Utilization of Multiwalled Carbon Nanotubes as Adsorbent for Removal of Acid Violet 17 Dye: Equilibrium, Kinetics and Thermodynamic Studies

The adsorption capacity and separation efficiency of multiwalled carbon nanotube (MWCNT) were investigated for the removal of Acid Violet 17 (AV 17) dye in an aqueous solution. The effect of reaction conditions, such as contact time, AV 17 initial concentration, pH, adsorbent dosage, and temperature, on the adsorption capacity of MWCNTs was investigated. It was found that a contact time of 180 min, an adsorbent dosage of 0.8 g/L, and 100 mg/L AV 17 concentration are ideal conditions for maximum adsorption capacity (119.45 mg/g). AV 17 dye adsorption on MWCNTs followed a pseudo-second-order kinetic model (R2 = 0.9998) and the Langmuir isotherm model (R2 = 0.9813) suggesting that adsorption was the uniform and homogenous process. The maximum adsorption capacity from the Langmuir isotherm model was determined to be 322.58 mg/g. Adsorption of AV 17 dye was determined to be spontaneous and thermodynamically favorable since the values of ΔGo were negative. Positive ΔH° and ΔS° values suggest that the process is endothermic and randomness. The research results showed the MWCNTs could be used successfully to remove dye for the water treatment process.