Construction of functionalized graphene separation membranes and their latest progress in water purification

Recent advancement on water filtration membranes: Navigating biofouling challenges

This study investigates the field of antifouling membranes for water filtration and desalination applications, specifically focusing on two-dimensional materials. The study examines the importance of these membranes in the context of climate change and its effects on coastal ecosystems. The occurrence of biofouling in seawater desalination membranes is closely connected to intricate processes influenced by factors such as water quality, microbial communities, hydrodynamics, and membrane properties. Microorganism adhesion initiates the process, which then advances into irreversible attachment and the creation of biofilm. Detached pieces contribute to the perpetuation of fouling. Biofouling is caused by a variety of biomaterials and organics, including bacteria, extracellular polymeric substances (EPS), proteins, and humic compounds. Innovative methods such as surface alterations using two-dimensional materials like graphene and graphene oxide, as well as the use of biofouling-resistant materials, provide promising possibilities. These materials have antifouling characteristics, making them environmentally beneficial options that reduce the need for chemical cleaning. Their application improves the water treatment process by preventing fouling and enhancing membrane performance. Real-world research applications can enhance and optimize these tactics to effectively reduce biofouling in seawater desalination systems, hence improving efficiency and sustainability. This is particularly important in light of climate change and its impact on coastal ecosystems. The findings obtained from the literature review emphasise the utmost significance of tackling biofouling in the face of a changing environment, particularly with regard to microorganisms. Important factors to consider are the selection of coating materials, the implementation of environmentally friendly cleaning solutions made from natural chemicals, and the improvement of pretreatment systems. Green cleaning agents are important eco-friendly alternatives to typical biocides, as they possess antibacterial, antifungal, and antifouling capabilities. Given the existence of climate change, these observations serve as a basis for promoting environmentally friendly methods in water treatment technology.

High-Porosity Lamellar Films Prepared by a Multistage Assembly Strategy for Efficient Photothermal Water Evaporation and Power Generation

The frame structure combined with water- and heat-transfer capabilities fully satisfies the requirements of photothermal conversion materials in seawater evaporation applications. Meanwhile, it must integrate the characteristics of a high photothermal conversion rate, thermal management, and water transportation. Herein, lamellar porous films were successfully designed and synthesized by a simple ultrasonic-assisted vacuum filtration method. In this process, polystyrene sulfonate@carbon nanotubes/reduced graphene oxide (PSS@CNT/rGO) lamellar films were constructed by the one-dimensional synthesis of PSS@CNT self-assembled at the molecular scale and the two-dimensional matrix material rGO. It is worth noting that the lamellar film exhibits a high specific surface area (285.5 m²·g^-1), which is reflected in its abundant nanopores. Among them, the porous network system composed of nanochannels can provide efficient water supply and steam-transfer ability and strengthen the heat insulation performance of thermal localization, which is beneficial to photothermal evaporation. The obtained PSS@CNT/rGO lamellar films achieved a condensed water yield of 1.825 kg·m^-2·h^-1 under 1 sun illumination (1 kW·m^-2), and their solar-vapor conversion efficiency was 97.1%. Simultaneously, the interaction between the water flow and the carbon material interface was also used to generate additional electric energy output. The maximum open-circuit voltage of 0.46 V was generated at both termini of the PSS@CNT/rGO lamellar film, which successfully realized the multieffect utilization of energy. These results show that the multistage assembly strategy is a facile and effective means for the development of an efficient evaporation photothermal film, which offers significant value in the field of photothermal seawater evaporation and power generation.