Separating chalcopyrite and molybdenite is difficult owing to their similarly high floatability. Accordingly, this paper considers the depressant 2-Amino-5-mercapto-1,3,4-thiadiazole (AMT), in order to separate chalcopyrite and molybdenite and investigate the relevant mechanism of AMT depression. Single-mineral flotation tests showed that when kerosene was used as the collector and AMT as the depressant, molybdenite showed excellent flotation while chalcopyrite was completely depressed. Mixed mineral flotation tests showed that separation of these two minerals could be achieved when AMT was applied as the depressant. Combining the test results of adsorption, Zeta potential , and XPS, the mechanism of AMT depression is suggested. Therefore, the adsorption mechanism of AMT on the chalcopyrite and molybdenite can be revealed. The adsorption of AMT on the chalcopyrite surface is unquestionably greater than that on the molybdenite surface. The results suggest that AMT is chemisorbed on chalcopyrite surfaces through the Cu-S bonds. By contrast, physisorption on molybdenite surfaces is through electrostatic action. Thus, selective depression of chalcopyrite can be achieved with the use of AMT. This study promises a more environmentally friendly flotation separation process for chalcopyrite and molybdenite.
Hollow mesoporous silica microspheres (HMSN) were selected as carriers for storing 2-aminino-5-mercato-1,3,4-thiadizole (ATM) in this experiment. The synthesised microspheres were uniformly dispersed, with a diameter of approximately 500 nm, as identified by scanning electron microscopy. HMSN, as excellent nanocarriers, were used to encapsulate ATM with a 19 wt% loading rate. Then, 18 wt% HMSN loaded with ATM was added to the coating. Electrochemical impedance spectroscopy and scanning Kelvin probes were used to investigate the self-healing ability of the coating with ATM encapsulated in hollow mesoporous silica microspheres. The copper corrosion caused by microdefects in the coating was delayed by controlling the slow release of ATM from the microspheres. The active corrosion resistance of the coatings was strengthened. By optimising the coating, the service life of the coating can be extended to achieve the long-term corrosion protection of copper.
Sheng Deng,Shuxuan Wu,Xu Han,Fu Xia,Xiangjian Xu,Liangjing Zhang,Yonghai Jiang,Yuhui Liu,Yu Yang
Mercury (Hg 2+ ) contamination in water is associated with potential toxicity to human health and ecosystems. Many research studies have been ongoing to develop new materials for the remediation of Hg 2+ pollution in water. In this study, a novel thiol- and amino-containing fibrous adsorbent was prepared by grafting 2-amino-5-mercapto-1,3,4-thiadiazol (AMTD) onto PAN fiber through a microwave-assisted method. The synthesized functional fiber was characterized by FTIR, SEM, and elemental analysis. Adsorption tests depicted that for mercury uptake, PAN MW -AMTD fiber exhibited enhanced adsorption capacity compared with other fibrous adsorbents and selective adsorption feature under the interference of other metal ions , including Pb 2+ , Cu 2+ , Cd 2+ , and Zn 2+ . The influence of pH on the adsorption process was investigated and the effect of temperature revealed that the adsorption sorption process was endothermic and the adsorption performance of PAN MW -AMTD was elevated with the increase of temperature. Kinetic studies of PAN MW -AMTD fiber followed the pseudo-second-order and the adsorption isotherm of Hg 2+ was well fitted by Sips and Langmuir equations, given the maximum adsorption amount of 332.9 mg/g. XPS results suggested that a synergetic coordination effect of sulfur and nitrogen in functional fiber with mercury took responsibility for the adsorption mechanism in the uptake process. In addition, the prepared PAN MW -AMTD fiber could easily be regenerated with 0.1 M HCl for five times without significant reduction of mercury removal efficiency. Thus, this study will facilitate the research on novel functional material for the removal of mercury from water.
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