ABSTRACT
Nowadays, increasing the risk for copper leaching into the drinking water in homes, hotels and schools has become unresolved issues all around the countries such as Canada, the United States, and Malaysia. The leaching of copper in tap water is due to a combination of acidic water, damaged pipes, and corroded plumbing fixtures. To remedy this global problem, a triple interconnected structure of CdS/Au/GQDs was designed as a photo-to-electron conversion medium for a real time and selective visible-light-prompt photoelectrochemical (PEC) sensor for Cu2+ ions in real water samples. The synergistic interaction of the CdS/Au/GQDs enabled the smooth transportation of charge carriers to the charge collector and provided a channel to inhibit the charge recombination reaction. Thus, a detection limit of 2.27â¯nM was obtained, which is 10,000 fold lower than that of WHO's Guidelines for Drinking-water Quality (â¼30⯵M). The photocurrent reduction was negligible after 30 days of storage under ambient conditions, suggesting the high stability of photoelectrode. Moreover, the real-time monitoring of Cu2+ ions in real samples was performed with satisfactory results, confirming the capability of the investigated photoelectrode as the most practical detector for trace amounts of Cu2+ ions.
Subject(s)
Cadmium Compounds/radiation effects , Copper/analysis , Electrochemical Techniques , Light , Nanotubes/radiation effects , Sulfides/radiation effects , Water Pollutants, Chemical/analysis , Cadmium Compounds/chemistry , Copper/chemistry , Electrodes , Gold/chemistry , Graphite/chemistry , Nanotubes/chemistry , Quantum Dots/chemistry , Sulfides/chemistry , Water Pollutants, Chemical/chemistryABSTRACT
A multi-functional hybrid of cellulose acetate with cadmium sulfide and Methylene blue (CA/CdS/MB) in a bead composition was synthesized and investigated as a photosensor-adsorbent for the rapid, selective, and sensitive detection, and adsorption of Cu(II) ions. These hybrid CA-modified beads are composed of multiple adsorption active sites and possess a surface area of 58 cm2 g-1. They are an efficient adsorbent with a maximum adsorption capacity of 0.57 mg g-1. Photoelectrochemical (PEC) detection of Cu(II) was accomplished by modifying the beads on a glassy carbon electrode. The beads containing 20 mmol of sulfur displayed the widest linear analytical range (0.1-290 nM) and the lowest detection limit (16.9 nM) for Cu(II) with high selectivity and reliable reproducibility. The successful application of the beads has provided a new insight for the selection of a responsive photoactive material for a PEC assay, as well as an effective adsorbent material for Cu(II) ions. Graphical abstract A multi-functional hybrid of cellulose acetate with cadmium sulfide and Methylene blue (CA/CdS/MB) in a bead composition was synthesized and investigated as a photosensor-adsorbent for the rapid, selective and sensitive detection and adsorption of Cu(II) ions.
ABSTRACT
Discovering the distinctive photophysical properties of semiconductor nanoparticles (NPs) has made these a popular subject in recent advances in nanotechnology-related analytical methods. Semiconductor NPs are well-known materials that have been widely used in photovoltaic devices such as optical sensors and bioimaging, and dye-sensitized solar cells (DSSCs), as well as for light-emitting diodes (LEDs). The use of a narrow-bandgap semiconductor such as CdS NPs in the photoelectrochemical (PEC) detection of chemicals and biological molecules plays a key role as a photosensitizer and promotes some specific advantages in light-harvesting media. Their size-controlled optical and electrical properties make NPs fascinating and promising materials for a variety of nanoscale photovoltaic devices. Moreover, charge injection from the narrow bandgap to the adjacent material leads to efficient charge separation and prolongs the electron lifetime by the elimination of the charge carrier recombination probability. In this regard, a single photon enables the production of multiple photogenerated charge carriers in CdS NPs, which subsequently boosts the effectiveness of the photovoltaic devices. In particular, the present review article highlights the recent emerging PEC detection methods based on CdS NPs, specifically related to the direct and indirect interactions of NPs with target analytes. The current opportunities and challenges in achieving real-world applications of CdS-based PEC sensing are also presented.
