RESUMEN
The recovery of valuable gold from wastewater is of great interest because of the widespread use of the precious metal in various fields and the pollution generated by gold-containing wastes in water. In this paper, a water-insoluble cross-linked adsorbent material (TE) based on cyanuric chloride (TCT) and ethylenediamine (EDA) was designed and used for the adsorption of Au(III) from wastewater. It was found that TE showed extremely high selectivity (D = 49,213.46) and adsorption capacity (256.19 mg/g) for Au(III) under acidic conditions. The adsorption rate remained above 90% eVen after five adsorption-desorption cycles. The adsorption process followed the pseudo-first-order kinetic model and the Freundlich isotherm model, suggesting that physical adsorption with a multilayer molecular overlay dominates. Meanwhile, the adsorption mechanism was obtained by DFT calculation and XPS analysis, and the adsorption mechanism was mainly the electrostatic interaction and electron transfer between the protonated N atoms in the adsorbent (TE) and AuCl4-, which resulted in the redox reaction. The whole adsorption process was the result of the simultaneous action of physical and chemical adsorption. In conclusion, the adsorbent material TE shows great potential for gold adsorption and recovery.
RESUMEN
The ultralight space mirror has long been a hot topic in the research field of space telescopes. In this paper, an ultralight mirror is designed by obtaining the structure and parameters of a mirror with an aperture of 2 m through experimental design and multiobjective integrated optimization. Specifically, the materials near the neutral surface were replaced with elliptical holes. The back of the mirror was supported at three points. Finite-element analysis shows that the mirror had a surface figure error of 10.4 nm under 1 g in the x direction (gravity direction), which is sufficiently high to be applied to visible light optical systems. Further, the eigenfrequencies of mirror components were obtained through finite-element analysis: 70 Hz in the x direction, 70 Hz in the y direction, and 90 Hz in the z direction. The results demonstrate the excellent dynamics performance of the designed mirror. Compared with test results, the relative error of eigenfrequencies was within 4%. Hence, our ultralight design outputs reliable optimization results and applies to the development of large-aperture ultralight space mirrors. Finally, the ultralight mirror was prepared from reaction-bonded silicon carbide. The mass and surface density of the prepared mirror were 105 kg and 34kg/m2, respectively. The mirror mass was 50% lighter than that of the mirrors designed by traditional lightweight methods.