Efficacy of Polyaniline (PANI) nanofibres for capturing Diclofenac (DC) drug from its aqueous solutions

Abstract

Pharmaceutical drug contamination in water nowadays is deteriorating the ecological components. A remedial approach is therefore a necessity. This study focuses on the synthesis of PANI nanofibres employing the oxidative polymerization method using ammonium persulphate (APS) as oxidant. The synthesized nanofibres were characterized using HR-TEM, FT-IR and XRD. The HRTEM image exhibited the nano-range structure of PANI with a rough surface. The FT-IR spectra inferred about the role of surface capping groups involved in the uptake mechanism. The crystallinity of PANI was well assessed by the X-Ray Diffraction analysis. The interaction between the studied drug diclofenac (DC) and polyaniline (PANI) showed a rapid equilibrium time 120 min favored at pH 5.0 achieving maximum adsorptive capacity (qe) of 471.08 mg g −1. The uptake process followed the pseudo-second order kinetic model (R2 = 1) with intra-particle diffusivity model (R2 = 0.9810) as the governing step and best fitting values into Langmuir isotherm model (R2 = 0.9822) inferred about the favourable adsorption of DC forming monolayer over PANI having qm to be 943.83 mg g−1. The drug DC was easily desorbed up to 85.31% by using 0.1 M aq ethanol and was exhausted after five cycles of reusability. The whole adsorptive mechanism involved electrostatic interactions along with hydrogen bonding.