Perfluorinated compounds in water and sediment from coastal regions of the northern Bohai Sea,China

Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and other perfluorinated compounds (PFCs) were measured in water and sediment from coastal Bohai Bay and surrounding rivers flowing into the bay. Of the 15 PFCs measured, PFOS and PFOA were detected with the greatest frequency. Concentrations in water ranged from<0.2 to 31 ng·L^?1 and<1.0 to 82 ng·L^?1 for PFOS and PFOA, respectively. Concentrations of PFOS and PFOA in sediments ranged from<0.1 to 2.0 ng·g^?1 dw and<0.1 to 0.5 ng·g^?1 dw, respectively. Concentrations of PFCs in Bohai Bay were less than those observed in other areas in Asia, but greater concentrations of ∑PFCs were observed in the Dalin River with concentrations increasing from upstream to downstream, and the greatest concentrations in sediment were observed in tidal flats. The ratio of ∑PFCs in sediment and water indicated that sediment could serve as a significant sink for PFUnA.     

A hybrid membrane process for simultaneous thickening and digestion of waste activated sludge

A hybrid membrane process for simultaneous sludge thickening and digestion (MSTD) was studied. During one cycle (15 d) of operation under a hydraulic retention time of 1 d, the concentration of mixed liquor suspended solids (MLSS) continuously increased from about 4 g·L⁻¹ to 34 g·L⁻¹, and the mixed liquor volatile suspended solids (MLVSS) increased from about 3 g·L⁻¹ to over 22 g·L⁻¹. About 42% of the MLVSS and 39% of the MLSS reduction were achieved. The thickening and digestion effects in the MSTD were further analyzed based on a mass balance analysis. Test results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the process. It was also found that the capillary suction time, colloidal chemical oxygen demand, soluble microbial products, viscosity, and MLSS had significant positive correlations with the membrane fouling rate, whereas extracellular polymeric substances, polysaccharides, and proteins extracted from biomass had negative impacts on membrane fouling.     

Ultrasound-assisted emulsification solidified floating organic drop microextraction for the determination of trace amounts of copper in water samples

A simple and efficient liquid-phase microextraction (LPME) technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction (USAE-SFODME) combined with flame atomic absorption spectrometry, for the extraction and determination of trace copper in water samples. 1-(2-Pyridylazo)-2-naphthol (PAN) was used as chelating agent. Microextraction efficiency factors (including extraction solvent type, extraction volume, time, temperature, and pH), the amount of the chelating agent, and salt effect were investigated and optimized. Under the optimum extraction conditions, figures of merit of the proposed method were evaluated. The calibration graph was linear in the range of 20–600 mg·L⁻¹ with a detection limit of 0.76 mg·L⁻¹. The relative standard deviation (R.S.D) for ten replicate measurements of 20 and 400 mg·L⁻¹ of copper was 3.83% and 2.65%, respectively. Finally, the proposed method was applied to tap water, river water, and sea water, and accuracy was assessed through the analysis of certified reference water or recovery experiments.     

北京水源地鱼体全氟化合物的暴露水平及其健康风险

全氟化合物(PFASs)作为一类新型的有机污染物,因具有持久性、可长距离传输、生物蓄积性和生物毒性等POPs特性,近年来得到全世界的广泛关注。本文以北京市水源地(密云水库和官厅水库)为研究区域,采用固相萃取(SPE)前处理与高效液相色谱串联质谱联用(HPLC-MS/MS)相结合的方法,分析测定了鱼样品中包括全氟辛烷磺酸(PFOS)、全氟辛酸(PFOA)、全氟丁酸(PFBA)、全氟丁烷磺酸(PFBS)等在内的12种PFASs的含量。利用同位素法确定了不同种类鱼的营养级关系,研究不同营养级中的PFASs浓度及生物放大效应,重点对全氟辛烷磺酸(PFOS)与全氟辛酸(PFOA)的生态风险以及对人体的健康风险进行评价。结果表明:北京市水源地的鱼体中的PFASs存在不同程度的检出,其中,全氟辛烷磺酸(PFOS)、全氟辛酸(PFOA)、全氟壬酸(PFNA)、全氟癸酸(PFDA)、全氟十一酸(PFUdA)和全氟十二酸(PFDoA)的检出率均达到100%,PFASs总量浓度达1.70~14.32 ng·g~(-1) wet weight(w.w.),PFOS和长链全氟羧酸PFCAs是鱼体中的主要污染物。同位素鉴定水库鱼的营养级层次范围在2.11~4.10,且肉食性鱼类营养级大多高于杂食性鱼类,PFOS沿着食物链生物放大的过程与稳定碳氮同位素富集过程基本同步。此外,采用人均日摄入量法(average daily intake,ADI)评估得到PFOS与PFOA的风险值分别为1.16 ng·kg~(-1)·d~(-1)和0.31ng·kg~(-1)·d~(-1),整体低于人均每天可承受摄入量(tolerable daily intake,TDI),结果表明,北京水源地鱼体中PFOS和PFOA含量未达到对生态系统和人体健康具有风险的水平。     

