Preparation of Mannitol-Modified Loofah and Its High-Efficient Adsorption of Cu(II) Ions in Aqueous Solution

Adsorption is considered the most favorable method for heavy metal removal. In this paper, a low-cost, high-efficiency heavy metal adsorbent, mannitol-modified loofah (MML) was prepared. Some characterization methods are used to characterize the structure of MML, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The adsorption behavior of MML for Cu(II) ions was explored under different conditions, such as the amount of adsorbent, pH, initial concentration of Cu(II) ions, and adsorption time. The results indicated that the adsorption capacity of MML for Cu(II) ions was greatly improved. When the initial concentration of Cu(II) ions was 900 mg/L and the pH is 5.0, the adsorption capacity (Q_e) was 888.9 mg/g at 298K, which was significantly higher than that of some other modified cellulose adsorbents. Isothermal adsorption results showed that the adsorption process was consistent with the Freundlich model. The adsorption kinetics conformed to the pseudo-second-order equation. Furthermore, the regeneration capability of MML indicates that MML is a cheap and excellent adsorbent for Cu(II) ions removal in wastewater treatment.