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摘要
The adsorption of o-nitrophenol, m-nitrophenol, and p-nitrophenol in aqueous solution by aminopropyl-modified MCM-48 (NH2-MCM-48) was studied. Investigations were focused on the factors such as the effect of pH, dosage of sorbent, initial concentrations of nitrophenols, temperature, and adsorption 7 time on the adsorption of nitrophenols. It is very exciting to see that NH2-MCM-48 exhibits superior adsorption capacity for these three kinds of nitrophenols. Such remarkable adsorption affinity is attributed to the hydrogen bonding between nitrophenols and the amino groups in NH2-MCM-48. The Freundlich and Langmuir adsorption isotherm models were applied to fit the experimental equilibrium adsorption data, and the corresponding results show that the equilibrium data fit well into the Langmuir adsorption isotherm. Kinetic studies show that the pseudo-second-order kinetic model fit the adsorption experimental data better than the pseudo-first-order kinetic model. According to the calculated thermodynamic parameters, it is noticeable that the adsorption of o-nitrophenol, m-nitrophenol, and p-nitrophenol by NH2-MCM-48 adsorbents was spontaneous and exothermic in nature. Additionally, cycle rate experiments demonstrate that NH2-MCM-48 is an effective and reusable sorbent for the nitrophenols in aqueous solutions.
