Application of Multi-Walled Carbon Nanotubes in the Removal of Reactive Red 120 from Aqueous Solutions

Background and purpose: Textile effluents are very difficult to treat satisfactorily due to high variations in their compositions. Strong color is one of the main characteristics of textile effluent and, if not eliminated, it can cause serious problems to the environment. In the present study, multi-walled carbon nanotubes (MWCNTs) were used as an adsorbent for the removal of Reactive Red-120 (RR-120) textile dye from aqueous solutions. Materials and Methods: The influence of key parameters including pH (2-12), concentration of dye (10 to 200 mg/L), contact time (30-270 min), adsorbent dosage (0.01-0.07 g/L) have been investigated in order to find the optimum adsorption conditions (sample size = 48). Results: Optimum pH for removing of RR-120 dye was found to be 5 and for this condition maximum adsorption capacity was obtained as 3453.4 mg/g. Experimental results have shown that by increasing the adsorbent dosage, the rate of dye removal was increased, but the amount of adsorbed dyes per mass unit of MWCNTs was declined. It was found that the data fitted to Langmuir better than BET and Freundlich model. Conclusion: Results suggest the potential of using the MWCNTs as an adsorbent for effective treatment of dye-contaminated wastewaters.