Methylmercury (MeHg), derived from industrial processes and microbial methylation , is still a worldwide environmental concern. A rapid and efficient strategy is necessary for MeHg degradation in waste and environmental waters. Here, we provide a new method with ligand-enhanced Fenton-like reaction to rapidly degrade MeHg under neutral pH. Three common chelating ligands were selected (nitriloacetic acid (NTA), citrate, and ethylenediaminetetraacetic disodium (EDTA)) to promote the Fenton-like reaction and degradation of MeHg. Results showed that MeHg can be rapidly degraded, with the following efficiency sequence: EDTA > NTA > citrate. Scavenger addition demonstrated that hydroxyl radical ( ▪ OH), superoxide radical (O 2 ▪– ), and ferryl (Fe Ⅳ O 2+ ) were involved in MeHg degradation, and their relative contributions highly depended on ligand type. Degradation product and total Hg analysis suggested that Hg(Ⅱ) and Hg 0 were generated with the demethylation of MeHg. Further, environmental factors, including initial pH, organic complexation (natural organic matter and cysteine), and inorganic ions (chloride and bicarbonate) on MeHg degradation, were investigated in NTA-enhanced system. Finally, rapid MeHg degradation was validated for MeHg-spiked waste and environmental waters. This study provided a simple and efficient strategy for MeHg remediation in contaminated waters , which is also helpful for understanding its degradation in the natural environment.
The long-term and excessive use of organophosphorus pesticides (OPs) leads to hazardous residues in the environment, which threatens human health to a considerable extent. Colorimetric methods can quickly and readily identify pesticide residue , but they still have various challenges in accuracy and stability. Herein, a smartphone-assisted and non-enzymatic colorimetric biosensor was constructed for rapid monitoring of multiple OPs based on the enhanced effect of aptamer on the catalytic ability of octahedral Ag 2 O. It was demonstrated that the aptamer sequence could enhance the affinity of colloidal Ag 2 O to chromogenic substrates, and accelerate the generation of oxygen radicals such as superoxide radical (·O 2 − ) and singlet oxygen ( 1 O 2 ) from dissolved oxygen, thereby significantly increasing the oxidase activity of octahedral Ag 2 O. The color change of the solution can be easily converted to the corresponding RGB values by a smartphone for quantitative and rapid detection of multiple OPs. Hence, the smartphone-based and visual biosensor of multiple OPs was acquired with limit of detection of 10 μg L −1 , 28 μg L −1 and 40 μg L −1 for isocarbophos , profenofos and omethoate , respectively. The colorimetric biosensor also exhibited good recoveries in several environmental and biological samples, showing that it may have broad application prospects for detecting OPs residues.
危险品化学品经营许可证（带存储）