Jingyuan Huang,Yueyong Ma,Qianqian Chen,Jinyan Zhu,Hongyi Jiang,Hanliang Li,Lian Yi,Haiyan Li,Mei Hong
Nowadays, nano-photocatalysts (NPs) have become the research focus in the field of photocatalysis due to their excellent photocatalytic activity, and microemulsion is an effective method to prepare high-efficiency nano-photocatalysts. Here, BiVO 4 NPs with high efficiency under visible light were prepared by a combination of reverse microemulsion method and calcination method. XRD, SEM, TEM , XPS, DRS, PL , BET and other characterization tests were used to comprehensively explore the influence of water-oil ratio on the physicochemical properties of the catalysts. The results show that BiVO 4 NPs of monoclinic scheelite with high crystallization degree can be obtained by this method. The microscopic morphology, specific surface area and total pore volume of BiVO 4 NPs are significantly affected by the water-oil ratio. It is difficult to obtain BiVO 4 NPs with small particle size and uniform dispersion under the condition of too low or too high water-oil ratio. Meanwhile, the photogenerated carrier recombination efficiency of the catalyst is significantly improved, thus reducing the photocatalytic activity of the catalyst. Strikingly, the BiVO 4 NPs obtained under the condition of water-oil ratio is 20 exhibited well-dispersed nanospheres with diameters ranging from 80 to 100 nm. It has the highest photocatalytic activity due to its high crystallinity , large specific surface area and total pore volume and relatively low photogenerated carrier recombination efficiency. Under visible light irradiation, the degradation efficiency of RhB can reach 97.69% in 100 min, and the rate constant is 0.03253 min −1 .
Hydrophobic and dispersible functionalized reduced graphene oxide (FrGO) was employed to prepare chitosan gel droplets by crosslinking an inverse Pickering emulsion. The emulsion was prepared using toluene as the continuous phase and a chitosan aqueous solution as the dispersed phase. The effects of the FrGO concentration and the water/oil ratio on the chitosan droplet morphology were studied. At appropriate concentrations, the FrGO acted as a stabilizer and chitosan gel droplets were formed. Decreasing the FrGO concentration or increasing the water/oil ratio was unfavorable to the formation of chitosan droplets. Using this method, drug loaded chitosan gel droplets (microgels) were prepared and their release profiles as well as the factors that influence the drug release were investigated.
Jiajun Gao,Pengcheng Cui,Lingyun Ding,Taiyi Xu,Yuanlai Ju,Bibo Yu,Wenwu Zhang,Zhilv Zhang,Wei Sun
The relationships between three steps of the inverse emulsion-breath figure (Ie-BF) method, including emulsion preparation, film casting and hydrophilic component loading, are explored by adjusting the experimental factors of the three implementing processes. For emulsion preparation step, the influence of the ultrasonification, the concentration of emulsifier and the addition of polymer on the size of the emulsion droplets are investigated. For film casting step, the influence of environmental humidity and several factors concerning the emulsion preparation on the porous structure of the resultant films are studied. It has been proved that high humidity is a necessity for obtaining surface pores, and multi-layered pores with disordered distribution can be formed in the bulk layer of the film when high water/oil ratio is used in making the emulsion. Bovine serum albumin is loaded into the emulsion water droplets, and by implementing the Ie-BF method under the condition of water/oil ratio being as low as 0.02 vol%, selective protein enrichment within the interior of the top-layer pores is still realized. It reflects the characteristics of “high efficiency, targeted assembly” in the step of hydrophilic component loading. Graphical
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