NOM Accumulation at NF Membrane Surface: Impact of Chemistry and Shear

The effects of solution chemistry, surface shear, and composition of natural organic matter (NOM) were investigated for their impact on accumulation of foulant material at the surface of charged polymeric nanofiltration membranes. The source of NOM was the Suwannee River. A bench-scale, batch recycle system was used with 20 hollow fiber, nanofiltration membranes. Membrane flux decline and foulant accumulation increased at low pH and high ionic strength as a result of neutralization of charge, electric double layer compression, and the apparent shift in conformation of charged NOM macromolecules. The rate of NOM accumulation decreased with operating time, suggestive of an eventual steady state between adsorption and desorption. The effect of NOM composition on membrane fouling could not be discerned by a standard technique to isolate hydrophobic and hydrophilic NOM fractions, quite possibly because of the fractionation methodology's failure to recover a small but important fouling fraction or because of NOM interactions that are lost when individual fractions are separately tested. However, a greater percentage of the hydrophilic than hydrophobic fraction permeated the membrane, in agreement with prior observations by others. Increasing the cross flow velocity from 85 to 255 cm∕s reduced the extent of flux decline, presumably due to hydrodynamic disruption of cake layer formation.     

Investigation on fouling mechanisms for recombinant human growth hormone sterile filtration

During sterile filtration of recombinant human growth hormone solutions, severe membrane fouling was experienced compared to other protein preparations of significantly higher molecular weights and concentrations. This phenomenon was attributed to rhGH aggregation/adsorption occurring in the filter pore. To better understand this phenomenon, we examined several possible fouling mechanisms: (1) pore constriction, (2) adsorption due to nonspecific binding between protein and the membrane, (3) shear-induced adsorption, (4) hydrophobic interface-induced aggregation/adsorption. The protein solutions were sterily filtered using 0.22 mm filters, and their filtration fluxes were monitored. Filtration on the capillary and the noncapillary filters suggested that constraints by pore constriction and tortuosity played only a limited role. Filtration using filters with different degrees of protein binding tendency suggested that nonspecific adsorption was insignificant. The shear stress acting on the protein during filtration was small. RhGH which was intentionally sheared in a high-speed concentrically rotating device did not aggravate fouling tendency, suggesting that the shear-induced adsorption might not be the major fouling mechanism. The dynamic light scattering data showed a trace amount of rhGH aggregates always present in equilibrium with the hydrophobic (air-water and membrane-water) interface. These aggregates tended to be adsorbed to the membrane, and more aggregates were generated presumably due to the equilibrium between aggregates and protein monomers. This adsorption/aggregation process eventually fouled the membrane. When the hydrophobic interface was occupied by surfactant molecules, the equilibration kinetics ceased to generate aggregates, thereby minimizing membrane fouling. This study clarified the cause of such an unusual fouling phenomenon upon microfiltration.     

Use of Iron Oxides to Enhance Metal Removal in Crossflow Microfiltration

This research investigated whether iron oxyhydroxides used in conjunction with microfiltration could improve the removal of metals from a waste while maintaining adequate flux. Filtration of individual metals, a mixture of metals, and the mixture with two iron oxides were investigated. The research indicated that use of a coagulant (an iron-containing salt) might not be as important in microfiltration systems as in conventional gravity separation systems, because of the small pore size of microfilters. In some cases, filtration efficiency was relatively poor at the beginning of a treatment cycle, but in almost all cases it became excellent once a layer had built up on the membrane surface. The greatest benefit provided by iron oxides might be to reduce membrane fouling. A crystalline iron oxide such as goethite is more attractive than ferrihydrite. The flux improvement with goethite is greatest if a thin layer is deposited on the membrane surface before the contaminant metals are injected into the system, so that the goethite can trap the potentially foulant metal hydroxide particles away from the membrane surface.     

