The Influence of Graphene Addition on the Properties of Composite rGO/PAN Membranes and Their Potential Application for Water Disinfection

Abstract

The paper presents a method of obtaining composite polyacrylonitrile-based (PAN) membranes with the addition of reduced graphene oxide (rGO). The membranes were obtained using phase inversion method from a homogeneous rGO dispersion in a solution of PAN dissolved in N, N-dimethylformamide (DMF). The impact of the amount of rGO addition to the PAN matrix on the physicochemical, structural, transport, and separation properties and on fouling resistance was studied. Composite membranes, due to the method of preparation used and the addition of rGO, are characterized by very good transport properties (~390 L/m2 h) and by a high degree of protein retention (85%). Reduced graphene oxide has biocidal properties, which, as we have shown, depend on the size of nanoparticles and the type of microorganism. rGO/PAN membranes, on the other hand, show biostatic properties against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcuc aureus) and fungi (Candida albicans). Thus, the obtained composite membranes can be potentially used in water disinfection.

Investigation of membrane fouling using molecular dynamics simulation

“…The resultant flat substrate PAN membrane has dimensions of approximately 80 Å length by 80 Å width by 22 Å depth. The final density of the PAN membrane is around 1.14 g/cm 3 , which is close to experimental value of 1.18 g/cm 3 [314].…”

Membranas de matriz mista Polisulfona/GRAFENO para remoção de contaminante emergente

“…Figura5.3(a), (b), (c), (d), mostram a estrutura assimétrica, o que é consistente com outros estudos que caracterizaram a morfologia de membranas desta natureza (Fryczkowska et al, 2020;Jiang et al, 2019;Ravishankar, Christy e Jegatheesan, 2018). Analisando as imagens da superfície das membranas pode-se observar uma morfologia de superfície lisa e uniforme, que muda para cada membrana em razão da carga adicionada.…”

“…Por outro lado, tem-se reconhecido em muitas investigações que a cristalização do polímero é fortemente influenciada pela presença de nanocarga, pois o tamanho nanométrico dos enchimentos leva ao aumento da área interfacial, criando assim uma fração de volume significativa de cadeias poliméricas "interfaciais" que podem cristalizar sob confinamento (Fryczkowska et al, 2020;Winey e Vaia, 2007). Cabe enfatizar que além do tamanho e formato das nanopartículas, um efeito significativo no confinamento da cristalização advém da quantidade de carga e a dispersão das nanopartículas dentro da matriz polimérica.…”

“…Quanto maior a carga de partículas, menor é a distância entre as partículas vizinhas, o que leva a um maior impedimento estérico no processo de cristalização (Fryczkowska et al, 2020).…”

Nanocomposite Cellulose Fibres Doped with Graphene Oxide and Their Biocidal Properties

“…Thanks to its specific structure, graphene oxide has a number of interesting properties. The most important of them are bactericidal and fungicidal properties, used in many composite materials, such as fibres or membranes [ 12 , 13 , 14 ]. In general, the development of antimicrobial activity for GO proceeds in three steps: (1) Deposition of nanosheets on the bacterial surface, (2) membrane disruption by sharp nanosheets, and (3) the ensuing superoxide anion-independent oxidation [ 15 , 16 ].…”