自动化顶空平衡-气相色谱法测定京杭运河中溶解甲烷

Determination of dissolved methane in the Beijing-Hangzhou Grand Canal using automated head space-GC system

温军 ¹臧昆鹏 ²潘凤梅 ¹申小龙 ¹魏康轩 ¹兰文港 ¹胡智伟 ¹陈啸鸣 ¹陈炳江 ¹李珊 ¹鲁嫣冉 ¹陈丽涵 ¹郭朋 ¹方双喜 ²林溢 ²陈圆圆 ²刘硕 ²徐宏辉³

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作者信息

1. 浙江工业大学环境学院,浙江杭州 310014
2. 浙江工业大学环境学院,浙江杭州 310014;浙江工业大学浙江碳中和创新研究院,浙江杭州 310014
3. 浙江省气象科学研究所,浙江杭州 310008
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摘要

将顶空平衡法和气相色谱仪相结合,通过自主设计和优化测试实现了技术升级,建立了可自动化进样并同步测定水中溶解 CH4 和 CO2 浓度的新型气相色谱系统及方法.结果表明,本系统线性范围宽且运行稳定,自动化程度更高,运行成本更低.该系统对 CH4 的测定精密度优于 0.16%,准确度优于0.02%,满足水中溶解CH4浓度监测需求.基于本方法,于 2022 年 8 月对京杭大运河杭州段水体中溶解CH4开展了试观测研究.结果显示:夏季京杭大运河杭州段水体中溶解 CH4 浓度平均值为(642.4±423.3)nmol/L,饱和度平均值为(22310±14701)%,水-气界面 CH4 扩散通量平均值为(548.57±603.70)μmol/(m2·d),是大气 CH4 的净源.根据该河段的面积,可估算观测期内 CH4 的日均排放量约为 1710mol,相当于大约 38.31m3 天然气或约82.94kg碳.

Abstract

A new head-space gas chromatography system equipped with a flame ionization detector and method was self-assembled and established,which could automatically and simultaneously measure concentrations of dissolved methane and carbon dioxide in water samples,with wider linear range and low operating cost.Precision and accuracy of this system for CH4 were better than 0.16%and 0.02%,respectively,which met the measurement requirements.In August 2022,dissolved CH4 concentration and related parameters were observed in the Beijing-Hangzhou Grand Canal in Hangzhou City.Results showed that mean dissolved CH4 concentration was(642.4±423.3)nmol/L,mean saturation was(22310±14701)%and mean air-water CH4 flux was(548.57±603.70)μmol/(m2·d)during field survey,indicated the observed area was a net source of atmospheric CH4.In addition,it was reasonable to estimate that the mean daily release rate of CH4 from the Canal was approximate 1710mol,which was equivalent to 38.31m3 of natural gas or 82.94kg of carbon.

关键词

顶空平衡/气相色谱/京杭大运河/甲烷/通量

Key words

head space/gas chromatograph/Beijing-Hangzhou Grand Canal/methane/flux

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基金项目

国家重点研发计划项目(2020YFA0607501)

浙江省自然科学基金联合基金资助项目(LZJMZ23D050002)

浙江省自然科学基金联合基金资助项目(LZJMZ24D050011)

浙江省基础公益研究计划项目(LGF22D050004)

出版年

2024

中国环境科学

中国环境科学学会

中国环境科学

CSTPCDCHSSCD北大核心

影响因子：2.174

ISSN：1000-6923

参考文献量41

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