Biosorption of Cr(III) from aqueous solution by freeze-dried activated sludge: Equilibrium,kinetic and thermodynamic studies

Batch biosorption experiments were conducted to remove Cr(III) from aqueous solutions using activated sludge from a sewage treatment plant. An investigation was conducted on the effects of the initial pH, contact time, temperature, and initial Cr(III) concentration in the biosorption process. The results revealed that the activated sludge exhibited the highest Cr(III) uptake capacity (120 mg·g⁻¹) at 45°C, initial pH of 4, and initial Cr(III) concentration of 100 mg·L⁻¹. The biosorption results obtained at various temperatures showed that the biosorption pattern accurately followed the Langmuir model. The calculated thermodynamic parameters, ΔG^o (−0.8– −4.58 kJ·mol⁻¹), ΔH^o (15.6–44.4 kJ·mol⁻¹), and ΔS^o (0.06–0.15 kJ·mol⁻¹·K⁻¹) clearly indicated that the biosorption process was feasible, spontaneous, endothermic, and physical. The pseudo first-order and second-order kinetic models were adopted to describe the experimental data, which revealed that the Cr(III) biosorption process conformed to the second-order rate expression and the biosorption rate constants decreased with increasing Cr(III) concentration. The analysis of the values of biosorption activation energy (E_a = −7 kJ·mol⁻¹) and the intra-particle diffusion model demonstrated that Cr(III) biosorption was film-diffusion-controlled.     

Determination and occurrence of endocrine disrupting compounds,pharmaceuticals and personal care products in fish (Morone saxatilis)

Endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products (PPCPs) have attracted much attention due to widespread contamination in aquatic environment. In this study, we determined 13 EDCs and PPCPs in fish blood, bile and muscle by using gas chromatography-mass spectrometry (GC-MS). The limits of quantitation (LOQ) were in the ranges of 0.23–2.54, 0.22–2.36 ng·mL⁻¹, and 0.24–2.57 ng·g⁻¹ dry weight (dw) for fish blood, bile and muscle, respectively. Recoveries of target compounds spiked into sample matrices and passed through the entire analytical procedure ranged from 65% to 95%, from 60% to 92% and from 62% to 91% for blood, bile and muscle, respectively. The methods were applied to the analysis of fish from a lake in California. Target compounds were relatively low in bile, and only bisphenol A (BPA) and diclofenac were measurable near the LOQ. Seven of 13 compounds were detected in blood, with total concentrations up to 39 ng·mL⁻¹. Only BPA was frequently found in muscle, with mean concentration of 7.26 ng·g⁻¹ dw. The estimated daily intake of BPA through fish consumption for U.S. resident was significantly lower than the tolerable daily intake recommended by the European Food Safety Authority. This study showed that the exposure to the bisphenol A from fish diet is unlikely to pose a health risk.     

Oxidation and biotoxicity assessment of microcystin-LR using different AOPs based on UV,O3 and H2O2

MC-LR removal performances under different AOPs were compared systematically. Higher removal efficiency and synergistic effects were obtained by combined process. The acute biotoxicity raised in different degrees after oxidation. Microcystin-LR attracts attention due to its high toxicity, high concentration and high frequency. The removal characteristics of UV/H₂O₂ and O₃/H₂O₂ advanced oxidation processes and their individual process for MC-LR were investigated and compared in this study. Both the removal efficiencies and rates of MC-LR as well as the biotoxicity of degradation products was analyzed. Results showed that the UV/H₂O₂ process and O₃/H₂O₂ were effective methods to remove MC-LR from water, and they two performed better than UV-, O₃-, H₂O₂-alone processes under the same conditions. The effects of UV intensity, H₂O₂ concentration and O₃ concentration on the removal performance were explored. The synergistic effects between UV and H₂O₂, O₃ and H₂O₂ were observed. UV dosage of 1800 mJ·cm⁻² was required to remove 90% of 100 mg·L⁻¹ MC-LR, which amount significantly decreased to 500 mJ·cm⁻² when 1.7 mg·L⁻¹ H₂O₂ was added. 0.25 mg·L⁻¹ O₃, or 0.125 mg·L⁻¹ O₃ with 1.7 mg·L⁻¹ H₂O₂ was needed to reach 90% removal efficiency. Furthermore, the biotoxicity results about these UV/H₂O₂, O₃/H₂O₂ and O₃-alone processes all present rising trends with oxidation degree of MC-LR. Biotoxicity of solution, equivalent to 0.01 mg·L⁻¹ Zn²⁺, raised to 0.05 mg·L⁻¹ Zn²⁺ after UV/H₂O₂ or O₃/H₂O₂ reaction. This phenomenon may be attributed to the aldehydes and ketones with small molecular weight generated during reaction. Advice about the selection of MC-LR removal methods in real cases was provided.     

