Photocatalytic Dye Removal Research Articles

Recent Developments in Applications of G-CuO Nanocomposites for Photocatalytic Dye Removal

Abstract The extensive application of synthetic dyes across industries poses significant environmental challenges, particularly concerning water quality degradation. Regarding the possible solutions, copper oxide (CuO) stands out as a feasible candidate. Being a p-type Nano-heterogeneous semiconductor with a bandgap of 1.2–2.71 eV, CuO is a reasonable choice and widely studied photocatalyst for addressing such challenges. When the wavelength exceeded the UV-visible region, its functionality showed deterioration. At the same time, there are difficulties associated with reproducibility and reusability, as well as rapid electron-hole recombination, which prevent the widespread application of this technology within this spectral range. In an attempt to eliminate this defect, researchers have been investigating strategies to activate CuO under visible light, with one promising approach being carbon nanomaterials such as graphene to form carbon-CuO composites. The unique properties of graphene, i.e., its large surface area and excellent electron mobility, make it a remarkable candidate for the enhancement of CuO photoactivity. This study highlighted the recent progress in the synthesis of graphene-based CuO photocatalysts, with the main characteristic of extending the light absorption capacity of CuO into the visible spectrum. It reveals achievements in material innovations and applications, with a focus on photocatalytic dye degradation. These breakthroughs are a sign that the field is growing in popularity and is evolving.

Precursor impurity‐mediated effect in the photocatalytic activity of precipitated zinc oxide

AbstractPhotocatalytic degradation of pollutants using nanoparticles presents a promising method globally. However, effectively harnessing light absorption while mitigating recombination and nanoparticle agglomeration remains challenging. Here, we explore the synthesis and characterization of zinc oxide nanoparticles for photocatalytic dye removal in water. The ZnO catalyst, controlled by impurity amount, is developed, demonstrating a notable impact on photolytic performance. Various zinc precursors, namely, zinc acetate, zinc sulfate, zinc nitrate, and zinc chloride, were used in the precipitation technique. Optical characterization showed distinct band transitions and UV‐dominant absorption peaks, indicating the presence of different impurities in each precursor. Photocatalytic performance is assessed using Rhodamine B decomposition with the sample prepared from zinc acetate, demonstrating enhanced photocatalytic activity attributed to its larger surface area, surface defects, and superior morphology, enabling efficient organic pollutant degradation. Oxygen vacancies aid in charge carrier separation, crucial for effective photocatalysis. The material's intense interaction with pollutants and a high photocurrent density of 5.18 µAcm−2 highlight superior electron–hole pair separation capabilities influenced by morphology and impurity‐generated defects, significantly boosting its overall photocatalytic reaction. These findings emphasize the critical role of precursor selection in designing effective ZnO‐based photocatalysts, water treatment, and environmental remediation applications.

Trimetallic doped hematite (α-Fe2O3) nanoparticles using biomolecules of Azadirachta indica leaf extract for photocatalytic dye removal: insights into catalyst stability and reusability

Trimetallic doped hematite (α-Fe2O3) nanoparticles using biomolecules of Azadirachta indica leaf extract for photocatalytic dye removal: insights into catalyst stability and reusability

Tailored transition metal-doped TiO2@Fe3O4 nanohybrids for efficient photocatalytic dye removal: Optimization via neural networks and response surface approaches

The study focused on predicting the degradation of Remazol Turquoise Blue (RTB) dye using a photocatalyst comprised of transition metal-doped TiO2@Fe3O4. Out of the transition metal ions considered, namely Cu, Cr, Co, and Ni, Cr emerges as the most effective dopant for TiO2@Fe3O4 nanohybrid photocatalysts. This optimal performance was achieved with a catalyst loading of 50 mg and a dye concentration of 10 ppm within a 1-h reaction time, resulting in a photocatalytic efficiency of 96.70%. The optimization strategy employed a combination of Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). To conduct experiments systematically, a Box-Behnken Design (BBD) rooted in RSM principles was utilized to create experimental setups for the photocatalytic degradation of the dye with the doped photocatalyst. The variables such as reaction time, catalyst dosage and dye concentration were designed to optimize the RTB dye degradation. The Regression coefficient (R2) for the developed RSM and ANN models were found to be 0.9299 and 0.9925 respectively, and revealed that the ANN has higher prediction capability and accuracy than other model. The outcomes underlined that the dosage of the catalyst prominently emerged as the principal determinant governing the efficacy of the photocatalytic activity. Remarkably, the Cr doped TiO2@Fe3O4 photocatalyst maintained its activity through six degradation cycles, with efficiencies of 99.7%, 99.4%, 99.1%, 88.8%, 87.3%, and 86.3%, respectively.

