Membrane fouling assessed from a fundamental standpoint within the context of the Derjaguin-Landau-Verwey-Overbeek (DLVO) model. The DLVO model requires that the properties of the membrane and foulant(s) be quantified. Membrane surface charge (zeta potential) and free energy values are characterized using streaming potential and contact angle measurements, respectively. Comparing theoretical as...

The present work aims to ascertain the mechanisms of surfactant (dodecylbenzene sulfonate; DBS) effects on the aggregation behaviors of TiO2 nanoparticles (TiO2-NPs) in natural water samples. Aggregation experiments were conducted at a TiO2-NPs concentration of 10mg/L in deionized water and in natural water samples via dynamic light scattering and Zeta potential determination. Average attachmen...

A typical dense non-Brownian particulate suspension exhibits shear thinning (decreasing viscosity) at low rate or stress followed by a Newtonian plateau (constant intermediate values which transitions to thickening (increasing beyond critical value and finally undergoes second transition extremely high values. In this study, we unify quantitatively reproduce all the disparate rate-dependent reg...

This study aimed to clarify the mechanism of effect surface charge clay particles on separation pressure between adjacent frozen particles. A general mathematical model spherical was given based extended colloidal stability (DLVO) theory; it introduced into frost heave process, and functional expression freezing temperature derived by using relationship pore throat’s radius temperature, which v...

Bacterial cells and other biological particles carry charged macromolecules on their surface that form a "soft" ion-permeable layer. In this paper, we test the applicability of an electrokinetic theory for soft particles to characterize the electrophoretic mobility (EPM) and adhesion kinetics of bacterial cells. The theory allows the calculation of two parameters--the electrophoretic softness a...

Accumulation at the air-water interface of four bacterial strains with different hydrophobicities was studied. To exclude system influences, both a static batch system and a dynamic system involving rising bubbles were used. All bacteria accumulated at the air-water interface in both systems. Generally, attachment to the air-water interface increased with bacterial surface hydrophobicity. Accum...

Chemical reactions can be described by an energy diagram along a reaction coordinate in which an activation barrier limits the rate at which reactants can be transformed into products. This reaction impedance can be overcome by reducing the magnitude of the barrier through the use of catalysis, increasing the thermal energy of the system, or through macroscopic mechanical processes. Here, we de...

The activated sludge (AS) flocculability markedly improved after the addition of Al(3+) and Fe(3+) compared to Ca(2+) at a concentration of 2 mEq/L. Though the energy barrier decreased about 30% when Ca(2+) was added, the AS flocculability did not improve substantially. This indicates that extended DLVO theory can explain AS flocculation with Al(3+) and Fe(3+) as additives but is not appropriat...

This is a review of physical, chemical, and biological processes governing microbial transport in the saturated subsurface. We begin with the conceptual models of the biophase that underlie mathematical descriptions of these processes and the physical processes that provide the framework for recent focus on less understood processes. Novel conceptual models of the interactions between cell surf...

An important quality of yeast cell wall is the ability to adhere to other cell walls or solid surfaces. This feature of yeast is responsible for technologically important phenomena such as flocculation at the end of beer fermentation and cell adhesion to immobilization supports e.g. spent grains, DEAE-cellulose etc. Physicochemical properties of yeast surfaces, e.g. hydrophobicity and surface c...