Competitive Adsorption of Pb(II) and Phenol Onto Modified Chitosan/Vermiculite Adsorbents

Many industrial wastewaters are contaminated with both heavy metal ions and organic compounds, posing a major threat to public health and the ecosystem. In this work, pristine chitosan modified vermiculite (CSVT) with high specific surface area (17.24 m2/g) was prepared by drop-wise method and applied to simultaneous adsorption of Pb(II) and phenol from aqueous solution. The prepared adsorbents were characterized by X-ray diffraction, Brunauer, Emmett, Teller, energy dispersive X-ray spectroscopy, Fourier-transform infrared, and scanning electron microscopy. The simultaneous adsorption performance was investigated systematically at different solution-pH, adsorbent dosage, initial Pb(II) and phenol concentrations, and contact time. Kinetic experiments indicated that the adsorption process of both pollutants could be better represented by a pseudo-second-order model. The maximal adsorption capacities of Pb(II) and phenol in the binary system depending on Langmuir isotherm model are 98.52 and 67.08 mg/g, respectively. In the binary adsorption system, the adsorption of one contaminant was not affected by the other adsorbed one. Finally, the results clearly showed that chitosan modified vermiculite had the ability to simultaneously adsorb Pb(II) and phenol.