Heavy metal removal using multisubstrate fruit waste-derived granular activated carbon and electrospun membrane: structural insights

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Test An electrospun nanofiber membrane and granular activated carbon were synthesized using the waste of the fruit in the presence of various substrates. The aim was to determine their usefulness in water purification, based on the growing panic about water-related illnesses due to water contamination with heavy metals. The lignocellulosic properties and characteristics of the fruit debris made it a renewable source of activated carbon because it could be used as an alternative source instead of the more traditional sources, which use fossil fuels. The use of chemicals such as ZnCl₂, KOH, K₂CO₃, H₃PO₄, H₃BO₃ and HNO₃ as chemical activators improved the porosity, surface activity and adsorption of the materials. Scanning electron microscopy of the loaded samples showed that the activated samples had discontinuous surfaces, irregular pore structure and intricate fibre network, unlike the untreated materials, which were agglomerated and compact with low porosity. X-ray diffraction analysis results indicated that most of the untreated samples were amorphous and the activated carbons and membranes possessed distinct crystalline characteristics, which indicated the enhancement of the structural strength and graphitic structure. The T₄ granular activated carbon recorded the greatest rates of adsorption of metal ions, with an arsenic and cadmium removal efficiency of 64.67% and 99.55%, respectively. On the other hand, the lowest removal percentages of arsenic and cadmium in the electrospun membranes were 2.98% in T₁ and 1.84% in T₀M. These results suggest that chemically modified granular activated carbon prepared using fruit waste can have great adsorption potential, especially in the treatment of polluted water.