Removal of 17β Estradiol and Fluoranthene by Nanofiltration and Ultrafiltration

With the recent emergence of endocrine disrupting compounds as an important potable drinking water and reclaimed wastewater quality issue, the removal of two estrogenic compounds (17β-estradiol and fluoranthene) by nanofiltration and ultrafiltration membranes was investigated. A less hydrophobic organic compound model species [parachlorobenzoic acid (PCBA)] was tested. 17β-estradiol (E2), fluoranthene, and PCBA were applied to the membrane in the presence and absence of natural organic matter (NOM). Both batch adsorption and dead-end stirred-cell filtration experiments indicated that adsorption is an important mechanism for transport/removal of relatively hydrophobic compounds, and is related to the octanol-water partition coefficient (KOW) values. All filtration measurements were performed approximately the same permeate flow rate in order to minimize artifacts from concentration polarization varied with different hydrodynamic operating conditions at the membrane interface. The percent removal by dead-end stirred-cell filtration ranged from 10 to >95% depending upon membrane pore size/hydrophobicity and presence/absence of NOM at an initial concentration ranging from 0.1 to 0.5 μM. Additional batch adsorption experiments with radio-label (3H) E2 at lower concentrations ranging 0.025 to 5 nM showed that E2 removal due to adsorption was independent of its initial concentration. Adsorption occurs both on the membrane surface and interior membrane pore surfaces. However, adsorption was insignificant for PCBA (log?KOW = 2.7), but removal presumably occurred due to electrostatic exclusion. Partition coefficients (log?K) of 0.44 to 4.86 measured in this study increased with log?KOW and membrane pore size.     

Immunoglobulin E, viral antibodies and obstructive lung disease in adults. The relation between antibody level in serum, lung function and non-specific bronchial reactivity

The electrophoretic mobilities of DNA molecules in three different molecular weight ladders were measured in polyacrylamide gels containing different acrylamide concentrations (%T) and cross-linker ratios (%C), cast and run in Trisacetate-EDTA (TAE) buffer. The apparent pore radius of each gel was estimated from Ferguson plots of the relative mobilities of each of the DNA molecules, using the mobility of the monomer fragment in each molecular weight ladder as the reference mobility. The effective size of each of the DNA molecules was estimated from its radius of gyration. The apparent gel pore radii calculated in this manner ranged from 21 nm in gels containing 10.5%T, 5%C to 200 nm in gels with 4.6%T, 2%C, similar to the values observed for polyacrylamide gels cast and run in Tris-borate-EDTA (TBE) buffer (Holmes and Stellwagen, Electrophoresis 1991, 12, 612-619). Hence, the effective pore size of polyacrylamide gels is essentially independent of whether the gels are cast and run in TAE or TBE buffer.     

Removal of Copper Ions from Waters Using Surfactant-Enhanced Hybrid PAC/MF Process

This paper deals with the removal of copper ions from aqueous solutions by using surfactant-enhanced powdered activated carbon (PAC)/microfiltration (MF) hybrid process, including the evaluation of process performance and fouling dynamics at various linear alkyl benzene sulfonate (LABS), PAC, and Cu2+ concentrations of feed solution. Although the use of surfactant as an additive material increased the adsorption efficiency in PAC/MF hybrid process, a considerable amount of the flux was lost for surfactant concentration above critical micelle concentration. The process could be employed with a performance of 74.7%, 97.2% and 87?L/m2?h for LABS rejection, Cu2+ rejection and permeate flux at the conditions of 2?g PAC/L, 5?mM LABS, 0.2?mM Cu2+, and 60-min process time. Cu2+ rejection, which increased with increasing of LABS, and PAC amounts decreased with the increase in Cu2+ concentration. It was understood that the increments in LABS, PAC, and Cu2+ concentrations being an indicator for the feed solution quality led to the occurrence of more fouling on the membrane. The analyses of dynamics concerning the fouling behaviors, which were carried out using single and combined pore blocking models, put forward that the cake formation was the main predominant mechanism in the process. It was also determined that the variation of feed contents deduced the presence of rather complex fouling behaviors as a simultaneous function of secondary membrane layer formation and clogging and narrowing of membrane pores by surfactants.     