SiO2/WO3/ZnO based self-cleaning coatings for solar cells

The accumulation of pollution and any kinds of contamination on the glass cover of the solar cell affects the efficiency of the photovoltaic (PV) systems. The contamination on the glass cover can absorb and reflect a certain part of the sunlight irradiation, which can decrease the intensity of the light coming in through the glass cover. With the study, it was planned to develop self-cleaning coatings for the PV systems. It was aimed to prevent or reduce the contamination-induced efficiency loss of the existing PV systems. In the scope of the project, SiO2/WO3 and SiO2/WO3/ZnO composites were coated from their solutions on the glass substrates using a dip-coating technique. WO3 was selected as a photocatalyst semiconductor. Under the UV light irradiation, WO3 could absorb the photons of the UV light, generating the photoinduced charge carriers. The photoexcited charge carriers provide both the photoinduced hydrophilicity on the surface of the coating and the photocatalytic degradation of the organic contaminants accumulated on the surface of the coating, which allows water droplets to spread and flow on the surface of the cover glass to remove the contaminations. However, the recombination rate of the photoexcited charge carriers on the WO3 film was high. In order to suppress the recombination of the photoinduced charge carriers, WO3 was coupled with SiO2 and ZnO. Both of these semiconductors improved the photocatalytic activity of the WO3 film. Although SiO2 has superior features in terms of the light transmission, it was not very effective under UV light as a photocatalyst alone. The widely preferred photocatalyst ZnO was added into the composite film structure to enhance the photocatalytic activity. The self-cleaning mechanism of the film coatings on a solar cell was investigated through the photocatalytic dye removal efficiency on the as-prepared film samples. There was a slight decrease in the light transparency and the solar cell efficiency because of the WO3 content of the composite film. On the other hand, coupling the SiO2/WO3 film with ZnO enhanced the photocatalytic activity, and it suppressed the reduction effect of the WO3 phase on both the light transparency and the solar cell efficiency. The photocatalytic dye removal efficiency was increased to over 90% after 240 min of UVA light irradiation. In addition, the solar cell coated with the SiO2/WO3/ZnO film provided almost the same solar cell efficiency as the uncoated solar cell. The water contact angle measurement also exhibited the photocatalytic degradation of the model contamination on the glass cover of the solar cell under the UVA light irradiation.Graphical

Photocatalytic Degradation of Malachite Green by Titanium Dioxide/Covalent Organic Framework Composite: Characterization, Performance and Mechanism.

In this paper, a titanium dioxide/covalent organic framework (TiO2/COF) composite was prepared and its photocatalytic removal of dye was investigated. Using tetrabutyl titanate as a titanium source, TiO2 nanomaterial was prepared by sol-gel method. In the presence of TiO2, TiO2/COF core-shell composite was prepared by solvothermal synthesis using melamine and 1,4-phthalaldehyde as ligands. The prepared materials are characterized by SEM, TEM, XPS, XRD, TG, FTIR, BET, EPR, PL, and UV-Vis-DRS techniques. Using malachite green as a model of dye wastewater, the photocatalytic degradation performance of TiO2/COF composites was investigated under the irradiation of ultraviolet light. The results show that the modification of COF significantly improves the photocatalytic efficiency of TiO2, the degradation rate increases from 69.77 % to 93.64 %, and the reaction rate constant of the first-order kinetic equation is increased from 0.0078 min-1 to 0.0192 min-1. Based on the free radical capture experiment, the photocatalytic degradation mechanism of TiO2/COF was discussed, and the feasibility of its photocatalytic degradation of malachite green was theoretically clarified. Accordingly, a simple and practical method for photocatalytic degradation of malachite green was constructed, which has potential application value in the degradation of dye wastewater.

