Design and Performance of Novel Self-Cleaning g-C3N4/PMMA/PUR Membranes

Abstract

In the majority of photocatalytic applications, the photocatalyst is dispersed as a suspension of nanoparticles. The suspension provides a higher surface for the photocatalytic reaction in respect to immobilized photocatalysts. However, this implies that recovery of the particles by filtration or centrifugation is needed to collect and regenerate the photocatalyst. This complicates the regeneration process and, at the same time, leads to material loss and potential toxicity. In this work, a new nanofibrous membrane, g-C 3 N 4 /PMMA/PUR, was prepared by the fixation of exfoliated g-C 3 N 4 to polyurethane nanofibers using thin layers of poly(methyl methacrylate) (PMMA). The optimal amount of PMMA was determined by measuring the adsorption and photocatalytic properties of g-C 3 N 4 /PMMA/PUR membranes (with a different PMMA content) in an aqueous solution of methylene blue. It was found that the prepared membranes were able to effectively adsorb and decompose methylene blue. On top of that, the membranes evinced a self-cleaning behavior, showing no coloration on their surfaces after contact with methylene blue, unlike in the case of unmodified fabric. After further treatment with H 2 O 2 , no decrease in photocatalytic activity was observed, indicating that the prepared membrane can also be easily regenerated. This study promises possibilities for the production of photocatalytic membranes and fabrics for both chemical and biological contaminant control.Polymers 2020, 12, 850 2 of 20 aqueous solutions [11][12][13][14]. Adsorption by activated carbon is the most used method of dye removal due to good removal efficiency of a wide variety of dyes. Performance is dependent on the type of carbon used and the characteristics of the wastewater. The removal rate can be improved using massive doses of activated carbon. However, the re-use of regenerated activated carbon results in a steep reduction in adsorption capacity and the efficiency of dye removal becomes unpredictable and dependent on massive doses of such re-used activated carbon. Activated carbon is also very expensive and its reactivation results in 10%-15% loss of the sorbent [15][16][17].A promising method in order to overcome issues such as limited sorption capacity and regeneration is the use of materials with photocatalytic activity. Carbon nitride (g-C 3 N 4 ) is a metal-free organic semiconductor. This material is an attractive candidate in the field of photocatalysis due to its chemical stability, non-toxicity, straightforward preparation procedure and ability to absorb light efficiently in the visible range due to a narrow band gap (2.7 eV) [18][19][20]. g-C 3 N 4 has been used in photocatalytic applications such as water splitting [21,22], the photocatalytic degradation of air pollutants, such as NOx [23,24], water pollutants such as the dyes, rhodamine B [25][26][27], methyl orange [28], and methylene blue [29][30][31], and other industrial pollutants such as antibiotics [32] or phenols [33][34][35]. In recent years, g-C 3 N 4 was also successfully tes...

Facile Synthesis of Lacunary Keggin-Type Phosphotungstates-Decorated g-C3N4 Nanosheets for Enhancing Photocatalytic H2 Generation

“…It should be pointed out that the LUMO potential of PW 9 does not satisfy the demand of proton reduction, while the g-C 3 N 4 possesses a suitable conduction band (CB) potential for fulfilling the H 2 generation [ 37 , 38 ]. Thus, we could deduce that the photocatalytic sites in the PW 9 /g-C 3 N 4 heterojunction NSs should be located at the surface of g-C 3 N 4 hetero-component [ 39 , 40 ]. Meanwhile, the PW 9 hetero-component serves as the photosensitizer to boost the separation process of the photoinduced charge-carriers of the g-C 3 N 4 hetero-component.…”

Lamelary Aggregation of Nanoparticles from Frozen Liquid on the Sublimation Interface—Experimental Preparation and Application of Nanomaterials

“…5.26. [13,14] The decomposition was represented by the decolorization of the dye simulant solution when irradiated with blue visible light from a 10 W LED source at a wavelength of 416 nm. The measurement results in Fig.…”

“…Fig. 5.26 Experimental photocatalytic reactor with depth h = 2.5 mm of photocatalytic bath for aqueous solution of simulant (MB-methylene blue) and diameter d = 55 mm of the tested fabric circular area[13,14] …”