Linear and nonlinear regression analysis of phenol and P-nitrophenol adsorption on a hybrid nanocarbon of ACTF: kinetics, isotherm, and thermodynamic modeling

Abstract This study aimed to create activated carbon thin film (ACTF) as a hybrid nanocarbon via a simple and efficient method through a single-step mixing process using thermal functionalization techniques. TEM, BET, BJH, FTIR, XRD, and TGA analyses were used to investigate the prepared ACTF. The results exhibited that ACTF has a porous structure with a high surface area of 318 m 2 /g and important functional groups, which are considered significant adsorption sites. The adsorption performance of ACTF for phenol and p-nitrophenol (PNP) removal from aqueous solutions using batch adsorption mode was studied. Evaluations were conducted on experimental factors influencing the adsorption process, such as pH, initial phenol and PNP concentrations, adsorbent dose, contact time, and temperature. Under the optimized conditions, the phenol and PNP were removed with a maximum efficiency of 89.98% and 92.5%, respectively. The results of linear and nonlinear isotherms and kinetic models of phenol and PNP showed that both pollutants were well fitted with the Freundlich model ( R 2 = 0.99, χ 2 = 0.13, RMSE = 1.6), ( R 2 = 0.99, χ 2 = 0.42, RMSE = 2.8), and the pseudo-second-order model ( R 2 = 0.999, χ 2 = 0.03, RMSE = 0.31), ( R 2 = 0.99, χ 2 = 0.01, RMSE = 0.24), for phenol and PNP, respectively. According to the calculated thermodynamic results, the adsorption of phenol and p-nitrophenol onto the ACTF surface was a spontaneous and exothermic reaction. The regeneration experiments showed that the spent ACTF could be reused up to the fifth cycle while maintaining noteworthy removal efficiency.