Using polypyrrole nanocomposites coated on rice husk ash for the removal of anions, heavy metals, COD from textile wastewater

Abstract

In this study, a new application of polypyrrole (PPy) synthesized chemically in presence of ferric chloride as an oxidant coated on rice husk ash (RHA) by oxidative chemical polymerization method is used, ferric chloride has been found to be the chemical oxidant and water has been reported the best solvent for chemical polymerization of pyrrole. The removal of anions, heavy metals such as copper, iron and zinc and COD (chemical oxygen demand) from textile wastewater using completely mixed batch reactor (CMBR) technique is investigated when polypyrrole and its blend and nanocomposites with rice husk ash were used. Experiments were done using PPy/RHA during 30min with 5min intervals. It is observed that by increasing the time (5–20min) removal efficiency increased but, after 20min the efficiency did not increase significantly. It can be concluded that RHA in the composites does not play significant role in the anions and COD removal but the role of RHA in the removal of the metals is considerable and it causes an increase in the removal efficiency of the composites. Besides, the morphology was tested by scanning electron microscopy (SEM) to characterize the surface of PPy nanocomposites at very high magnification at an accelerating voltage of 15kV, and chemical structure was tested by Fourier Transform Infrared spectroscopy (FTIR) in the wavelength range of 400–4000cm−1, respectively. It was found that PPy/RHA can be used as an effective adsorbent in the removal of anions, heavy metals and COD from textile wastewater.