Degradation Of Rhodamine B Dye Research Articles

An experimental look into efficient quaternary Bi5O7I/Bi(IO3)3/Bi2(IO4) (IO3)3/BiOIO3 photocatalytic composite

The prototypical toxic dye rhodamine B (RhB) is perhaps one of the most abundant pollutants in industrial wastewater. Its efficient photocatalytic degradation through composite photocatalysts is crucial for environmental remediation. Here, we synthesized quaternary Bi5O7I/Bi(IO3)3/Bi2(IO4)(IO3)3/BiOIO3 bismuth iodate composites through facile hydrothermal and solvothermal methods. The coexistence of multiple bismuth iodate phases was confirmed by x-ray diffraction analysis, room temperature Raman, and Fourier-transform infrared spectroscopy. The desired chemical states of Bi, I, and O inside the composites were confirmed by x-ray photoelectron spectroscopy. Field emission electron microscopy revealed flower-shaped nanosheet morphology for the composite synthesized at 120 °C, whereas randomly shaped nanoparticles with an average size of 80 nm were formed in the composite calcined at 400 °C. High-resolution transmission electron microscopy further corroborated the existence of multiple phases in the composites. The diffuse reflectance spectroscopy confirmed the optical absorption edges of the composites to be located within the visible range of 1.68–3.16 eV. The flower-shaped quaternary bismuth iodate composite demonstrated 100% degradation of RhB dye within 40 min of optical exposure. This quaternary bismuth iodate composite is suitable for solar harvesting-driven toxic dye remediation.

Effective adsorption and visible light driven enhanced photocatalytic degradation of rhodamine B using ZnO nanoparticles immobilized on graphene oxide nanosheets

In this study, graphene oxide (GO), ZnO nanoparticles (NPs) and GO based ZnO nanocomposites (GO-ZnO) have been successfully synthesized by modified Hummer’s method, chemical co-precipitation method and ultrasonication method, respectively. Powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy were employed to study the crystallographic structure, phase, surface micro-morphology and different functional groups in the prepared catalysts. The optical band gap of pristine ZnO NPs was found in the UV region (3.2 eV), whereas the ZnO NPs immobilized on GO nanosheets possesses it in the visible wavelength region (2.67 eV). GO-ZnO catalysts demonstrate excellent degradation efficiency (97.7 %) within just 85 min due to its effective adsorption and visible light driven photocatalytic activity in the degradation of rhodamine B (RhB) dye. The adsorption capacity of GO-ZnO catalysts was found ∼ 24 times higher with the second order kinetic rate constant as low as 0.0014 min ∙ g/mg and the visible light driven photocatalytic activity was ∼ 9 times faster when compared to unmodified ZnO catalyst. Effect of GO-ZnO catalyst dosages in the degradation of RhB was also conducted. The scavenger test firmly evidenced that super oxide radicals (•O2–) play the lead role in RhB dye degradation process by GO-ZnO nanocomposites. Reusability studies of GO-ZnO catalysts demonstrate more than 91 % degradation efficiency up to 4 back-to-back cycles along with retaining the crystal structure. These findings suggest the viable application of GO-ZnO catalysts for the degradation of RhB dye in wastewater.

Aminated graphene quantum dots/CdS nanobelts for enhanced photocatalytic degradation of RhB dye under visible light.

CdS nanoparticles have wide applications as photocatalysts for degradation of organic pollutants, but due to their limited turnover number and off-pathway charge recombination processes, their degradation efficiency is low. Herein, aminated graphene quantum dots/CdS (GQDs/CdS) nanobelts were successfully fabricated by solvothermal and hydrothermal processes. The prepared GQDs/CdS were characterized by physical methods to investigate their structure, morphology, optical properties, specific surface area, element composition, and chemical state. GQDs/CdS materials promoted efficient charge separation, and showed high efficiency in the photocatalytic degradation of the organic dye Rhodamine B (RhB) under visible light. The degradation efficiency of RhB samples over 0.05 g of catalysts reached 97.40% after 150 min, a much higher efficiency in comparison to pure CdS. Electron paramagnetic resonance (EPR) spectroscopy provided direct evidence for ˙OH and ˙O2- as the reactive oxidative species using DMPO as a spin trap. Consistent with the experimental results, a possible mechanism of RhB photocatalytic degradation by GQDs/CdS under visible light was proposed. This work may provide environmentally friendly photocatalysts for degrading organic dyes and purifying water.

Synthesis of visible-light-responsive lanthanum-doped copper ferrite/graphitic carbon nitride composites for the photocatalytic degradation of toxic organic pollutants