Management of adrenal cysts

Electrophoretic mobility data of SR vesicles reconstituted with uncharged and two mixtures of charged and uncharged lipids (Brethes, D., Dulon, D., Johannin, G., Arrio, B., Gulik-Krzywicki, T., Chevallier, J. 1986. Study of the electrokinetic properties of reconstituted sarcoplasmic reticulum vesicles. Arch. Biochem. Biophys. 246:355-356) were analyzed in terms of four models of the membrane-water interface: (I) a smooth, negatively charged surface; (II) a negatively charged surface of lipid bilayer covered with an electrically neutral surface frictional layer; (III) an electrically neutral lipid bilayer covered with a neutral frictional layer containing a sheet of negative charge at some distance above the surface of the bilayer; (IV) an electrically neutral lipid bilayer covered with a homogeneously charged frictional layer. The electrophoretic mobility was predicted from the numerical integration of Poisson-Boltzmann and Navier-Stokes equations. Experimental results were consistent only with predictions based on Model-III with charged sheet about 4 nm above the bilayer and frictional layer about 10 nm thick. Assuming that the charge of the SR membrane is solely due to that on Ca++-ATPase pumps, the dominant SR protein, the mobility data of SR and reconstituted SR vesicles are consistent with 12 electron charges/ATPase. This value compares well to the net charge of the cytoplasmic portion of ATPase estimated from the amino acid sequence (-11e). The position of the charged sheet suggests that the charge on the ATPase is concentrated in the middle of the cytoplasmic portion. The frictional layer of SR can be also assigned to the cytoplasmic portion of Ca++-ATPase. The layer has been characterized with hydrodynamic shielding length of 1. 1 nm. Its thickness is comparable to the height of the cytoplasmic portion of Ca++-ATPase.     

New General Pore Size Distribution Model by Classical Thermodynamics Application: Activated Carbon

A model is developed using classical thermodynamics to characterize pore size distributions (PSDs) of materials containing micropores and mesopores. The thermal equation of equilibrium adsorption (TEEA) is used to provide thermodynamic properties and relate the relative pore filling pressure of vapors to the characteristic pore energies of the adsorbent/adsorbate system for micropore sizes. Pore characteristic energies are calculated by averaging of interaction energies between adsorbate molecules and adsorbent pore walls as well as considering adsorbate-adsorbate interactions. A modified Kelvin equation is used to characterize mesopore sizes by considering variation of the adsorbate surface tension and by excluding the adsorbed film layer for the pore size. The modified-Kelvin equation provides similar pore filling pressures as predicted by density functional theory. Combination of these models provides a complete PSD of the adsorbent for the micropores and mesopores. The resulting PSD is compared with the PSDs from Jaroniec and Choma and Horvath and Kawazoe models as well as a first-order approximation model using Polanyi theory. The major importance of this model is its basis on classical thermodynamic properties, less simplifying assumptions in its derivation compared to other methods, and ease of use.     

Impact of Membrane Surface Modification on the Treatment of Surface Water

New polyethersulfone (PES) based membranes for ultrafiltration (UF) were developed by blending a surface-modifying macromolecule (SMM) in the casting solution, in an attempt to minimize the impact of fouling. Fouling was evaluated using concentrated Ottawa River water (CORW), either unfractionated or fractionated via UF. These membranes also included some polyvinylpyrrolidone (PVP), a pore forming additive. A statistical analysis was conducted to evaluate the impact of some variables on the treatment of the surface water. The independent variables included PVP/PES ratio in the casting solution, with and without SMM, and the nature of the feed CORW [low molecular weight (LMW) fraction, unfractionated, high molecular weight (HMW) fraction]. The performance variables studied were total organic carbon (TOC) removal, the foulant accumulation at the membrane surface after filtration, the flux reduction, and the final permeate flux. The most important variable was the feed water. Filtration of LMW had a higher final flux, less fouling, but slightly lower TOC removal. The SMM did not significantly impact the membrane performance. TOC removal was high, compared with results reported in the literature for UF membranes.     

Geographic factors and plasma selenium in uremia and dialysis

The effects of the adsorption of the fluorescent potential-sensitive dyes RH-421, RH-237 and RH-160 on the bilayer lipid membrane were studied. It was shown that a dipole potential drop, positive in the hydrophobic part of the membrane, arose due to the dye adsorption. The dye adsorption led to a considerable increase of the rate constant of hydrophobic anion translocation through the membrane, but did not affect their partition coefficient between membrane and water. It implies that the region of the membrane where the potential drops is located deeper than the adsorption plane of hydrophobic ions. The values of boundary potential differences were estimated by two independent methods with unilateral and bilateral application of the dyes to lipid bilayer membranes. The results suggest that RH dye molecules penetrate through the lipid bilayers. The values of zeta-potential in liposomes did not change on dye adsorption. Hence, dye molecules are adsorbed in a form that does not change the surface charge. We estimated the effects of electric field of dye dipole layer on an individual dipole located in the same layer and on ion transport through a membrane protein Na+/K+-ATPase. It turned out that the local electric field of each dye dipole decayed so rapidly that a neighbouring dye molecule did not feel it. It also appeared that RH dyes could have but a minor effect on the electrogenic transport performed by the sodium pump in the examined range of dye concentrations.     

