The development of new, sensitive and simple methods for the rapid detection of dimethoate (DMT) in water is vitally important. A fluorescent probe technique has been developed for the rapid trace detection of pesticide residues. In our study, the method used is based on the fluorescence resonance energy transfer, which is also known as FRET. Dithizone (DZ) was bound to cadmium (Cd) on the surface of CdTe QDs to form a DZ–Cd complex. Then, the fluorescence of the CdTe QDs was immediately quenched because of the FRET between the CdTe QDs and the surface of DZ–Cd complex. After the addition of DMT to the DZ-functionalized QDs, DZ was separated from the surface of the QDs and was replaced by DMT, and the fluorescence of the QDs was restored. This method was validated using water samples spiked with DMT. Two good linear relationships were obtained in the range from 0.01 to 5.0 μg mL−1 and 5.0 to 40 μg mL−1; the detection limit was calculated to be 0.005 μg mL−1, and reasonable recoveries (88.6–95.3%) were achieved for the direct detection of DMT in water samples. This method is rapid, convenient and environmentally acceptable and shows potential for the rapid detection of DTM in water samples.
In this study, graphene-like biochar (IZBC) was prepared by pyrolysis of wheat straw in the presence of catalyst and activator. The formation of graphene in IZBC could be divided into three stages: shell core generation, carburization, and carbon precipitation. When the pyrolysis temperatures were in the ranges of 500–600 ℃, 600–700 ℃, 700–800 ℃ and 800–900 ℃, 17%, 32%, 13% and 38% of graphene were produced, respectively. The contribution ratios of graphene by FeCl 3 , ZnCl 2 and HCl were 64%, 23% and 13%, respectively. Moreover, IZBC was filled with porous wavy three-dimensional graphene nanosheets that enabled self-aggregation to be effectively prevented, which was superior to the striped two-dimensional structure. The adsorption of IZBC for dimethoate was a spontaneous exothermic reaction with the adsorption capacity of 980 μmol/g, which was consistent with the pseudo-second-order and intraparticle diffusion models. The adsorption was inhibited by coexisting cations, anions, and humic acid in water. Dimethoate was adsorbed on graphene through embedded separation, with pore filling, cation- π and electrostatic attraction as the key driving forces. In addition, the adsorbed saturated IZBC could be effectively regenerated for many times by 2 mol/L HCl solution.
危险品化学品经营许可证（带存储）