Irreversible protein fouling

The membranes remain positively charged over a pH of 3-10. In addition, the membranes show an improved capacity to reduce irreversible protein fouling [87]. 

For the conditions in Fig. 9, improvements of 35-50% in the permeate flux were observed when a secondary membrane was used, owing to a reduction in the protein fouling of the primary membrane. Little or no flux recovery was observed with each backpulse, as might be expected from the relatively low resistance of the yeast layer and the irreversible nature of the protein fouling. The flux continuously declined with time owing to irreversible fouling, though the rate of decline was reduced by the SMY. 

This hydrogel coating may penetrate the larger pores of the cellulose membrane and can exclude protein from entering them (100% protein retention). So, the hydrogel coating reduces the irreversible fouling of the cellulosic surface. 

Proteins and colloids Reversible adsorbed layer Transition from reversible to irreversible fouling... 

Hydrophobic membranes attracted a thicker irreversible adsorption layer than hydrophilic membranes [127, 128]. Hydrophilic membranes display low sorptivity for fouling macrosolutes such as proteins. In some situations, ionically charged membranes are more fouling-resistant than electroneutral membranes. The apparent high fouling-resistance of ceramic (alumina) membranes is worthy of special note, although the explanation of this... 

Calcium can be expected to create a more compact fouling layer and thus enhance flux decline. Malleviallc et al (1989) used various ME and UF membranes to evaluate the irreversible fouling of HS. Flux decreases of up to 90% were observed in the initial stages of filtration. An analytical scheme to analyse water and the deposit was established. Fouling could be linked to the organic matrix of HS, and carbohydrates, proteins, and polyhydroxy aromatic compounds were believed to be the major contributors. 

UF of BSA solutions membranes modified by NVP, AMPS, and AA showed high protein retention, high solution flux, and low irreversible fouling (Taiuguchi and Belfort 2004)... 

UF of pasteurized and homogenized milk with 3.2% protein and 1.5% fat antifouling properties flux recovery, irreversible flux loss, total flux loss, and fouling resistance of modified membranes were enhanced due to an increase in membrane hydrophilicity (Rahimpour et al. 2009)... 

UF PAN membranes. The coated membranes were immersed in isopropanol for 30 min and thereafter in a water bath. It was shown that during precipitation, the copolymer undergoes microphase separation, forming interpenetrating networks of PAN-rich and PEO-rich nanodomains. Transmission electron microscopy reveals that PEO domains act as water-permeable nanochannels and provide the size-based separation capability of the membrane. A small decline in flux (15%) was observed in a 24 h dead-end filtration experiment with 1 g/1 BSA solution using the modified membrane, while the base UF membrane lost 81% of its flux irreversibly in the same conditions. It was concluded that the PEO brush layer, formed on the membrane surface, acts as a steric barrier to protein adsorption, endowing these membranes with exceptional fouling resistance. 

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