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using voltammetry

The main purpose of this work was to develop a reliable method for the determination of vanadium (V) and molybdenum (Mo) in atmosphere particles or aerosols because they can not be readily measured using conventional techniques. For this research, 30 particulate samples were collected from five different stations located at Palermo, Italy. We used the catalytic adsorptive stripping voltammetry and differential pulsed voltammetry to measure V and Mo in atmospheric particulate, respectively. The represented method includes advantages of high sensitivity, high selectivity, simplicity, reproducibility, speed and low costs. The quantification limits for V and Mo are, respectively, 0.57 and 0.80 ng·m⁻³. The precision, expressed as relative standard deviation (RSD %), was about 2% for both metals. The mean recoveries of added V and Mo were about 99.5% and ranged from 97% to 101%. Vanadium concentrations in particulate samples collected in Palermo area ranged from 0.57 to 7.7 ng·m⁻³, while Mo concentrations were in the range 0.8–51 ng·m⁻³. In many cases the concentrations of two elements in the particulate samples fall below the detection limits. The mean concentrations for V and Mo in particulate samples, collected in Palermo area, were respectively 3.1 and 5.9 ng·m⁻³.     

Phenanthrene sorption to environmental black carbon in sediments from the Song-Liao watershed (China)

Black carbon (BC) in ten contaminated sediments from the Song-Liao watershed, NE China, was isolated upon treatments using a combustion method at 375°C, and the isolates’ sorption isotherms for phenanthrene (Phen) were determined. All sorption isotherms were nonlinear and fitted well by the Freundlich model. A negative relation was found between Freundlich sorption nonlinearity parameter (n values) and BC/total organic carbon (TOC) content of the original sediments (r²=0.687, p<0.01), indicating the dominance of BC in Phen sorption nonlinearity. The BC isolates from this industrialized region had n values of 0.342 to 0.505 and logK_FOC values of 6.02 to 6.42(μg·kg⁻¹·OC⁻¹)/(μg·L⁻¹) ⁿ for Phen. At a given C_e, the BC had higher K_oc value than the original sediments, revealing a higher sorption capacity for BC. BC was responsible for 50.0% to 87.3% of the total sorption at C_e=0.05 S_w, clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.     

云南省会泽县农田土壤中全氟化合物污染特征研究

为探究云南省会泽县农田土壤中全氟化合物(perfluorinated compounds,PFCs)的污染特征及其潜在来源,2015年6月采集云南省会泽县农田土壤42份,利用高效液相色谱-串联质谱仪(HPLC-MS/MS)分析了11种PFCs的含量水平。结果表明,云南省会泽县农田土壤中全氟己酸(perfluorohexanoic acid,PFHx A)、全氟庚酸(perfluoroheptanoic acid,PFHp A)和全氟己烷磺酸(perfluorohexane sulfonate,PFHx S)均未检出,其余8种PFCs(ΣPFCs)的平均含量水平为0.392 ng·g-1,含量范围为0.298~0.998ng·g-1。全氟辛酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)是最主要的PFCs,相对百分含量范围为45.93%~81.86%,其平均含量水平分别为0.116 ng·g-1和0.120 ng·g-1。与国内其他地区土壤中PFCs的含量水平相比,云南省会泽县农田土壤中PFCs含量水平低于上海,与广州、深圳、东莞、安徽、中国东部农村等地区土壤中PFCs的含量相当。主成分分析结果表明,以全氟癸酸(perfluorodecanoic acid,PFDA)、全氟辛烷磺酸(PFOS)和全氟十三酸(perfluorotridecanoic acid,PFTr DA)为主要标志物的2个主成分可以解释云南省会泽县农田土壤中73%的ΣPFCs。工业活动、大气沉降及长距离传输为云南省会泽县农田土壤中PFCs的主要来源。     

