Linear and nonlinear modeling of kinetics and isotherms characterizing adsorptive removal of 4-nitrophenol by biochar BC-PFP773

In this research article the batch adsorption of 4-nitrophenol on chemically treated biomaterial BC-PFP773 was studied at three different temperatures (10 degrees C, 20 degrees C, 45 degrees C). The consequences of various operating factors including biosorbent dosage, contact time and pH on the percentage removal of 4-nitrophenol was detected. The perceived optimum contact time for the adsorption of 4-nitrophenol was 60 min. The optimum biomass dosage (BC-PFP773) was 2.5 g/L for the adsorption of 4-nitrophenol. The value of regression coefficient R-2 for first order and second-order are 0.95 and 0.99, respectively which shows that second-order is most appropriate model for determination of kinetics. Experimental results were verified by applying different linear and nonlinear isotherm models such as Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Hill, Sips, Toth, Fritz-Schlunder (4 parameters) and Fritz-Schlunder (5 parameter). The value of thermodynamic parameters, that is, Delta H degrees is -3.74 kJ/mol and Delta S degrees is 44.31 J/mol/K respectively. The thermodynamic parameters revealed the thermodynamic feasibility of the adsorption process. The negative value of Delta G degrees indicates the spontaneous process and the negative value of Delta H degrees illustrates that the process is exothermic.