Yuxie Jiang,Kai Wang,Yingzhen Zhang,Yan Cheng,Tianxue Zhu,Jianying Huang,Weilong Cai,Yuekun Lai
In this paper, a stainless steel mesh coated with titanium dioxide (TiO 2 @SSM) membrane was developed for the separation of stable oil-water emulsions and the degradation of soluble pollutants. The TiO 2 @SSM membrane showed excellent underwater anti-oil adhesion performance and efficient emulsion separation under gravity (flux of 207.7 L m −2 h −1 and efficiency of 99.58 % for toluene-water emulsion). The emulsion could also be pre-broken by microbubble flotation to enhance the separation performance of the TiO 2 @SSM membrane (microbubble flotation followed by separation has a flux of 369.3 L m −2 h −1 , and efficiency of 99.71 %). And the synergistic operation of separation and microbubble flotation can increase the flux to 451.6 L m −2 h −1 . The membrane showed outstanding stability and could be recycled for more than 20 times without significant deterioration, and demonstrated chemical stability for corrosion resistance test (pH 0–14). In addition, the membrane, which is easily modified with silver nanoparticles , achieves improved photocatalytic degradation properties (efficiency from 58.8 % to 88.7 %) and microbubble flotation effect (flux of 613.4 L m −2 h −1 ). This work provides a rational strategy for the preparation and optimization of inorganic functional membranes for effective emulsion separation and dye degradation, and demonstrates promising applications of the separation and purification in oil-containing sewage and wastewater remediation.
Wenjuan Wang,Yanfang Huang,Junpeng Zuo,Lulu Kou,Bingbing Liu,Hu Sun,Guihong Han
Microfine metal–organic frameworks (MOFs) are promising adsorbents for water treatment, but their commercial applicability is severely constrained by poor separability. Herein, we designed a feasible bubble flotation strategy for achieving the effective separation of oxyanions-loaded Fe-MOF particles in the solution after adsorption, by modifying the particle interface properties and introducing bubbles mineralization. The results showed that the separation of P(V), Mo(VI) and W(VI) oxyanions-loaded Fe-MOF could be completely achieved under optimum conditions. FTIR, XPS and DFT analyses revealed that the particle size and hydrophobicity of oxyanions-loaded Fe-MOF increased by sodium dodecyl sulfate (SDS) collector via chemisorption and electrostatic interactions. The collision and attachment models analysis of bubbles with particles demonstrated that the separation efficiencies of collector modified oxyanions-loaded Fe-MOFs were significantly enhanced with increasing bubble mineralization. EDLVO theoretical calculations and bubble-particle carrying ability analysis demonstrated that the gravitational interactions between oxyanions-loaded Fe-MOF particles and particles/bubbles were intensified by the collector. The gravitational interaction further induced particle aggregation and enhanced the carrying capacity of individual bubbles. This work provides a feasible strategy for the removal of oxyanions and the separation of oxyanions-loaded microfine Fe-MOF in the adsorption process.
Shengpeng Su,Yanfang Huang,Bingbing Liu,Guihong Han,Yubin Xue,Yizhuang Wang
Deep separation of low concentrations of molybdenum from tungstate solution has been a technical bottleneck in tungsten metallurgy and subsequent value-added utilization of tungsten products. A feasible strategy, named microbubble floating-extraction, was proposed and employed to achieve the high-efficiency and deep separation of molybdenum from tungstate solutions in this work. It was demonstrated that reagent mineralization is crucial for the formation of MoS42––N263 hydrophobic complexes, which is the rate-determining step of microbubble floating-extraction. Owing to the higher bubble and interface mass transfer rates, microbubble floating-extraction can achieve high-efficiency enrichment and deep separation of MoS42––N263 complexes with a large aqueous-to-oil phase ratio. The separation mechanisms of microbubble floating-extraction include the attachment process of MoS42––N263 hydrophobic complexes on the surface of rising microbubbles and the mass transfer process at the oil–water interface. Compared with solvent extraction, the flotation efficiency of molybdenum increases from 98.61 to 99.14%, while the loss rate of tungsten decreases from 3.31 to 2.12% under the optimal conditions. The microbubble floating-extraction exhibits significant advantages of high separation efficiency, a high enrichment coefficient, and low consumption of organic solvents.
Wang Hanyu,Su Shengpeng,Huang Yanfang,Liu Bingbing,Sun Hu,Han Guihong
Selective separation of dissolved tungsten and vanadium is of great significance for the utilization of the secondary resources of these elements. In this work, selective removal of vanadium from tungstate solutions via microbubble floating-extraction was systematically investigated. The results indicated that vanadium can be more easily mineralized over tungsten from tungstate solutions using methyl trioctyl ammonium chloride as mineralization reagent under weak alkaline conditions. Owing to the higher bubble and interface mass transfer rates, high-efficiency enrichment and deep separation of vanadium could be achieved easily. Additionally, the deep recovery of tungsten and vanadium from the floated organic phase could be easily realized using a mixed solution of sodium hydroxide and sodium chloride as stripping agents. The separation mechanism mainly included the formation of hydrophobic complexes, their attachment on the surface of rising bubbles, and their mass transfer at the oil-water interface. Under the optimal conditions, the removal efficiency of vanadium reached 98.5% with tungsten loss below 8% after two-stage microbubble floating-extraction. Therefore, the microbubble floating-extraction could be an efficient approach for separating selectively vanadium from tungstate solutions, exhibiting outstanding advantages of high separation efficiency and low consumption of organic solvents.
危险品化学品经营许可证（带存储）