广州PM2.5污染特征及影响因素分析

对广州市2008—2010年PM_2.5质量浓度、影响因素数据资料进行整理统计,通过定性分析、定量计算以及对各物理量之间的相互作用过程研究,得出PM_2.5质量浓度变化特征和各影响因素之间的关系。结果表明,PM_2.5质量浓度变化呈现夏季和非夏季2种典型的季节性特征,夏季月平均值0.049 mg/m³,主要分布在0.03～0.05 mg/m³,非夏季月均值为0.063 mg/m³,分布于0.05～0.08 mg/m³之间;夏季、非夏季PM_2.5质量浓度超标率(采用美国EPA标准)分别为70.7%、77.8%,质量标准2倍、3倍以上出现的概率都表现出明显的季节性差异;PM_2.5与温度正相关,和其他因素负相关,其中与能见度相关性最大,其次是温度、风速,与降雨量相关性最差,与气压、相对湿度相关系数季节性特征显著。     

锅炉煤炭燃烧过程NOx释放规律及累积转化率影响因素

选用某电厂的实际用煤及焦炭,模拟燃煤电厂的煤炭燃烧过程,在不同温度、助燃气体流量、煤粉粒径和氧含量等多种条件下分别进行实验,得出不同燃烧条件下NOx的释放规律。实验表明,相同条件下,挥发分越大,氮的转化率也相对越大;煤的粒径越小,氮的转化效率越低;随着助燃气体流量的增加,燃料N转化为NOx的总转化效率增加;氧含量增加缩短了反应时间,但燃料N总效率变化不大。     

VPT511BF-SY多孔流速仪在烟气流量在线监测中的应用

针对目前国内基于单个探头的单点在线测试烟气流量与参比方法监测比对合格率不高的问题,提出一种新颖的基于平均差压皮托管法的多孔流速仪,通过对不同的安装位置及安装数量的多孔烟气流速仪的烟气在线流量监测结果与手工监测结果进行比对,验证在适当位置安装一定数量的多孔烟气流速仪可以确保与手工监测比对结果满足要求。     

北方泥炭地泥炭土矿化速率、温度敏感性及其影响因素研究

北方泥炭地是全球重要的碳汇,也是全球变暖最为敏感的区域之一.然而,由于泥炭地表层和亚表层泥炭土碳排放过程对全球变暖的响应过程及机制仍存在一定争议,目前对全球变暖背景下泥炭地碳排放的认识仍存在一定不足.本研究于2019年8月在大兴安岭满归泥炭地采集表层(0～10 cm)和亚表层(15～30 cm)泥炭土进行室内增温模拟有氧培养,测定其矿化速率、有机质性质和水解酶活性.结果表明,表层泥炭土矿化速率在5、15、25℃下培养时((142.8±66.9)～(545.3±30.6)、(575.0±62.1)～(1843.0±547.4)、(888.4±123.9)～(3646.7±167.9)μg·g^-1·d^-1)均高于亚表层((113.0±41.5)～(367.1±64.1)、(357.4±52.3)～(1122.1±218.8)、(697.1±38.1)～(2336.4±150.6)μg·g^-1·d^-1),但表层和亚表层矿化作用的温度敏感性不具有显著差异;培养过程中,表层与亚表层泥炭土β-1,4-N-乙酰葡...     