Synergistic effect of oxygen vacancies and doped sulfur over BiOBr for efficient visible photocatalytic removal of dyes

Herein, the BiOBr co-modified with oxygen vacancies (Vo) and doped by sulfur was a promising photocatalyst (Vo-BiOBr-S), which was synthesized by a one-pot solvothermal approach. The TEM showed that Vo-BiOBr-S is a sea urchin-shaped microsphere with a diameter of about 4 μm. The photocatalytic efficiency of Vo-BiOBr-S was studied by removing rhodamine B and methylene blue, which were higher than that of BiOBr, Vo-BiOBr and BiOBr-0.8S, respectively. Additionally, the photocatalyst exhibits high degradation of aqueous solutions containing both rhodamine B and methylene blue. The photocurrent and photoluminescence tests showed that the improved photocatalytic performance of Vo-BiOBr-S was due to the accelerated charge transfer and separation by the internal electric field, which extended the visible light absorption range. Furthermore, experiments free radical trapping revealed that superoxide radicals were the principal active species in this system, contributing to the superior degradation performance of Vo-BiOBr-S. The density of states of the samples was calculated via DFT to analyse the energy band structure. The effectiveness of Vo-BiOBr-S in mineralising RhB under LED light was demonstrated through total organic carbon tests. This study presents a method to design efficient photocatalysts for use in environmental preservation.

Facile synthesis of Mn3O4–ZnO composite for photocatalytic dye removal and capacitive applications

Researchers are focusing on the designing a material's chemistry with novel composition to enhance the efficiency of wastewater treatment and energy storage applications with sufficient stability. Current manuscript presents a detailed comparative study of Mn3O4–ZnO composite for photocatalytic and capacitive applications. The composite samples were prepared through chemical precipitation route to understand the effect of concentration of each component (Mn3O4 and ZnO) on structural and optical characteristics. X-ray diffraction (XRD) and Fourier Transformed Infra-Red spectroscopy (FTIR) confirmed the successful development of both phases with structural modifications in composite sample. Optical absorbance spectroscopy supported the structural amendments with variation in optical band gap (2.71–2.92 eV). Further, the equal concentration (1:1) of Mn3O4 and ZnO exhibited ∼98 % removal of methylene blue dye under UV–visible lamp (Hg lamp) with highest rate of removal (0.037 min−1) among all the prepared samples. Here, the degradation efficiency has been reduced significantly (to 30 %) in alkaline dye solution at pH = 11. Further, the capacitive measurements revealed the highest total capacitance (0.97 F/g) among all the mixed compositions.

Cu and Fe doped NiCo2O4/g-C3N4 nanocomposite ferroelectric, magnetic, dielectric and optical properties: Visible light-driven photocatalytic degradation of RhB and CR dyes

A novel Cu and Fe doped NiCo2O4/g-C3N4 nanocomposites were prepared with varying dopant concentrations via a precipitation and ultrasonication route. The resulting Ni1-xCuxCo2-yFeyO4/g-C3N4 nanocomposites were characterized by advanced techniques and effect of doping was investigated based on ferroelectric, dielectric, magnetic, electrical, optical and photocatalytic properties. The results confirmed the FCC spinel geometry of NiCo2O4 nanoparticles with a spherical shape (ranging from 18 to 32 nm). The absorption range in the visible region and the suppression of electron-hole recombination were investigated through UV–Vis diffused reflectance spectra and PL analysis. The Cu and Fe doping significantly influenced the dielectric properties and the AC conductivity of Ni1-xCuxCo2-yFeyO4/g-C3N4 nanocomposites was also increased with Cu and Fe substitution. The photocatalytic activity of doped Ni0.75Cu0.25Co1.5Fe0.25O4/g-C3N4 (NCCF3/g-CN) were evaluated for the removal of rhodamine B (RhB) and Congo red dyes under visible light irradiation. The NCCF3/gCN nanocomposite exhibited the dye removal of 89 % versus undoped nanocomposite (50 %). The rate constants for CR dye degradation were found to be 0.04366 and 0.1009 (min−1) for the NCCF3/gCN nanocomposite and undoped nanocomposite NiCo2O4/gC3N4 (NCO/gCN), respectively. The efficient separation of charge carriers was facilitated by the migration of photo-induced electrons from the g-C3N4 surface to the NiCo2O4. The influence of pH and catalyst dose on the kinetics of photocatalytic activity revealed a significant effect on the dye degradation rate. The results indicate that the NiCo2O4/g-C3N4 shows a promising potential for photocatalytic removal of dyes under visible light illumination, which could be employed for the removal of dyes from the effluents.

