Adsorption of Aqueous Cr(VI) by Novel Fibrous Adsorbent with Amino and Quaternary Ammonium Groups

A novel fibrous adsorbent functionalized with both amino and quaternary ammonium groups (QAPAN) was prepared through a simple two-step route (i.e., amination followed by quaternization reactions) for removing aqueous Cr(VI) through batch and column experiments. As compared with traditional adsorbents, the QAPAN had an extremely fast adsorption kinetic (equilibrium achieved within 10 min) and an exceptionally high adsorption capacity (Qm = 248 mg/g). The QAPAN worked well even in strong basic conditions, and ionic strength and coexisting anions had minor inhibitory effects on the adsorption. Besides, the QAPAN could be repeatedly used for Cr(VI) adsorption with no obvious decrease of uptake after regeneration with 0.1 mol/L NaOH. By analyzing FTIR and XPS spectra, an electrostatic interaction mechanism between Cr(VI) oxyanions and the surface amino and quaternary ammonium groups was proposed. Findings of the current study provided a novel material and technology for treatment of Cr(VI) contaminated waters.