江苏省颗粒物激光雷达组网在一次复合过程中的应用分析

基于2022年9月5—11日江苏省发生臭氧连续超标,细颗粒物（PM_2.5）浓度同步上升的一次典型复合污染过程,利用颗粒物激光雷达组网对江苏省6个城市的大气垂直剖面进行了连续监测,并结合近地面污染物浓度和气象要素观测数据分析了此次污染过程的成因。结果表明,污染过程期间各城市呈现高温、小风、强太阳辐射的特征,造成日间二次生成的颗粒物在本地积聚。各城市颗粒物浓度的小时变化趋势大致相同,颗粒物浓度大幅升高期间,ρ（PM_2.5）/ρ（PM₁₀）值也同步上升,以PM_2.5生成为主导。激光雷达探测结果显示,1 km以内的355 nm消光系数显著增强,表明此次污染过程是由于强大气氧化性导致以极细颗粒物为主导的PM_2.5大量二次生成,无明显的区域传输,同时夜间伴随边界层高度降低,白天生成的高浓度PM_2.5沉降至地面,期间淮安市、扬州市和镇江市受浮尘、扬尘等粗粒子影响,边界层内粗颗粒物浓度也较高。     

2种人工湿地的水力停留时间及净化效果

以复合垂直流人工湿地(IVCW)和水平潜流人工湿地(HSCW)为研究对象,研究了2种湿地运行的季节性最佳水力停留时间(HRT)参数,并监测了2种湿地在最佳HRT参数下运行时对污水的净化效果。结果显示:(1)在IVCW中,最佳HRT在春、秋季为8～10 h;夏季为6 h;冬季为12 h。在HSCW中,最佳HRT在春、秋季为10～12 h;夏季为6～8h;冬季为24～36 h。(2)2种湿地对COD的去除率均无显著的季节性差异;湿地进水中NH4+-N/TN比值与TN去除率显著负相关;不同季节下IVCW对TN的去除效果均高于HSCW。(3)水温对TN、TP去除率的影响在IVCW中比HSCW中的明显;水温高时,2种湿地中的TN去除率较高,IVCW中的TP去除率也较高,但HSCW中的TP去除率则较低,它们间均未达到显著的相关性。     

Photodecomposition of o-cresol by UV-LED/TiO2 process with controlled periodic illumination

This study investigated the effect of controlled periodic illumination on the photonic efficiency and temporal decomposition behavior of o-cresol by UV/TiO2 process in a slurry reactor using light emitting diodes as the light source. Based on the same UV light intensity of 6.7 W m(-2), the calculated photonic efficiencies increased from 1.5% to 6.3% with the decreasing duty cycle from 1.0 to 0.1 possibly ascribed to the decreasing electron-hole recombination. Actually, the calculated photonic efficiency under periodic illumination at sufficiently intermittence was inferior to, but approached, those under continuous illumination at equivalent average UV light intensity. The calculated electric energy per order increased from 32 to 37 k W h m(-3)order(-1) for experiments conducted with the increasing duty cycle from 0.1 to 1.0, and the electric energy consumption decreased significantly due to the lower duty cycle and average UV light intensity. The photocatalytic decomposition of o-cresol with the UV-light emitting diodes light could be well modeled by the Langmuir-Hinshelwood kinetic equation.     

土壤中咪唑啉酮类除草剂的分析及归趋研究

咪唑啉酮类除草剂具有较长的残留活性,研究其在土壤中的环境行为具有重要的意义.介绍了咪唑啉酮类除草剂的特性,评述了咪唑啉酮类除草剂在土壤中的前处理方法和分析方法以及该类除草剂在土壤中的吸附、降解和迁移特性,并针对目前的状况和存在的问题提出了今后的研究方向.     

生物填料在重污染河道治理中的应用研究

将生物填料应用于城市重污染河道治理,研究了随时间的推移,填料垂直方向上生物膜的膜量、膜组成、膜活性变化规律以及生物填料对水质的改善效果.试验结果表明,该生物填料生物膜活性以比基质耗氧速率表示为0.153～0.174 mg/(g·h) .在挂膜进行到第40天、悬挂密度为24根/m2 时,对水质改善达到最佳效果,对TN、TP、COD、Chla、浊度的去除率分别为53%、35%、50%、5%、44%.     

高铁酸钾降解苯酚的机制研究

借助高效液相色谱(HPLC),通过标准物比对法和添加标准物法,研究了高铁酸钾降解苯酚的开环产物.结果表明,高铁酸钾降解苯酚的主要稳定的中间产物有顺丁烯二酸、反丁烯二酸、草酸和甲酸.并据此推导出苯酚被高铁酸钾氧化降解的可能途径.     