Green tea waste-derived carbon dots: efficient degradation of RhB dye and selective sensing of Cu2+ ions.

Herein, we have synthesized carbon dots (CDs) using a one-step hydrothermal method from green tea waste, a biomass-derived source with high fluorescent properties and excellent solubility in water. The synthesis of CDs was confirmed through a comprehensive range of characterization techniques, including HRTEM (high-resolution transmission electron microscopy), XPS (X-ray photoelectron spectroscopy), and EDX (energy-dispersive X-ray spectroscopy). The optical properties of the synthesized CDs were assessed using UV-Vis spectroscopy and fluorescence (FL) spectroscopy. The CDs displayed exceptional stability across a wide pH range and various concentrations. Moreover, these CDs exhibited a photoluminescence quantum yield (PLQY) of 21.6%, indicating their efficiency in emitting fluorescent light upon excitation. The CDs also showcased their prowess in fluorometrically detecting Cu2+ ions, displaying high sensitivity and selectivity. They presented two distinct linear ranges: 0.02 to 50µM and 50 to 100µM, with recovery rates ranging from 94.2 to 104.06%. Moreover, under visible light irradiation, the CDs exhibited significant efficiency in the photocatalytic removal of dyes. Specifically, the CDs achieved degradation rate of 97.89% for Rhodamine B (RhB) within a 30-min irradiation period. In the context of RhB adsorption, it is evident that the experimental data align more closely with the Freundlich isotherm than the Langmuir isotherm. This is substantiated by a higher R2 value (0.97) for the Freundlich isotherm model compared to the Langmuir adsorption isotherm model (0.93). Notably, the adsorption kinetics was effectively described by pseudo first-order kinetics models. Overall, these results highlight the promising potential of CDs in applications such as environmental remediation and waste treatment processes due to their photocatalytic and sensing capabilities.

Advances in Polyoxometalates as Electron Mediators for Photocatalytic Dye Degradation.

The increasing concerns over the environment and the growing demand for sustainable water treatment technologies have sparked substantial interest in the field of photocatalytic dye removal. Polyoxometalates (POMs), known for their intricate metal-oxygen anion clusters, have received considerable attention due to their versatile structures, compositions, and efficient facilitation of photo-induced electron transfers. This paper provides an overview of the ongoing research progress in the realm of photocatalytic dye degradation utilizing POMs and their derivatives. The details encompass the compositions of catalysts, catalytic efficacy, and light absorption propensities, and the photocatalytic mechanisms inherent to POM-based materials for dye degradation are exhaustively expounded upon. This review not only contributes to a better understanding of the potential of POM-based materials in photocatalytic dye degradation, but also presents the advancements and future prospects in this domain of environmental remediation.

