فهرست نشریات علمی دسترسی آزاد ایران

This study investigated the effectiveness of a composite low-cost adsorbent, comprising coconut shell-based activated carbon, zeolite, and claystone, in removing iron (Fe) and manganese (Mn) from acid mine drainage (AMD) generated by coal mining activities. Batch adsorption experiments were conducted at laboratory scale to evaluate the influence of contact time and adsorbent dosage. The adsorbents were immersed in AMD samples with an initial pH of 2.6 and stirred under controlled conditions. The removal efficiencies were measured over time, and kinetic modeling was applied to assess the adsorption mechanism. The composite adsorbent successfully increased the AMD pH from 2.6 to 6.3 and achieved a 58.73% improvement within the first 5 minutes. Iron concentration was reduced from 13.006 ppm to 0.021 ppm with 2.5 g of adsorbent in 15 minutes, corresponding to a 99.84% removal efficiency. Manganese removal was less consistent, achieving a maximum reduction of 53.42% under the same conditions. Adsorption capacities for Fe and Mn were 1.299 mg/g and 1.487 mg/g, respectively. Kinetic analysis indicated that Fe removal followed a pseudo-second-order model, suggesting chemisorption, while Mn removal exhibited a slower, less predictable behavior. The results highlighted the composite's strong potential as a rapid and environmentally friendly treatment option for AMD, particularly for effective iron removal. The adsorbents demonstrated significant efficiency in Mn removal under the tested conditions, although with less consistency than Fe. This approach offers a sustainable solution using locally available materials, contributing to improved water quality management in mining-affected areas.