餐饮源挥发性有机物组成及排放特征

餐饮油烟是城市挥发性有机物（VOCs）的重要来源之一,对人体健康有较大的危害性,对室内外空气质量也有重要的影响,因此对其排放特征的研究具有十分重大的意义.本实验通过模拟油的加热及烹饪过程,利用气相色谱-质谱联用仪（GC-MS）,以油品、调味料和菜品为变量,对不同情况下排放油烟中VOCs的排放特征及化学组成进行了分析.结果表明,油品的排放因子范围为0.81~2.53g·kg^-1,主要排放卤代烃和烷烃;调味料的排放因子范围为25.06~40.18g·kg^-1,主要排放烷烃;辣椒炒肉排放量远高于番茄炒蛋,辣椒炒肉主要排放卤代烃,番茄炒蛋主要排放芳香烃和烷烃.     

生物营养物去除(BNR)工艺模型参数校正与验证方法

研究了结合活性污泥系统物料平衡的生物营养物去除(BNR)工艺模型参数校正与验证方法.首先采用代尔夫特理工大学开发的TUD模型及其参数缺省值进行初步模拟,并将模拟结果与实测数据进行对比以明确模拟偏差.同时,对原始运行数据进行物料平衡衡算,以消除测量误差并获得TP排放量、反硝化量及氧的净消耗量等平衡计算值,为模型校正提供依据.初步模拟结果显示,TP排放量(3913mg·d-1,以P计)和反硝化量(16170mg·d-1,以N计)均超出了平衡计算值的误差范围(分别为(3762.0±43.1)mg·d-1和(14150±237)mg·d-1),且沿程溶解性COD(SCOD)、PO34--P、NH4+-N、NO3--N不能完全与实测数据吻合,表明工艺模型参数的默认值需得到必要的校正.结合TP平衡,先修正污泥龄(SRT)的计算误差;应用平衡后的运行数据,将SRT由初始值10.3d调整为10d.SRT调整后,再次模拟得出的TP排放量为3750mg·d-1,已在平衡计算结果的范围之内,TP平衡得到了闭合.将发酵过程最大反应速率常数qfe从3d-1提高到15d-1后,沿程及PO43--P拟合结果同时得到了显著改善.通过调整DO及NH4+-N的亲和系数KNH4(从1mg·L-1至0.2mg·L-1),沿程NH4+-N得到了拟合.出水及沿程NO3--N的拟合通过调整氧的亲和系数KO2从0.7至0.1mg·L-1)得以实现.最后校核反硝化负荷及氧的净消耗量,模拟计算的反硝化负荷为14090mg·d-1,氧的净消耗量为126900mg·d-1,均在平衡计算值的误差范围之内(分别为(14150±237)mg·d-1和(129700±2910)mg·d-1),说明校正过程合理、可靠.     

地表水体中同时分析18种糖皮质激素方法的建立

建立了一种采用固相萃取-超高效液相色谱串极质谱联用系统(UPLC-MS/MS)同时测定地表水体中18种糖皮质激素的高灵敏分析方法.样品经过HLB固相萃取柱富集净化、V(乙腈)/V(乙酸乙酯)=1∶1,洗脱后,用UPLC-MS/MS测定.流动相为甲醇和0.1%乙酸水溶液(体积比),采用梯度洗脱,实现了18种目标物质的基线分离,线性范围为1.0~1 000μg·L-1.实际水样的加标回收率为65%~108%.整个分析的方法检出限(MDL)除醋酸可的松和醋酸氢化可的松为10 ng·L-1外,其他均在0.10 ng·L-1和1.0 ng·L-1之间.应用此方法于北京地表水体5个样品,检测到8种糖皮质激素,浓度范围0.20~476ng·L-1,其中曲安西龙、曲安奈德、醋酸氢化可的松和丙酸氯倍他索在地表水中首次检出,证明了该方法的有效性.     

TiO2/Ag modified penta-bismuth hepta-oxide nitrate and its adsorption performance for azo dye removal

A modified hydrophilic penta-bismuth hepta-oxide nitrate (Bi₅O₇NO₃) surface was synthesized via a precipitation method using TiO₂ and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono-and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy (XPS) results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure Bi₅O₇NO₃;however, the presence of hydrophilic centres such as TiO₂ and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.     

Fe(0)-活性炭强化短程反硝化脱氮及影响因素

为减少生物短程反硝化对外碳源的依赖,研究了无机环境下Fe(0)-活性炭强化短程反硝化的脱氮效果,并探究了不同铁碳比及初始pH值对系统脱氮效果及N+2O释放的影响.结果表明Fe(0)-活性炭可强化生物短程反硝化,将亚硝氮去除率由7.4%提高到31.1%.当m(铁)∶m(碳)由2∶1降至1∶1和1∶2时,反硝化速率与亚硝氮去除率均呈现先升后降的趋势,m(铁)∶m(碳)为1∶1时达到最大,分别为5.58 mg·(g·h)~(-1)与41.1%,且此时N+2O的释放量较小,为0.10 mg.当pH值由6.0升至9.0的过程中,反硝化速率由7.39 mg·(g·h)~(-1)下降至5.96 mg·(g·h)~(-1),N+2O的释放量由0.19 mg下降至0.12 mg.以上结果表明,在m(铁)∶m(碳)为1∶1和pH为弱酸性的条件下,Fe(0)-活性炭能强化短程反硝化获得较好的脱氮效果,但低pH值会增加N+2O的释放量.     

