Lin Yang,Xueling Liu,Bingyue Song,Sixian Yang,Xiaojie Zhang,Chong Zhao,Yixiao Wu,Lei Zhang,Yanjun Huang
Effective and selective recovery of precious metal silver (Ag(I)) from wastewater can promote resource recycling and mitigate environmental pollution. In this study, dimercaptosuccinic acid (DMSA) functionalized polyhedral oligomeric silsesquioxane (POSS)-based hybrid polymer (DPHP) was synthesized and employed for the adsorption of Ag(I) from aqueous solution. The obtained adsorbent was characterized using SEM-EDS, XPS, solid-state 13 C NMR, and 29 Si NMR spectra. Batch adsorption experiments were conducted to evaluate the adsorption performance of DPHP for Ag(I). The results revealed that the maximum adsorption capacity of DPHP for Ag(I) was 494.65 mg g −1 at pH 4, and the adsorption process could be well described by pseudo-second-order and Sips models. Thermodynamic studies implied the adsorption of Ag(I) was an endothermic and spontaneous adsorption process in nature. Adsorption and desorption experiments demonstrated that the regeneration efficiency of DPHP remained above 83 % after five cycles and the preconcentration factor of DPHP was determined to be 125. Furthermore, DPHP exhibited selectivity to Ag(I) in solutions containing a variety of competitive metal ions and simulated industrial wastewater. Based on density functional theory (DFT) calculations, as well as XPS, FTIR, and Raman analyses, the interaction between Ag(I) and DPHP involved electrostatic attraction, ion exchange, and coordination, with the coordination mainly between thioether and carboxy groups and Ag(I) ions. Overall, DPHP is a promising adsorbent for the recovery of Ag(I) from aqueous solutions.
Qiming Huo,Zhuo Lv,Shengyu Feng,Dengxu Wang,Hongzhi Liu
The development of a straightforward strategy for preparing organic fluorescent materials, fine-tuning white-light emission, and subsequently constructing white light-emitting diodes (LEDs) is of great significance. Herein, we report on the modulation of white-light emission and the fabrication of white LEDs using polyhedral oligomeric silsesquioxane (POSS)-based fluorescent hybrid porous polymers (HPPs) through simple physical blending. Two HPPs, namely HPP-1 and HPP-2, which emit blue and red light, respectively, were synthesized via the efficient Heck reactions of octavinylsilsesquioxane with 4,4′-dibromobiphenyl and 1,3,6,8-tetrabromopyrene. By physically doping of HPP-1 and HPP-2 in variable ratios in solvent suspensions, it was discovered that white-light emission is significantly influenced by the concentrations of the materials and the excitation wavelength. Similar findings were also observed in the solid-state physical doping. An ideal white light emission with a CIE coordinate of (0.33, 0.33) can be achieved when excited at 380 nm with a mass ratio of HPP-1 to HPP-2 of 1:2. Finally, the two HPPs were dispersed in polysiloxane matrices, and a white LED with a CIE coordinate of (0.42, 0.36) was obtained. The LED exhibited a color rendering index of up to 90 and a correlated color temperature of 2858 K, realizing warm white light emission. This simple and convenient white-light regulation strategy holds great promise for application in the development of novel white LEDs based on organic fluorescent porous materials.
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