Yi, Peng

In this research, a multistage (i.e., three stages) planar, and a tubular passive permeateside-heated interfacial solar membrane distillation (ISMD) has been developed. The three-stage system had an system energy efficiency of 62% in producing distilled water at an average daytime irradiance of 422 W/m2 with average distillate flux of 5 kg/(m2·day), which is higher than that of the single-stage planar systems. Production rate of distilled water in each stage of the three-stage planar system per unit area of footprint was 3.3 kg/(m2·day), while the production rate per unit area of footprint of single-stage system was 1.6 kg/(m2·day). Also, a hydrophilic nanoporous (PES NF) membrane was used in our study, which has not been found in the research of conventional MD systems. No penetration of hydrophilic nanoporous membrane was found during the operation of single-stage planar systems under simulated sunlight. The membrane was able to produce distilled water for 114 days under simulated sunlight using municipal wastewater as feed water. On the other hand, hydrophobic (0.20 and 0.45 μm) PVDF membranes were penetrated by feed water (i.e., wastewater) after approximately 50 days.

The Supported red blood cell membrane (SRBCm) was developed on a piezoelectric sensor to study the attachment of nanoparticles to erythrocyte surfaces. A well-dispersed colloidal suspension of fragments of RBCm was prepared from whole blood, and characterized thoroughly using cryogenic transmission electron microscopy, dynamic light scattering, and zeta potential analysis. To develop SRBCm, RBCm fragments were immobilized onthe sensor in a quartz crystal microbalance with dissipation monitoring system. A complete monolayer of flattened fragments of RBCm was formed on the positively charged surface of the piezoelectric sensor in 1 mM NaCl and 0.2 mM NaHCO3 at pH 7.1. The surface morphology of SRBCm was characterized via atomic force microscopy. The even distribution of surface proteins expressed on erythrocytes was found on SRBCm through indirect immunofluorescence microscopy. The attachment efficiencies of model nanoparticles, e.g. hematite nanoparticles and carboxylated polystyrene nanoparticles, on the SRBCm were quantified using a classic methodology.
KEYWORDS: Supported erythrocyte membrane, piezoelectric sensor, phospholipid bilayers, nanoparticles

Core-shell nanohybrids have wide applications in pollutant degradation. In this study, core-shell nanohybrid was formed through heteroaggregation between neutral nanoparticles (i.e., hematite nanoparticles or HemNPs) and charged nanoparticles (i.e., carboxylated polystyrene nanoparticles or PSNPs). In the dispersant solution of 1 mM NaCl at pH 6.3, HemNPs were neutral and underwent favorable homoaggregation, whereas PSNPs were negatively charged and underwent no homoaggregation. When the two types of particles were mixed, homoaggregation of HemNPs and heteroaggregation between HemNPs and PSNPs took place simultaneously, forming HemNPs-PSNPs heteroaggregates. The transmission electron microscopy images of heteroaggregates show that HemNPs and PSNPs formed core-shell structure in which HemNPs were the cores and PSNPs were the shells. The size of the core-shell nanohybrids can be controlled by varying the concentration ratio of HemNPs to PSNPs. The increase of the size of charged nanoparticles resulted in larger nanohybrids. This new method has lower energy footprint than existing ones.

In this research, a heat localizing solar thermal membrane distillation system has been developed for producing potable water from untreated surface water, wastewater, and seawater, using solely solar thermal energy. Unlike most other membrane technologies, this system requires no electrical power or equipment for its operation. The high production rate was achieved through the effective evaporation of water molecules within the pores of the membrane without dissipating much heat to the bulk feed water. It can remove suspending particles, microorganisms, inorganic salts, as well as organic contaminants from the feed water. The system can produce potable water for 32, 18, and 10 days on average under simulated sunlight when distilling seawater, canal water, and municipal wastewater, respectively, without cleaning the membrane. Low cost, high energy efficiency (i.e., 55%), and good water quality make the new system feasible for undeveloped areas where basic water treatment is lacking.