资源,也发挥了巨大的生态环境、经济及社会效益.就已完成景观绿化亮化提升工程的相思湖湿地公园展开相关调查,对其生态多样性进行分析及按照相关标准计算湿地景观特征指数,评价了其现状并提出保护对策.相思湖湿地公园具有丰富的动植物资源,从水域、林地、草地、沼泽、滩涂五种景观类型的数据可以看出:水域面积占到了52.74%,说明湿地功能显著;破碎度最大的是草地跟林地,分别达到了1.29和0.81,说明南宁市生态恢复工程和绿色提升工程效果明显.相思湖湿地公园是保护和利用当地湿地资源的有效措施.     

纵向通风下坡度隧道火灾烟气特性数值模拟研究

为探讨纵向通风情况下坡度隧道火灾烟气的温度分布、回流长度等特性参数,运用火灾动力学模拟软件FDS建立一个长为500 m的公路隧道模型,对不同坡度、不同纵向通风速率的20组火灾工况进行模拟研究,通过分析各工况的模拟结果,并结合前人在隧道火灾烟气特性研究方面的成果,得到火灾情况下隧道内烟气的纵向温度分布规律、隧道拱顶温度变化规律、温度偏移及烟气回流长度变化规律等。     

Mobilization and plant accumulation of prometryne in soil by two different sources of organic matter

Prometryne is a selective herbicide of the s-triazine chemical family. Due to its weak absorption onto soil, it readily leaches down through the soil and contaminates underground water. Application of organic manure to soil has become a widespread practice as a disposal strategy to improve soil properties. In this study, we demonstrated the effect of pig manure compost (PMC) and lake-bed sludge (SL) on the sorption/desorption, mobility and bioavailability of prometryne in soil using comprehensive analysis approaches. Downward movement of prometryne was monitored in the packed soil column. Addition of PMC or SL decreased considerably the mobility and total concentration of prometryne in the soil leachate. Bioavailability analyses with wheat plants revealed that addition of the organic matter reduced accumulation of prometryne in tissues and increased plant elongation and biomass. These results indicate that the organic amendments are effective in modifying adsorption and mobility of the pesticide in soil.     

黄土高原不同植被带人工刺槐林土壤团聚体稳定性及其化学计量特征

为研究黄土高原不同植被带对土壤团聚体稳定性及团聚体化学计量变化特征的影响,本研究选取黄土高原不同植被带人工刺槐林地土壤为研究对象,分析了不同粒径团聚体含量,团聚体化学计量及稳定性指标.结果表明, 2 mm和0. 25～2 mm粒径团聚体含量,机械团聚体的平均重量直径(E_(MWD))和机械团聚体的几何平均直径(E_(GMD))表现为森林带森林草原带草原带,而0. 053～0. 25 mm粒径团聚体含量和可蚀性因子K呈现相反的变化特点;各粒径团聚体有机碳和全氮含量在3个植被带整体表现为森林带显著高于森林草原带和草原带,而全磷含量在各植被带间无明显变化规律;有机碳和全氮含量在草原带以0. 053 mm和0. 25～2 mm粒径占绝对优势,在森林草原带以0. 053～0. 25 mm和0. 25～2 mm粒径为主,而森林带各粒径间均无显著差异;草原带和森林草原带0. 053 mm粒径全磷含量最高,而森林带全磷含量在各粒径间无显著差异;0. 053 mm和0. 053～0. 25 mm粒径团聚体C∶N值以草原带和森林草原带高于森林带,而0. 25～2 mm和 2 mm粒径在3个植被带间无显著差异;各粒径C∶P和N∶P值以森林带显著高于森林草原带和草原带.综上可见,土壤团聚体稳定性和团聚体化学计量在3个植被带间存在较大差异,团聚体稳定性和团聚体有机碳、全氮含量整体表现为森林带显著高于森林草原带和草原带.     

天津黑碳气溶胶潜在来源分析与健康风险评估

采用2010~2013年BC连续在线观测资料,分析天津地区BC的季节分布、潜在来源及其健康效应.结果表明,2010~2013年BC气溶胶浓度平均值为（4.49±3.26）μg/m³,秋季浓度最高,为6.31μg/m³,冬季和夏季次之,春季最低,为2.59μg/m³.各季节BC浓度的日变化特征类似,均呈早晚双峰分布,早间峰值高于晚间,且夜间高于日间.混合层高度和近地层风从垂直和水平两方面影响BC的时空分布,各季节作用强度并不相同.浓度权重轨迹分析表明天津高浓度BC的主要贡献区域为河北、山东、河南等华北平原地区.此外,秋季内蒙古中部和山西北部等西北区域也会影响天津.天津城区各季节成人和儿童的致癌风险（CR）均高于EPA给定的可接受风险水平（10^-6）,非致癌风险水平较低,秋季因高浓度BC引发的呼吸系统死亡率相对风险为1.118,需要引起高度关注.     

