Abstract
Carbon nanofibers (CNFs) have been extensively investigated due to their strong uptake and complexation ability. In this work, CNFs was characterized by using SEM, TEM, FTIR, XPS and Raman spectra. The uptake of Co(II) and Ni(II) on bacterium-derived CNFs as a function of contact time, pH, ionic strength and temperature was investigated using batch techniques. The pH-dependent uptake indicated that the uptake of Co(II) and Ni(II) onto CNFs was significantly higher at high pH values than that at low pH values. The uptake of Co(II) and Ni(II) onto CNFs was hardly affected by ionic strength, suggesting the formation of inner-sphere surface complexation of Co(II) and Ni(II) onto CNFs over a wide pH range. The Langmuir model described the uptake of Co(II) and Ni(II) onto CNFs better than the other models did. According to regeneration experiments, CNFs displayed good recoverability and recyclability in the Co(II) and Ni(II) uptake process. The findings presented herein play a significant role in the scavenging of metal ions on inexpensive and available CNFs in environmental cleanup applications.