Metallic porous supports and ceramic interface layer development for H2 separation membranes

Abstract

Hydrogen separation membranes are typically composed of three components: the porous support (ceramic or metallic, as studied in the present work), the porous ceramic interface layer and the hydrogen selective dense layer (usually Pd or a Pd based alloy). The development of a good support and an appropriate ceramic interface layer is a key issue in the high performance membrane manufacturing process. Metallic supports specifically developed for this application have yet to be developed; those used have different features and are manufactured for applications such as filtering devices. There is a clear need to develop porous supports for hydrogen separation membranes that have good surface quality (roughness and pore size) to allow the deposition of a thin selective layer (typically of Pd). In addition, the development of the ceramic layer is of importance, to allow the deposition of a Pd continuous layer of minimum thickness to increase hydrogen permeation and decrease manufacturing costs by minimising use of expensive Pd. The development and characterisation of a thin Pd–Ag membrane deposited by PVD on a composite metallic–ceramic porous support is reported. The surface properties of AISI 316L and nickel supports were improved and the interdiffusion of Pd and Ag was avoided by deposition of an yttria stabilised zirconia (YSZ) layer by dip coating of nanosized YSZ powders.     

Use of Dubinin–Astakhov Equation to Describe Preloading Effect of Natural Organic Matter

This note presents a simple model to quantify the preloading effect of naturally occurring organic matter (NOM) in water on the adsorption capacity of activated carbon for a trace synthetic organic chemical (SOC). The model was developed from the Dubinin–Astakhov (DA) equation based on the assumption that the NOM preloading irreversibly reduced the limiting adsorption pore volume for the target SOC. Given that the DA-n value equal to one, the model reduces to a form similar to the one obtained by modifying the Freundlich equation directly. By assuming that the reduction of the limiting adsorption pore volume was proportional to the volume of NOM adsorbed, the NOM preloading effect was correlated directly to the amount of total organic carbon preloaded on the carbon. The resulting model was then compared with the experimental data in the literature. This simple model may be useful for certain practical applications that require only the estimation of the NOM preloading effect on the adsorption capacity of a target SOC from natural water.     

Membrane Fouling in Membrane Bioreactors for Wastewater Treatment

Membrane bioreactors (MBRs), in which membranes are applied to biological wastewater treatment for biomass separation, provide many advantages over conventional treatment. However, membrane fouling in MBRs restricts their widespread application because it reduces productivity and increases maintenance and operating costs. Recently much research and development has taken place to investigate, model, and control membrane fouling processes. However, unified and well-structured theories on membrane fouling are not currently available because of the complexity of the biomass matrix, which is highly heterogeneous and includes living microorganisms. Membrane fouling in MBR systems can be reversible (i.e., removable by physical washing) or irreversible (removable by chemical cleaning only), and can take place on the membrane surface or into the membrane pores. Although establishing a general model to describe membrane fouling in such a process is made extremely difficult by the inherent heterogeneity of the system, the nature and extent of fouling in MBRs is strongly influenced by three factors: biomass characteristics, operating conditions, and membrane characteristics. Fouling control techniques which have been investigated include low-flux operation, high-shear slug flow aeration in submerged configuration, periodical air or permeate backflushing, intermittent suction operation or addition of powdered activated carbon (PAC). Of these, only PAC addition is currently not used in existing large-scale installations.     

Diffusion and relaxation in interface layers of crystals in nanoporous glass

Below the freezing point, experimental data provide evidence for the existence of a non-frozen interface layer (NFL) between the crystal in the pore and the pore walls. The molecules in this layer are effectively confined in a quasi-two-dimensional space that forces them to reorient when moving along the curved pore surface. Through this relaxation mechanism, the translational mobility in the unfrozen phase reveals itself in a pronounced frequency dependence of the spin-lattice relaxation time. The experimentally observed drop of the self-diffusion coefficients by more than one order of magnitude below the phase transition can be interpreted in terms of geometric restrictions as well as interactions with the surface.     

