Abstract The speciations of Arsenic (As) in coal will inevitably convert during the combustion process. The As speciations in coal and its by-products are closely related to human health and environmental safety which is urgent to be identified. However, there is a lack of pretreatment procedure and analysis method on the As species in coal-related products in power plants. In this study, the As species in coal, fly ash (FA), and gypsum were successfully determined by high performance liquid chromatography coupled with hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS). The instrument parameters, extract reagents, and pretreatment methods (i.e. ultrasound and microwave-assisted) were optimized. The whole separation time of inorganic As was shorten to 7 min after optimization, with the detection limit of 1.8 and 4.6 ng/g for As(III) and As(V), respectively. The efficient As extract reagent was the mixture of 1.0 mol/L H3PO4 and 0.1 mol/L ascorbic acid solution. Microwave-assisted (2000 W, 80°C, 40 min) and ultrasound-assisted (40 kHz, 20°C, 40 min) schemes were the optimal extraction methods for coal/FA and gypsum samples, respectively. Under the proposed microwave and ultrasound extraction procedure, the recovery of As(III) and As(V) could reach to 95.8%/104.5% and 90.6%/89.7%, respectively. The dominant occurrence of As species in coal was As(V) with a small percentage of As(III), while As(V) was the only occurrence form observed in FA and gypsum. It is indicated that revealing the transformation of As(III) to As(V) is the key for gaseous As capture. The As species distribution investigation provides a scientific insight to the controlling of As emission from power plant.

中文翻译：

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燃煤电厂煤及其燃烧副产物中砷的形态分析

摘要 煤中砷（As）的形态在燃烧过程中不可避免地会发生转化。煤及其副产品中的砷形态与人类健康和环境安全密切相关，亟待查明。然而，目前缺乏电厂煤相关产品中As的预处理程序和分析方法。本研究采用高效液相色谱-氢化物发生原子荧光光谱法 (HPLC-HG-AFS) 成功测定煤、粉煤灰 (FA) 和石膏中的 As 形态。对仪器参数、提取试剂和预处理方法（即超声和微波辅助）进行了优化。优化后无机As的整体分离时间缩短至7 min，检测限分别为1.8和4。As(III) 和 As(V) 分别为 6 ng/g。高效的 As 萃取试剂是 1.0 mol/L H3PO4 和 0.1 mol/L 抗坏血酸溶液的混合物。微波辅助（2000 W，80°C，40 分钟）和超声辅助（40 kHz，20°C，40 分钟）方案分别是煤/FA 和石膏样品的最佳提取方法。在所提出的微波和超声提取程序下，As(III) 和 As(V) 的回收率分别可以达到 95.8%/104.5% 和 90.6%/89.7%。煤中 As 的主要存在形式是 As(V)，As(III) 的比例很小，而 As(V) 是在 FA 和石膏中观察到的唯一存在形式。表明揭示As(III)向As(V)的转变是气态As捕获的关键。