Novel hierarchical composite adsorbent for selective lead(II) ions capturing from wastewater samples

Abstract

A novel hierarchical composite adsorbent was developed for sensitive and selective lead (Pb(II)) ions detection and removal from wastewater as well as biological samples optically. In the fabrication of composite adsorbent, highly mesoporous silica with nanospheres was used as substrate and the organic ligand of 2,5-dimercapto-1,3,4-thiadiazole was anchored successfully. An optimum condition was evaluated for the detection and removal of Pb(II) ions. Several experimental parameters were carried out systematically in terms of detection and removal operations. The detection and removal of Pb(II) ions were significantly affected by the solution acidity, initial Pb(II) ion concentration and contact time. Upon the addition of Pb(II) ions to the composite adsorbent at optimum conditions, the clear color was visible to the naked-eye in the detection and removal system. The composite adsorbent was exhibited high sensitivity to the Pb(II) ions as characterized by UV–vis spectroscopy with significant color formation. The lower limit of detection of Pb(II) ions was 0.48µg/L in waster solution. In the presence of competing ions, the composite adsorbent was not affected for the sensitive and selective detection adsorption of Pb(II) ions. The results demonstrated that the composite adsorbent exhibited excellent adsorption performance for Pb(II) ions and maximum adsorption capacity was 67.20mg/g. The adsorbed Pb(II) ions were eluted with suitable eluent and simultaneously regenerated into the initial form for next operation without destroying of case cavities in its nanostructure as it was clarified in the detection system. The data also confirmed that the composite adsorbent was a cost-effective and environmentally friendly procedure for Pb(II) ion treatment in wastewater and biological samples such as blood and viscera.