Shangxing Chen,Linjian Li,Yangping Wen,Guangyao Yang,Guangbin Liu,Yufu Yi,Qingyin Shang,Xiuxia Yang,Shuo Cai
A simple and cheap thick-walled Moso biochar (BC) was selected and combined with carbonate minerals dolomite (DM) to construct a voltammetric sensing platform for application in stripping analysis of thiamethoxam in agricultural and environmental samples. The BC based on thick-walled Moso was prepared by pyrolyzing biomass wastes in limited oxygen atmosphere at temperatures of 600 °C for 2 h, and the BC-DM nanocomposite was obtained through milling and sieving, then liquidphase ultrasonic assistance by dispersing grinded DM and moso bamboo BC into ultra-pure water. The morphology and structure of the BC-DM nanocomposite were characterized by FT-IR, XRD, and SEM-EDX. Under optimal conditions, the BC-DM modified electrode showed high sensitivity and good stripping voltammetric response towards thiamethoxam in a linear range from 0.5 to 35 μg mL -1 with a limit of detection (LOD) of 0.22 μg mL -1 . The prepared nanocomposite sensor was employed for the determination of thiamethoxam in different real samples with acceptable recoveries. Thickwalled moso as biochar with post-modification provides a new promising platform for potential applications in electrochemistry.
Yan Xiaoju,Sun Yue,Ma Cong,Kong Xiangji,Zhang Yan,Tao Wen
Abstract This research compared the adsorption behavior of anionic dye methyl orange (MO) and cationic dye methylene blue (MB) by five carbon materials, i.e. rice husk biochar (RH), sawdust biochar (SD), activated carbon (AC), bamboo biochar (BB) and palm biochar (PB). Scanning electron microscopy (SEM), Boehm titration, Brunauer–Emmett–Teller (BET) analysis and zeta potential were used to characterize the physicochemical properties of the adsorbents. The pH had a great influence on the adsorption processes. The adsorption processes for two dyes followed the pseudo-second order kinetic model. The Langmuir, Freundlich and Temkin isotherm models all showed good fit to the experimental adsorption data. The thermodynamic studies revealed that all the reactions of MO were exothermic processes with decrease in entropy, while those of MB were just the opposite. The adsorption capacity of RH was the highest, which may be due to its physicochemical properties. The adsorption capacities of SD were the smallest, and the poor physiochemical properties of PB caused that the dyes adsorption onto PB was non-spontaneous and non-feasible. All adsorbents showed higher adsorption capacity for MB than that for MO, which may be due to the additional electrostatic attraction effect between adsorbents and cationic MB dye.
危险品化学品经营许可证（带存储）