Radiocarbon Measurements of Black Carbon in Aerosols and Ocean Sediments
Radiocarbon Measurements of Black Carbon in Aerosols and Ocean Sediments
复制标题
DOI：
10.1016/s0016-7037(01)00831-6
复制
发表时间：
2002-03
影响因子：
5
通讯作者：
C. Masiello;E. Druffel;L. Currie
中科院分区：
文献类型：
--
作者：
C. Masiello;E. Druffel;L. Currie
黑碳（BC）是生物质燃烧和化石燃料燃烧后残留的燃烧改变的固体残留物。BC的放射性碳测量提供了BC在土壤和沉积物等有机碳库中停留时间的信息，并通过区分化石燃料和生物质燃烧副产品提供了BC来源的信息。我们优化了重铬酸盐-硫酸氧化法测定BC中的放射性碳。我们还提出了NIST气溶胶SRM 1649 a的BC 14 C测量与先前公布的散装aromatic 14 C测量和个人多环芳烃（PAH）14 C测量相同的NIST标准的比较。重铬酸盐-硫酸氧化法属于化学类BC测量方法，其依赖于某些形式的BC对强化学氧化剂的耐受性。重铬酸盐-硫酸稀溶液以特征速率降解BC和海洋衍生碳，由此可使用简单的动力学公式计算单个组分的浓度（沃尔巴赫和安德斯，1989年）。我们证明：（1）重铬酸钾-硫酸氧化法可进行精确、可重复的14 C BC测量;（2）动力学计算在% OC基础上进行时可提供更精确的BC产率信息（3）动力学计算的BC浓度是相似的，无论氧化是在23°C还是50°C下进行;和（4）该方法产生的14 C BC结果与先前公布的NIST标准的芳香族14 C数据一致。出于相互比较的目的，我们报告了两种市售BC标准品的质量百分比和碳含量结果。我们还报告了一种新的热方法应用于SRM 1649 a的比较数据，表明这种材料的热氧化也遵循简单的动力学和指数模型，虽然具有不同的时间常数。
Black carbon (BC) is the combustion-altered, solid residue remaining after biomass burning and fossil fuel combustion. Radiocarbon measurements of BC provide information on the residence time of BC in organic carbon pools like soils and sediments, and also provide information on the source of BC by distinguishing between fossil fuel and biomass combustion byproducts. We have optimized dichromate-sulfuric acid oxidation for the measurement of radiocarbon in BC. We also present comparisons of BC14C measurements on NIST aerosol SRM 1649a with previously published bulk aromatic14C measurements and individual polycyclic aromatic hydrocarbon (PAH)14C measurements on the same NIST standard. Dichromate-sulfuric acid oxidation belongs to the chemical class of BC measurement methods, which rely on the resistance of some forms of BC to strong chemical oxidants. Dilute solutions of dichromate-sulfuric acid degrade BC and marine-derived carbon at characteristic rates from which a simple kinetic formula can be used to calculate concentrations of individual components (Wolbach and Anders, 1989). We show that: (1) dichromate-sulfuric acid oxidation allows precise, reproducible14C BC measurements; (2) kinetics calculations give more precise BC yield information when performed on a % OC basis (vs. a % mass basis); (3) kinetically calculated BC concentrations are similar regardless of whether the oxidation is performed at 23°C or 50°C; and (4) this method yields14C BC results consistent with previously published aromatic14C data for an NIST standard. For the purposes of intercomparison, we report % mass and carbon results for two commercially available BC standards. We also report comparative data from a new thermal method applied to SRM 1649a, showing that thermal oxidation of this material also follows the simple kinetic sum of exponentials model, although with different time constants.