Synthesis of Ag Nanoparticles Decorated Carbon Nanotubes as an Electrochemical Sensor for Determination of Phenolic Compounds in Shale Gas Wastewater

In this study, silver nanoparticles (Ag NPs) were decorated on carbon nanotubes (CNTs) for electrochemical determination of o-cresol and phenol as phenolic compounds in shale gas wastewater. The glassy carbon electrode (GCE) surface was modified with functionalized CNTs (CNTs/GCE) and Ag NPs were electrodeposited on CNTs/GCE (Ag NPs/CNTs/GCE). Morphology and structures analysis of synthesized electrodes were done using SEM and XRD which exhibited that the uniformly Ag NPs in fcc structure were electrodeposited on the side wall of CNTs. Electrochemical studies with cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry illustrated that there are stable and sensitive electrochemical signal for Ag NPs/CNTs/GCE due to enhancement of the surface area by synergetic effects of CNTs and Ag NPs. Electrochemical studies represented that the limit of detection, sensitivity and linear range of sensor were obtained 0.01 mu M, 0.20046 mu A/mu M and 10 to 200 mu M, respectively, for detection of o-cresol and 0.01 mu M, 0.29759 mu A/mu M and 10 to 160 mu M, respectively for determination of phenol. The selectivity and applicability of the sensor was considered to determine phenolic compounds in the prepared real sample of shale gas wastewater which implied the o-cresol concentration and phenol in the real sample were achieved 0.97 mu M and 0.69 mu M, respectively.