DBD低温等离子体气化杨木及模型化合物

本文利用低温等离子体技术,使用介质阻挡放电反应器气化杨木屑、纤维素、木聚糖和木质素,用控制变量法研究了频率、载气对反应系统产气能力的影响以及生物质化学组成的气化特性.结果表明,频率越小、载气电离能越低,气化率越高,杨木的最佳气化率为64.11%;木聚糖和纤维素气化产物相似,较纤维素和木质素产气率更高并且能够产生更多CO;木质素主要生成气化炭.同时,利用SEM、BET对原料及气化炭进行了表征研究得出碱金属在高温下发生结晶;木聚糖在气化过程中会发生熔融;等离子体的高功率以及更多的氧化性物质能够使气化炭比表面积显著增加,达到150.71m²/g.     

螺形龟甲轮虫形态结构对环境变化的响应

以螺形龟甲轮虫为研究对象,于2015年7月至2018年12月,选取广东南澳岛及湖南常德中营养至中度富营养水体共14个样点进行采样,对螺形龟甲轮虫进行了形态特征测量分析.结果表明,水温是螺形龟甲轮虫形态变化最主要影响因子,且与背甲长、背甲宽、棘刺长度均呈显著负相关（P<0.01）.不同纬度条件下螺形龟甲轮虫形态参数差异显著,常德地区螺形龟甲轮虫个体显著大于南澳地区（P<0.05）.螺形龟甲轮虫形态存在显著季节性变化,各形态参数随季节波动呈现夏秋、冬春分化模式.螺形龟甲轮虫后棘刺长随水体营养程度增加而减小（F=159.4,P<0.01）,富营养条件下后棘刺长度占全长的比例减小（F=167.5,P<0.01）.研究结果表明,螺形龟甲轮虫棘刺长度可作为水质生物监测指标,并为研究全球气候变暖提供重要参考.     

Chemical characteristics, oxidative potential, and sources of PM2.5 in wintertime in Lahore and Peshawar, Pakistan

The chemical characteristics, oxidative potential, and sources of PM_2.5 were analyzed at the urban sites of Lahore and Peshawar, Pakistan in February 2019. Carbonaceous species, water soluble ions, and metal elements were measured to investigate the chemical composition and sources of PM_2.5. The dithiothreitol (DTT) consumption rate was measured to evaluate the oxidative potential of PM_2.5. Both cities showed a high exposure risk of PM_2.5 regarding its oxidative potential (DTT_v). Carbonaceous and some of the elemental species of PM_2.5 correlated well with DTT_v in both Lahore and Peshawar. Besides, the DTT_v of PM_2.5 in Lahore showed significant positive correlation with most of the measured water soluble ions, however, ions were DTT-inactive in Peshawar. Due to the higher proportions of carbonaceous species and metal elements, Peshawar showed higher mass-normalized DTT activity of PM_2.5 compared to Lahore although the average PM_2.5 concentration in Peshawar was lower. The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities. Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM_2.5 and its oxidative potential. Mixed sources of traffic and road dust resuspension and coal combustion, direct vehicle emission, and biomass burning and formation of secondary aerosol were identified as the major sources of PM_2.5 in both cities. The findings of this study provide important data for evaluation of the potential health risks of PM_2.5 and for formulation of efficient control strategies in major cities of Pakistan.     

Preparation and characterization of boron-doped corn straw biochar: Fe (Ⅱ) removal equilibrium and kinetics

Nowadays, iron ions as a ubiquitous heavy metal pollutant are gradually concerned and the convenient and quick removal of excessive iron ions in groundwater has become a major challenge for the safety of drinking water. In this study, boron-doped biochar (B-BC) was successfully prepared at various preparation conditions with the addition of boric acid. The as-prepared material has a more developed pore structure and a larger specific surface area (up to 897.97 m²/g). A series of characterization results shows that boric acid effectively activates biochar, and boron atoms are successfully doped on biochar. Compared with the ratio of raw materials, the pyrolysis temperature has a greater influence on the amount of boron doping. Based on Langmuir model, the maximum adsorption capacity of 800B-BC_1:2 at 25 °C, 40 °C, 55 °C are 50.02 mg/g, 95.09 mg/g, 132.78 mg/g, respectively. Pseudo-second-order kinetic model can better describe the adsorption process, the adsorption process is mainly chemical adsorption. Chemical complexation, ions exchange, and co-precipitation may be the main mechanisms for Fe²⁺ removal.