John O Adongo
Humboldt-Universität zu Berlin, Germany
Title: Fabrication of surfaces modified with carboxymethylthio ligands towards chelate-assisted trace-level extraction of copper
Biography
Biography: John O Adongo
Abstract
Statement of the Problem: Copper (Cu) is an essential metal in biological systems; however, at concentrations beyond threshold limits, it can become highly toxic to humans and aquatic organisms. Excessive Cu in the blood has been associated with the Wilson’s disease. Copper can bind onto certain organic ligands via coordination mechanisms. Electrochemical grafting of aryl diazonium derivatives have successfully been used to modify substrates by introducing layers of various organic functional groups onto metallic and semiconducting substrate surfaces.
1 Strategies involving functionalization of substrates with large-molecular-weight oligomers and peptides via diazonium grafting routes for extraction of heavy metal ion (HMI) pollutants have been reported. Some of these methods involve introduction of chelating groups in more than a single step. However, a simpler one-step quick grafting of low-molecular-weight HMI - chelating agents may not only present some cost reduction advantages towards devising kits for HMI extraction but also permit the fabrication of thinner layers with optimal surface grafting and excellent chelation efficiency. Silicon is one of the most abundant materials on the earth’s crust and its suitable surface chemistry has motivated organic functionalization efforts towards developing a wide range of applications. The purpose of this study is to explore a one-step functionalization strategy for introducing carboxymethylthio (CMT) chelating groups via direct electrografting of the diazonium cation 4-[(carboxymethyl)thio]benzenediazonium cation, (4-CMTBD), onto Si surface, leading to fabrication of the Si-(4-CMTB) surface. The investigation of Cu chelation is also studied. Findings: The fabricated surface, Si-(4-CMTB), is capable of chelating Cu ions from aqueous solutions at trace amounts as shown by Raman spectroscopy.
2 Conclusion & Significance: Chelate functionalized Si surfaces may be of potential engineering interests for HMI sensing and/or extraction. This study offers positive contributions in the fields of environmental protection, forensic diagnostics, biosensing, and mineral prospecting among other related disciplines.
