Development of mesoporous activated carbon from waste tires rubber via one-step activation using a blend of ZnCl2/FeCl3 and its application in Eriochrome Black T and Cr(VI) removal from aqueous phase

Abstract

ABSTRACT A mesoporous activated carbon (MAC) was synthesized from waste tires rubber (WTR) via a one-step ZnCl2/FeCl3 activation route, and the typical sample was implemented in eliminating Eriochrome Black-T (EBT) dye and Cr(VI) from their synthetic effluents. The impact of the impregnation ratio of ZnCl2/FeCl3, the activation temperature, and the activation period was optimized . The best AC was created at 750°C for 60 minutes using a 2:1 ZnCl2/FeCl3:WTR impregnation ratio. This AC was analyzed for its BET surface area and pore volume, Fourier Transform Infra-Red spectroscopy (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), Boehm titration, and pHPZC. The outcomes disclosed that it had a surface area of 122.68 m2/g with a mean pore diameter of 8.53, indicating its mesoporosity. It also exhibited an acidic surface due to its pHPZC, which amounted to 4.80. The highest elimination of EBT (99.33%) and Cr ions (98.05%) from thier aqueous phases was achieved using 0.35 g dosage of MAC, a pH = 2.0 at 40°C for 210 minutes. The EBT and Cr(VI) isothermal and kinetics studies disclosed that the Langmuir and pseudo-2nd-order models best described their adsorption over the said AC. Thermodynamic functions showed that the MAC adsorption for EBT and Cr(VI) was endothermic and spontaneous. Reusability tests suggested that the regenerated AC could be utilized four times with reasonable efficiency. In conclusion, the application of the MAC described above because of its high efficiency in eliminating EBT and Cr(VI) from synthetic samples can be assessed in future studies to be applied in actual scales.