Tan Yang,Zhang Zheng,Guo Fuqiang,Guo Renqing,Bai Haineng,Zhang Baohua,Li Xin,Yang Qian,Liu Xuebo
In this study, multi-shaped CdS was synthesized by hydro- and solvothermal methods. Interestingly, the results of scanning electron microscopy and transmission electron microscopy showed that branch-like CdS could be transformed into ball-like and flake-like in deionized water by ethylenediaminetetraacetic acid and l -cysteine, respectively, and the growth mechanism of CdS was discussed and explored: the ion-binding rate might be the main factor for the morphology transformation of CdS. X-ray diffraction and energy dispersive spectroscopy revealed branch-like CdS which exhibited the hexagonal phase. Besides, the optical characteristics of CdS were performed by ultraviolet–visible and photoluminescence spectrum. Also, CdS was utilized to explore the photocatalytic activity of rhodamine B, and the result showed that the photocatalytic activity of ball-like CdS was higher than flake-like and branch-like CdS.
Hailin Yu,Huili Zhang,Meijuan Hu,Gang Liu,Zhengnan Sun,Jingxue Xu,Yingjun Wang,Guolin Jing,Hongsheng Liu
During oil extraction, a substantial volume of oily sewage (water-in-oil emulsion) is generated. The existence of emulsified oil diminishes the effectiveness of conventional coagulants used for purification. Furthermore, coagulants frequently precipitate emulsified oil as impurities, leading to resource wastage. Hence, there is an urgent need to develop multifunctional coagulation/demulsification agents that are environmentally safe. In this study, we synthesized the branched-chain compound coagulant (PPFS-PAD-RGO) and investigated its coagulation and demulsification properties. The results of dynamic and static light scattering and FTIR show that chitosan grafted onto the surface of modified PPFS forms a dendritic flocculation system. In addition, PPFS-PAD is fixed to a reduced graphene oxide carrier with a high specific surface area, which improves the positive charge density and dispersion of the coagulant. The layered structure amplifies the effect of adsorption bridge formation and net aggregation. At a concentration of 80 mg/L, PPFS-PAD-RGO exhibited a turbidity removal rate of 96.15 % and demulsification rate of 74 %. By comparing the structure of PPFS, it was found that the floc volume of PPFS-PAD-RGO is larger. This demulsification ability is mainly attributed to an amine matrix in the chitosan extension chain, which destroys the oil–water interface of the oil-in-water emulsion and induces demulsification. The introduction of RGO increases the local concentration of coagulant molecules. Therefore, the coagulation effect of PPFS-PAD-RGO in oily sewage is attributed to the introduction of demulsifier groups and nanomaterials, which strengthen the synergistic effect of charge neutralization, bridge adsorption and sweeping.
The branched TiO 2 nanotubes (BTNTs) were synthesized by a combined method of electrospinning, hydrothermal treatment , calcination , and ultrasonic treatment . Various morphologies of BTNTs were obtained by adjusting the hydrothermal temperature or time, and this yielded a morphologically-controllable BTNTs geometry. The CNTs incorporated TiO 2 nanorods (CTNRs) were fabricated via a combined method. The novel bilayer photoanodic film made of the CTNRs as an underlayer and the BTNTs as a light-scattering overlayer was fabricated for flexible dye-sensitized solar cells (FDSSCs). With addition of the BTNTs, the conversion efficiency of FDSSCs was greatly enhanced due to the improved light-scattering, the increased dye loading, and the more effective electron collection. The highest conversion efficiency of 4.18% was achieved with the 150 °C hydrothermal treatment for 30 min, which is nearly twice that of the FDSSCs using single-layer CTNRs film.
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