2k Optimization approach for the removal of Pb2+ ions from water contaminated from oil-well drilling point on to MWCNTs

Abstract

The release of Pb2+ into the surrounding ecosystem has adverse effects on man and animal, hence, removing such harmful heavy metal from water system calls for urgent attention. The potential application of Multi-walled carbon nanotubes, MWCNTs, towards the lead (II) ions removal from oil polluted water body was studied and optimized via 2k factorial experimental approach. The MWCNTs produced was characterized via High Resolution Transmission Electron Microscope (HR-TEM), High Resolution Scanning Electron microscope (HR-SEM), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and Brenuer-Emmette-Teller (BET) to determine the internal morphology, surface morphology, thermal stability, functional group and surface area respectively. The results of the HR-TEM depict the nano-structural diameter of the produced MWCNTs with continuous strands of tubes as depicted by SEM micrograph. The MWCNTs surface area produced was obtained to be 540 m2/g. The sorption of Pb2+ ions was optimized using 2k design approach where speed (rpm), absorbent dosage (g), temperature (°C) and time (min) were studied in a batch condition. The optimum conditions that give maximum sorption of Pb2+ ions on to the surfaces and the pores of the developed MWCNTs adsorbent were obtained at 60 min contact time, 59.89 °C, 0.20 g of adsorbent dosage and 599.98 rpm of agitation. Thus, the highest percentage sorption of Pb2+ ions by the MWCNTs from the oil-polluted water body was 99.5%. Hence, this study has demonstrated the potentials of MWCNTs as an effective and efficient sorbent for Pb2+ sorption from oil polluted wastewater.