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Hongying Zhao

Publications and source records attributed to Hongying Zhao.

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Combining Transport of Pendular Water with Wind-Assisted Interfacial Evaporation for Dewatering of Concentrated Slurry Waste

Drying concentrated slurry waste is slow, particularly due to the entrapment and limited accessibility of water entrained between the particles in the slurry. A sailboat evaporator with a root-like structure is a new system that enables wind-assisted interfacial evaporation of concentrated particle slurries. In this work, we create access to the disconnected water pockets in concentrated slurry waste, facilitating faster water conduction and efficient evaporation at extremely high solid concentration. The evaporator's long roots effectively extracted water beneath 150 cm deep supernatant water layer. Through replantation of the evaporator to a separate location, an impressive evaporation rate (ER) of 4 kg/(m^2*h) close to 80 wt% solid concentration, a 25% increase to a non-replanted sample. Furthermore, long periods of efficient of evaporation was achieved even at high solid concentration through hydrodynamic flushing of roots. Outdoor experiments achieved substantial volumetric reduction, yielding dried residues with over 75 wt% solid concentration. These results underscore the system's reliable performance against highly concentrated slurries, yet to be by conventional industrial methods, including flocculation and tail-lift drying. The integration of renewable energy coupled with efficient enhancement techniques makes the sailboat evaporator a scalable and sustainable pathway for industrial wastewater dewatering.

physics.app-ph

Dissolution Dynamics of a Binary Switchable Hydrophilicty Solvent -- Polymer Drop into an Acidic Aqueous Phase

Switchable hydrophilicity solvents (SHSs) are solvents defined by their ability to switch from their hydrophobic form to a hydrophilic form when put in contact with an acidic trigger such as $CO_2$. As a consequence, SHSs qualify as promising alternatives to volatile organic compounds during the industrial solvent extraction processes, as greener and inexpensive methods can be applied to separate and recover SHSs. Furthermore, because of their less volatile nature, SHSs are less flammable and so increase the safety of a larger-scale extraction process. In this work, we study the dynamics and in-drop phase separation during the dissolution process of a drop composed of SHS and polymer, triggered by an acid in the surrounding aqueous environment. From 70 different experimental conditions, we found a scaling relationship between the drop dissolution time and initial volume with an overall scaling coefficient $\sim$ 0.53. We quantitatively assessed and found a shorter dissolution time related with a decrease in pH of the aqueous phase or an increase in initial polymer concentration in the drop. Examining the internal state of the drop during the dissolution revealed an in-drop phase separation behavior, resulting in a porous morphology of the final polymer particle. Our experimental results provide a microscopic view of the SHS dissolution process from droplets, and findings may help design SHS extraction processes for particle formation from emulsions.

cond-mat.soft