Use of PMMA/(rice husk ash)/polypyrrole membranes for the removal of dyes and heavy metal ions

Abstract

We describe the preparation of polymethylmethacrylate/(rice husk ash)/polypyrrole (PMMA/RHA/PPy) composite membranes and their use as active agents for the removal of hexavalent chromium (Cr(VI)) and the organic dyes tartrazine (E102) and indigo carmine (IC). We prepared the membranes following a two-step process: initially, using the electrospinning technique, we obtained PMMA:RHA mats with various relative concentrations, and afterward we used an in situ chemical polymerization to incorporate polypyrrole chains onto the surface of the membrane fibers. We characterized the membranes by SEM, water contact angle and fiber diameter measurements, tensile tests, UV–Vis and FTIR spectroscopy. We have found that the incorporation of RHA in the ratio 1:0.1 led to an enhanced mechanical strength of the polymeric fibers. At pH 2, the PMMA/RHA/PPy membranes exhibited a good removal capacity for all three contaminants, estimated as 360.5 mg/g (after 150 min), 165.7 mg/g (after 60 min) and 142.9 mg/g (after 70 min), for Cr(VI), E102 and IC, respectively. We suggest that the PMMA/RHA/PPy membrane is a promising active material for application in efficient water remediation protocols, for combining advantages as a simple preparation methodology and a high adsorption capacity toward different types of contaminants.