Synthesis of Novel High Flux Thin-Film Nanocomposite Nanofiltration Membranes Containing GO–SiO2 via Interfacial Polymerization

Nanostructure-manipulated filtration performance in nanocomposite membranes: A comprehensive investigation for water and wastewater treatment

The main objective of this article is to examine one of the most important challenges facing researchers in the field of nanocomposite membranes: what is the most suitable arrangement (unmodified, functionalized, coated, or composite) and the most suitable loading site for the nanostructure? In the review articles published on nanocomposite membranes in recent years, the focus has been either on a specific application area (such as nanofiltration or desalination), or on a specific type of polymeric materials (such as polyamide), or on a specific feature of the membrane (such as antibacterial, antimicrobial, or antifouling). However, none of them have targeted the aforementioned objectives on the efficacy of improving filtration performance (IFP). Through IFP calculation, the results will be repeatable and generalizable in this field. The novelty of the current research lies in examining and assessing the impact of the loading site and the type of nanostructure modification on enhancing IFP. Based on the performed review results, for the researchers who tend to use nanocomposite membranes for treatment of organic, textile, brine and pharmaceutical wastewaters as well as membrane bioreactors, thePES NH 2 - PDA - Fe 3 O 4 M ,PAN Fe 3 O 4 / ZrO 2 M ,PVDF CMC - ZnO M ,AA AA - CuS PSf M andPVDF OCMCS / Fe 3 O 4 M with IFP equal to 132.27, 15, 423.6, 16.025 and 5, were proposed, respectively.

The effect of silica-doped graphene oxide (GO-SiO2) on persulfate activation for the removal of Acid Blue 25

The release of synthetic dyes into water bodies poses many environmental issues, and their removal is a necessity. Advanced oxidation processes (AOPs) can be employed for removal, in many of which a catalyst is used. graphene oxide (GO) is a viable catalyst due to its distinctive structural properties; however, it is reportedly incapable of effectively activating persulfate. Thus, this study delves for the first time into the influence of doping silica on enhancing GO's catalytic performance to activate persulfate for decolorizing Acid Blue 25 (AB25). Based on the results, an equal weight proportion of GO to silica was selected as the most efficient ratio. In addition, pH had no significant effect on removal efficiency, while temperature had the highest impact. Within 150 min with 0.075 gr/L of GO-SiO2 as the catalyst and 1 gr/L of Na2S2O8 as the oxidant, the investigated process removed Acid Blue 25 up to 82%, which was 9% higher than when GO alone was used as the catalyst. As for COD removal, the contribution of doping silica was more significant and led to 37% COD removal, which was 17% higher than when GO alone was used.

Nanoparticles and nanofiltration for wastewater treatment: From polluted to fresh water

Water pollution poses significant threats to both ecosystems and human health. Mitigating this issue requires effective treatment of domestic wastewater to convert waste into bio-fertilizers and gas. Neglecting liquid waste treatment carries severe consequences for health and the environment. This review focuses on intelligent technologies for water and wastewater treatment, targeting waterborne diseases. It covers pollution prevention and purification methods, including hydrotherapy, membrane filtration, mechanical filters, reverse osmosis, ion exchange, and copper-zinc cleaning. The article also highlights domestic purification, field techniques, heavy metal removal, and emerging technologies like nanochips, graphene, nanofiltration, atmospheric water generation, and wastewater treatment plants (WWTPs)-based cleaning. Emphasizing water cleaning's significance for ecosystem protection and human health, the review discusses pollution challenges and explores the integration of wastewater treatment, coagulant processes, and nanoparticle utilization in management. It advocates collaborative efforts and innovative research for freshwater preservation and pollution mitigation. Innovative biological systems, combined with filtration, disinfection, and membranes, can elevate recovery rates by up to 90%, surpassing individual primary (<10%) or biological methods (≤50%). Advanced treatment methods can achieve up to 95% water recovery, exceeding UN goals for clean water and sanitation (Goal 6). This progress aligns with climate action objectives and safeguards vital water-rich habitats (Goal 13). The future holds promise with advanced purification techniques enhancing water quality and availability, underscoring the need for responsible water conservation and management for a sustainable future.

Metal-Coordinated Nanofiltration Membranes Constructed on Metal Ions Blended Support toward Enhanced Dye/Salt Separation and Antifouling Performances

Metal-phenol coordination is a widely used method to prepare nanofiltration membrane. However, the facile, controllable and scaled fabrication remains a great challenge. Herein, a novel strategy was developed to fabricate a loose nanofiltration membrane via integrating blending and interfacial coordination strategy. Specifically, iron acetylacetonate was firstly blended in Polyether sulfone (PES) substrate via non-solvent induced phase separation (NIPS), and then the loose selective layer was formed on the membrane surface with tannic acid (TA) crosslinking reaction with Fe3+. The surface properties, morphologies, permeability and selectivity of the membranes were carefully investigated. The introduction of TA improved the surface hydrophilicity and negative charge. Moreover, the thickness of top layer increased about from ~30 nm to 119 nm with the increase of TA assembly time. Under the optimum preparation condition, the membrane with assembly 3 h (PES/Fe-TA3h) showed pure water flux of 175.8 L·m−2·h−1, dye rejections of 97.7%, 97.1% and 95.0% for Congo red (CR), Methyl blue (MB) and Eriochrome Black T (EBT), along with a salt penetration rate of 93.8%, 95.1%, 97.4% and 98.1% for Na2SO4, MgSO4, NaCl and MgCl2 at 0.2 MPa, respectively. Both static adhesion tests and dynamic fouling experiments implied that the TA modified membranes showed significantly reduced adsorption and high FRR for the dye solutions separation. The PES/Fe-TA3h membrane exhibited high FRR of 90.3%, 87.5% and 81.6% for CR, EBT and MB in the fouling test, stable CR rejection (>97.2%) and NaCl permeation (>94.6%) in 24 h continuous filtration test. The combination of blending and interfacial coordination assembly method could be expected to be a universal way to fabricate the loose nanofiltration membrane for effective fractionation of dyes and salts in the saline textile wastewater.

Antifouling Nanofiltration Membrane Fabrication via Surface Assembling Light-Responsive and Regenerable Functional Layer

Membrane fouling, caused by aggregation of organics and microorganisms from filtrate on the membrane surface, seriously reduces the service life of a nanofiltration (NF) membrane. Developing facile and renewable antifouling modification methods without sacrificing separation properties of the membrane remain an imperative requirement. Herein, a thin-film composite (TFC) NF membrane with a light-responsive and regenerable functional layer (P-TFC) was fabricated via host-guest interactions between the azobenzene (guest) labeled functional polymers and the β-cyclodextrin (host) bonded membrane surface (H-TFC). The P-TFC-3 not only showed outstanding antifouling ability and high flux recovery ratio (FRR > 90% at the fourth antiadhesive test) but also exhibited enhanced water permeability (17.9 L m^-2 h^-1 bar^-1) and high selectivity (α_MgSO4^NaCl = 33.4 and fast antibiotics enrichment capacity) compared with the pristine membrane. Furthermore, when the functional layer was contaminated, it can be removed by ultraviolet light irradiation and a new functional layer can be rebuilt by adding fresh azobenzene labeled functional polymers. After several regeneration processes, the membranes still showed constant separation properties and high flux recovery ability (FRR > 90%). This work proposes an easy-to-assemble and regenerable surface modification strategy to endow TFC NF membranes with excellent fouling resistance and sustainable utilization ability while maintaining high separation properties.