H-BN nanosheet-modified Ag2WO4 nanocomposite for improved photocatalytic dye removal: Insights into catalyst stability and reusability

Hexagonal boron nitride (h-BN)/Ag2WO4 nanocomposite photocatalyst was successfully synthesized using a simple wet chemical approach. Various spectroscopic, microscopic and gravimetric techniques were employed to examine the nanocomposite's structural, morphological, and optical properties. The catalyst showed excellent photocatalytic efficiency for degradation of Indigo Carmine (IC) dye under visible light irradiation with high catalyst stability and hence long reusability. A comprehensive evaluation and comparison of photocatalytic performance was accomplished where we examined the photocatalytic performance of several boron-nitride (BN-based) composites for their ability to degrade various pollutants. As a result, the composites demonstrated variable quantum yields (QY), space–time yields (SY), figures of merit (FOMs), and kinetic reaction rates. As a result of the efficient utilization of photons and effective promotion of photocatalytic reactions, the BN/Ag2WO4 nanocomposite exhibited the highest metrics performance values. A plausible reaction mechanism was also demonstrated.

Screen-printed Sn-doped TiO2 nanoparticles for photocatalytic dye removal from wastewater: A technological perspective

TiO2 is widely used as a photocatalyst with a wide band gap, which limited its application. Ion doping and formulating a high-quality screen-printing paste enhance its features. However, the printability of objects for advanced application seems essential nowadays. In this research, the Sn-doped TiO2 nanoparticles were prepared through a sol-gel method followed by calcination at various temperatures of 450 °C, 550 °C, 650 °C, 750 °C, and 850 °C. Screen-printing pastes were prepared with 18 wt% of the synthesized Sn-doped TiO2 nanoparticles to evaluate photocatalytic activity. Finally, the prepared paste with optimum nanoparticle concentration was screen printed onto the microscope glass slides at various printing times (1, 3, and 5 runs) and annealed at 500 °C temperature to investigate the thickness of printed Sn-doped TiO2 nanoparticles effect. The photocatalytic activity and crystal structure of nano Sn-doped-TiO2 were characterized using photoluminescence (PL) spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) and scanning electron microscope (SEM) analyses were conducted to investigate the size and morphology of the prepared nanoparticles, respectively. The highest photocatalytic activity for the degradation of methylene blue was obtained at the calcination temperature of 450 °C.

Highly Efficient Photodegradation of RHB-MO-MB Mixture Dye Wastewater by WO3/Fe3O4/Diatomite under Different Condition

In this study, the composite photocatalyst WO3/Fe3O4/Diatomite was developed by solvent thermal method to remove composite dyes from wastewater. The structure and properties of the photocatalyst were characterized and analyzed. Under the effect of Fe3O4, WO3 was found to be enhanced in the direction of (101) and (200) and loaded on the surface of diatomite (DT). The results of UV–vis analysis imply that the Fe3O4 and diatomite can significantly improve the photocatalytic efficiency. The magnetic hysteresis loop shows that the WO3/Fe3O4/DT composites can be recycled by a magnet, indicating the good recyclability of the composite photocatalyst. The WO3/Fe3O4/DT composite showed a good photocatalytic effect in both acidic and alkaline conditions for RHB-MO-MB mixture dye, which exhibits broad application prospects. The results of the free radical analysis indicate that ·O2 − and ·OH were the main active species. The mechanism of photocatalytic removal of dyes was investigated based on radical trapping experiments and energy band structure analysis. It was proved by three photocatalytic cycle experiments that the morphology of the WO3/Fe3O4/DT composites remains unchanged, and the photocatalytic activity is maintained during recycled operations. This work provides a new idea for dye removal from wastewater using photocatalysts.

Preparation of graphitic carbon nitride (g-C3N4) for novel dielectric and photocatalytic dye removal applications

Recent developments in 2D nanomaterials have greatly expanded their use in engineering applications. Graphitic carbon nitride (g-C3N4) shows a combination of electrical conductivity, sensing and luminescence abilities, biocompatibility, and chemical stability. The present study showcases the effectiveness of g-C3N4 as a photocatalyst for removing various organic molecules from water (such as methylene blue, 4-nitrophenol, and pharmaceutical drugs) and its potential use in dielectric applications when combined with an organic polymer (polyvinylidene fluoride; PVDF). XRD patterns confirmed the formation of g-C3N4 (which is complimented by the UV-Visible and FTIR results) and PVDF-g-C3N4 composite film. SEM-EDS verified the chemical homogeneity of the as-prepared g-C3N4 powder. Maximum photocatalytic degradation was observed for methylene blue dye (96.48%) with a half-life of 24.18 min, whereas the least degradation was detected for hydroxychloroquine (53.10%) with a half-life of 90.12 min after 120 min of UV-visible exposure. 10 wt% C3N4 reinforced PVDF thick films exhibited stable dielectric properties at low temperature (below 60°C) as compared to PVDF alone. At 1 kHz, the dielectric permittivity and tangent loss of the PVDF-g-C3N4 composites come out to be ∼6 and ∼0.05, respectively (at room temperature). The AC conductivity and activation energy of the synthesized composite was also studied.

