Graphene Oxide and Silver Ions Coassisted Zeolitic Imidazolate Framework for Antifouling and Uranium Enrichment from Seawater

Abstract

Seawater environmental limitation from antifouling due to microorganisms presents a great challenge in uranium extraction from seawater. Herein, a bifunctional graphene oxide-silver ions-zeolitic imidazolate framework-67 composite was successfully synthesized for minimizing the effects of antifouling in the enrichment of uranium. A series of antialga assays were carried out using Phaeodactylum tricornutum as a fouling template alga. Interestingly, the adsorbents clearly display an algae inhibitory behavior with more than 80% alga death rate after 7 days, as well as enhance U­(VI) adsorption performance via the coassistance of graphene oxide and silver ions. Adsorption amounts of composites reach 189.36 mg g–1 at a pH 7.0. In addition, composites still retain a high U­(VI) adsorption amount which increases by 177% in comparison to the zeolitic imidazolate framework-67 at pH 8.0 (nearly seawater pH). The adsorption experiment was carried out in actual seawater, with the removal rate of U­(VI) reaching nearly 70%, which proves that the graphene oxide and silver ions coassisted zeolitic imidazolate framework-67 composites are applicable to a seawater environment.

Graphene: An Antibacterial Agent or a Promoter of Bacterial Proliferation?

“…Numerous studies have successfully combined antimicrobial GMs with polymeric membranes or foams to prevent biofouling ( Firouzjaei et al., 2020 ; Wang et al., 2019a ; Perreault et al., 2015a ). These composite materials can be employed for different applications such as ultrafiltration, nanofiltration, forward or reverse osmosis desalination, wastewater treatment, as well as radioactive metal recovery from seawater ( Zinadini et al., 2014 ; Choi et al., 2013 ; Lee et al., 2013 ; Perreault et al., 2014 ; Zeng et al., 2016 ; Guo et al., 2019 , 2020 ; Singh et al., 2018 ; Mokkapati et al., 2017 ; Bao et al., 2011 ). Recent studies describing GM-comprising membranes with antifouling capacity include the development of polysulfone coated with a PDA layer and GO nanosheets ( Cheng et al., 2020 ).…”

Metal‐Organic‐Framework Based Functional Materials for Uranium Recovery: Performance Optimization and Structure/Functionality‐Activity Relationships

“…Wang et al. reported a GO‐ZIF‐67 composite with Ag + dopants (GZA) as anti‐biofouling uranium adsorbents [43] . Noteworthy, the amount of P. tricornutum remained stable in the presence of ZIF‐67 and GZ (GO/ZIF‐67), while being greatly inhibited in the presence of ZA (ZIF‐67‐Ag) and GZA.…”

Toward the Application of Graphene for Combating Marine Biofouling

“…Currently, the mainstream approach in preparing composites for uranium enrichment is using GO as a substrate. Figure a shows an example of synthetic GO/zeolitic imidazolate framework (ZIF)/Ag/composites (GZA), [ 123 ] in which Ag + ions were doped in ZIF‐67. The SEM images in Figure 10b shows the appearance of i) GO, ii) ZIF‐67, and iii) GZA, revealing that GO exhibits a sheet structure, ZIF‐67 exhibits a hexagonal structure, and GZA exhibits a sheet structure with a similar hexagonal structure to ZIF‐67.…”

“…The antifouling mechanism of GZA was considered as the synergistic effect of GO, Ag, and ZIF‐67. [ 123 ] A recent study reported a chitosan–graphene oxide/ZIF/Ag (GCZ8A) foam, [ 124 ] which showed a high algal death (≈70%) compared to the control group. In addition, these materials all showed a 70% uranium removal rate.…”

“…In addition, these materials all showed a 70% uranium removal rate. [ 123–124 ] These prominent properties suggest that graphene‐related antifouling materials have the potential to be applied for the recovery of uranium from the ocean. However, these applications are still in the primary stage, and more investigations are necessary.…”