Annexin V and vesicle membrane electroporation

The method of membrane electroporation (ME) has been used as an analytical tool to quantify the effect of membrane curvature on transient electric pore formation, and on the adsorption of the protein annexin V (M(r)= 35,800) to the outer surface of unilamellar lipid vesicles (of radii 25 < or = a/nm < or = 200). Relaxation kinetic studies using optical membrane probes of the diphenylhexatriene type suggest that electric pore formation is induced by ionic interfacial polarization causing entrance of the (more polarizable) water into the lipid bilayer membrane yielding (hydrophobic and hydrophilic) pore states with a mean stationary pore radius rp = 0.35 (+/-0.05) nm. Extent and rate of ME, compared at the same induced transmembrane voltage, were found to decrease both with increasing vesicle radius and with increasing protein concentration. This 'inhibitory' effect of annexin V is apparently allosteric and saturates at about [ANT]sat = 4 microM annexin V for vesicles of a = 100 nm at 1 mM total lipid concentration, 0.13 mM total Ca2+ concentration and at T = 293 K. Data analysis in terms of Gibbs area-difference-elasticity energy suggests that the bound annexin V reduces the gradient of the lateral pressure across the membrane. At [ANT]sat, about 20% of the vesicle surface is covered by the bound protein, but it is only 0.01% of the surface of the outer lipid leaflet in which a part of the protein, perhaps the aromatic residue of the tryptophan (W 187), is inserted. Insertion leads to a denser packing of the lipid molecules in the outer membrane leaflet. As a consequence, the radius of the electropores in the remaining membrane part, not covered by annexin V decreases (rp/nm = 0.37, 0.36 and 0.27) with increasing adsorption of the protein ([ANT] = 0, 2 and 4 microM, respectively).     

Investigative study into the hydrodynamics of heap leaching processes

Three mathematical models (mixed side-pore diffusion (MSPD) and profile side-pore diffusion (PSPD) with uniform or distributed pore lengths) are derived in dimensionless form to simulate the transport of solutes through the flowing channels and the stagnant pores of an unsaturated heap. Model parameters are determined from experimental tracer residence-time distributions using the least-squares minimization approach. It is shown that the residence-time distribution curves display a long tail resulting from the very slow mass transfer (or diffusion) into the 1- to 6-cm-long stagnant pores, which take up 5 times more space than the flowing liquid. The very large coefficients of determination (R ²>0.99) confirm the validity of all models and especially that of the PSPD model with a distributed pore length. The effects of five factors (agglomeration, addition of binder, particle size, solution flow rate, and bed height) are examined. Data from experimental residence-time distributions prove that the advection time is directly proportional to the column height and inversely proportional to the flow rate. The two estimated parameters (stagnant liquid holdup and pore length) are only marginally affected by any change in crush size, agglomeration technique, or operating conditions. This, in turn, suggests that the model can predict and/or simulate the hydrodynamic behavior in taller columns and, possibly, heaps.     

Isolation and characterization of S-layer proteins from a vent prosthecate bacterium

MWapp 116,000 and 29,000 proteins (p116 and p29), major outer membrane proteins of Hyphomonas jannaschiana reproductive cells, were extracted from cell envelopes by dialysis against EDTA, 2 M urea or distilled water. These proteins were precipitated by divalent cations and resolubilized by EDTA-Na, reflecting alternate monomer, multimer states. From two-dimensional gel electrophoresis it was determined that p116 and p29 had a pl of 4.5. Both were glycoproteins. Results suggest that p116 and p29 are surface layer (S-layer) proteins, with p116 a tetramer of the p29. The S-layer could protect the adherent H. jannaschiana reproductive cell from exoenzyme activity, antibiotics and other bacteriocidal molecules produced in the bacterial films formed on many marine surfaces.     

Fasciola gigantica: studies of the tegument as a basis for the developments of immunodiagnosis and vaccine

