Synthesis of reduced graphene oxit from graphite and application of analysis Cd(II) and Pb(II) in wastewater samples by stripping voltammetry

Abstract

Abstract: In this paper, we report the results of synthesizing reduced-form graphene oxide (ERGO) from graphene by the improved Hummers synthesis and the cyclic voltammetry (CV) methods. The newly synthesized material was applied in simultaneous analysis of Cd and Pb metals in three urban wastewater samples by the differential pulse anodic stripping voltammetry (DP-ASV). Method evaluation results show that the average LOD and LOQ are low, respectively: 1,383 ± 0,174 (n = 4) ppb and 4,892 ± 0,774 (n = 4) ppb for Cd(II);  4,666 ± 1,391 (n = 4) ppb and 15,56 ± 4,626 (n = 4) ppb for Pb(II); between the intensity of peak dissolved current and concentration of Cd (II) and Pb (II), the correlation coefficient is quite large, r ³ 0,990; good accuracy with the recovery value (Rev) ranges from 85,8 % to 115,4 %. The content of cadmium and lead in three wastewater samples is less than the A level of QCVN 08: 2015/BTNMT for surface water for domestic use.