Efficient removal of high- or low-concentration copper ions using diethylenetriamine-grafted electrospun polyacrylonitrile fibers

Abstract

The heavy metal copper is a serious hazard to human health and the environment. It is challenging to develop a highly efficient adsorbent that is easy to prepare, low cost, having large adsorption capacity, and non-polluting to the environment. Herein, an aminated electrospun polyacrylonitrile (PAN) staple fiber was prepared by grafting diethylenetriamine (DETA) after a hydrothermal reaction. DETA possessed numerous amino functional groups, thus providing more adsorption sites and higher adsorption capacity for copper ions (Cu²⁺). The Cu²⁺ adsorption behavior of the aminated fiber conformed to the pseudo-second-order kinetic model. It not only possessed high adsorption activity in the pH range of 3.0–6.0 and could reach a high saturated adsorption capacity of 349.65 mg g⁻¹ at high Cu²⁺ concentrations but also had the ability to reduce the concentration below 1 mg L⁻¹ at low Cu²⁺ concentrations with a small amount of adsorbent (0.5 mg). After 5 adsorption–desorption experiments, the removal efficiency of Cu²⁺ was maintained at more than 90%. This aminated PAN fiber is expected to become a candidate material for dealing with Cu²⁺ pollution.