塔克拉玛干沙漠和青藏高原地区沙尘气溶胶光学特性及其加热率的时空分布特征

沙尘不同的垂直分布对大气的加热作用不同,通过卫星观测结合数值模拟,可以更清楚地了解沙尘辐射加热作用,有利于理解沙尘对该地区大气热结构的影响机制.因此,本研究利用CALIPSO气溶胶产品和SBDART模式,分析了2007—2020年塔克拉玛干沙漠和青藏高原沙尘气溶胶及其短波加热率的时空分布特征.结果表明,塔克拉玛干沙漠和青藏高原的年平均沙尘气溶胶光学厚度（DAOD,532 nm）分别为0.300～0.350和0.086～0.108,平均值分别为0.328和0.097.塔克拉玛干沙漠季节平均DAOD的最大、最小值分别出现在春季和冬季,而青藏高原的最大、最小值分别出现在夏季和秋季.塔克拉玛干沙漠和青藏高原的沙尘消光系数（σD）最大值分别出现在春季和夏季.2007—2020年,两地的σD在春季均呈增加趋势,而在秋季则呈减小趋势.春季和夏季的短波沙尘加热率（SW DHR）均大于其它两个季节,其中春季最大,塔克拉玛干沙漠上空冬季最弱,青藏高原上空秋季最弱.春夏季,青藏高原北坡存在较强沙尘加热层,其顶部高于5 km,其强度及高值区从春季到冬季逐渐减小.从年变化来看,春季短波加热率呈加强趋势,秋季呈减...     

Earthworm cast production as a new behavioural biomarker for toxicity testing

There is currently a lack of ecotoxicity tests adapted to earthworm species of higher ecological relevance and whose endpoints could be directly related to their ecological role in the soil. We propose a new and relatively simple ecotoxicity test based on the estimation of cast production (CP) by Lumbricus terrestris under laboratory conditions. CP was found to be linearly correlated to earthworm biomass and to be greatly influenced by soil water content. Azinphos-methyl had no effect on CP at all the concentrations tested. Significant decreases were observed at the normal application rate for other pesticides with (imidacloprid, carbaryl, methomyl) or without (ethyl-parathion and chlorpyrifos-ethyl) a clear concentration-effect response. For the highest concentration tested, reduction in CP varied between 35 and 67%. CP is straightforward and rapidly measured and ecologically meaningful. We thus believe it to be of great use as an endpoint in ecotoxicity testing.     

Diffusion mechanism of lindane into wood charcoal

Abstract

The wood charcoal treated by 1N HNO₃ (WCT) was used to remove toxic chlorinated pesticide lindane (y‐HCH) residue from water by the sorption process. Using a simple first order reversible kinetics constants and half time equations, the film and pore diffusion coefficients were determined. Film diffusion was found to be rate limiting step in sorbing lindane by WCT. This was further authenticated by kinetics studies at different initial sorbate concentrations, different sorbent sizes, and different agitation speeds besides interruption test. A pore diffusion model was used to fit the data of kinetics in continuously mixed batch reactors (CMBR), and the tortuosity, external resistance, and surface diffusion effects on lindane sorption by WCT were noticed. The tortuosity values of 15 to 28 were obtained for WCT‐lindane system.     

Photodegradation of sulfonamide antibiotics in simulated and natural sunlight: Implications for their environmental fate

The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.     

电解法处理含镍废水及纯镍的回收

采用电解回收法处理Ni2+含量为2g/L的废水,在阴极回收纯镍。研究了电解电流、极距、NH4Cl浓度、pH值等因素对Ni2+去除率、槽压、阴极能耗的影响,得出最优工艺参数为:温度20℃,电解时间20min时、电解电流300mA,极距15mm,NH4Cl浓度5g/L,pH值8.0,该条件下Ni2+去除率为96.926%,槽压16.21V,阴极能耗22.418kW.h/kg,在阴极可得到沉积6.45μm厚的镍板。     

EFFECTS OF RATE STRUCTURE KNOWLEDGE ON HOUSEHOLD WATER USE1

ABSTRACT: Socioeconomic determinants of individual household water use were estimated using regressions of these characteristics with actual household water use for winter and summer. Results were disaggregated between those consumers who were aware of an increasing block rate price structure and those who were not. Most of the informed group members believed that this price structure did result in significant reductions in water use. Nevertheless, overall water use was greater for the informed group. The determinants of water use were found to differ between informed and uninformed users as well as between winter and summer. The uninformed users were influenced by a larger set of variables in each season than the informed group. In winter, the informed group members with swimming pools and/or arid landscaping used less water than their uninformed counterparts. Summer water use increased with length of tenancy in home for the uninformed group but not for informed, while increasing with ownership for informed consumers.