Environmental Science: Nano, 2016, 3, 894-901

Jiao Chang, Jianqiang Wang, Jin Qu*, Yan Vivian Li, Lijing Ma, Lifang Wang, Xiuxing Wang, Kai Pan*

α-Fe2O3 nanoparticles have been widely used in water purification because of their effective adsorption performance. However, aggregation and difficulty in separation limit their practical application. Herein, we presented a polyacrylonitrile (PAN) nanofiber mat decorated with α-Fe2O3 as an adsorbent for effective removal of Pb2+ from contaminated water, which can solve the above problems easily. The α-Fe2O3/PAN nanofiber mats were prepared via electrospinning followed by a facile hydrothermal method and characterized by SEM, HRTEM, FTIR and XRD. We demonstrated that the formation mechani** of α-Fe2O3 anchored on the PAN nanofiber surface consists of the adsorption of iron ions on the surface of PAN, and then the nucleation and growth of α-Fe2O3. The pH value of FeCl3 solution has a great impact on the formation process of the α-Fe2O3/PAN nanofiber mat, which leads to the variation of morphology and quantity of the coating coverage. When the pH value was 2.4, polyhedral particles were coated on PAN nanofibers uniformly and the optimized α-Fe2O3/PAN nanofiber mat was obtained. Control experiments were carried out to quantify the adsorption capacities of different samples and adsorption kinetics. The isotherm data from our experiments fitted well to the Langmuir model and the adsorption process can be described using the pseudo-second-order model. Finally, the adsorption mechani** for Pb2+ was investigated and the results revealed that ion exchange between the proton of surface hydroxyl groups and Pb2+ accounted for the adsorption.