Adsorption of pollutants from rainwater: An efficient combination of fly ash and activated carbon

This study explores the use of waste materials such as activated fly ash (AP1) and its mixture with activated carbon (AP2) for rainwater treatment. The adsorption of heavy metals (Ni, Pb, Cu) and bisphenol A (BPA) was tested under varying adsorbent doses, contact times, and solution pH. Fly ash was chemically activated with NaOH, while activated carbon was obtained from spent filter cartridges and similarly treated. Both adsorbents were characterized for surface area, porosity, pore size distribution, and point of zero charge. Activation significantly increased the surface area of fly ash and combining it with activated carbon further improved adsorption performance. AP2 showed the highest removal efficiencies, indicating a synergistic effect of the two materials. The results demonstrate the potential of reusing industrial and municipal waste in rainwater treatment, supporting sustainable development and circular economy practices.