Desalination Characteristics of Cellulose Acetate FO Membrane Incorporated with ZIF-8 Nanoparticles

Abstract

Forward osmosis membranes have a wide range of applications in the field of water treatment. However, the application of seawater desalination is restricted, so the research of forward osmosis membranes for seawater desalination poses new challenges. In this study, zeolitic imidazolate framework-8 (ZIF-8) was synthesized by a mechanical stirring method, and its crystal structure, surface morphology, functional group characteristics, thermochemical stability, pore size distribution and specific surface area were analyzed. The cellulose acetate (CA)/ZIF-8 mixed matrix forward osmosis membrane was prepared by using the synthesized ZIF-8 as a modified additive. The effects of the additive ZIF-8 content, coagulation bath temperature, mixing temperature and heat treatment temperature on the properties of the CA/ZIF-8 forward osmosis membrane were systematically studied, and the causes were analyzed to determine the best membrane preparation parameters. The structure of the CA membrane and CA/ZIF-8 mixed matrix forward osmosis membranes prepared under the optimal conditions were characterized by Fourier Transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), contact angle and Atomic force microscope (AFM). Finally, the properties of the HTI membrane (Membrane manufactured by Hydration Technology Innovations Inc.), CA forward osmosis membrane and CA/ZIF-8 mixed matrix forward osmosis membrane were compared under laboratory conditions. For the CA membrane, the water flux and reverse salt flux reached 48.85 L·m−2·h−1 and 3.4 g·m−2·h−1, respectively. The reverse salt flux and water flux of the CA/ZIF-8 membrane are 2.84 g·m−2·h−1 and 50.14 L·m−2·h−1, respectively. ZIF-8 has a promising application in seawater desalination.

Biopolymer-Based Films Reinforced with Green Synthesized Zinc Oxide Nanoparticles

“…However, upon the incorporation of ZnO-NPs into the CA-based film, its surface character changed from hydrophilic to hydrophobic, since the WCA increased to 92.1, indicating the hydrophobicity of ZnO-NPs. Similar results have been reported regarding the contribution of nanoparticles that lead to the enhancement of the hydrophobicity or impairment of the hydrophilicity of the membrane surfaces with increasing WCA values [ 73 ], such as the incorporation of silica nanoparticles (Si-NPs) into CA/CH-based films (CA/CH-Si) [ 79 ], and Cu-NPs into CA-based films [ 80 ]. On the other hand, the CH-based neat film seemed to be more hydrophilic, with the WCA ≈ 74.2°.…”

“…The WCA of the food packaging films is used to determine the wettability of the film surface and evaluate its hydrophobic/hydrophilic character [ 65 ]. A hydrophilic surface is characterized by a smaller drop contact angle (an acute angle inside the drop or <90°), whereas a hydrophobic surface is characterized by a greater drop contact angle (obtuse angles or >90°) [ 65 , 73 ]. Figure 4 displays the WCAs of neat and composite films with ZnO-NPs, while Table 1 presents their respective mean values.…”

Biopolymer-Based Films Reinforced with FexOy-Nanoparticles

“…In the design of food packaging films, the WCA plays an important role, indicating the hydrophilic/hydrophobic character or the surface’s wettability [ 51 ]. Hydrophilicity and hydrophobicity are related to WCA values, thus the smaller the angle (acute angle inside the drop), the greater the hydrophilicity, whereas the greater the angle (obtuse angles or over 90 °), the greater the hydrophobicity [ 51 , 66 ]. The water contact angles of neat films and composite films are illustrated in Figure 3 , and their corresponding values are shown in Table 1 .…”

“…This value is significantly higher than that of commercial material. It has been reported that hydrophobic nanoparticles increase water contact angles when exposed to membrane surfaces [ 66 ]. Similar findings were reported for the incorporation of Cu-NPs into cellulose acetate films [ 72 ] and silica particles into cellulose acetate/chitosan films (CA/CS-Si) [ 73 ].…”

Novel hybrid electrospun poly(ε‐caprolactone) nanofibers containing green and chemical magnetic iron oxide nanoparticles

“…55 According to WCA values, hydrophilicity, and hydrophobicity are determined by the angle inside a drop in contact with a film surface (hydrophilic surface < 90 < hydrophobic surface), and the increase in this angle indicates a higher degree of hydrophobicity. 55,60 Figure 1 shows the WCA values of neat PCL and composite membranes (PCL/GMIONPs and PCL/CMIONPs, respectively), and Table 1 provides the mean WCA values of each system. The measured WCA value for the neat PCL (118.9 ± 0.8 ) was consistent with its hydrophobic properties.…”