Eco-friendly TiO2-doped Fe3O4/rGO nanocomposites synthesized using plant extracts for photodegradation of organic dye

Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various organic dyes into water, CO2, and other organic compounds via direct photodegradation or a sensitization-mediated degradation process. The overall efficiency of the photocatalysis system is closely dependent upon operational parameters that govern the adsorption and photodegradation of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity. Additionally, the charge-carrier properties of the photocatalyst strongly affect the generation of reactive species in the heterogeneous photodegradation and thereby dictate the photodegradation efficiency. Herein, this comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions. The operational factors affecting the photodegradation of either cationic or anionic dye molecules, as well as the charge-carrier properties of the photocatalyst, are also fully explored. By further analyzing past works to clarify key active species for photodegradation reactions and optimal conditions, this review provides helpful guidelines that can be applied to foster the development of efficient photodegradation systems.

Comparative study on the mechanism in photocatalytic degradation of different-type organic dyes on SnS2 and CdS

Photodegradation of organic dyes in the presence of [Fe(III)-salen]Cl complex and H 2O 2 under visible light irradiation

Hydrogels have excellent properties that make them ideally suited as host matrices for the immobilization of photoreactive materials such as TiO2 nanoparticles that serve as catalysts in the photodegradation of organic dyes, which is of great importance in practical water pollution treatment applications. However, the application of hydrogels for this purpose remains poorly studied. The present study addresses this issue by developing two types of hydrogels based on poly(methyl acrylate) and succinamide acid with embedded TiO2 nanoparticles for use as photocatalysts in the photodegradation of organic dyes. The results of the analysis demonstrate that the TiO2 nanoparticles are distributed uniformly in the hydrogel matrices, and the hydrogels maintain their original structures after use. The photodegradation efficiencies of the developed TiO2-hydrogels are demonstrated to be reasonably close to that of freely distributed TiO2 nanoparticles in solution for four different organic dyes. In addition, the results of degradation-regeneration cycling tests demonstrate that immobilizing the TiO2 nanoparticles into the hydrogels greatly reduces their loss during utilization, and the photocatalysts can be easily reused. In fact, the two TiO2-hydrogels retain reasonably high photocatalytic degradation performance after four degradation-regeneration cycles.

MXene/Ag3PO4 modified PVDF composite membranes for efficient interfacial evaporation and photodegradation

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using plant extracts has been receiving tremendous attention as an alternative to conventional physical and chemical methods. The Lamiaceae plant family is one of the largest herbal families in the world and is famous for its aromatic and polyphenolic biomolecules that can be utilised as reducing and stabilising agents during the synthesis of ZnO NPs. This review will go over the synthesis and how synthesis parameters affect the Lamiaceae-derived ZnO NPs. The Lamiaceae-mediated ZnO NPs have been utilised in a variety of applications, including photocatalysis, antimicrobial, anticancer, antioxidant, solar cells, and so on. Owing to their optical properties, ZnO NPs have emerged as potential catalysts for the photodegradation of organic dyes from wastewater. Furthermore, the low toxicity, biocompatibility, and antibacterial activity of ZnO against various bacteria have led to the application of ZnO NPs as antibacterial agents. Thus, this review will focus on the application of Lamiaceae-mediated ZnO NPs for the photodegradation of organic dyes and antibacterial applications.

Cadmium sulfide (CdS)-decorated, cross-linked melamine-formaldehyde polymer-based nanocomposite (MFP-CdS) has been synthesized. MFP-CdS is utilized here as a photoactive material for the photodegradation of six model organic dyes and their mixture in an aqueous medium in the presence of sunlight. The half-life values from the kinetic study of multiple dyes strongly support the importance of sunlight on the fast degradation of all six dyes compared to bulb light and control (dark) conditions. A comparative 1H NMR analysis of the dyes and their degraded products has been performed to support the breakdown of the aromatic framework of organic dyes using MFP-CdS in sunlight. The mechanisms involved in the photodegradation of dyes have been investigated based on radical trapping studies that support the significant involvement of superoxide radicals along with holes. Moreover, the dye removal efficiency using MFP-CdS from real industrial wastewater samples is evaluated via the external spiking of organic dyes and their mixture in unknown industrial effluents where they showed similar photodegradation results. Based on the high recyclability of MFP-CdS, these are used for multiple cycles.

