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题名: 基于半渗透复合膜器件的被动式连续采样技术及其现场应用
作者: 唐剑锋
学位类别: 博士
答辩日期: 2012
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 马梅
关键词: 被动式采样 ; passive sampling ; 三油酸酯-醋酸纤维素复合膜 ; triolein embedded cellulose acetate membrane, TECAM ; 时间加权平均浓度 ; time-weighted average concentrations,TWA ; 疏水性有机化合物 ; hydrophobic organic compounds,HOCs ; 现场校正 ; in situ calibration
其他题名: Calibration and field performance of triolein based semipermeable membrane for passive sampling persistant organic pollutants in water
中文摘要:       本研究组开发的三油酸酯/醋酸纤维素半透复合膜(TECAM)就是被国际同行认可的优秀半透膜采样器之一。TECAM的使用成本低廉,易于制备,前处理操作简单,以往的研究结果已表明TECAM具有很好的应用前景,既能用于富集自由溶解态的污染物和评价生物有效性,又能通过连续采样提供污染物的时间加权平均浓度信息。 然而,TECAM的野外现场应用遇到了挑战,特别是缺乏适宜的现场采样设备、可靠的质量控制手段和数据计算模型。因此,本研究从以下几个方面进行了深入探讨:在原有工作的基础上,对半透膜材料组成与制膜条件进行改进,使膜的制备过程标准化;探讨环境因素如温度、流速及水体污染物浓度波动等因素对TECAM的影响;并发展TECAM被动式采样技术的野外现场校正方法和应用,以及发展配套的现场采样设备。主要成果如下: 1. 改进了半透膜材料配方与制膜液蒸发、凝胶浴等参数条件,三醋酸纤维素 (CTA) 聚合物膜材料具有更好的机械性能和更高的吸收效率;发展了“生物类脂-聚合物高分子”半透复合膜的半自动制备技术与设备,规范化控制膜的制备过程,提高了半透复合膜的稳定性和采样性能。 2. 温度和流速均能显著影响TECAM对目标污染物的采样速率. 3. 建立了基于效能参考化合物 (performance reference compounds, PRCs) 的TECAM现场应用采样数据校正方法。以多环芳烃为目标污染物,筛选出pyrene-d10作为适宜的现场采样PRC,并进一步比较优化了不同的校正数学模型;在野外应用案例中,所建立的TECAM-PRCs方法可将现场水力学差异引起的实验误差控制在2倍以内。 4. 建立了水体浓度的不同波动情景下,采用TECAM连续采样预测水中污染物的时间加权平均 (TWA) 浓度的方法。对强疏水性化合物(log Kow>5),TECAM能够很好的应对各种污染物浓度波动情景,准确预测其TWA浓度(相对误差小于25%) 。而对于中等疏水性化合物(log Kow<5),TECAM连续采样预测TWA浓度的准确性与浓度的波动情景密切相关,当浓度波动出现在采样后期时误差最大。 5. 发展了一种新的TECAM被动式现场连续采样方法和设备。该方法主要通过控制野外水流环境条件与实验室条件保持一致,直接应用实验室准确测定的吸收速率常数(ku)等参数值估算水体TWA浓度。野外验证结果显示,TECAM连续采样预测的TWA浓度与多次瞬时采样SPE方法得到的TWA浓度相一致。 本研究在改进半透复合膜材料和开发现场采样设备的基础上,发展了基于半渗透复合膜器件的被动式现场连续采样技术体系,建立了野外应用的现场采样数据校正方法,建立了水体浓度不同波动情景下疏水性污染物时间加权平均(TWA)浓度的可靠预测方法,为疏水性污染物的环境监测和环境暴露评价提供有力工具。
英文摘要:       Passive water sampling has several advantages over active methods; it improves detection limits and provides time-integrated data. Semipermeable membrane devices (SPMDs) are currently the most widely used types of passive samplers to measure pollutants in aquatic environments. The triolein embedded cellulose acetate membrane (TECAM) passive sampler, developed by our group, is one of the accepted excellent passive samplers for in situ passive sampling of HOCs in water. This passive sampler is cost-effective, easy to prepare, and involves simple pretreatment procedures, and can quickly and efficiently accumulate HOCs. TECAM passive sampler can be used as a powerful potential to predict the bioavailability of HOCs and can provide the information of time-weighted average (TWA) concentration of pollutants. TECAM has much to offer in response to the challenge of measuring TWA concentrations of a wide variety of HOCs in aquatic environments, but widespread acceptance has been restricted by several factors. Some of the biggest chanllenges facing the quantitative use of such sampler is the lack of suitable field sampling equipment, reliable quality control procedure and mathematical model. Several aspects were discussed in this dissertation as follows: based on the previous research work, the design of TECAM and the precudure of membrane preparation were optimized; the effects of temperature, water turbulence and pulsed events on TECAM were also studied; the use of performance reference compounds (PRCs) for in situ calibration for PAHs in water of TECAM was evaluated and an innovalative integrative sampling devices have been developed enabling high sampling rates unaffected by turbulences thus avoiding the use of PRCs. The main results are as follows: 1. The membrane material and sampler prepation was optimized and standardized; cellulose triacetate (CTA) gave the best performance (best tensile strength and highest uptake rates) among all the tested composite semipermeable membranes. And we have developed an approach to standardize the semipermeable membranes preparation which improved the quality of the sampler. 2. The uptake rate constants (ku) with the increasing exposure temperatue and water flow rates, on the other hand, temperature effects on ku of TECAM were relatively small which showed less sensitive than other passive samplers such as Chemcather. TECAM ku are quite sensitive to slight changes in water flow rates, which showed the flow velocity is a key factor to accurately estimate water concentrations in field. 3. A performance reference compounds (PRCs) method for in situ calibration was successfully developed in TECAM passive sampler. Pyrene-d10 was selected as the most suitable PRCs of TECAM for sampling PAHs. With comparing and optimizing the mathematical model, most of the effects of environmental factors on the uptake rate constants with a wide range of hydrophobicities can be deduced from PRCs, and the use of PRCs permit prediction of in situ TECAM uptake rate constants within 2-fold of directly measured values. 4. A modified mathematical model was introduced to predict TWA concentrations when TECAM encounter to several fluctuating concentration event scenarios. Good agreements were observed between TWA concentrations measured from the grab samples and estimated from TECAM for most hydrophobic compounds (relative error <25% for log Kow>5 compounds). For compounds with log Kow<5, relative errors resulted mainly from the pulse scenarios, the greatest deviation was found when the highest concentration occurred in later stage of the exposure, TECAM predicted TWA concentrations with a factor of 3 after 7 days exposure when a pulsed event of 10-fold greater concentration for 24 hours occurred at the end of exposure period. 5. An innovative integrative sampler has been developed enabling high sampling rates unaffected by turbulences. The sampler consist a peristaltic pump which produces a constant flow through an aquarium. The uptake rate constants ku from 0.63 to 3.2 L/g/d for OCPs and PAHs were obtained with the continous flow integrative devices. And an in field evaluation for the devices was carried out for a 7 days sampling period in the outlet of a waste water treatment plant with comparable results to those obtained with a repeat spot sampling. In conclusion, based on the optimize of TECAM passive devices, we developed an in situ calibration approach for triolein embedded semipermeable membranes, and developed a stategy that can be used to detect and quantify peaks of concentrations during short but significant pollution events, which provide a powerful tool for monitoring programs and for better risk assessment of pressures.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35114
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
唐剑锋. 基于半渗透复合膜器件的被动式连续采样技术及其现场应用[D]. 北京. 中国科学院研究生院. 2012.
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