Regeneration of Carbon Nanotubes Exhausted with Humic Acid Using Electro-Fenton Technology

Among the adsorbents, carbon nanotubes (CNTs) are relatively new nanomaterials which are frequently used for water purification. In this work, experiments were carried out to study the feasibility of regeneration of humic acid-exhausted CNTs using electro-Fenton process. The results showed that electro-Fenton process has high efficiency at pH equal to 3. The results also clearly indicated that the regeneration efficiency at lower molarities of H2O2 such as 0.05 is higher than at higher molarities. The results also implied that the regeneration efficiency at current density equal to 0.1 mA was 98.32% and with increasing current density, the regeneration efficiency decreased. The regeneration efficiency at molar ratios of Fe2+: H2O2 as 0.03: 10 was higher than other examined molar ratios and after five cycles of regeneration decreased to 87%. The results of the present study indicated that electro-Fenton process has high efficiency for the regeneration of CNTs exhausted with humic acid.