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Tailor‐Made Micro‐Object Optical Sensor Based on Mesoporous Pellets for Visual Monitoring and Removal of Toxic Metal Ions from Aqueous Media
Author(s) -
ElSafty Sherif A.,
Shenashen M. A.,
Shahat A.
Publication year - 2013
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201202407
Subject(s) - aqueous solution , metal ions in aqueous solution , chelation , materials science , mesoporous material , pellets , mercury (programming language) , naked eye , adsorption , ultraviolet light , nanotechnology , chemistry , chemical engineering , detection limit , metal , chromatography , inorganic chemistry , organic chemistry , computer science , optoelectronics , metallurgy , composite material , programming language , engineering , catalysis
Methods for the continuous monitoring and removal of ultra‐trace levels of toxic inorganic species (e.g., mercury, copper, and cadmium ions) from aqueous media such as drinking water and biological fluids are essential. In this paper, the design and engineering of a simple, pH‐dependent, micro‐object optical sensor is described based on mesoporous aluminosilica pellets with an adsorbed dressing receptor (a porphyrinic chelating ligand). This tailor‐made optical sensor permits ultra‐fast (≤ 60 s), specific, pH‐dependent visualization and removal of Cu 2+ , Cd 2+ , and Hg 2+ at sub‐picomolar concentrations (∼10 −11 mol dm −3 ) from aqueous media, including drinking water and a suspension of red blood cells. The acidic active acid sites of the pellets consist of heteroatoms arranged around uniformly shaped pores in 3D nanoscale gyroidal mesostructures densely coated with the chelating ligand. The sensor can be used in batch mode, as well as in a flow‐through system in which sampling, target ion recognition and removal, and analysis are integrated in a highly automated and efficient manner. Because the pellets exhibit long‐term stability, reproducibility, and versatility over a number of analysis/regeneration cycles, they can be expected to be useful for the fabrication of inexpensive sensor devices for naked‐eye detection of toxic pollutants.