Abstract

Introduction: Dye effluents of some industries contain many toxic, carcinogenic, and mutagenic compounds therefore, wastewater colored contaminants of such industries should be meticulously refined using an appropriate method before discharging waste-water to the environment. Therefore, this study aimed to evaluate the effectiveness of Multi-Walled Carbon Nanotubes (MWCNT_S) in dye removal of Acid Black 1 (AB1) from colored wastewater.

Methods: This laboratory study was conducted in the batch system and MWCNT_S were used as absorbents to remove AB1 dye. In fact, this study investigated the effect of various factors influencing dye removal, such as adsorbent dose, initial dye concentration, contact time, and pH.

Results: The study results showed that pH=3 is regarded the best pH for the dye removal. The equilibrium time for AB1 dye absorption on MWCNT_S was 60 minutes. As dye concentration increased, dye removal rate decreased. Besides, increasing the amount of adsorbent increased the dye removal efficiency and at the absorbent dose of 600 mg/L, dye removal efficiency was reported 98.86% and 94.62% for 30 and 50 mg/L dye concentrations respectively. AB1 dye removal followed Langmuir isotherm and Pseudo-second-order kinetic models.

Conclusion: The results of absorption studies revealed that increasing the contact time and the absorbent dose as well as reducing the pH lead to an increase in dye removal efficiency. Overall, the study findings demonstrated that MWCNT_S could be used as an efficient absorbent in regard with decolorization of azo dyes from wastewater.