MXene/polypyrrole coated melamine-foam for efficient interfacial evaporation and photodegradation

The interaction of three photoactive organic dyes, Rhodamine B, Rhodamine 6G and a stilbazolium derivative 4'-dimethylamino-N-methyl-4-stilbazolium with synthetic sodium-saponite has been examined by UV-visible absorption spectroscopy. In all cases, bathochromic shifts and the reduction of peak absorbance for the dyes were observed in the absorption spectra at a low dye concentration (25% adsorption of the cation exchange capacity (CEC) of the clay), although the shape and the width of their absorption bands were similar to those in aqueous solution. This absorption behavior indicates that the organic dye molecules adsorbed onto the surface of the negatively charged clay particles and the adsorbed molecules were well dispersed. The photodegradation of the organic dyes in aqueous solution and in the clay suspension has been also examined by the irradiation of a laser beam at a wavelength of 532 nm. We have found that the hybridization of the organic dyes with the exfoliated clay particles largely enhanced a photodegradation. The clay particles acted as a catalyst even at a high concentration such as approximately 300% of CEC.

In situ synthesis of ternary hybrid nanocomposites on natural Juncus effusus fiber for adsorption and photodegradation of organic dyes

Adsorption of phosphate and photodegradation of cationic dyes with BiOI in phosphate-cationic dye binary system

Tuning the concentration of surface/bulk oxygen vacancies in CeO2 nanorods to promote highly efficient photodegradation of organic dyes

Facile sono-design of 3D flower-like NiO–CuFe2O4 nano-heterostructure as an efficient and magnetically separable catalyst for photodegradation of organic dyes

Herein, a simple method for the growth of the CdS shell around CdTe QDs and the formation of the CdTe/CdS core–shell structure is proposed. The synthesized QDs are characterized using Raman, Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and UV–vis analyses. XRD patterns confirm the formation of a core–shell‐type structure and particle sizes, lattice strain (ε), and displacement density (δ) are calculated using Williamson–Hall (W–H) and Williamson–Smallman (W–S) approaches. Obtained results show that the CdTe/CdS QDs are spherical with an average crystal size about 5.41 nm. In this work, derivation of absorption spectrum fitting (DASF) is used for the determination of the optical bandgap of the prepared QDs. Prepared CdTe/CdS QDs are applied for the detection of the heavy metal ions and photodegradation of the different organic dyes in aqueous media. The prepared QDs show good performance for the detection of mercury ions (Hg2+) in water with superior selectivity and for photodegradation of the methylene orange (MO) under UV light. The comparison of the obtained results for CdTe/CdS with bare CdTe QDs shows that the core–shell CdTe/CdS QDs have higher sensitivity and enhanced photocatalyst properties compared to the CdTe QDs.

Super‐wetting multifunctional membranes are highly attractive in the current decade in the environmental remediation of wastewater containing water‐insoluble emulsified oils and water‐soluble hazardous organic pollutants. Herein, hydroxyl modified porous g‐C3N4 nanosheets (CNNS) coated polyvinylidene fluoride (PVDF) membrane is fabricated by a facile vacuum pumping process. Hydroxyl modified porous g‐C3N4 nanosheets are firmly immobilized on flexible PVDF substrate via sodium alginate (SA) adhesive to create a stable surface micro/nanohierarchical structure. The fabricated CNNS/SA/PVDF membrane achieves the desired surface wettability of superhydrophilicity/underwater superoleophobicity with an anti‐oil‐fouling property. The functionalized membrane exhibits above 99% emulsified oil rejection rate with excellent stability and recyclability when separating oil‐in‐water emulsions. Besides, visible‐light‐response CNNS endow the as‐prepared membrane with excellent photocatalytic activity. The resulted CNNS/SA/PVDF membrane can eliminate organic dye both in static and dynamic water with high flux recovery ratio and renewability, which conducted the procedures of photodegradation of organic dye adsorbed on the membrane surface after filtering the contaminative flowing aqueous solution, and directly the photodegradation of organic dye in stationary aqueous solution, respectively. This facile‐fabrication and high‐performance CNNS/SA/PVDF membrane provides a promising practical application toward oily and organic wastewater treatment. It also promotes the utilization of surface wettability modified g‐C3N4 nanomaterial in the construction of multifunctional interface membrane for environmental purification.