Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal

One-Pot Synthesis of Cellulose-Based Carbon Aerogel Loaded with TiO2 and g-C3N4 and Its Photocatalytic Degradation of Rhodamine B

A cellulose-based carbon aerogel (CTN) loaded with titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) was prepared using sol-gel, freeze-drying, and high-temperature carbonization methods. The formation of the sol-gel was carried out through a one-pot method using refining papermaking pulp, tetrabutyl titanate, and urea as raw materials and hectorite as a cross-linking and reinforcing agent. Due to the cross-linking ability of hectorite, the carbonized aerogel maintained a porous structure and had a large specific surface area with low density (0.0209 g/cm3). The analysis of XRD, XPS, and Raman spectra revealed that the titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) were uniformly distributed in the CTN, while TEM and SEM observations demonstrated the uniformly distributed three-dimensional porous structure of CTN. The photocatalytic activity of the CTN was determined according to its ability to degrade rhodamine B. The removal rate reached 89% under visible light after 120 min. In addition, the CTN was still stable after five reuse cycles. The proposed catalyst exhibits excellent photocatalytic performance under visible light conditions.

Recent Developments of Electrospinning-Based Photocatalysts in Degradation of Organic Pollutants: Principles and Strategies

Electrospinning is a simple and cheap process for forming one-dimensional (1D) nanofibers with controllable size, morphology, and chemistry. Besides these, the ultrahigh surface area with industrialization capability has attracted extensive interest in the research community. On the other hand, a photocatalytic process is a promising method for degrading organic pollutants that cannot be removed by conventional wastewater treatment. This review focuses on the recent progress of electrospun nanofibers for the photocatalytic degradation of water pollutants. The linkage between the electrospinning technique and the photocatalytic process is classified into two main categories: (1) polymeric electrospun nanofibers as a sacrificed template to form 1D photocatalysts and (2) polymeric electrospun nanofibers as a carrier of photocatalyst materials. We have thoroughly discussed the principles and fundamental issues of electrospinning as well as two main strategies to design and fabricate nanofiber-based photocatalysts for the ideal photodegradation of organics pollutants. The results of data mapping using VOSviewer demonstrated the recent trend and the importance of this field among researchers and engineers. Moreover, we have elaborated on the limitations and potential benefits of the two categories of electrospinning-based photocatalyst fabrication and practical application that will open new directions for future research.

Rational construction of ZnO/CuS heterostructures-modified PVDF nanofiber photocatalysts with enhanced photocatalytic activity

PVDF/ZnO/CuS photocatalysts with ZnO/CuS heterojunctions were synthesized via electrospinning, hydrothermal, and ion-exchange techniques. As matrix materials, electrospun PVDF nanofibers are easy to be recycled and reused. ZnO nanorods anchored on PVDF nanofiber with high specific surface area provide abundant active reaction sites for photocatalysis. While the loaded CuS nanoparticles as a photosensitizer compensate the low quantum efficiency of ZnO and improve the visible-light photocatalytic efficiency. As a result, the PVDF/ZnO/CuS composited photocatalyst exhibits outstanding photocatalytic performance in exposure to UV and visible light owing to the suppressed recombination of electron-hole pairs and widened visible light absorption range. The kinetic constants of PVDF/ZnO/CuS nanocomposites under UV irradiation (9.01 × 10^-3 min^-1) and visible light (6.53 × 10^-3 min^-1) irradiation were 3.66 and 2.53 times higher than that of PVDF/ZnO (2.46 × 10^-3 min^-1 & 2.58 × 10^-3 min^-1), respectively. Furthermore, PVDF/ZnO/CuS nanocomposites demonstrate excellent robustness in terms of recycling and reuse, which is advantageous in practical applications.