Electrochemical sensor construction based on Nafion/calcium lignosulphonate functionalized porous graphene nanocomposite and its application for simultaneous detection of trace Pb~(2+) and Cd~(2+)

摘要

Graphical abstractDisplay OmittedHighlights•Calcium lignosulfonate (CLS) was firstly introduced for preparing graphene.•Porous structure of CLS/graphene was obtained.•The nanocomposite was used to construct sensor for the detection of Pb2+and Cd2+.•The proposed sensor was sensitive and selective.AbstractHere, a new porous graphene (PGR) based nanocomposite was synthesized by a chemical and thermal reduction of graphite oxide in the assistance of calcium lignosulfonate (CLS), and characterized by scanning electron microscopy SEM, TEM, XPS, Zeta potential analysis, FTIR and EIS. Then the as-prepared CLS/PGR was used along with Nafion to modify a glassy carbon electrode (GCE) for constructing electrochemical sensor to detect Pb2+and Cd2+simultaneously. Compared with the bare GCE, the reduced graphene oxide/GCE, and the CLS/PGR/GCE, the Nafion/CLS/PGR/GCE exhibited improved electrochemical performance in detecting the two ions. It could be ascribed to the synergistic contribution from PGR, CLS and Nafion, which integrated the advantageous features of high active surface area, good cation exchange ability and strong adsorption capacity. Under optimum conditions, this novel sensor showed a wide detection range for Pb2+and Cd2+(0.05–5.0 μM) with the limit of detection and limit of quantification for Pb2+0.01 and 0.03 μM, for Cd2+0.003 and 0.01 μM, respectively. It was successfully applied for the simultaneous determination of Pb2+and Cd2+in real water samples with satisfying recoveries of 93.6–105.3% for Pb2+and 93.5–102.5% for Cd2+, demonstrating its feasibility for the determination of environmental metallic pollutants.