Molecularly engineered carbon nanostructures derived from Parthenium hysterophorus for ultralow detection of lead(ii) ions†

This study has explored a novel and sustainable solution for detecting lead after designing a highly selective and efficient sensor from Parthenium hysterophorus. Two nanocomposites were developed after the functionalization of biomass-derived carbon with nitrogen and sulfur-rich organic molecule 1-methyl-1,3,4-thiadiazole-2-thiol and carboxylic acid functionalized carbon nanotubes, respectively, through a facile refluxing method. The layered morphology and partially crystalline structure of MTT-NC were observed through HR-TEM, FE-SEM, Raman, and XRD studies. At the same time, CNT-NC has a hybrid layered and tube-like structure with high crystallinity. The high efficiency, excellent sensitivity and selectivity of CNT-NC toward lead can be due to the pyridine groups, unique hybrid morphology, high crystallinity and conductivity of the nanocomposite. The detection limit of CNT-NC was 100 nM, while MTT-NC demonstrated a detection limit of up to 800 nM. Both the sensors MTT-NC and CNT-NC are also compared with pure nanocarbon, which indicates that functionalization and hybridization enhance the performance and improve the crystallinity and sensitivity of the nanomaterial. The study supports exploring simple and sustainable methods for developing cost-effective and safe nanosensors to monitor the most common and toxic heavy metal ion lead.