The tegument of bile-dwelling Fasciola gigantica is the interfacing layer that helps the parasite to maintain its homeostasis, and evade the hostile environment, including the host's immune attacks. The tegument is a syncytial layer about 10 mm thick, that is formed by the fusion of cytoplasmic processes of tegument cells, whose soma lie underneath the two muscle layers. The surface of the tegument is highly folded and invaginated into numerous ridges, pits and spines, which help to increase the surface area of the tegument for the absorption and exchanging of molecules, as well as for attachment. The outer membrane covering the tegument is a trilaminate sheet about 12 nm thick, and coated with a carbohydrate-rich glycocalyx layer that also bears high negative charges. Some host molecules may also be adsorbed onto this layer. These unique characteristics enable the parasite to evade the antibody-dependent cell-mediated cytotoxicity (ADCC) reaction exerted by the host. The outer membrane and glycocalyx is continuously replaced by the reserved membrane synthesized and stored in secretory granules of tegument cells, that are transported via cell processes towards the tegument by microtubules. The basal membrane of the tegument is trilaminate and invaginated to form membrane infoldings with closely aligned mitochondria. The tegument cytoskeleton is composed of a highly cross-linked network of 4-6 nm knobby microtrabecular fibers, bundles of intermediate filaments, microtubules that splay out from the tegument cells' processes. Major proteins of the cytoskeleton are actin, paramyosin and tubulin. The flukes' antigens that can elicit strong immunological responses in animal hosts are synthesized and released mainly from the tegument and the cecum. The majority of antigens derived from the surface membrane and the tegument are of MW 97, 66, 58, 54, 47 and 14 kDa, while those released from the cecum are cysteine proteases of MW 27, 26 kDa. Monoclonal antibodies have been raised against some of these antigens, and have been employed in immunodiagnosis of the infection. From the protection conferred to animal models and the in vitro killing assays of young parasites by specific antibodies, candidate vaccines could be selected from these antigens, such as, an antioxidant enzyme, glutathione-S-transferase, the digestive enzyme cysteine proteases, the surface-tegument proteins, such as fatty acid binding protein (14 kDa), membrane proteins (at 66 kDa), as well as muscle protein paramyosin, and hemoprotein. Ongoing research have been directed at deciphering the genetic codes and the syntheses of some of these antigens by recombinant DNA technology.     

Velocity Pulse Model for Turbulent Diffusion from Flowing Water into a Sediment Bed

The “velocity pulse model” simulates the transfer of turbulence from flowing water into a sediment bed, and its effect on the diffusional mass transfer of a solute (e.g., oxygen, sulfate, or nitrate) in the sediment bed. In the “pulse model,” turbulence above the sediment surface is described by sinusoidal variations of vertical velocity in time. It is shown that vertical velocity components dampen quickly inside the sediment when the frequency of velocity fluctuations is high and viscous dissipation is strong. Viscous dissipation (ν) inside the sediment is related to the apparent viscosity depending on the structure of the sediment pore space, i.e., the porosity and grain diameter, as well as inertial effects when the flow is turbulent. A value ν/ν0 between 1 and 20 (ν0 is kinematic viscosity of water) has been considered. Turbulence penetration into the sediment is parametrized by the Reynolds number Re = UL/ν and the relative penetration velocity W/U, where U=amplitude of the velocity pulse; and W=penetration velocity; L = WT=wave length of the velocity pulse; and T is its period. Amplitudes of vertical velocity components inside the sediment and their autocorrelation functions are computed, and the results are used to estimate eddy viscosity inside the sediment pore system as a function of depth. Diffusivity in the sediment pore system is inferred by using turbulent or molecular Schmidt numbers. Turbulence penetration from flowing water can enhance the vertical diffusion coefficient in a sediment bed by an order of magnitude or more. Penetration depth of turbulence is higher for low frequency velocity pulses. Vertical diffusivity inside the pore system is shown to decrease more or less exponentially with depth below the sediment/water interface. Vertical diffusivities in a sediment bed estimated by the “velocity pulse model” can be used in pore water quality models to describe vertical transport from or into flowing surface water. The analysis has been conducted for a conservative material, but source and sink terms can be added to the vertical transport equation.     

Impacts of Hydrophilic Membrane Additives on the Ultrafiltration of River Water

One of the most serious disadvantages of membrane applications in water treatment is the decreasing water permeation rate with time, which is often called fouling. This study investigates surface modification of polyethersulfone (PES) ultrafiltration membranes as a fouling reduction strategy for drinking water treatment applications. Surface modification was achieved through the addition of three different tailor-made hydrophilic surface modifying macromolecules (LSMM200, LSMM400, and LSMM600). Flat sheet membranes were prepared via a single-step casting procedure; their surface hydrophilicity was quantified via contact angle measurements. The incorporation of hydrophilic additives produced slightly more hydrophilic membranes (contact angle reduction of up to 8°) and improved membrane performance compared with the PES membrane without blending. In the treatment of highly colored river water, LSMM400- and LSMM600-modified membranes achieved up to 32% higher final fluxes. Surface modification resulted in significantly decreased flux reductions and natural organic matter accumulation. Dissolved organic carbon removals were approximately 70% for all the membranes studied. No clear correlation between membrane hydrophilicity and fouling reduction was observed.