Removal of methylene blue from water by low-cost activated carbon prepared from tea waste: A study of adsorption isotherm and kinetics

Three different types of activated carbon were synthesized from tea-waste by chemical activation method using three activating agents - H3PO4 (H-AC), KOH (K-AC) and ZnCl2 (Z-AC) for analyzing the influence of activating agents on the physicochemical and adsorptive properties of materials. Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectrometer (FT-IR), field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), thermogravimetric analyzer (TGA), N2 gas adsorption-desorption analyzer, and point of zero charge (pHPZC) were employed for the characterization of the synthesized materials. Adsorption capacity of H-AC was found to be higher than those of K-AC and Z-AC, and methylene blue (MB) removal efficiency of H-AC was around 98 % for the adsorbent dose of 0.15 g/L. The greater MB removal…