Enhancement in hydrophilicity of different polymer phase-inversion ultrafiltration membranes by introducing PEG/Al2O3 nanoparticles

Engineering design of a biofilm formed on a pH-sensitive ZnO/PSf nanocomposite membrane with antibacterial properties

The interaction between the membrane and BSA at different pHs influences the biofilm formed on the membrane after which other filtration steps are performed in the presence of the engineered and pH sensitive membrane.

Influence of Reduced Cleaning-In-Place on Aged Membranes during Ultrafiltration of Whey

Optimization of cleaning-in-place (CIP) procedures using bench-scale equipment is severely restricted by the short testing times (typically 1–3 days) compared with the normal lifespans of industrial membrane materials (years). In our research, industrially used polyethersulfone membrane material (“aged membrane”) was migrated to a lab-scale filtration apparatus. Performance (flux) of aged membranes was found to be 10% lower compared to new membranes of the same specification. For each set of membranes, performance was on the same level during multiple filtrations with intermediate CIPs. Reducing the CIP from a three-step procedure (caustic, enzymatic, acid) to only one step (caustic) had no influence on subsequent filtration performance even though flux recovery after reduced CIP was as low as 38% compared to 90% after three-step CIP. Consequences of reduced cleaning could first be observed in the subsequent CIP where the level of resistance during the respective CIP steps was increased.

Microstructured Films Formed on Liquid Substrates via Initiated Chemical Vapor Deposition of Cross-Linked Polymers

We studied the formation of microstructured films at liquid surfaces via vapor phase polymerization of cross-linked polymers. The films were composed of micron-sized coral-like structures that originate at the liquid-vapor interface and extend vertically. The growth mechanism of the microstructures was determined to be simultaneous aggregation of the polymer on the liquid surface and wetting of the liquid on the growing aggregates. We demonstrated that we can increase the height of the microstructures and increase the surface roughness of the films by either decreasing the liquid viscosity or decreasing the polymer deposition rate. Our vapor phase method can be extended to synthesize functional, free-standing copolymer microstructured thin films for potential applications in tissue engineering, electrolyte membranes, and separations.

Treatment of table olive processing wastewaters using novel photomodified ultrafiltration membranes as first step for recovering phenolic compounds

Table olive processing wastewaters (TOPW) have high salt concentration and total phenolic content (TPC) causing many environmental problems. To reduce them, ultrafiltration (UF) was applied for treating TOPW. However, NaCl, which is the main responsible of salinity in TOPW, and phenols are small molecules that cannot be separated by conventional UF membranes. They have serious problems caused by fouling, which can be overcome using membrane modification techniques. For these reasons, photomodification may be an effective technique to obtain a stream rich in TPC due to the changes in membrane surface properties. UV-modification in the presence of two hydrophilic compounds (polyethylene glycol and aluminium oxide) was performed to achieve membranes with high reductions of organic matter and to keep the TPC as high as possible. Commercial polyethersulfone (PES) membranes of 30 kDa were used. Surface modification was evaluated using FTIR-ATR spectroscopy and membrane performance was studied by calculating the rejection ratios of colour, chemical oxygen demand (COD) and TPC. Results demonstrated that UF is a useful pre-treatment to reduce organic matter from TOPW, obtaining a permeate rich in TPC. PES/Al2O3 membranes displayed superior antifouling properties and rejection values, keeping high the TPC (>95%). Therefore, UF using modified membranes is an appropriate and sustainable technique for treating TOPW.

Use of CS–PAA nanoparticles as an alternative to metal oxide nanoparticles and their effect on fouling mitigation of a PSF ultrafiltration membrane

H-bonding between –SO group of PSF and –OH group of CS–PAA nanoparticles. Cross-linked CS–PAA nanoparticles were blended to prepare a hydrophilic PSF membrane.