Impact of solids on biphasic biodegradation of phenanthrene in the presence of hydroxypropyl- &#946; -cyclodextrin (HPCD)

The consequence of polycyclic aromatic hydrocarbons (PAHs) in the environment is of great concern. The hydrophobic properties of PAHs significantly impact phase distribution causing limited bioavailability. Enhanced biodegradation has been extensively carried out by surfactants and the redeployment effect was recognized. However, the quantitative relationship concerning the impact of solids was rarely reported. A batch of biphasic tests were carried out by introducing Mycobacterium vanbaalenii PYR-1 and hydroxypropyl-β-cyclodextrin (HPCD) into a mixture of phenanthrene solution and various glass beads (GB37-63, GB105-125, and GB350-500). The comparative results demonstrated that HPCD had little effect on microbial growth and was not degradable by bacterium. A model was proposed to describe the biodegradation process. The regression results indicated that the partition coefficient k_d (1.234, 0.726 and 0.448 L·g⁻¹) and the degradation rate k (0 mmol·L⁻¹: 0.055, 0.094, and 0.112; 20 mmol·L⁻¹: 0.126, 0.141, and 0.156; 40 mmol·L⁻¹: 0.141, 0.156 and 0.184 d⁻¹) were positively and negatively correlated with the calculated total surface area (TSA) of solids, respectively. Degradation enhanced in the presence of HPCD, and the enhancing factor f was calculated (20 mmol·L⁻¹: 15.16, 40.01, and 145.5; 40 mmol·L⁻¹: 13.29, 37.97, and 138.4), indicating that the impact of solids was significant for the enhancement of biodegradation.     

A review of spatial and temporal assessment of PFOS and PFOA contamination in China

The current state of concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in China is presented. While products that are known to degrade to either PFOS or PFOA have been used in China, concentrations in environmental media have been reported to be relatively low across China. Greater concentrations of PFOS and PFOA were observed in southern and eastern China than in other areas of China. Concentrations of PFOS and PFOA were relatively great in the Huangpu River, with concentrations of 20.5 ng l^?1 and 1590 ng l^?1, respectively. Surface waters of Dongguan and Shanghai were more contaminated by PFOS and PFOA than that of other cities. Dongguan was the only city in China in which PFOS value in surface water exceeded the water quality criterion, while PFOA concentration in Shanghai was 152 ng l^?1. Similar to other contaminants, point-source pollution was also the common pattern of PFOS and PFOA contamination. Concentrations of PFOS in human blood in China were relatively greater in China than other countries, with drinking water contamination given as the most likely source. Concentrations of PFOS in human blood have increased from the 1980s to the 2000s, while such a trend was not observed for PFOA.     

3种微藻对全氟烷基化合物的生物富集效应

全氟烷基化合物(perfluoroalkyl substances,PFASs)是一系列人工合成的新型有机污染物,由于长链的PFASs具有较高的生物蓄积性,短链PFASs逐渐作为替代品而被广泛利用。为探讨不同碳链长度的PFASs在水生浮游植物中的蓄积能力,选取7种PFASs为目标物,以斜生栅藻(Scenedesmus obliquus)、钝顶螺旋藻(Spirulina platensis)和蛋白核小球藻(Chlorella pyrenoidosa)作为受试生物进行富集动力学实验,测定24 h时的生物富集因子(Bioconcentration factors,BCF)。结果表明,染毒浓度为10μg·L-1时,全氟癸烷羧酸的富集能力最强,在斜生栅藻、钝顶螺旋藻和蛋白核小球藻中的浓度分别为1 894 ng·g~(-1)、88.0ng·g~(-1)、990 ng·g~(-1)。3种微藻中全氟烷基磺酸的BCF均随碳链长度的增加而增大;全氟烷基羧酸的BCF基本遵循同样的规律,只是在钝顶螺旋藻体内,全氟己烷羧酸的BCF高于全氟辛烷羧酸。此外,PFASs在斜生栅藻中的浓度均高于蛋白核小球藻和钝顶螺旋藻,不同藻类的富集能力与其表面积、脂肪及蛋白质组成有关。     

