EQUILIBRIUM STUDY ON ADSORPTION PROCESSES OF 4-NITROPHENOL AND 2, 6-DINITROPHENOL ONTO GRANULAR ACTIVATED CARBON

摘要

Adsorption of 4-nitrophenol and 2, 6-dinitrophenol onto granular activated carbon has been studied. Adsorption experiments were carried out in a batch system and were followed by UV-Visible spectroscopy over a period of 120 min. Adsorption isotherms were derived at 25°C and the isotherm data were treated according to Langmuir, Freundlich and Tempkin isotherm equations. The fitting of experimental data was tested and the parameters of these equations were determined. Based on the correlation coefficients both Langmuir and Freundlich models are suitable for the study (the squares of correlation coefficients are all > 0.97). Based on the values of normalized percent deviation P, the Freundlich model is suitable for 4-NP and the Langmuir model is suitable 2,6-DNP adsorption onto granular activated carbon type NORIT GAC 1240W (value of P less than 5). The calculated adsorption capacity values (q_(max),) are: 277.77 mg g~(-1) for 4-NP, respective 41.15 mg g~(-1)for2, 6-DNP.