Preparation of amino-modified cellulose aerogels and adsorption on typical diclofenac sodium contaminant
2022
Chen, Mingxiang | Yang, Guifang | Liu, Yifan | Lv, Yuancai | Sun, Shengxun | Liu, Minghua
A new functional cellulose aerogel (Cell@PEI) with high adsorption efficiency was prepared for the removal of diclofenac sodium (DCF) by ammonification cross-linked polyethyleneimine (PEI) with the surface of cellulose. The fabricated Cell@PEI adsorbent was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), etc. The results demonstrated that the Cell@PEI exhibited a distinct three-dimensional cell structure and was rich in functional groups, i.e., -OH, C = O, -NH₂, and C = C. The Cell@PEI presented a stable crystal structure and large specific surface area (241.41 m²·g⁻¹), which was approximately 42 times as much as bare cellulose aerogel (5.82 m²·g⁻¹). In addition, a series of adsorption experiments showed that the adsorbent had good adsorption performance for DCF with a maximum adsorption capacity of 294.12 mg·g⁻¹. Furthermore, the adsorption of DCF on Cell@PEI was well corresponded with the Langmuir isotherm and pseudo-second-order adsorption model. Thermodynamic study proved that adsorption was a spontaneous exothermic reaction. Moreover, the introduction of PEI into Cell@PEI aerogel enhanced the electrostatic interaction and hydrogen bonding, promoting DCF adsorption. Importantly, the Cell@PEI aerogel could be reused up to five times desorbed by NaOH (0.5 mol/L). Considering the above results, the fabricated aerogel material can be applied to remove organic pollutants.
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