Comparative study of the sequential extraction methodologies for fractionation analysis of mercury in coal of Thar coalfield.

The primary objective of this study was to evaluate the bound fractions of mercury (Hg), physicochemical parameters, and mineral composition of coal. Coal samples were collected from various depths within Block-VII of the Thar coalfield in Pakistan. The Hg associated with different chemical fractions of coal was extracted using a sequential extraction scheme as per the community bureau of reference (BCR) protocol. This study utilized both the BCR-sequential extraction method (BCR-SEM) and a single-step sequential extraction based on an ultrasonic-assisted method (SSE-UAM) for the fractionation analysis of Hg in coal. The extraction methodologies, BCR-SEM and SSE-UAM, were specifically designed for analyzing Hg fractionation in coal samples. The SSE-UAM offers an operational advantage, requiring only 2 h compared to the 51 h needed for BCR-SEM. The analyses were validated using standard reference material (SRM-1635a) and the spiking addition method, achieving a recovery percentage of 97.1% for total Hg concentrations using the pseudo-extraction method in SRM-1635A. Total Hg content in the coal samples ranged from 0.60 to 2.34 µg g-1 across four different coal seams from Block-VII of the Thar coalfield. Additionally, Hg concentration was observed to decrease with increasing depth, attributed to changes in mineralogical composition. The highest concentration of Hg was detected at a depth of 200-203 m, while the lowest concentration was at a depth of 152-154 m. The concentration of Hg in various fractions was 32-60% in the acid-soluble fraction, 1.72-4.92% in the reducible fraction, and 9.58-50.8% in the oxidizable fractions. The coal sample characteristics were analyzed using an elemental analyzer and scanning electron microscopy with energy-dispersive spectroscopy. Cold vapor atomic absorption spectrometry (CV-AAS) was used to measure the extracted fractional concentration of Hg in coal.

The utilization of date palm waste as an efficient adsorbent for the elimination of heavy metals from polluted water.

This study focuses on the removal of heavy metal ions, such as cadmium (Cd2+), lead (Pb2+), chromium (Cr6+), and zinc (Zn2+) from water. Metals, which are often present in water, can have various origins, i.e., industrial emissions, mining, melting, corrosion, municipal, industrial waste, and agrochemicals. These metals have the potential to cause adverse effects on human health. The study employed activated carbon derived from date palm waste as a means of removing heavy metals. The activated nanoparticles were characterized using various analytical techniques, including SEM, ICP, XRD, BET, Raman, and FTIR analysis. Batch studies were conducted to optimize the metal ion adsorption onto the activated carbon of date palm waste. The adsorption process was evaluated using isotherm models and reaction kinetics under various conditions, including contact time, dosage, pH, and initial concentration. The findings of this study revealed that the prepared activated carbon from date palm waste effectively removed up to 85% of Cr6+, Pb2+, Cd2+, and Zn2+ ions from water. This study highlights the potential of using agricultural waste, to produce effective adsorbents for heavy metal removal.