This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction...This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.展开更多
Increased attention has been given to the fate of pollutants such as polycyclic aromatic hydrocarbons (PAHs) introduced to the wastewater treatment plants.Dissolved and adsorbed PAHs were detected in the centralized w...Increased attention has been given to the fate of pollutants such as polycyclic aromatic hydrocarbons (PAHs) introduced to the wastewater treatment plants.Dissolved and adsorbed PAHs were detected in the centralized wastewater treatment plant of a chemical industry zone in Zhejiang Province,China.The most abundant PAHs were the low molecular weight PAHs (e.g.,Acy,Ace,Flu and Phe),accounting for more than 80% of the total 16 PAHs in each treatment stage.Phase partitioning suggested that the removal of PAHs in every treatment stage was influenced greater by the sorption of particles or microorganisms.The removal efficiencies of individual PAHs ranged between 4% and 87% in the primary sedimentation stage,between 1% and 42% in anaerobic hydrolysis stage,between <1% and 70% in aerobic bio-process stage,between 1.5% and 80% in high-density clarifier stage,and between 44% and 97% in the whole treatment process.Mass balance calculations in primary stage showed significant losses for low molecular weight PAHs and relatively good agreements for high molecular weight PAHs as well as in anaerobic hydrolysis,high-density clarifier stage and sludge stream for most PAHs.Great gains of 60%-150% were obtained for high molecular weight PAHs in aerobic bio-process stage due to biosorption and bioaccumulation.Our investigations found that PAHs entering the wastewater treatment plant (WWTP) could be derived from the dyeing chemical processes as the byproducts,and the contribution supported by the largest dyeing chemical group was up to 48%.展开更多
基金supported by the National Natural Science Foundation of China (NSFC project 20775074)
文摘This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.
基金support to this study provided by National Key Technology R&D Program of China (2008BAC32B06)the National Natural Science Foundation of China (21076188,20836008, 20976158,20990221 & 21076189)the Key Innovation Team for Science and Technology of Zhejiang Province of China (2009R50047)
文摘Increased attention has been given to the fate of pollutants such as polycyclic aromatic hydrocarbons (PAHs) introduced to the wastewater treatment plants.Dissolved and adsorbed PAHs were detected in the centralized wastewater treatment plant of a chemical industry zone in Zhejiang Province,China.The most abundant PAHs were the low molecular weight PAHs (e.g.,Acy,Ace,Flu and Phe),accounting for more than 80% of the total 16 PAHs in each treatment stage.Phase partitioning suggested that the removal of PAHs in every treatment stage was influenced greater by the sorption of particles or microorganisms.The removal efficiencies of individual PAHs ranged between 4% and 87% in the primary sedimentation stage,between 1% and 42% in anaerobic hydrolysis stage,between <1% and 70% in aerobic bio-process stage,between 1.5% and 80% in high-density clarifier stage,and between 44% and 97% in the whole treatment process.Mass balance calculations in primary stage showed significant losses for low molecular weight PAHs and relatively good agreements for high molecular weight PAHs as well as in anaerobic hydrolysis,high-density clarifier stage and sludge stream for most PAHs.Great gains of 60%-150% were obtained for high molecular weight PAHs in aerobic bio-process stage due to biosorption and bioaccumulation.Our investigations found that PAHs entering the wastewater treatment plant (WWTP) could be derived from the dyeing chemical processes as the byproducts,and the contribution supported by the largest dyeing chemical group was up to 48%.
