Self-cleaning PDA/ZIF-67@PP membrane for dye wastewater remediation with peroxymonosulfate and visible light activation

Efficient degradation of bentazone via peroxymonosulfate activation by 1D/2D γ-MnOOH-rGO under simulated sunlight: Performance and mechanism insight

An innovative 1D/2D γ-MnOOH-rGO catalyst was successfully synthesized by anchoring γ-MnOOH nanowires on rGO nanosheets. Its catalytic activity was comprehensively evaluated by bentazone degradation in PMS/simulated sunlight system. Results showed that the γ-MnOOH-rGO catalyst achieved 96.1% decomposition of bentazone within 90 min in the coupled system, improving by 26.7% compared to that obtained in the γ-MnOOH mediated system. Moreover, the newly-designed γ-MnOOH-rGO exhibited stability, recyclability and practicability for bentazone elimination. Mechanism insight highlighted that more active sites exposed on γ-MnOOH-rGO surface, providing more opportunities for PMS activation and bentazone degradation. Besides, the rGO could transfer photo-induced electrons, accelerating radical-based reactions. More importantly, ∙OH and ¹O₂ appeared in γ-MnOOH-rGO/PMS/simulated sunlight system, which played an overwhelming role in bentazone removal. In prospect, the γ-MnOOH-rGO showed promising potential for refractory contaminants remediation from aquatic environment in PMS/photocatalytic system.

Biomimetic design and synthesis of visible-light-driven g-C3N4 nanotube @polydopamine/NiCo-layered double hydroxides composite photocatalysts for improved photocatalytic hydrogen evolution activity

In the practical process of photocatalytic H₂ evolution, optimizing the ability of light absorption and charge spatial separation is the top priority for improving the photocatalytic performance. In this study, we elaborately engineer neoteric g-C₃N₄ nanotube@polydopamine(pDA)/NiCo-LDH (LPC) composite photocatalyst by combining hydrothermal and calcination method. In the LPC composite system, the one-dimensional (1D) g-C₃N₄ nanotubes with larger specific surface area can afford more active sites and conduce to shorten the charge migration distance, as well as the high-speed mass transfer in the nanotube can accelerate the reaction course. The g-C₃N₄/NiCo-LDH type-II heterojunction can efficaciously stimulate the spatial separation of photo-produced charge. In addition, pDA as heterojunction metal-free interface mediums can provide multiple action (π-π* electron delocalization effect, adhesive action and photosensitization). The optimized LPC nanocomposite displays about 3.3-fold high photoactivity for H₂ evolution compared with the g-C₃N₄ nanotube under solar light irradiation. In addition, the cycle experiment result shows that the LPC composite photocatalyst possesses superior stability and recyclability. The resultant g-C₃N₄@pDA/NiCo-LDH composite photocatalyst displays the potential practical application in the field of energy conversion.

Microbial degradation of dyes: An overview

Industrialization increases use of dyes due to its high demand in paper, cosmetic, textile, leather and food industries. This in turn would increase wastewater generation from dye industrial activities. Various dyes and its structural compounds present in dye industrial wastewater have harmful effects on plants, animals and humans. Synthetic dyes are more resistant than natural dyes to physical and chemical methods for remediation which makes them more difficult to get decolorize. Microbial degradation has been researched and reviewed largely for quicker dye degradation. Genetically engineered microorganisms (GEMs) play important role in achieving complete dye degradation. This paper provides scientific and technical information about dyes & dye intermediates and biodegradation of azo dye. It also compiles information about factors affecting dye(s) biodegradation, role of genetically modified organisms (GMOs) in process of dye(s) degradation and perspectives in this field of research.

Functional catalytic membrane development: A review of catalyst coating techniques

Catalytic membranes combine catalytic activity with conventional filtration membranes, thus enabling diverse attractive benefits into the conventional membrane filtration processes, such as easy catalyst reuse, antifouling, anti-microbial, and enhancing process efficiency. Up to date, tremendous progresses have been made on functional catalytic membrane preparation and applications, which significantly advances the competitiveness of membrane technologies in process industries. The present article provides a critical and holistic overview of the current state of knowledge on existing catalyst coating techniques for functional catalytic membrane development. Based on coating mechanisms, the techniques are generally categorized into physical and chemical surface coating routes. For each technique, we first introduce fundamental principle, followed by a critical discussion of their applications with representative case studies. Advantages and drawbacks are also emphasized for different surface coating technologies. Finally, future perspectives are highlighted to provide deep insights into their future developments.