Supplementation of tea polyphenols in sludge Fenton oxidation improves sludge dewaterability and reduces chemicals consumption.

The Fenton oxidation improves sludge dewatering but faces notable technical and economic challenges, including a narrow acidic pH range, slow reduction of Fe(III), and the use of high doses of chemicals. Herein, we used a natural polyhydroxyphenol tea polyphenols (TP), as an iron redox conversion enhancer, to mitigate these issues. Compared with the classical Fenton process at pH 3.

Moringa oleifera-derived coagulants for water treatment: Floc structure, residual organics, and performance trade-offs.

The study explored the suitability of unfractionated extracts from the seeds of the Moringa oleifera tree as a coagulant for water treatment. The coagulant was obtained by soaking crushed and sieved seeds in a low salinity aqueous solution: a simple and inexpensive alternative to conventional coagulants in settings where specialized expertise and equipment are lacking. The performance of M.

Attachment of human adenovirus onto household paints.

Attachment of human adenovirus 40 (HAdV40) onto surfaces coated with three compositionally different household paints was evaluated experimentally and interpreted based on measured physicochemical properties of the paints. Polar, dispersive and electrostatic interactions between HAdV40 and the paints were predicted using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) model. Quartz crystal microbalance (QCM-D) was used to quantify virus attachment to paints from 1 mM and 150 mM NaCl solutions, with the latter having the ionic strength of a typical respiratory fluid.

Microfiltration of saline crude oil emulsions: Effects of dispersant and salinity.

Dispersants reduce oil-water interfacial tension making the separation of oil-water emulsions challenging. In this study, crude oil stabilized by the dispersant, Corexit EC9500A, was emulsified in synthetic sea water using a range of Corexit/crude oil concentration ratios (up to 10% by volume). With an interfacial tension of only 8.

Virus recovery by tangential flow filtration: A model to guide the design of a sample concentration process.

A simple model is developed to describe the instantaneous (r ) and cumulative (R ) recovery of viruses from water during sample concentration by tangential flow filtration in the regime of constant water recovery, r. A figure of merit, M = r r, is proposed as an aggregate performance metric that captures both the efficiency of virus recovery and the speed of sample concentration. We derive an expression for virus concentration in the sample as a function of filtration time with the rate-normalized virus loss, , as a parameter.

Lip balm drying promotes virus attachment: Characterization of lip balm coatings and XDLVO modeling.

Hypothesis: Drying-induced decrease in lip balm surface energy enhances virus adhesion due to the emergence of strong hydrophobic colloid-surface interactions.

Experiments: A protocol was developed for preparing lip balm coatings to enable physicochemical characterization and adhesion studies. Surface charge and hydrophobicity of four brands of lip balm (dry and hydrated) and human adenovirus 5 (HAdV5) were measured and used to calculate the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) energy of interactions between lip balm coatings and HAdV5 as well as four other colloids: HAdV40, MS2 and P22 bacteriophages, and SiO.

Fabrication and characterization of polysulfone reinforced hollow fibre membrane.

In this study, reinforced hollow fibre membranes were fabricated using different molecular weights of polyvinylidene prolidone (PVP Mw: 10, 40 and 360 kDa) and different take-up speeds (1, 2, 2.6 and 3.5 m/min).

Oil droplet behavior on model nanofiltration membrane surfaces under conditions of hydrodynamic shear and salinity.

Hypotheses: Oil droplet stability and electrical charge, and membrane's affinity for oil govern droplet attachment to a membrane surface. Moderate droplet-surface affinity encourages surface coalescence and removal of droplets to help maintain the membrane relatively oil-free.

Experiments: Droplet attachment onto model nanofiltration membranes was studied, in situ and in real time, using the Direct Observation Through the Membrane method.

Membrane-based separation for oily wastewater: A practical perspective.

The large volumes of oily wastewater generated by various industries, such as oil and gas, food and beverage, and metal processing, need to be de-oiled prior to being discharged into the environment. Compared to conventional technologies such as dissolved air flotation (DAF), coagulation or solvent extraction, membrane filtration can treat oily wastewater of a much broader compositional range and still ensure high oil removals. In the present review, various aspects related to the practical implementation of membranes for the treatment of oily wastewater are summarized.