石油降解菌的筛选优化及其对油污土壤的修复特性

分别以牛肉膏蛋白胨-布氏哈斯培养基、蓝色凝胶培养基作为初筛和复筛培养基,从石油污染土壤中筛选出2株可产生微生物表面活性剂的石油烃降解菌。并将菌株投加到油污土壤中进行修复研究,考查了不同影响因素对修复效果的影响。研究结果表明,(1)2株菌对中度石油污染土壤有较好的修复效果,向油污土壤中直接投加菌株修复70 d时对石油烃的去除率为52%;(2)向油污土壤中投加降解菌并同时补充氮营养液,修复70 d时对土壤中总石油烃的去除率可达到75%;对土壤中正构烷烃的去除率为66%;(3)与土壤的含水率及土著菌的降解效果相比,向油污土壤中投加降解菌以及补充氮磷营养液是影响石油污染土壤修复效果的关键因素。     

Comparison of two dynamic measurement methods of odor and odorant emission rates from freshly dewatered biosolids

Odor and odorant emission rates from freshly dewatered biosolids in a dewatering building of a Water Reclamation Plant (WRP) are measured using the EPA flux chamber and wind tunnel methods. Experimental results are compared statistically to test whether the two methods result in similar emission rates when experiments are performed under field conditions. To the best of our knowledge the literature is void of studies comparing the two methods indoors. In this paper the two methods are compared indoors where the wind velocity and air exchange rate are pertinent field conditions and can be measured. The difference between emission rates of odor and hydrogen sulfide measured with the two methods is not statistically significant (P values: 0.505 for odor, 0.130 for H(2)S). It is concluded that both methods can be used to estimate source emissions but selection of the most effective or efficient method depends on prevailing environmental conditions. The wind tunnel is appropriate for outdoor environments where wind effects on source emissions are more pronounced than indoors. The EPA flux chamber depends on the air exchange rate of the chamber, which simulates corresponding conditions of the indoor environment under investigation and is recommended for estimation of indoor pollution sources.     

CMC改性的纳米Fe/Cu双金属去除2,4-二氯苯酚的研究

为解决纳米零价金属在水中暴露出的极易聚集与氧化的问题,本研究使用铜作为纳米零价铁(NZVI)的复合金属,制得纳米Fe/Cu双金属,并用羧甲基纤维素钠(CMC)对其包覆改性.使用扫描电子显微镜、X射线衍射以及氮气吸附/脱附等温线对改性前后的双金属进行表征.结果表明,改性之后的材料具有更大的尺寸以及比表面积,且抗氧化性得到显著增强.材料的沉降实验以及对2,4-二氯苯酚(2,4-DCP)降解实验的结果揭示,CMC的包覆比对改性后双金属的分散性与反应活性影响较大.当包覆比为80%时,双金属的分散稳定性最强,释放的活性位点个数最多,表现为最高的反应活性.此时脱氯效率达到90.3%,且脱氯过程和产物发生明显改变.     

Investigation of suitable precursors for manganese oxide catalysts in ethyl acetate oxidation

The control of ethyl acetate emissions from fermentation and extraction processes in the pharmaceutical industry is of great importance to the environment. We have developed three Mn₂O₃ catalysts by using different Mn precursors (MnCl₂, Mn(CH₃COO)₂, MnSO₄), named as Mn₂O₃-Cl, -Ac, -SO₄. The tested catalytic activity results showed a sequence with Mn precursors as: Mn₂O₃-Cl > Mn₂O₃-Ac > Mn₂O₃-SO₄. The Mn₂O₃-Cl catalyst reached a complete ethyl acetate conversion at 212℃ (75℃ lower than that of Mn₂O₃-SO₄), and this high activity 100% could be maintained high at 212℃ for at least 100 hr. The characterization data about the physical properties of catalysts did not show an obvious correlation between the structure and morphology of Mn₂O₃ catalysts and catalytic performance, neither was the surface area the determining factor for catalytic activity in the ethyl acetate oxidation. Here we firstly found there is a close linear relationship between the catalytic activity and the amount of lattice oxygen species in the ethyl acetate oxidation, indicating that lattice oxygen species were essential for excellent catalytic activity. Through H₂ temperature-programmed reduction (H₂-TPR) results, we found that the lowest initial reduction temperature over the Mn₂O₃-Cl had stronger oxygen mobility, thus more oxygen species participated in the oxidation reaction, resulting in the highest catalytic performance. With convenient preparation, high efficiency, and stability, Mn₂O₃ prepared with MnCl₂ will be a promising catalyst for removing ethyl acetate in practical application.