查看更多>>摘要：In recent years, the development of porous materials with excellent reactivity and absorption properties has attracted significant attention. We fabricated poly(lactic acid) (PLA) microfibers with uniform nanopores via a one-step rotary centrifugal spinning method using a PLA/chloroform solution. To evaluate the solvent stability of the nanoporous microfibers, vapor annealing was performed with three different organic solvents, and the structural changes and oil adsorption abilities of the nanoporous PLA fibers before and after solvent vapor annealing were systematically evaluated. The results showed that acetone or ethanol vapor annealing induced internal structural changes in the nanoporous PLA microfibers, but did not affect the nanoporous structure. Furthermore, we demonstrated that the nanoporous PLA fibers fabricated in this study had a high oil absorption capacity of up to 26.78 g/g, and that the acetone or ethanol vapor annealed fibers could maintain almost the same absorption capacity. Therefore, the nanoporous PLA fibers prepared using the proposed one-step centrifugal spinning method have a high potential as environmentally friendly biodegradable filters or high-absorption materials.
查看更多>>摘要：Membrane distillation (MD) is increasingly regarded as a promising technique for brine management and zero liquid discharge (ZLD) disposal of seawater and brackish water owing to its excellent effluent quality and higher salt tolerance. However, membrane fouling issues of MD, especially scaling, have been confirmed as a crucial challenge impeding its large-scale utilization. Presently, the scaling issue of conventional membrane-based desalination techniques including reverse osmosis (RO) and ultrafiltration (UF), has been effectively controlled via the usage of antiscalants. Hence, this work applied three representative antiscalants of 2-phospho-nobutane-l,2,4-tricarboxylic acid (PBTCA), diethylene diamine penta methylene phosphonic acid (DTPMPA), and polymaleic acid (HPMA) in MD devices to restrain the scaling of polytetrafluoroethylene (PTFE) membrane during the ZLD treatment of synthetic brackish water. Furthermore, influences of antiscalant presence on variations of feed water qualities and the corresponding biofilm formation were also comprehensively studied via the high throughput sequencing method of 16S rDNA and 16S rRNA as well as a confocal laser scanning microscopy (CLSM). Compared to DTPMPA (77.4%-97.8%) and HPMA (42.1%-97.8%), a higher anti-scaling efficiency was obtained for PBTCA (90.6%-98.1%) in MD system, while the membrane biofilm formed in PBTCA group exhibited a remarkable appearance of live cells (14.046 μm~3/μm~2). The secondary fouling of phosphate scale and pore wetting might be induced by the utilization of DTPMPA in MD plants, sharply increasing the effluent conductivity to 176.4 μS/cm (12 d). Comparatively, HPMA could be largely combined with salt ions to form loose slags with good fluidity, promoting the reuse of MD membranes and the subsequent disposal of MD brine.
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