Hybrid hierarchically porous carbon micron tubes for trace cadmium and lead ions electrochemical detection

The nitrogen, sulfur codoped hierarchical porous carbon tubes were synthesized using oxidized asphaltene, melamine and trithiocyanuric acid, it showed excellent performance in the detection of trace amounts of Cd2+/Pb2+ thanks to its rich sulfur and nitrogen functional groups as well as hierarchical porous tube structure. The introduction of oxidized asphaltene increased the conductivity of the resultant carbon material while retaining a high sulfur content (6.13 wt%). Under the optimum conditions, the resultant porous carbon tube was used as electrochemical detection sensor for heavy metal ions. The sensitivities and detection limits for individual Cd2+ and Pb2+ were 19.4802 and 33.2850 μA/μM, 2.80 and 1.38 nM; while the sensitivities and detection limits for simultaneous Cd2+ and Pb2+ were 14.5474 and 37.3337 μA/μM, 3.75 and 1.23 nM, respectively. This sensor also was utilized to detect actual water samples, and it was successful in measuring environmental heavy metal contaminants with acceptable recoveries of 97.34–102.83% for Cd2+ and 97.46–106.47% for Pb2+.