Visible Light Photodegradation of Glyphosate and Methylene Blue using Defect-Modified Graphitic Carbon Nitride Decorated with Ag/TiO2

The presence of various organic pollutants in surface and ground waters has raised serious environmental threats across the world. In the present work, the solvothermal process was applied to prepare a ternary composite of barium defect-modified graphitic carbon nitride (DM g. C3N4) decorated with silver and titanium oxide for the photocatalytic removal of dyes and pesticides in visible light. Methylene blue (MB) and glyphosate were targeted pollutants. Enhanced structural defects in the carbon nitride framework were reported and characterized by using FTIR, SEM, EDS, XRD, and UV/Visible spectroscopy. Various analytical techniques confirmed the proficient coating of titanium oxide and silver on the surface of DM g. C3N4. The photocatalytic efficiency of synthesized materials for the degradation of persistent organic pollutants and various parameters such as the effect of pH, catalytic dosage, the concentration of pollutant, reusability of the catalyst, etc., were estimated by using UV/Visible spectroscopy. Batch experiments were performed to estimate the degradation efficiency and other parameters by using an absorption study. A scavenger analysis confirmed hydroxyl radicals as the main reactive species for the degradation of various pollutants. The results confirm that the ternary composite of barium DM g. C3N4 showed an increased response in the visible region, greater stability, and excellent photocatalytic efficiency toward the degradation of the organic compounds. The results confirm that the maximum degradation of the said organic pollutants occurs in 105 min.

Study on the interaction of anions and cations in the synthesis of nanoflower bismuth silicate and its photocatalytic removal of dyes and antibiotics

It is challenging to construct photocatalysts with excellent adsorption-photocatalytic synergy and multi-system pollutant degradation by utilizing double heterostructure with unique nanoflower structure and energy band modulation. Here, a nanoflower-like double-heterojunction composite photocatalyst with high visible light activity is prepared in situ by ion exchange, namely BOSBM (M=I, B, C, K, L; the modified ions are I-, Br-, Cl-, K- and Li-). On the other hand, surface-charged ions provide multiple adsorption sites for pollutants. In BOSBC-6 (the ion is Cl-, the concentration is 1.05 mol/L) photocatalyst, the photocatalytic performance (10 min, degradation rate of 98 %) is 4 times that of BOS. It still has excellent catalytic stability (30 min, 98 % degradation rate) even after 3 cycles of testing. Meanwhile, BOSBM exhibited high degradation efficiency for dye (RhB) and various antibiotics (norfloxacin, ciprofloxacin, and tetracycline hydrochloride). Due to its upward shifting structure (Vo level), BOSBM plays an important role in the degradation of multi-system pollutants. In particular, the formation of Bi2O2SiO3-BiOCl and Si2Bi24O40-BiOCl double heterojunctions in BOSBC-6, which significantly improves the separation efficiency and increases the redox capacity of the sample. Therefore, this work broadens the application range of bismuth silicate photocatalysts and provides a new strategy for obtaining photocatalysts with excellent adsorption-photocatalytic synergistic effect by utilizing the heterojunction structure for modification purposes.

