Non-Covalent Assembly of Maghemite-Multiwalled Carbon Nanotubes for Efficient Lead Removal from Aqueous Solution

Non-covalent assemblies of maghemite-embedded multiwalled carbon nanotubes (MWCNTs) were synthesised and characterised, and their applicability in the magnetic removal of Pb-II from aqueous solutions in batches was evaluated. The nanohybrids were prepared using a wet-chemical technique and characterised by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, zeta potential, vibrating sample magnetometer, and Brunauer-Emmett-Teller surface area measurements. Kinetics rate, adsorption isotherms, and effects of pH, contact time, adsorbent dosage, and agitation speed on Pb-II removal were studied. Results revealed maximum adsorption (similar to 96%, 24ppm) was achieved in less than 2h in a pH range of 6-7. Repeated adsorption-desorption cycles were conducted, which demonstrated that the nanohybrid could be used for prolonged cycles.