Source apportionment of PM2.5 and visibility in Jinan, China

Atmospheric extinction is impacted by the chemical composition of particles. To better understand the chemical composition of PM_2.5 (particles with diameters of less than 2.5 μm) and its relationship with extinction, one-month sampling campaigns were carried out in four different seasons from 2013 to 2014 in Jinan, China. The seasonal average concentrations of PM_2.5 were 120.9 (autumn), 156.6 (winter), 102.5 (spring), and 111.8 μg/m³ (summer). The reconstructed PM_2.5 chemical composition showed that sulfate, nitrate, chlorine salt, organic matter (OM), mineral dust, elemental carbon (EC) and others accounted for 25%, 14%, 2%, 24%, 22%, 3% and 10%, respectively. The relationship between the chemical composition of PM_2.5 and visibility was reconstructed by the IMPROVE method, and ammonium sulfate, ammonium nitrate, OM and EC dominated the visibility. Seven main sources were resolved for PM_2.5, including secondary particles, coal combustion, biomass burning, industry, motor vehicle exhaust, soil dust and cooking, which accounted for 37%, 21%, 13%, 13%, 12%, 3% and 1%, respectively. The contributions of different sources to visibility were similar to those to PM_2.5. With increasing severity of air pollution, the contributions of secondary particles and coal combustion increased, while the contribution of motor vehicle exhaust decreased. The results showed that coal combustion and biomass burning were still the main sources of air pollution in Jinan.     

Release characteristics and control of hydrogen sulfide during thermal drying of municipal wastewater sludge

Journal of Material Cycles and Waste Management - Hydrogen sulfide (H2S) is the most predominant malodorous gas released during the thermal drying of municipal wastewater sludge. Experiment using a...     

Recycling of biogenic hydroxyapatite (HAP) for cleaning of lead from wastewater: performance and mechanism

Environmental Science and Pollution Research - In China, the utilization and recycling of chicken waste have become a significant environmental issue. In this study, we investigate the efficacy of...     

五箱一体化脱氮除磷工艺在示范工程中的应用

五箱一体化工艺是东南大学开发的新型脱氮除磷工艺.示范工程运行表明,该工艺具有自动化程度高、投资少、占地小和运行费用低等优点,并具有良好的脱氮除磷效果.出水水质满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)的一级A标准,氮、磷的去除率分别可达70%和90%左右.示范工程的成功运行为该工艺的推广应用奠定了基础.     

海河渤海湾地区沉积物、鱼体样品中多溴联苯醚的水平与分布

从海河、渤海湾水域内采集了沉积物和鱼体(鲫鱼)样品.采用气相色谱/质谱(GC/MS)方法测定了样品中的多溴联苯醚(PBDEs).结果表明,沉积物(以干重计)和鱼体(以干重计)中PBDEs的检出水平分别为0.35～5.53、6.81～35.50 ng/g,其中相对含量较高的PBDEs单体为BDE-28和BDE-47.鱼体内脏组织中PBDEs的检出水平较肌肉组织中的PBDEs要高,表明其更容易富集PBDEs.     

吹扫捕集/气相色谱/质谱法测定水体中54种常见挥发性有机物的研究

运用吹扫捕集/气相色谱/质谱(P＆T/GC/MS)法对水体中54种常见的挥发性有机物(VOCs)进行了测定.结果表明,VOCs的色谱分离情况较好,平均加标回收率为88.5%～117.0%,相对标准偏差为0.71%～8.50%,准确度和精密度均符合有关分析测试的要求;方法检出限为0.10～0.61μg/L,远低于<地表水环境质量标准>(GB 3838-2002)、<生活饮用水卫生标准>(GB3838-2002)及国外相关标准的限值;54种VOCs的线性范围不同,低沸点的VOCs线性范围较宽,高沸点的VOCs的线性范围较窄,因此在分析VOCs样品配制标准工作曲线时,应注意不同沸点VOCs的线性范围.     