Enhancement of Photocatalytic and Photoelectrochemical Performance of ZnO by Mg Doping: Experimental and Density Functional Theory Insights

Doped ZnO nanostructures have shown great potential for solar energy applications. Considering the compatible ionic radius, Mg atoms can be doped into ZnO at different concentrations. The current work reports a combined experimental and density functional theory study on the influence of the Mg dopant concentration on ZnO performance simultaneously for photocatalytic dye removal and photoelectrochemical water splitting. Among all the samples, Mg(3)-ZnO (3 at. % Mg) exhibits superior sunlight-driven photocatalytic performance. The optimal Mg-ZnO shows an 8-fold increase in the photocatalytic activity compared to the pristine ZnO. Likewise, the most active photocatalyst shows high photoelectrochemical performance with a photocurrent response of 1.54 mA at the lowest onset potential, 11 times higher than the pristine ZnO. Tuning of the Mg content results in the generation of extra charge carriers and a reduced recombination rate, which are the crucial factors responsible for enhanced photocatalytic and photoelectrochemical performance.

Hibiscus cannabinus seeds assisted spherical silver nanoparticles and its antibacterial and photocatalytic applications

Green nanomaterial manufacture limits hazardous substances and encourages noxious-free environments. The fields of photocatalysis and antibacterial resistance are more promising because of their chemical reductants and sterile environments. Here, we used Hibiscus Cannabinus seed as a bio source and developed a simple, environmentally friendly approach for the biosynthesis of AgNPs. Researchers and scientists have recently shown a strong interest in the green synthesis of silver nanoparticles due to their ease, eco-friendliness, non-toxicity, low cost, and ability to function as an antibacterial agent. Research goals include producing environmentally friendly, bacteriocidal, and photocatalytic dye removal products that can be applied to biomedical and water reuse applications. In this paper, we have reported spherical-shaped silver nanoparticles synthesized from Hibiscus cannabinus seeds and their characterization by X-ray Diffraction method, UV-Visible Spectroscopy, and Transmission Electron Micrograph. The surface functionalization of prepared silver particles by phenolic compounds in Hibiscus cannabinus seeds enhances antibacterial activity. Both Staphylococcus aureus and Escherichia coli are inhibited by the prepared silver nanoparticles. By preparing silver nanoparticles at a significantly higher extract concentration, we were able to obtain effective and increased bactericidal activity. The photocatalytic degradation of congo red by prepared silver particles was studied under 150 min of UV light irradiation. The produced silver nanoparticles' structural, optical, morphological, compositional, and bactericidal activity are all shown to be dependent on the concentration of Hibiscus cannabinus seeds extract that is attached to the silver surface.

Constructing Z-scheme AuAg@δ-Bi2O3/BiOBr multi-heterojunction for efficient photocatalytic removal of dye, antibiotic and heavy metal ions: Performance and mechanism investigation

The AuAg alloy nanoparticles were decorated on the δ-Bi2O3 surface to obtain AuAg@δ-Bi2O3, then AuAg@δ-Bi2O3 were hydrothermally combined with BiOBr plate to form Z-scheme AuAg@δ-Bi2O3/BiOBr. The photocatalytic activity of samples were evaluated by the removal of dyes (rhodamine B (RhB) and acid orange 7 (AO7)), tetracycline (TC) and reduction of Cr(VI) under simulated sunlight irradiation. With the decoration of δ-Bi2O3, the δ-Bi2O3/BiOBr composites exhibit higher photocatalytic activity than bare BiOBr. The optimal catalytic efficiency is achieved by 10%δ-Bi2O3/BiOBr sample, which leads to ∼75.7% of AO7, 84.9% of RhB and 67.5% of Cr(VI) removed after 25 min irradiation. After the introduction of AuAg nanoparticles, the photocataltyic activity of 10%δ-Bi2O3/BiOBr can be further enhanced. The removal efficiency of AO7, RhB and Cr(VI) can reach ∼97.9%, ∼97.3% and ∼84.5% after 25 min irradiation, respectively. The AuAg alloy nanoparticles located at the interface of Z-scheme δ-Bi2O3/BiOBr can accelerate the photogenerated charges separation over the way of a Z-scheme charge migration mechanism. In addition, AuAg alloy nanoparticles located at δ-Bi2O3 surface compensates the consumption of photogenerated charges in the direct Z-scheme δ-Bi2O3/BiOBr heterojunction due to their SPR effect, and even further promotes the separation of photogenerated charges in the composite.