Efficiency of Activated Carbon Produced by Physical Activation Using Nitrogen Gas for Maximum Dye Adsorption from Polluted Effluents: Genetic Programming and Neural Network

Background and purpose: This study was conducted for the first time to produce activated carbon (AC) from Milkvetch wood by physical activation in order to achieve the maximum adsorbent capacity in adsorption of dye. The aim of this study was to remove acid orange 7 (AO7) dye using AC produced by physical activation with nitrogen gas. Materials and methods: AC activation was performed by physical method using nitrogen gas at 700°C. Scanning electron microscopy and isotherm technique were used to determine the structural characteristics of the adsorbent. The effect of operating parameters was investigated. The isotherms and kinetics of the dye adsorption were also studied. Results: The synthesized AC-700°C sample had a specific surface area and a total pore volume of 774 m2/g and 181.49 m3/g, respectively. The maximum adsorption of dye was 57.125 mg/g (removal efficiency 91.4%) that occurred at pH= 3, 0.04 g absorbent in 50 ml of solution, and 50 mg/l of dye in 75 min. The adsorption data followed the Langmuir adsorption isotherm model and the pseudo-second order model kinetics. Also, the ability to reuse the adsorbent using the heating method showed that the synthesized adsorbent can be used for three consecutive times with good performance. Correlation coefficients (R2) for genetic program and neural network were 0.98 and 0.99, respectively, indicating the agreement of laboratory data with the models. Conclusion: The as-prepared AC by physical activation has a high potential for adsorption of AO7 dye from aqueous solutions.