Virus deposition onto polyelectrolyte-coated surfaces: A study with bacteriophage MS2.

Hypotheses: By selecting constituent polyelectrolytes and controlling conditions of their deposition, the resulting polyelectrolyte multilayers can be designed as surface coatings with controlled adhesive properties with respect to viruses. Charge and hydrophilicity of the polyelectrolyte multilayers govern virus adhesion.

Experiments: Four surfaces of different charges and hydrophobicities were designed using a layer-by-layer assembly of poly(styrene-4-sulfonate) and poly(dimethyl diallyl ammonium chloride).

Charge, size distribution and hydrophobicity of viruses: Effect of propagation and purification methods.

Two virus propagation methods (in broth and on double agar overlay) and three purification procedures (PEG precipitation, centrifugal diafiltration and CsCl density gradient centrifugation) were comparatively evaluated using MS2 and P22 bacteriophages as model viruses. The prepared stocks were characterized in terms of electrophoretic mobility as a function of pH, particle size distribution, surface tension components and the overall hydrophobicity of the virus, as well as the percentage of infectious and total virus recovered. The obtained data were used to rank the purification methods according to six criteria of likely practical relevance.

Diversity of DNA viruses in effluents of membrane bioreactors in Traverse City, MI (USA) and La Grande Motte (France).

This study assesses diversity of DNA viruses in the effluents of two membrane bioreactor (MBR) wastewater treatment plants (WWTPs): an MBR in the United States and an MBR in France. Viral diversity of these effluents is compared to that of a conventional activated sludge WWTP in the U.S.

Elution Is a Critical Step for Recovering Human Adenovirus 40 from Tap Water and Surface Water by Cross-Flow Ultrafiltration.

Unlabelled: This paper examines the recovery of the enteric adenovirus human adenovirus 40 (HAdV 40) by cross-flow ultrafiltration and interprets recovery values in terms of physicochemical interactions of virions during sample concentration. Prior to ultrafiltration, membranes were either blocked by exposure to calf serum (CS) or coated with a polyelectrolyte multilayer (PEM). HAdV 40 is a hydrophobic virus with a point of zero charge between pH 4.

Effect of pressure relaxation and membrane backwash on adenovirus removal in a membrane bioreactor.

Pressure relaxation and permeate backwash are two commonly used physical methods for membrane fouling mitigation in membrane bioreactor (MBR) systems. In order to assess the impact of these methods on virus removal by MBRs, experiments were conducted in a bench-scale submerged MBR treating synthetic wastewater. The membranes employed were hollow fibers with the nominal pore size of 0.

Adsorption of Anionic or Cationic Surfactants in Polyanionic Brushes and Its Effect on Brush Swelling and Fouling Resistance during Emulsion Filtration.

Atom transfer radical polymerization of ionic monomers from membrane surfaces yields polyelectrolyte brushes that swell in water and repel oil droplets to resist fouling during filtration of oil-in-water emulsions. However, surfactant adsorption to polyelectrolyte brushes may overcome this fouling resistance. This work examines adsorption of cationic and anionic surfactants in polyanionic brushes and the effect of these surfactants on emulsion filtration.

Polymer nanocomposites with graphene-based hierarchical fillers as materials for multifunctional water treatment membranes.

Phase inversion of polymer casting mixtures filled with hierarchical functional nanostructures is proposed as a synthetic route for the design of multifunctional membranes. The study tested the hypothesis that by regulating the relative content of components representing different levels in the nanofiller hierarchy, the structure and additional functions of such membranes could be controlled separately. Exfoliated graphite nanoplatelets (xGnPs) decorated by Au nanoparticles (Au NPs), used as a model hierarchical nanofiller, were added to the casting mixture of polysulfone, N-Methyl-2-pyrrolidone and polyethylene glycol prior to forming the membrane by phase inversion.

