Centrifugal reverse osmosis (CRO) − a novel energy-efficient membrane process for desalination near local thermodynamic equilibrium

Near dissolved organic matter microfiltration (NDOM MF) coupled with UVC LED disinfection to maximize the efficiency of water treatment for the removal of Giardia and Cryptosporidium

Microfiltration (MF) membranes with a mean pore size same as or smaller than 0.45 µm have been typically used to separate pathogenic protozoa in water since materials larger than 0.45 µm are considered particulates. However, 0.45 µm is too small to separate protozoa which are 4-6 µm (Cryptosporidium oocyst) or 8-15 µm (Giardia cyst) in size. In this study, we optimized the mean pore size of MF membranes to maximize the producibility and guarantee a high removal rate simultaneously and proposed the membrane filtration using an MF membrane with an optimum mean pore size larger than but close to dissolved organic matter (DOM), which is called near DOM MF (NDOM MF). According to the MF test using polystyrene surrogate beads with diameters of 3 and 8 µm, an MF membrane with a 0.8 µm mean pore size was the best in that it showed 52% to 146% higher water fluxes than a 0.45 µm MF membrane while maintaining the removal rate at 3-4 log. It was also the case for a low-temperature MF test, revealing the NDOM MF is highly effective regardless of temperature changes. Lastly, we tried to find the possibility of combining the NDOM MF with disinfection by an ultraviolet light emitting diode (UVC LED) to further guarantee the high quality of treated water while providing high process efficiency.

Hybrid superhydrophobic/hydrophilic patterns deposited on glass by laser-induced forward transfer method for efficient water harvesting

In recent years, the combination of factors such as growing population and global climate change has resulted in freshwater shortages. Therefore, water harvesting from the atmospheric fog in order to produce freshwater supply inspired by nature has received much attention. The water harvesting capability of the creatures is significantly based on the combination of both wettability states on their surfaces. In this study, a facile physicochemical hybrid method was used for the fabrication of glass surfaces with contrast wettability. First, fractal and regular repeated geometric patterns were deposited on a glass substrate using brass sheet as donor material by laser induced forward transfer (LIFT) method. Subsequently, stearic acid (SA) treatment was used to convert the wettability of the superhydrophilic (SHL) deposited patterns on glass to superhydrophobic. In order to investigate the effect of the shape of designed patterns on glass surfaces in the water harvesting efficiency, the amount of collected water for a period of time from untreated hydrophilic (HL) glass, superhydrophobic (SHB) glass and hybrid superhydrophobic/hydrophilic (SHB-HL) surfaces were measured. The obtained results indicate that the hybrid of superhydrophobic and hydrophilic regions and selecting the optimal pattern can improve the water harvesting performance by up to 300%.