台湾儿童血清全氟化合物与血脂关联的性别差异研究

目的:全氟辛烷磺酸(PFOS)和全氟辛酸(PFOA)是广泛应用于工业和生活领域的全氟化合物,在人体及环境介质中均可检出。近几年的流行病学研究表明儿童PFOS和PFOA的暴露水平与血脂水平具有相关性。本研究拟进一步研究血清全氟化合物水平与儿童血脂间关联的性别差异。方法:以台湾儿童为研究对象,分析血清中总胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、甘油三脂(TG)等生化指标与PFOS和PFOA血清水平的相关性。结果:线性回归模型分析表明男生血清PFOS、PFOA水平与血脂水平具有显著相关性。当男生血清中ln-PFOS和ln-PFOA水平每增加1 ng·m L~(-1)时,TC含量分别增高0.51 mg·d L~(-1)(95%CI:0.30~0.72)和6.53 mg·d L~(-1)(95%CI:1.96~11.11),但在女生中则没有观察到血清PFOS和PFOA水平与TC的相关性。趋势分析结果显示,随着儿童血清中PFOS和PFOA水平的增加,男生和女生血脂的TC、LDL和TG含量呈增高趋势。结论:台湾儿童血清PFOS和PFOA水平与血脂水平存在正相关,且在男生中观察到的效应强于女生。     

武汉地区水环境中全氟化合物污染水平及其分布特征

武汉作为中国氟化工行业的主要生产基地之一,其水环境中全氟及多氟类化合物(PFASs)污染情况对评估该地区水环境生态安全至关重要。采集了武汉城区10个污水处理厂进、出口污水和19个地表水样品,利用HPLC-ESI-MS/MS技术分析研究该区域水环境中PFASs污染水平及其分布特征。结果发现,武汉地区的污水和地表水样品中,PFASs污染均以短链同系物全氟丁酸(PFBA)和全氟丁基磺酸(PFBS)为主。污水处理厂进、出口污水中PFASs总浓度分别为11.8~12 700 ng·L~(-1)和19.1~9 970 ng·L~(-1)。在城区15个湖水样品中,PFASs总浓度为21.0~10 900 ng·L~(-1);在流经城区的4个江水样品中,PFASs总浓度为4.11~4.77 ng·L~(-1),比湖水样品中PFASs浓度水平低1~2个数量级。与污水中PFASs空间分布趋势一致,各湖泊水样中PFASs总体水平呈现汉口汉阳武昌的趋势,表明城市工业布局与人口密度程度直接影响城市PFASs污染空间分布。值得注意的是,与以往水环境中PFASs污染以全氟辛酸(PFOA)和全氟辛基磺酸(PFOS)为主不同,武汉地区水环境中PFASs污染以短链同系物为主,表明短链替代效应已经渐渐在中国化工领域出现,中国全氟行业在响应国际组织规范和建议的基础上做出了实质性进展。然而,对于短链PFASs的污染特征、迁移运输以及生态风险等科学问题,还需要更进一步的研究。     

Modified landfill gas generation rate model of first-order kinetics and two-stage reaction

This investigation was carried out to establish a new domestic landfill gas (LFG) generation rate model that takes into account the impact of leachate recirculation. The first-order kinetics and two-stage reaction (FKTSR) model of the LFG generation rate includes mechanisms of the nutrient balance for biochemical reaction in two main stages. In this study, the FKTSR model was modified by the introduction of the outflow function and the organic acid conversion coefficient in order to represent the in-situ condition of nutrient loss through leachate. Laboratory experiments were carried out to simulate the impact of leachate recirculation and verify the modified FKTSR model. The model calibration was then calculated by using the experimental data. The results suggested that the new model was in line with the experimental data. The main parameters of the modified FKTSR model, including the LFG production potential (L₀), the reaction rate constant in the first stage (K₁), and the reaction rate constant in the second stage (K₂) of 64.746 L, 0.202 d⁻¹, and 0.338 d⁻¹, respectively, were comparable to the old ones of 42.069 L, 0.231 d⁻¹, and 0.231 d⁻¹. The new model is better able to explain the mechanisms involved in LFG generation.     

Occurrence and behavior of pharmaceuticals in sewage treatment plants in eastern China

The occurrence and removal efficiency of seven pharmaceuticals (norfloxacin, trimethoprim, roxithromycin, sulfamethoxazole, ibuprofen, diclofenac and carbamazepine) were determined in three sewage treatment plants (STPs) with anaerobic/anoxic/oxic, anoxic/oxic and oxidation ditches processes in Xuzhou City, Eastern China. The results showed that seven pharmaceuticals were detected in the influent samples with concentrations ranging from 93 to 2540 ng·L⁻¹. The removal of these substances among the three different STPs varied from 36 to 84%, with the highest performance obtained by the wastewater treatment works with tertiary treatment (sand filtration). Most of the compounds were removed effectively during biologic treatment while sand filtration treatment also made a contribution to the total elimination of most pharmaceuticals. The efficiency comparison of the three sewage treatment processes showed that the STP which employed anaerobic/anoxic/oxic was more effective to remove pharmaceuticals than the oxidation ditches and anoxic/oxic.     

