| With the development of industry and the improvement of human life, our environment have been damaged seriously. There is no doubt that pesticides has speed up the development of industrial and agricultural. However, pesticides abuse has not only lead to irreversible destruction of water, soil and other natural environment, but also cause serious harm to animals, plants and human beings. Apart from this problem, heavy metal pollution also could not be overlooked. Cu(Ⅱ)and Cd(Ⅱ) are typical heavy metal pollutants. They have carcinogenicity and teratogenicity to human beings. Therefore, an effective, sensitive detection technology is very necessary to ease the damage.Nano material is star of materials in the21st century, because of its unique and excellent properties. It is playing more and more important role in many field such as industry, materials science, biology, physics, chemistry and so on. Nanocomposite combines physical and chemical properties of two or more different nanomaterials. Through efficient preparation approach, it can be successfully assemble, forming a new material. Nowadays, nanocomposite has been applied to the detection of environmental pollutants. Many research has focus on this issue.In this paper, based on the above understanding, I have done the following research:1. The organic-inorganic hybrid ultrathin films were fabricated by alternate assembly of humic acid (HA) and exfoliated Mg-Al-layered double hydroxide (LDH) nanosheets onto ITO substrates via a layer-by-layer (LBL) approach. Their electrochemical performances were systematically investigated. Our results demonstrate that such newly designed (LDH/HA)n multilayer films, combining the individual properties of HA (dual recognition ability for organic herbicides and metal ions) together with LDH nanosheets (a rigid inorganic matrix), and the merits of LBL film architectures, can be applied to the simultaneous analysis of PCP and Cu(II) without interference from each other. Under the optimized conditions, the detection limit was found to be as low as1nM PCP. Toward the goal for practical applications, this simple and cost-effective probe was further evaluated by monitoring PCP and Cu(Ⅱ) in real water samples.2. The nano-assembly of HA/LDH@CNs was obtained via direct assembling the exfoliated layered double hydroxide and humic acid onto the surface of carbon nanospheres. Then the HA/LDH@CNs was modified onto the glass carbon electrode. It was found that the modified electrode has a great potential to detetect Cd2+. Under the optimized conditions, the linear range was2-25nM. The detection limit was found to be as low as1nM Cd2+.3. We adopted Kamat’s method to prepare graphene-TiO2composite. Then we synthetised CdS QDs refereed to the method which has been reported. The as-prepared graphene-TiO2composites was coated onto FTO glass, and CdS QDs was further modified on FTO glass. It was found that the addition of CdS QDs provided significant advantages for enhanced light absorption and charge separation, resulting in the improvement of the photocurrent intensity. A sensitive photoelectrochemical for the detection of Cu2+was developed based on the selective interaction between Cu2+and CdS QDs. The sensor shows promising application in the analysis of Cu2+. A highly sensitive and selective biosensor for the photoelectrochemical (PEC) detection of pentachlorophenol (PCP) has been developed, whereby newly synthesized crossed BiOI nanoflake arrays (BiOI NFs) are fabricated as a photoactive electrode via a successive ionic layer adsorption and reaction (SILAR) approach. The smart integration of BiOI NFs with biomolecules PCP antibody yields a novel ab-BiOI NFs hybrid, constructing a three-dimensional (3D) porous network biosensing platform. |
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