Fractionation of lead in lignite coal samples of Thar coalfield, Pakistan by time‐saving single‐step based on BCR sequential extraction scheme.

The toxic metals in coal have different modes of occurrence required their frequent assessment by accurate and time‐saving chemical fractionation schemes. In the current study, the conventional sequential extraction BCR (SE‐BCR) method applied to recognize the chemical fraction of lead (Pb) in coal samples of recently developed Thar coalfield. The SE‐BCR scheme modified with a time‐saving single‐step extraction (SSE) method assisted with ultrasound energy and conventional shaking devices under the same operating conditions applied for the original SE‐BCR scheme. The conventional single‐step extraction (CSS) and ultrasonic‐assisted extractions (USE) methods efficiently reduced the time expected to separate all fractions by the SE‐BCR method in 51 h to 22 and 2 h, respectively. The validity of both single‐step extraction (SSE and USE) and SE‐BCR methods were confirmed by applying certified reference material (CRM) of sediment (BCR‐701) followed by the standard addition method. The Pb observed to be highest in the organic fraction (28.9–35.2%) and lowest in the acid‐soluble fractions (1.39–2.61%) of coal samples at both blocks (X and XI) of Thar coalfield. [ABSTRACT FROM AUTHOR]