Prediction of single salt rejection in nanofiltration membranes by independent measurements

Silva, Verónica; Montalvillo, Miguel; Carmona, Francisco javier García; Palacio, Laura; Hernández, Antonio; Prádanos, Pedro

doi:10.1016/j.desal.2015.12.012

Cited by 22 publications

(18 citation statements)

References 55 publications

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“…A Nanoscope Multimode IIIa scanning probe microscope from Digital Instruments (Veeco Metrology Inc., USA) was used, following the method described elsewhere [19]. The calculated values of surface roughness were averaged over 5 different profiles for each membrane sample using a scanning area of 1×1 μm 2 .…”

Section: Atomic Force Microscopy (Afm)mentioning

confidence: 99%

Assessing the ageing process of cation exchange membranes in bioelectrochemical systems

San-Martín

Carmona

Alonso

et al. 2019

International Journal of Hydrogen Energy

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Bioelectrochemical systems (BES) encompass a group of biobased technologies capable of directly converting organic matter into electricity. In these systems, which are derived from conventional electrochemical technologies, the ion exchange membrane represents a key element because of its influence on the economic feasibility and on the performance of BES. This study examines the impact of long-term operation of a BES on the mechanical, chemical and electrochemical properties of five different kind of cation exchange membranes (Nafion-117, CMI-7001, Zirfon UTP 500, FKE and FKB) through several techniques: (i) scanning electron microscopy (SEM) and atomic force microscopy (AFM) to assess the changes on the membranes surface, (ii) thermogravimetric analysis (TGA) to evaluate the structural stability of the membranes, and (iii) ion exchange capacity (IEC) to monitor any change in their electrochemical properties. Results confirmed that there is not an ideal membrane for BES. While Nafion and CMI-7000 exhibited the strongest chemical structure, they also underwent the highest fouling as revealed by a fast increase in surface roughness.

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Section: Atomic Force Microscopy (Afm)mentioning

confidence: 99%

Assessing the ageing process of cation exchange membranes in bioelectrochemical systems

San-Martín

Carmona

Alonso

et al. 2019

International Journal of Hydrogen Energy

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“…The dominance of the shielding phenomenon is found for all types of membranes for all salt concentrations and types. This phenomenon has been previously investigated in the literature by many researchers (Labban, Liu, Chong, Lienhard, & J. H., 2017; Nicolini, Borges, & Ferraz, 2016; Silva et al, 2016). According to the shielding effect, for any charged membrane surface when it meets counterions, these ions then diminish or reduce the membrane surface charge.…”

Section: Resultsmentioning

confidence: 78%

Synthesis, characterization, and performance analysis of carbon molecular sieve‐embedded polyethersulfone mixed‐matrix membranes for the removal of dissolved ions

Qadir

Nasir

Mukhtar

et al. 2020

Water Environment Research

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The asymmetric polyethersulfone (PES‐15 wt.%) mixed‐matrix membranes were prepared by incorporation of carbon molecular sieve (CMS) with varying concentrations (1, 3, and 5 wt.%). Physicochemical characterization of synthesized membranes was carried out using field emission scanning electron microscope, atomic force microscopy, contact angle, thermogravimetric analysis, zeta potential analyzer, porosity, and mean pore sizes. Performance analysis of synthesized mixed‐matrix membranes was carried out by varying the operating parameters such as pressure (2–10 bar), feed concentration (100–1,000 mg/L), and cations type (Na+, Ca2+, Mg2+, and Sn2+). Effect of operating parameters and CMS concentration was investigated on pure water flux (PWF), permeate flux, and rejection of membranes. It was found that mixed‐matrix membrane containing 15 wt.% PES with 1 wt.% CMS displayed the superior physicochemical characteristics in terms of hydrophilicity (37.9°), surface charge (−13.8 mV), mean pore diameter (6.04 nm), and thermal properties (Tg = 218.5°C), and overall performance. E5C1 membrane showed 1.5 times higher PWF (75.5 L m−2 hr−1) and incremented in rejection for all salts than the nascent membrane. Practitioner points Carbon molecular sieve‐embedded mixed‐matrix membranes were synthesized by phase inversion method. The resultant membranes experienced improved hydrophilicity, roughness, surface charge, porosity, and mean pore diameter with 1 wt.% CMS loading. The pure water flux was improved from 55.77 to 75.05 L m−2 hr−1 when 1 wt.% CMS was added in pure PES. The observed rejection of a mixed‐matrix membrane with 1 wt.% CMS was the maximum for all salts.

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“…AFM images were obtained using a Nanoscope Multimode IIIa ® from Digital Instruments (Veeco Metrology Inc., Santa Barbara, CA, USA) in the tapping mode, in accordance with the methods described elsewhere [25]. Roughness and power spectral density (PSD) were analyzed using the NanoScope Software Version 5.30 (Veeco Metrology Inc., Santa Barbara, CA, USA).…”

Section: Methodsmentioning

confidence: 99%

Morphological, Electrical, and Chemical Characteristics of Poly(sodium 4-styrenesulfonate) Coated PVDF Ultrafiltration Membranes after Plasma Treatment

et al. 2019

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A commercial ultrafiltration (UF) membrane (HFM-183 de Koch Membrane Systems) made of poly(vinylidene fluoride) (PVDF), was recovered with a negatively-charged polyelectrolyte (poly(sodium 4-styrenesulfonate)) (PSS), and the effects on its electric, chemical, and morphological properties were analyzed. Atomic force microscopy (AFM), liquid–liquid displacement porometry, Electrical Impedance Spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to investigate the modifications induced by the deposition of PSS on the PVDF positively-charged membrane and after its treatment by a radio frequency Ar-plasma. These techniques confirmed a real deposition and posterior compaction of PSS with increasing roughness and decreasing pore sizes. The evolution of the electric resistances of the membranes confirmed crosslinking and compaction with shielding of the sulfonated groups from PSS. In this way, a membrane with a negatively-charged active layer and a pore size which was 60% lower than the original membrane was obtained. The composition of the additive used by manufacturers to modify PVDF to make it positively charged was obtained by different procedures, all of which depended upon the results of X-ray photoelectron spectroscopy, leading to fairly consistent results. This polymer, carrying positive charges, contains quaternary nitrogen, as confirmed by XPS. Moreover, Raman spectroscopy confirmed that PVDF changes from mostly the β to the α phase, which is more stable as a substrate for the deposited PSS. The aim of the tested modifications was to increase the retention of divalent anions without reducing permeability.

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Prediction of single salt rejection in nanofiltration membranes by independent measurements

Cited by 22 publications

References 55 publications

Assessing the ageing process of cation exchange membranes in bioelectrochemical systems

Assessing the ageing process of cation exchange membranes in bioelectrochemical systems

Synthesis, characterization, and performance analysis of carbon molecular sieve‐embedded polyethersulfone mixed‐matrix membranes for the removal of dissolved ions

Morphological, Electrical, and Chemical Characteristics of Poly(sodium 4-styrenesulfonate) Coated PVDF Ultrafiltration Membranes after Plasma Treatment

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