强化活性炭处理工艺去除焦化厂生化出水中的氰化物

以某焦化厂生化出水为研究对象,考寨了金属负载活性炭(简称负载炭)和Fenton氧化预处理等强化活性炭工艺对总氰化物(TCN)的去除效果.在TCN批式实验中,对负载炭的金属离子种类和固定方式进行了考察,同时研究了接触时间、DO对游离氰(KCN配水)、络合氰(K3Fe(CN)6配水)及焦化厂生化出水中TCN的去除效果.结果表明,负载金属离子可以有效提高活性炭对TCN的去除量,KI固定后的载铜活性炭对TCN的去除更有效.吸附作用在活性炭去除TCN过程中起着主要作用,同时TCN在活性炭表面也发生缓慢的催化氧化反应.在穿透实验中,采用了小型炭柱穿透和微型快速穿透实验方法,得到的TCN穿透曲线基本相同.含不同比例原煤炭和负载炭的小型炭柱处理经Fenton氧化预处理的焦化厂生化出水时,在18 d的启动阶段后形成生物活性炭柱,其出水能长期达到<城镇污水处理厂污染物排放标准>(GB 18918-2002)规定的要求.载铜话性炭可以提高活性炭工艺对TCN的去除能力,确保处理全程(57 d)出水的TCN达标.     

New insights into the sorption mechanism of cadmium on red mud

Effectiveness and mechanism of cadmium (Cd) sorption on original, acidified and ball milling nano-particle red muds were investigated using batch sorption experiments, sequential extraction analysis and X-ray absorption near edge structure (XANES) spectroscopy. The maximum sorption capacity of Cd was 0.16, 0.19, and 0.21 mol/kg for the original, acidified, and nano-particle red muds at pH 6.5, respectively. Both acidification and ball-milling treatments significantly enhanced Cd sorption and facilitated transformation of Cd into less extractable fractions. The Cd L_III-edge XANES analysis indicated the formation of inner-sphere complexes of Cd similar to XCdOH (X represents surface groups on red mud) on the red mud surfaces although outer-sphere complexes of Cd were the primary species. This work shed light on the potential application of red mud to remediate Cd-contaminated soils and illustrated the promising tool of XANES spectroscopy for speciation of multicomponent systems of environmental relevance.     

Cell absorption induced desorption of hydrophobic organic contaminants from digested soil residue

Oral ingestion of contaminated soil is an important pathway of human exposure to hydrophobic organic contaminants (HOCs), particularly for children in developing countries. The mobilization potential of various contaminants from ingested soil is often characterized using an in vitro gastrointestinal model, based on the quantities of contaminants remaining in digestive fluid after digestion and separation. Recently, it was experimentally demonstrated that a large fraction of mobilized contaminants sorbed on the digested residue could be released if the dissolved fraction was removed by intestinal absorption. This hypothesis was further tested in this study. Soil spiked with dichlorodiphenyltrichloroethane and its metabolites (DDXs) and polycyclic aromatic hydrocarbons (PAHs) was digested using an in vitro gastrointestinal model. A human colon carcinoma cell line (Caco-2) was cultured in digestive fluid with or without soil residue (pre-equilibrated with the soil) for 2 h. A large proportion of the contaminants (37-68%) was sorbed on the digested residue. Without this residue, 66 ± 13% of DDXs and 73 ± 14% of PAHs dissolved in the fluid, as means and standard deviations, were absorbed by the cell monolayer after exposure. With both digestive fluid and residue, the sorbed fraction of PAHs and DDXs decreased by 38-92%, while the ratios of the cellular to the dissolved concentrations were 2.7-2.8 times higher than those without the residue. This supported the hypothesis that the cell absorption of dissolved HOCs induces desorption of the sorbed fraction from digestive residue, and the desorbed HOCs can be absorbed as well.     

Uptake, translocation and metabolism of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in maize (Zea mays L.)

A hydroponic experiment was conducted in the present study to investigate and compare plant uptake, translocation and metabolism of polybrominated diphenyl ethers (PBDEs) of BDE-15, BDE-28 and BDE-47 and polychlorinated biphenyls (PCBs) of PCB-15, PCB-28 and PCB-47 in maize. Root concentrations of BDE-15, BDE-28 and BDE-47 were consistently higher than PCB-15, PCB-28 and PCB-47, respectively. A significantly positive correlation was found between logRCF (root concentration factor) and logKow of these PBDEs and PCBs, suggesting a control role of their partitioning in plant uptake. The translocation factors (TFs, Cstem/Croot) of PBDEs were generally lower than those of PCBs of the same halogen-substitutions, demonstrating easier transport of PCBs than PBDEs. Metabolites mono-, di- and tri-BDEs and PCBs were detected, suggesting the existence of in vivo metabolism of PBDEs and PCBs in maize. Dehalogenation and rearrangement of halogen atoms were identified, and some similarities but also significant differences existed between the PBDEs and PCBs. PBDEs in maize were, in general, more susceptible to metabolism compared with PCBs of the same halogen-substitutions. This is the first comparative report on the uptake, translocation and metabolism of PBDEs and PCBs in plants.