Removal of Reactive Black 5 dye from Aqueous Solutions by Adsorption onto Activated Carbon of Grape Seed

Background and purpose: The control of environmental pollution especially the pollution of water resources is one of the main challenges of researchers throughout the world. So, this study aimed to investigate the efficiency of reactive black 5 dye removal from aqueous solutions by adsorption onto activated carbon of grape seed. Materials and Methods: At first, the grape seed adsorbents were prepared in three forms of raw, treated by concentrated phosphoric acid, and calcined at 400, 600, and 800 °C. Then, the efficiency of adsorbents to the removal of the Black 5 dye was studied in the concentrations of 100 to 700 mg/Lat pH 2- 10 and 1- 10 g/L of adsorbent during 120 min. The change of concentration was studied via the spectrophotometry procedure at the wavelength of 597 nm. Finally, the Langmuir and Freundlich adsorption isotherm was determined. Results: The results showed that the dye removal efficiency decreased by increasing pH, and increased by raising the contact time and the amount of adsorbent. So, in this process, the highest percentage of Black 5 dye removal (83.08%) was obtained at pH 2 and t 120 min using the raw adsorbent, 200 mg/L initial concentration of dye, and 10 g/L of carbon. The process considerably followed the Langmuir adsorption isotherm (R2 0.999). Conclusion: The grape seed was found to have the highest level of efficiency in dye removal, and according to the availability of adsorbent and its low price, this method could be used as an applicable procedure for the removal of Black 5 dye from aqueous solutions.