Enhanced removal of trihalomethanes (THMs) from aqueous solutions using activated carbon from Walnut wood (WC) on Equilibrium, thermodynamic and kinetics

In this study, carbon was easily made from walnut wood as a low-cost and non-toxicnatural adsorbent. Walnut wood (WC), an excellent adsorbent, were successfully synthesized by an in chemical vapor deposition method then characterized using after heating. X-ray diffraction pattern, and FT-IR techniques and used for the removal of trihalomethanes (THMs) from aqueous solution. This adsorbent was reused after heating. The trihalomethanes (THMs) removal by the developed adsorbent was investigated using batch adsorption technique and allparameters influencing the removal efficiency such as: dose of adsorbent, pH and initial trihalomethanes (THMs) concentration were considered. The optimal conditions for the trihalomethanes (THMs) removal were found to be 5, 65 min, 10 mg/L, and 50 mg for pH, contact time, initial THMs concentration, and adsorbent dosage, respectively. The rapid adsorption of the THMs is an advantage of this adsorbent. Various isotherm models were used to fit the experimental equilibrium data. The results showed the suitability and applicability of Langmuir model. The maximum sorption capacity qmaxandR2 in Freundlichisotherm of trihalomethanes (THMs) 3.0 mg/g and 0.995 showed onto Walnut wood (WC). Kinetic models such as pseudo-first-order and pseudo-second-order diffusion models indicated that the second-order equation model controls the kinetic of the adsorption process. Thermodynamic parameters of adsorption process (G°,H°,S°) were also evaluated. The negative ΔGo value indicates that the process is feasible and the adsorption spontaneous in nature. The negative ΔHo value indicates the exothermic nature of adsorption and the value of ΔSo the change in the randomness at the activecarbon from Walnut wood (WC) solution interface during the sorption.The overall adsorption process was exothermic and spontaneous in nature. The results indicated that trihalomethanes (THMs) adsorption onto Walnut wood (WC) might be a physical adsorption.