The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using the host-guest binding of a supramolecular complex at a host surface by combining a self-assembled monolayer (SAM) of mono-(6-deoxy-6-mercapto)-beta-cyclodextrin (betaCDSH), iron (III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeTMPyP) and cyclodextrin-functionalized gold nanoparticles (CDAuNP). The supramolecular modified electrode showed excellent catalytic activity for oxygen reduction. The reduction potential of oxygen was shifted about 200 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare gold electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves probably 4-electrons with a rate constant (k(obs)) of 7 x 10(4) mol(-1) Ls(-1). A linear response range from 0.2 up to 6.5 mg L(-1), with a sensitivity of 5.5 microA L mg(-1) (or 77.5 microA cm(-2) L mg(-1)) and a detection limit of 0.02 mg L(-1) was obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation was 3.0% for 10 measurements of a solution of 6.5 mg L(-1) oxygen.
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http://dx.doi.org/10.1016/j.aca.2010.02.011 | DOI Listing |
J Colloid Interface Sci
December 2024
Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
Ferrous oxalate (FeCO)-based composite has been recognized as an eminent catalyst for Cr(III)-ethylenediamine tetraacetic acid (Cr(III)-EDTA) decomplexation. However, their practical application has been limited by low cycling capacity and an ambiguous mechanism. In this research, a composite catalyst consisting of biotite loaded with nano FeCO (CFS90) was prepared directly from iron-containing silicate tailing.
View Article and Find Full Text PDFWater Res
December 2024
State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China. Electronic address:
Estuarine and coastal environments have experienced dissolved oxygen (DO hereafter) depression and hypoxia due to increasingly intensified anthropogenic eutrophication and climate warming. This review compared diverse systems in Chinese coastal waters that experience DO depletion or hypoxia, aiming to identify essential aspects in advancing the abilities in comprehensively understanding DO dynamics across systems that span wide ranges of physical and biogeochemical environments. The coastal DO depression and relevant ecological consequences around the world are generally overviewed.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
Developing hybrid fluorescence (FL)/room-temperature phosphorescent (RTP) materials in dry-state, aqueous, and organic solvents holds paramount importance in broadening their applications. However, it is extremely challenging due to dissolved oxygen and solvent-assisted relaxation causing RTP quenching in an aqueous environment and great dependence on SiO-based materials. Herein, an efficient endogenetic carbon dot (CD) strategy within melamine-formaldehyde (MF) microspheres to activate RTP of CDs has been proposed through the pyrolysis of isophthalic acid (IPA) molecules and branched-chain intra-microspheres.
View Article and Find Full Text PDFEnviron Pollut
December 2024
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
In addition to traditional organophosphate esters (tOPEs), emerging organophosphate esters (eOPEs) have increasingly been detected in the environment, but their risks remain unclear. This study detected 12 tOPEs and 7 eOPEs in surface water, sediment, and suspended particulate matter (SPM) samples from important aquatic habitats and drinking water sources in Yibin (YB), Yichang (YC), Shanghai (SH), and Poyang Lake (PY) within the Yangtze River basin. The total concentration of OPEs (ΣOPEs) in surface water, sediment, and SPM from these four regions were 22.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
U.S. Geological Survey, U.S. Environmental Protection Agency Chesapeake Bay Program, 1750 Forest Drive, Suite 130, Annapolis, Maryland 21401, United States.
Many coastal ecosystems have suffered from cultural eutrophication and dead zones. In the Chesapeake Bay, water quality degradation is manifested in low dissolved oxygen, poor water clarity, and decreased submerged aquatic vegetation acreage. This research combines long-term monitoring data, science-based assessment methods, and novel data analysis approaches (i.
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