Effective Removal of Phosphate from Aqueous by Graphene Oxide Decorated with α-Fe_2O_3: Kinetic, Isotherm, Thermodynamic and Mechanism Study

摘要

The excessive phosphate discharged into the environment has damaged the ecosystem seriously. In this work, a kind of 3D adsorbents, $$upalpha hbox {-Fe}_{2}hbox {O}_{3}$$ α -Fe 2 O 3 decorated graphene oxide $$(hbox {GO--Fe}_{2}hbox {O}_{3})$$ ( GO--Fe 2 O 3 ) , was synthesized to deal with phosphate-polluted water. The phosphate adsorption capacity of $$hbox {GO--Fe}_{2}hbox {O}_{3}$$ GO--Fe 2 O 3 reached to $$93.28,hbox { mg,g}^{-1}$$ 93.28 mg g - 1 , in $$50,hbox { mg, L}^{-1}$$ 50 mg L - 1 phosphate solution at pH 6.0 and temperature 298 K, and the phosphate adsorption efficiency is very stable between the pH range of 2.0–10.5 and temperature range of 293–333 K. The adsorption progress is rapid, and adsorption equilibrium was reached within 5 min. The phosphate adsorption behavior of $$hbox {GO--Fe}_{2}hbox {O}_{3}$$ GO--Fe 2 O 3 fitted the Langmuir model, and the adsorption kinetic fitted the pseudo-second-order model. Ion exchange and electrostatic attraction are the main reactions in the adsorption process. Physical adsorption and chemical adsorption both are in the adsorption process. The phosphate adsorption progress is stable and rapid; thus, it is a good choice to deal with phosphate-polluted water by $$hbox {GO--Fe}_{2}hbox {O}_{3}$$ GO--Fe 2 O 3 .