Single-walled carbon nanotubes dispersed in aqueous media via non-covalent functionalization: effect of dispersant on the stability, cytotoxicity, and epigenetic toxicity of nanotube suspensions.

As the range of applications for carbon nanotubes (CNTs) rapidly expands, understanding the effect of CNTs on prokaryotic and eukaryotic cell systems has become an important research priority, especially in light of recent reports of the facile dispersion of CNTs in a variety of aqueous systems including natural water. In this study, single-walled carbon nanotubes (SWCNTs) were dispersed in water using a range of natural (gum arabic, amylose, Suwannee River natural organic matter) and synthetic (polyvinyl pyrrolidone, Triton X-100) dispersing agents (dispersants) that attach to the CNT surface non-covalently via different physiosorption mechanisms. The charge and the average effective hydrodynamic diameter of suspended SWCNTs as well as the concentration of exfoliated SWCNTs in the dispersion were found to remain relatively stable over a period of 4 weeks.

Interactions of aqueous NOM with nanoscale TiO2: implications for ceramic membrane filtration-ozonation hybrid process.

The combined effect of pH and calcium on the interactions of nonozonated and ozonated natural organic matter (NOM) with nanoscale TiO2 was investigated. The approach included characterization of TiO2 nanoparticles and NOM, extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) modeling of NOM-TiO2 and NOM-NOM interactions, batch study on the NOM adsorption onto TiO2 surface, and bench-scale study on the treatment of NOM-containing feed waters using a hybrid process that combines ozonation and ultrafiltration with a 5 kDa ceramic (TiO2 surface) membrane. It was demonstrated that depending on pH and TiO2 loading, the adsorption of NOM species is controlled by either the availability of divalent cations or by preozonation of NOM.

Pore blocking mechanisms during early stages of membrane fouling by colloids.

A method based on a simple linear regression fitting was proposed and used to determine the type, the chronological sequence, and the relative importance of individual fouling mechanisms in experiments on the dead-end filtration of colloidal suspensions with membranes ranging from loose ultrafiltration (UF) to nanofiltration (NF) to non-porous reverse osmosis (RO). For all membranes, flux decline was consistent with one or more pore blocking mechanisms during the earlier stages and with the cake filtration mechanism during the later stages of filtration. For ultrafiltration membranes, pore blocking was identified as the largest contributor to the observed flux decline.

Ordered adsorption of coagulation factor XII on negatively charged polymer surfaces probed by sum frequency generation vibrational spectroscopy.

Electrostatic interactions between negatively charged polymer surfaces and factor XII (FXII), a blood coagulation factor, were investigated by sum frequency generation (SFG) vibrational spectroscopy, supplemented by several analytical techniques including attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), quartz crystal microbalance (QCM), zeta-potential measurement, and chromogenic assay. A series of sulfonated polystyrenes (sPS) with different sulfonation levels were synthesized as model surfaces with different surface charge densities. SFG spectra collected from FXII adsorbed onto PS and sPS surfaces with different surface charge densities showed remarkable differences in spectral features and especially in spectral intensity.

Stable colloidal dispersions of C60 fullerenes in water: evidence for genotoxicity.

Stable aqueous suspensions of colloidal C60 fullerenes free of toxic organic solvents were prepared by two methods: ethanol to water solvent exchange (EthOH/nC60 suspensions) and extended mixing in water (aqu/nC60 suspensions). The extended mixing method resulted in the formation of larger (dp approximately 178 nm) and less negatively charged (zeta approximately -13.5 mV) nC60 colloids than nC60 prepared by ethanol to water solvent exchange (dp approximately 122 nm, zeta approximately -31.

Effect of Collision Efficiency on the Evolution of the Surface of Diffusion-Limited Deposits.

The effect of the collision efficiency of particles deposited onto a rough substrate and the evolution of the deposit profile were investigated using 2D on-lattice Monte Carlo simulations. The case of a diffusive long-range transport regime as representative of the colloidal deposition from the suspended phase was considered. The initial profile of the substrate was modeled as a sinusoidal wave.