Functional Modification of Cellulose Acetate Microfiltration Membranes by Supercritical Solvent Impregnation.

Irena Zizovic,Lidija Senerovic,Ivana Moric,Konrad Matyja,Marcin Tyrka,Anna Trusek

doi:10.3390/molecules26020411

Abstract

This study investigates the modification of commercial cellulose acetate microfiltration membranes by supercritical solvent impregnation with thymol to provide them with antibacterial properties. The impregnation process was conducted in a batch mode, and the effect of pressure and processing time on thymol loading was followed. The impact of the modification on the membrane’s microstructure was analyzed using scanning electron and ion-beam microscopy, and membranes’ functionality was tested in a cross-flow filtration system. The antibiofilm properties of the obtained materials were studied against Staphyloccocus aureus and Pseudomonas aeruginosa, while membranes’ blocking in contact with bacteria was examined for S. aureus and Escherichia coli. The results revealed a fast impregnation process with high thymol loadings achievable after just 0.5 h at 15 MPa and 20 MPa. The presence of 20% of thymol provided strong antibiofilm properties against the tested strains without affecting the membrane’s functionality. The study showed that these strong antibacterial properties could be implemented to the commercial membranes’ defined polymeric structure in a short and environmentally friendly process.

Highlights

Supercritical solvent impregnation (SSI) is an advanced technique for impregnating solid matrices with active substances soluble in the supercritical fluid [1,2,3]
This study aimed to prove the feasibility of adding antibacterial properties to commercial cellulose acetate (CA) membranes as polymeric forms with defined structures by the SSI with thymol
The experiments were performed in five replicates, with a standard deviation that can be considered low (Figure 1, Table A1)

Summary

Introduction

Supercritical solvent impregnation (SSI) is an advanced technique for impregnating solid matrices with active substances soluble in the supercritical fluid [1,2,3]. In SSI, a supercritical solution of the active substance is brought into contact with the substrate in a batch or semi-continuous process. The absence of surface tension in the supercritical state allows for easy penetration of the fluid into the solid matrix and its impregnation [2]. The process is environmentally friendly, with no waste generation, and is energy-efficient [1,2]. One of the advantages of SSI over other impregnation and encapsulation techniques is the possibility of delivering active substances throughout the whole volume of finished polymeric forms, e.g., SSI of hip and knee endoprosthesis with α-tocopherol [1,4]

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Conclusion