Equilibrium, Kinetics and Thermodynamic Study of 2-Chlorophenol Adsorption from Simulated Wastewater onto Bone Char

Numerous agricultural wastes, like cow bows, are underutilized in Nigeria, causing significant environmental solid waste menace. Incidentally, large amount of wastewater containing high concentrations of toxic organic compounds such as 2-chlorophenol (2-CP) are continuously being generated due to increased industrial and agricultural activities. Waste cow bones when suitably treated could serve as a good adsorbent for efficient removal of 2-CP from wastewater and also serve as a means of recycling bone wastes from various slaughterhouses in Nigeria. In this study, bone char labeled BC500-120 was produced by carbonization of treated waste cow bones at 5000C for 120 minutes. Characterization of the BC500-120 was carried out using BET surface area analysis, FTIR and SEM/EDX spectroscopy. Sorption experiment was conducted on the effect of constant time, solution pH, initial concentration of 2-CP and constant temperature on the adsorption of 2-CP onto BC500-120 from simulated wastewater. The Langmuir isotherm, Freundlich isotherm and kinetic models: (pseudo first order model, pseudo second order model and the Elovich model) were used to analyze the experimental data. The thermodynamic parameters were estimated from the Langmuir’s Constant. Adsorption capacity and removal efficiency of 151.70 and 98.3 % were attained and equilibrium was found to occur between 40-45 minutes. Adsorption capacity and removal efficiency were also observed to be maximum at an initial concentration of 0.09mol/L and pH=7.0 and better favored at higher temperatures. The removal of 2-CP was described by the Langmuir isotherm and the pseudo second order model, and calculated to be 557.05gmin-1mol-1 with an initial rate of 0.00072molg-1min-1 and equilibrium capacity of 0.00114mol/g. The adsorption process was found to be physical, spontaneous and endothermic. The results of the study indicated that BC500-120 can be used as an effective adsorbent for 2-CP removal from liquid wastes.