气相分子吸收光谱法测定垃圾填埋场渗滤液中的氨氮研究

垃圾填埋场渗滤液成分复杂,其氨氮的测定干扰物质多,测定难度大.气相分子吸收光谱法是一种较为新兴的方法,通过对气相分子吸收光谱法和传统纳氏试剂分光光度法系统的比较,研究气相分子吸收光谱法测定垃圾填埋场渗滤液中氨氮的分析方法.结果表明,气相分子吸收光谱法测定垃圾填埋场渗滤液中氨氮操作便捷、干扰小、精密度好,中浓度与高浓度废水测定结果能较好的与纳氏试剂光度法测定结果法吻合,超低浓度废水的测定结果低于纳氏试剂分光光度法.为监测工作者分析方法的选择提供依据.     

气提升交替循环流复合滤池的流体力学和氧传质特性研究

气提升交替流复合滤池（AALCF）在气提升循环流化床（ALR）和曝气生物滤池（BAF）研究基础上发明的一种新型生化反应器。通过该反应器,研究了其流体力学和氧传质特性以及它们的主要影响因素,即气体流量和颗粒滤料层高度。结果表明,气体流量对反应器内液体流速、循环时间、气含率以及氧传质系数均有线性的影响;而随着颗粒层高的增加,液体流速会减小从而循环时间延长,但其对气含率的影响并不明显,另外。氧传质系数随之呈现先增加后减小的趋势,且在颗粒层高为15cm时可达最大值。     

Degradation of indomethacin in river water under stress and non-stress laboratory conditions: degradation products, long-term evolution and adsorption to sediment

The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants,whose effluents flow into aquatic environments;concentrations in the 0.1-100 ng/L range are commonly found in surface waters,and its fate is unknown.Here,biological,photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time.The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin(2 μg/L) in less than 6 hr,but indomethacin was detected over a period of 4 months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited,as occurs inside a body of water.The biological degradation in water was negligible,while the hydrolysis at pH 7.8 was slow.Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction,and six degradation products were found;their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra.4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products,persisting for at least 30 weeks in water kept under non-stress conditions.Furthermore,the degradation in the presence of sediment was also monitored over time,with some differences being noted.The adsorption coefficients of indomethacin and degradation products on river sediment were calculated;long-term degradation products did not have significant adsorption to sediment.     

利用单颗粒气溶胶质谱仪研究燃煤尘质谱特征

采用单颗粒气溶胶质谱仪(SPAMS)和再悬浮采样器联用的方式对燃煤电厂烟道气样品和下载灰样品的质谱特征进行测定,并使用颗粒物粒径分级采样仪ELPI测定其粒径分布特征.研究表明,SPAMS监测得到的粒径分布与ELPI结果差异较大,SPAMS对于500 nm以上粒径段检测效果较好;两个样品正谱图中有非常明显的锂、钙、钛、铝等金属组分信号和碳组分信号特征,负谱图中硅酸盐、硝酸盐和硫酸盐等信号比较明显,并且随着粒径的增加碳组分、硫酸盐和硝酸盐等组分对应的信号强度逐渐减弱,而硅酸盐、铝、钙和钛等组分对应的信号强度逐渐增强;对两个样品使用ART-2a聚类获得多个颗粒物类别,分析表明,它们均含有元素碳二次类(硫酸盐和硝酸盐缩写为二次Sec)、有机碳二次类、铝元素碳类、铝钙硅酸盐类和富硅酸盐类等颗粒物类别,并且随着粒径的增加金属硅酸盐颗粒出现频率增大,而含碳颗粒与硫酸盐出现频率降低.但烟道气样品和下载灰样品的质谱特征呈显著差异,下载灰样品更能代表燃煤源真实排放特征.建议在今后建立基于单颗粒质谱固定源成分谱时,应使用单颗粒气溶胶质谱仪在外场进行实测,并使用聚类的方法提取不同粒径段上的源质谱特征,可能会取得更好的效果.     

有机酸强化废大理石粉脱硫的传质研究

在双搅拌釜上进行了3种有机酸强化废大理石粉浆液脱硫的传质实验研究,测定了脱硫效率η、传质速率Nm、液膜传质系数KL、气相总传质系数KG和浆液pH值等随时间t的变化关系,结果表明己二酸强化可提高传质速率约35%,有效促进了CaCO3的溶解和缓冲pH值的下降.同时,考察了己二酸添加量的变化和气、液两相浓度的改变对传质的影响,结果表明己二酸添加浓度在10mmol/L时强化效果最好;进气SO2体积分率小于1000×10-6时为完全气膜控制;液相浓度的改变对气相总传质系数KG影响不大.