A review of water treatment membrane nanotechnologies

Nanotechnology is being used to enhance conventional ceramic and polymeric water treatment membrane materials through various avenues. Among the numerous concepts proposed, the most promising to date include zeolitic and catalytic nanoparticle coated ceramic membranes, hybrid inorganic-organic nanocomposite membranes, and bio-inspired membranes such as hybrid protein-polymer biomimetic membranes, aligned nanotube membranes, and isoporous block copolymer membranes. A semi-quantitative ranking system was proposed considering projected performance enhancement (over state-of-the-art analogs) and state of commercial readiness. Performance enhancement was based on water permeability, solute selectivity, and operational robustness, while commercial readiness was based on known or anticipated material costs, scalability (for large scale water treatment applications), and compatibility with existing manufacturing infrastructure. Overall, bio-inspired membranes are farthest from commercial reality, but offer the most promise for performance enhancements; however, nanocomposite membranes offering significant performance enhancements are already commercially available. Zeolitic and catalytic membranes appear reasonably far from commercial reality and offer small to moderate performance enhancements. The ranking of each membrane nanotechnology is discussed along with the key commercialization hurdles for each membrane nanotechnology.This publication is based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST), in addition to the NSF Graduate Research Fellowship, UCLA Cota Robles Fellowship, and the UCLA Faculty Women’s Club Russell and Sallie O’Neill Memorial Scholarship

Role of specific ion interactions in seawater RO membrane fouling by alginic acid

Organic fouling plagues many environmental membrane processes. In this study, well-controlled laboratory experiments were performed to elucidate seawater RO membrane fouling by alginic acid. Interfacial free energies derived from multiple probe liquid contact angle analyses (including different seawater matrices) correlated strongly with the rates of membrane fouling. More importantly, the Lewis acid−base interfacial free energy quantitatively described the impacts of calcium-carboxylate complex formation and predicted membrane fouling and cleaning behavior. Calcium ions made polyamide composite RO membranes (and alginic acid) more hydrophobic, enhanced the rate and extent of flux decline, and reduced the effectiveness of chemical cleaning. The implications for seawater RO membrane fouling are clear. Selective removal of calcium ions via pretreatment can reduce the gel forming ability of carboxylate rich biomacromolecules and, hence, the extent to which they foul RO membranes. In addition, RO membranes should be produced with smooth, hydrophilic interfaces comprising monopolar electron-donor functionality and no carboxylic acid residue. More broadly, this paper presents a facile approach for quantifying the impacts of specific ion interactions on aquatic colloid stability, aggregation, and deposition

Dispersion and stability optimization of TiO2 nanoparticles in cell culture media

Accurate evaluation of engineered nanomaterial toxicity requires not only comprehensive physical−chemical characterization of nanomaterials as produced, but also thorough understanding of nanomaterial properties and behavior under conditions similar to those used for in vitro and in vivo toxicity studies. In this investigation, TiO2 nanoparticles were selected as a model nanoparticle and bovine serum albumin (BSA) was selected as a model protein for studying the effect of protein−nanoparticle interaction on TiO2 nanoparticle dispersion in six different mammalian, bacteria, and yeast cell culture media. Great improvement in TiO2 dispersion was observed upon the addition of BSA, even though the degree of dispersion varied from medium to medium and phosphate concentration in the cell culture media was one of the key factors governing nanoparticle dispersion. Fetal bovine serum (FBS) was an effective dispersing agent for TiO2 nanoparticles in all six media due to synergistic effects of its multiple protein components, successfully reproduced using a simple “FBS mimic” protein cocktail containing similar concentrations of BSA, γ-globulin, and apo-transferrin

Biomems and nanotechnology-based approaches for rapid detection of biological entities

In recent years, the areas of Bio-Microelectromechanical Systems (BioMEMS) and nanotechnology have gained a high level of prominence and have become almost inseparable with biological applications including detection, diagnostics, therapeutics and tissue engineering. This article reviews some of the current state-of-the-art interdisciplinary research from these fields, especially focusing on rapid detection of pathogens and microorganisms, a critical area of importance to food safety, clinical diagnostics and related applications