Facile Synthesis of Fe/Cr-Codoped ZnO Nanoparticles with Excellent Adsorption Performance for Various Pollutants

Adsorption is an effective and low-cost method for removing antibiotics and dyes. However, it remains a challenge to prepare an adsorbent with excellent adsorption properties for both various antibiotics and dyes. Herein, Fe/Cr-codoped ZnO with high adsorption capacity and fast adsorption rate are prepared by an environmentally friendly solvothermal method. Fe/Cr-codope ZnO with a diameter of 10–20nm exhibits superior adsorption capacities for the antibiotics of tetracycline hydrochloride (TC-HCl) (826.45 mg g−1) and tetracycline (TC) (331.01 mg g−1), and anionic dyes of methyl orange (MO) (1023.88 mg g−1), methyl blue (MB) (726.26 mg g−1) and direct red (DR) (642.25 mg g−1). Meanwhile, it presents fast adsorption rate, it only took 30min to reach more than 90% of the equilibrium adsorption amount for TC-HCl, TC, MO, MB and DR. The adsorption process closely fitted the Langmuir isotherm model and pseudo second-order rate equation. More importantly, simple method has been developed for separating the pollutant from the adsorbent, which not only regenerates the materials, but also completes the recovery of antibiotics and dyes, avoiding the secondary pollution. The broad-spectrum, rapid, environment-friendly and effective adsorption properties make Fe/Cr-codoped ZnO a promising adsorbent for water treatments.