Morphological, chemical and electrical characterization of a family of commercial nanofiltration polyvinyl alcohol coated polypiperazineamide membranes

Abstract

Three AFC membranes from PCI, of the thin film composite (TFC) nanofiltration type, have been characterized by using XPS, AFM, Contact angles, Zeta potential and permeation experiments. This plethora of complimentary methods portrays a deep and exhaustive description of these membranes.Morphological properties, including porosity, water permeability, fractal dimension, Wenzel parameter and roughness, correlate well with pore sizes. While functional characteristics as, for example wettability correlate well with the O/N ratio. Increasing O/N ratios should be interpreted as caused by increasing PVA coverages.The charge on the membrane's surface is ordered in a different way for different pH but are quite similar anyway. The effect of charges on retention of 1:1, 1:2 and 2:1 salts (as tested with: NaCl, Na2SO4 and CaCl2) increases with increasing O/N and wettability. Consequently, the trend of salt retentions can be explained in terms of the PVA coverage and the details of the amphoteric behavior of the three AFC membranes studied.

A Durable Fluorine‐Free MOF‐Based Self‐Cleaning Superhydrophobic Cotton Fabric for Oil‐Water Separation

“…Superhydrophobic surface with a water contact angle above 150° and a sliding hysteresis angle below 10° has gained tremendous attention for their multifunctional applications, such as self‐cleaning, [ 1–4 ] oil‐water separation, [ 5–7 ] drag reduction, [ 8 ] corrosion protection, [ 9,10 ] ice‐phobicity, [ 11,12 ] anti‐fouling, [ 13,14 ] and microfluidic devices. [ 15,16 ] Being inspired by the superhydrophobic surfaces in nature including lotus leaf, geckos, and rose petals, both the surface roughness and low‐surface energy molecules are summarized to be the key factors to form a superhydrophobic surface by a classical Wenzel and Cassie model.…”

Nature-Inspired Hierarchical Protrusion Structure Construction for Washable and Wear-Resistant Superhydrophobic Textiles with Self-Cleaning Ability

“…Superhydrophobic surface with a water contact angle (WCA) greater than 150° and a sliding hysteresis angle (SHA) below 10° plays a significant role in interfacial applications due to its extreme wettability, self-cleaning ability, − oil–water separation, − ocean drag reduction, metal corrosion protection, , ice-phobicity, , and microfluidic properties. , Being inspired by the superhydrophobic phenomenon in nature such as lotus leaf, geckos, water striders, rose petals, etc., two fundamental factors are found to be indispensable to design an artificial superhydrophobic surface for potential applications. Summarized by the classical Wenzel and Cassie model, both the surface roughness and surface wettability are highly related with the prosperity of hydrophobic.…”

Boosting the Performance of Nanofiltration Membranes in Removing Organic Micropollutants: Trade-Off Effect, Strategy Evaluation, and Prospective Development

“…96−98 The active layers of some membranes (AFC30, AFC40, NTR7250, and NTR-729HF) were further modified by poly(vinyl alcohol) (PVA) on the basis of PA chemistry according to the manufacturers. 37,44,46,51,63 Figure 1 displays the A/B OMP values, obtained experimentally, of these commercial NF membranes for various OMPs, in which the membranes and OMPs were classified into groups according to the MWCO of membranes and MW of OMPs, respectively, by considering the predominant role of steric exclusion in OMP rejection. The median A/B OMP value was given to indicate the general performance of each membrane in removing OMPs, which was however dependent on the number and molecular properties of the involved OMPs.…”

“…Five of the membranes (N30F, NFPES10, NTR7450, NTR7410, and HYDRACoRe 50) were made of poly­(ether sulfone) (PES) or sulfonated PES, ,,,,− ,, and the others were all TFC membranes mainly composed of a fully aromatic or semiaromatic PA selective layer atop a porous substrate. The PA layer was synthesized via the IP reaction between m -phenylenediamine (MPD) or piperazine (PIP) as aqueous monomers and trimesoyl chloride (TMC) as organic monomers. − The active layers of some membranes (AFC30, AFC40, NTR7250, and NTR-729HF) were further modified by poly­(vinyl alcohol) (PVA) on the basis of PA chemistry according to the manufacturers. ,,,, …”