Effects of textile dyes on health and the environment and bioremediation potential of living organisms

Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.

Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

Two-dimensional transition metal carbides and nitrides known as MXenes, with a general formula of Mn+1Xn (n = 1–3), integrate the advantages of metallic conductive transition metals with large groups of carbides, nitrides, or carbonitrides. They have led to a burgeoning research interest in biomedical applications due to their ultrathin structure and fascinating physiochemical (electronic, optical, magnetic, etc.) properties. In this review, we summarize recent advances in biomedical applications for MXenes. We first introduce the preparation methods and surface modifications with respect to MXenes. Their unique properties are then elaborated. Thirdly, we highlight their various biomedical applications, such as with biosensors, antibacterial materials, bioimaging probes, therapeutics, and theranostics. In the end, the current challenges and new opportunities for MXenes in regard to their biomedical applications are also discussed.

Two-dimensional transition metal carbides and nitrides (MXenes) for biomedical applications.

2D MXenes: Electromagnetic property for microwave absorption and electromagnetic interference shielding

Recent advances in the use of different substrates in microbial fuel cells toward wastewater treatment and simultaneous energy recovery

The performance of two-dimensional (2D) Ti3C2Tx MXene nanosheets in the adsorption and copper removal from aqueous media was investigated. Delaminated (DL)-Ti3C2Tx exhibited excellent Cu removal ability, because of their large specific surface area, hydrophilicity, and unique surface functional properties. Scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM–EDS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analyses were performed to analyze the structural changes in Ti3C2Tx MXene and its interaction with Cu ions. Oxygenated moieties in the layered structure of MXene facilitated reductive adsorption of Cu2+ forming Cu2O and CuO species. DL-Ti3C2Tx exhibited a higher and faster Cu uptake, compared to multilayer (ML)-Ti3C2Tx. The maximum experimental adsorption capacity (Qexp,max) was 78.45 mg g–1, and 80% of the total content of metal ions was adsorbed within 1 min. A pseudo-second-order k...

Two-Dimensional Ti3C2Tx MXene Nanosheets for Efficient Copper Removal from Water

Heterostructural TiO2/Ti3C2Tx (MXene) for photocatalytic degradation of antiepileptic drug carbamazepine

In this study, the three-dimensional (3D) reduced graphene oxide/TiO 2 (RGOT) aerogel was synthesized by a facile one-step hydrothermal treatment, and its photocatalytic efficiency was evaluated in the photodegradation of recalcitrant carbamazepine (CBZ) in aqueous solution. RGOT exhibited high adsorption and an almost two-fold higher photodegradation ability than bare TiO 2 as more than 99% CBZ removal was observed within 90 min in 10 ppm aqueous solution of the latter. The mass ratio of TiO 2 in the RGOT aerogel substantially affected CBZ adsorption and photocatalytic degradation, with the optimal TiO 2 /GO ratio in RGOT found to be 2:1. The chemical bonding between TiO 2 and GO and the effective reduction of the latter during RGOT synthesis were also considered to achieve high photocatalytic efficiency, because the physical mixture of GO and TiO 2 showed a lower photocatalytic CBZ degradation ability than bare TiO 2 . The macroporous 3D structure, abundant surface sites for anchoring the catalyst, effective charge separation, and mass transportation of CBZ near the photocatalyst surface are the attractive features of RGOT aerogels, promoting their use in resolving environmental issues.

One-step hydrothermal synthesis of porous 3D reduced graphene oxide/TiO2 aerogel for carbamazepine photodegradation in aqueous solution

Graphene-based two-dimensional materials have been explored in a variety of applications, including the treatment of heavy-metal-rich water/wastewater. Ethylenediaminetetraacetic acid (EDTA)-functionalized magnetic chitosan (CS) graphene oxide (GO) nanocomposites (EDTA-MCS/GO) were synthesized using a reduction precipitation method and applied to the removal of heavy metals, such as Pb2+, Cu2+, and As3+, from aqueous solutions. The synthesized nanocomposite was characterized by FT-IR, XRD, SEM, MPMS, zeta-potential and BET analyses. The influence of various operating parameters, such as pH, temperature, metal ion concentration, and contact time on the removal of the metal ions, was investigated. Owing to the large specific surface area, hydrophilic behavior, and functional moieties, the magnetic nanocomposite demonstrated excellent removal ability with a maximum adsorption capacity of 206.52, 207.26, and 42.75 mg g−1 for Pb2+, Cu2+, and As3+, respectively. The equilibrium data was evaluated by Langmuir and Freundlich isotherms, while the heavy metal adsorption reaction kinetics was analyzed by Lagergren pseudo-first-order and pseudo-second-order kinetic models. The nanocomposite was reused in four successive adsorption–desorption cycles, revealing a good regeneration capacity of the adsorbent.

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Jiseon Jang

Papers

Two-Dimensional Ti3C2Tx MXene Nanosheets for Efficient Copper Removal from Water

Heterostructural TiO2/Ti3C2Tx (MXene) for photocatalytic degradation of antiepileptic drug carbamazepine

One-step hydrothermal synthesis of porous 3D reduced graphene oxide/TiO2 aerogel for carbamazepine photodegradation in aqueous solution

Heavy metals removal by EDTA-functionalized chitosan graphene oxide nanocomposites

Mercuric ion capturing by recoverable titanium carbide magnetic nanocomposite.