Thermal defluorination behaviors of PFOS,PFOA and PFBS during regeneration of activated carbon by molten salt

• New method of mineralizing PFCs was proposed. • Activated carbon was regenerated while mineralizing PFCs. • Molten NaOH has good mineralization effect on PFOS and PFBS. Current study proposes a green regeneration method of activated carbon (AC) laden with Perfluorochemicals (PFCs) from the perspective of environmental safety and resource regeneration. The defluorination efficiencies of AC adsorbed perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanesulfonate (PFBS) using three molten sodium salts and one molten alkali were compared. Results showed that defluorination efficiencies of molten NaOH for the three PFCs were higher than the other three molten sodium salts at lower temperature. At 700°C, the defluorination efficiencies of PFOS and PFBS using molten NaOH reached to 84.2% and 79.2%, respectively, while the defluorination efficiency of PFOA was 35.3%. In addition, the temperature of molten salt, the holding time and the ratio of salt to carbon were directly proportional to the defluorination efficiency. The low defluorination efficiency of PFOA was due to the low thermal stability of PFOA, which made it difficult to be captured by molten salt.The weight loss range of PFOA was 75°C–125°C, which was much lower than PFOS and PFBS (400°C–500°C). From the perspective of gas production, fluorine-containing gases produced from molten NaOH-treated AC were significantly reduced, which means that environmental risks were significantly reduced. After molten NaOH treatment, the regenerated AC had higher adsorption capacity than that of pre-treated AC.     

Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst in the catalytic wet air oxidation (CWAO) of cationic red GTL under mild reaction conditions

Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃, an environmental friendly material, was investigated. The catalyst exhibited good catalytic performance in the CWAO of cationic red GTL. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. HO₂· and O₂·⁻ appeared as the main reactive species in the reaction. The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. Hydroperoxy radicals (HO₂·) and superoxide radicals (O₂⁻·) appeared as the main reactive species upon the CWAO of cationic red GTL.     

4种短链全氟化合物替代物在城市污水处理厂的污染特征研究

全氟辛烷羧酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctyl sulfonate,PFOS)等长链全氟化合物(perfluorinated compounds,PFCs)具有持久性、生物累积性和毒性,近年来发现一些短链PFCs具有相对较短的半衰期,可以成为PFOA和PFOS的替代品,这些物质包括C4和C6结构的PFCs,如全氟丁烷羧酸(perfluorobutanoic acid,PFBA)、全氟己烷羧酸(perfluorohexanoic acid,PFHx A)、全氟丁烷磺酸(perfluorobutyl sulfonate,PFBS)和全氟己烷磺酸(perfluorohexyl sulfonate,PFHx S)。为解析我国城市污水厂短链PFCs污染水平和地域分布特征,本研究调查了我国不同地区17座城市污水处理厂的进水、二沉出水和污泥中4种短链PFCs的分布和浓度水平。结果表明4种短链PFCs、PFOA和PFOS在17座污水厂进水中检出率均为100%(6种目标物单体浓度范围:0.19~274.72 ng·L-1);污泥中PFOS和PFOA检出率为100%(PFOS:2.08~72.31 ng·g-1,PFOA:1.03~24.81 ng·g-1),PFBA、PFHx A检出率为100%(0.60~3.33 ng·g-1),PFBS和PFHx S的检出率分别为42.11%和63.16%。在污水厂进水中,将PFOA和PFOS与其同类的短链PFCs浓度进行比较,发现短链PFCs分别相对于PFOA和PFOS的比例最高可达93.47%和94.57%。4种短链PFCs、PFOA和PFOS的地域分布差异明显,总浓度呈现出华东、华南地区高于西北、东北、华北地区的趋势,其中华东地区调查的污水处理厂浓度最高。污水厂4种短链替代物主要通过污水排放,不同污水厂的日排放总量(污泥和出水)为0.25~273.07 g·d-1,万吨水排放量范围为0.04~1.37 g。研究将为我国全氟化合物替代物污染和控制提供数据基础和科学依据。