RESUMEN

In this study, theoretical models for specific energy consumption (SEC) were established for water recovery in different integrated processes, such as RO-PRO, RO-MD and RO-MD-PRO. Our models can evaluate SEC under different water recovery conditions and for various proportions of supplied waste heat. Simulation results showed that SEC in RO increases with the water recovery rate when the rate is greater than 30%. For the RO-PRO process, the SEC also increases with the water recovery rate when the rate is higher than 38%, but an opposite trend can be observed at lower water recovery rates. If sufficient waste heat is available as the heat source for MD, the integration of MD with the RO or RO-PRO process can significantly reduce SEC. If the total water recovery rate is 50% and MD accounts for 10% of the recovery when sufficient waste heat is available, the SEC values of RO, RO-PRO, RO-MD and RO-MD-PRO are found to be 2.28, 1.47, 1.75 and 0.67 kWh/m3, respectively. These critical analyses provide a road map for the future development of process integration for desalination.

RESUMEN

The beneficial effects of Sr- and Mg-doped hydroxyapatite (HAp) on osteoblast proliferation and bone regeneration have been investigated in the past, and the antibacterial ability of Zn ions is well known. However, HAp coatings doped with these three elements via thermal spraying have not yet been investigated. In this study, HAp powder was synthesized at different pH values (4, 6, 8, and 10) and calcined at different temperatures (200, 400, 600, 800, and 1000 °C) to obtain HAp with the highest purity. Subsequently, strontium-, magnesium-, and zinc-doped HAp powders were synthesized at the optimal pH value and calcination temperature. The HAp powder was then coated onto Ti disks using atmospheric plasma spraying (APS) or vapor-induced pore-forming atmospheric plasma spraying (VIPF-APS) techniques at different working currents (350, 400, and 450 A) and spraying distances (10 and 15 cm). X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy equipped with energy-dispersive spectroscopy were used for material characterization to determine the optimal parameters. With these optimal coating parameters, HAp, Zn-HAp, SrMg-HAp, and ZnSrMg-HAp powders were deposited onto the Ti disks using VIPF-APS and named HAp-Ti, Zn-HAp-Ti, SrMg-HAp-Ti, and ZnSrMg-HAp-Ti, respectively. The in vitro bioactivity of these four groups was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and alkaline phosphatase (ALPase) activity assay. Besides, the antibacterial activities against Prevotella nigrescens, Porphyromonas gingivalis, and Fusobacterium nucleatum were assessed. The results showed that the purity of HAp synthesized at pH 10 and 800 °C was 98.40%. A porous coating without cracks was obtained at a 10 cm spraying distance and 400 A working current using VIPF-APS. SrMg-HAp-Ti and ZnSrMg-HAp-Ti resulted in higher osteoblast proliferation and ALPase activity than the control. Moreover, both Zn-HAp-Ti and ZnSrMg-HAp-Ti exhibited antibacterial activity against the three bacteria. Therefore, ZnSrMg-HAp has potential as a coating for biomedical materials due to its ability to reduce bacterial infection and enhance osseointegration.

Asunto(s)

Antibacterianos/farmacología , Atmósfera/química , Materiales Biocompatibles Revestidos/farmacología , Fusobacterium nucleatum/efectos de los fármacos , Porphyromonas gingivalis/efectos de los fármacos , Prevotella nigrescens/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Durapatita/química , Durapatita/farmacología , Magnesio/química , Magnesio/farmacología , Ensayo de Materiales , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Porosidad , Estroncio/química , Estroncio/farmacología , Propiedades de Superficie , Zinc/química , Zinc/farmacología

RESUMEN

We report on our use of a thin-layered vertical mesoporous silica thin film (MSTF) with tunable pore size overlaid on an anodic aluminum oxide (AAO) membrane for advancing water purification. The features of ultrathin thickness (about 20 nm), a uniform vertical pore orientation, low tortuosity, high porosity, and a hydrophilic surface endow the MSTF membranes with ultrahigh water permeability compared with that of state-of-the-art membranes. The modified E-MSTF membrane with a small pore diameter of 2.1 ± 0.1 nm demonstrates superior nanofiltration performance for dye molecules with a cutoff of 520 Da and ultrahigh water permeability of 310 ± 8 L m-2 h-1 bar-1. Furthermore, the precise molecular sieving of dye/salt mixtures was realized with outstanding salt permeation (97.5% NaCl, 96.0% Na2SO4) and a high retention of dye (99.0%). The water permeance and selectivity of the modified E-MSTF membrane are higher than that of reported membranes with similar dye rejections. This work opens up new avenues for constructing tailor-made membranes with tunable pore size and remarkable separation performance.