The aquatic ecosystems have been at high risk of destruction for the last many years due to the production and disposal of organic dyes from various textile and paint industries. A serious attention is required to cope with this environmental contamination by the removal of these dyes. An extremely effective and highly adaptive photocatalyst, La-CuFe2O4/g-C3N4 (LCFO/CN), was prepared by hydrothermal technique. The synthesized catalysts were carefully analyzed using a variety of characterization techniques in order to investigate the interaction among their catalytic activity and material characteristics. The Rhodamine B (RhB) dye was used to investigate the photodegradation efficiency of the LCFO/CN photocatalyst. An excellent photodegradation of 97.35 % was observed by the LCFO/CN-2 heterojunction photocatalyst compared to pure CFO (62.73 %), LCFO (67.13 %), and LCFO/CN-1 (83.14 %), respectively, under constant reaction conditions ([catalyst] = 0.4 g/L, [RhB] = 30 mg/L, pH = 6.0, T = 25 ± 1 °C). This enhancement of photodegradation of the RhB dye by the LCFO/CN-2 photocatalyst was due to an enhancement in surface area, an increase in active sites, and a reduction in bandgap energy. The effect of different factors was also determined by varying the reaction conditions. The generation of reactive oxygen species was accomplished through trapping agents and electron paramagnetic resonance analysis. The photostability and reusability of the photocatalyst LCFO/CN-2 nanocomposite were evaluated by performing five successive experiments under predefined reaction conditions. Ultimately, this work will provide an economically feasible and environment-friendly photocatalyst for the effective degradation of RhB dye in water bodies.

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.

Improving the photocatalytic dye degradation performance and bactericidal properties of Brazilian Amazon Kaolin-waste by adding ZnO and Ag3PO4

New sustainable methodologies for the technological valorization of industrial residues are essential for reducing environmental problems and for obtaining materials with high added value. Herein, a microwave synthesis method was used to produce ZnO/Ag3PO4 supported in Kaolin clay (Kaolin/ZnO/Ag3PO4) and applied to Rhodamine B (RhB) dye degradation under visible light and tested as an antimicrobial agent. The calcination process at 200 ºC was performed to verify if the photocatalytic and antimicrobial properties were improved. The calcined sample (KZAgc) shows a constant rate approximately 1.8 times higher than the non-calcined form in RhB dye degradation. This improved performance can be attributed to the efficient separation of photogenerated charge carriers through a Z-scheme mechanism where metallic Ag nanoparticles act as the charge transmission bridge. KZAgc sample also showed a potent antimicrobial action against Candida albicans, Staphylococcus aureus, and Escherichia coli. Therefore, the data obtained in this work demonstrate that this nanocomposite can be efficiently used for the degradation of RhB under visible light, and its calcined form can be mainly used in various environmental and medical applications due to its superior antimicrobial performance.

A facile synthesized Z-scheme Bi2O3/SnS/Ag ternary nanocomposite: An expedited visible photocatalysis by plasmonic silver for efficient organic decontamination

A facile precipitation and deposition method was used to synthesize the binary Bi2O3/SnS (2 & 4 wt %) and ternary Bi2O3/SnS (2 wt %)/Ag (2, 4, 6 & 8 wt %) nanocomposites. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence (PL) spectroscopy, energy dispersive X-Ray (EDX) spectroscopy, field emission scanning electron microscopy (FESEM) and photocatalytic degradation studies were carried out on all the nanomaterials for identify their characteristics and properties. Rhodamine B (RhB), an organic pollutant was taken to examine the photocatalytic efficacy of the resultant nanomaterials under visible light. Bi2O3/SnS and Bi2O3/SnS/Ag photocatalysts revealed the maximum activity in the acidic medium (pH = 3). As photocatalysts, ternary Bi2O3/SnS (2 wt %)/Ag (6 wt %) nanocomposite showed magnificent performance in the degradation of RhB dye (99.77% degradation in 50 min) as compared to binary Bi2O3/SnS (2 wt %) nanocomposite (99.02% degradation in 50 min). This is due to the formation of heterojunctions and deposition of Ag increasing the transfer of electrons through junction and resulting in intensifying the life expectancy of charged species and increasing the photocatalytic ability of Bi2O3/SnS/Ag nanocomposite. The role of trapping agents during the degradation process of RhB was also studied.

Enhanced photocatalytic activity in RhB dye degradation by Mn and B co-doped mixed phase TiO2 photocatalyst under visible light irradiation

Here, we report synthesis of undoped, manganese (Mn) doped, boron (B) doped and Mn-B co-doped TiO2 nanoparticles (NPs) by a cost-effective sol-gel method. The structural properties, phase, micro-morphology and particle size of the synthesized nanoparticles have been characterized by X-ray diffraction, Raman spectroscopy, Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) techniques. These studies revealed that undoped and mono (Mn/B) doped TiO2 NPs exhibit only anatase phase, whereas (Mn and B) co-doped TiO2 NPs exhibit anatase and rutile mixed phase structure. Furthermore, co-doping reduces the particle size, agglomeration in aqueous medium and the sample possesses crystal defects. UV–Visible diffusive reflectance spectroscopy (DRS) revealed that the co-doped sample demonstrates extended optical response in the visible wavelength range of the solar spectrum and is red shifted when compared to undoped and mono doped TiO2 NPs. The obtained optical band gap (2.11 eV) and the Urbach energy (1.12 eV) for the Mn and B co-doped TiO2 NPs suggest the formation of mid-gap energy states, which might make this NPs a suitable candidate for photocatalysis in the visible light spectrum. We investigated the photocatalytic degradation of rhodamine B (RhB) dye by the synthesized NPs under visible light irradiation. Our studies revealed that co-doped TiO2 photocatalyst can degrade 99% of RhB dye within 90 min of visible light irradiation and can retain 95% degradation efficiency up to the third consecutive cycles. Finally, we provide a plausible explanation for such enhanced visible light assisted photocatalytic performance.

Thermal Polymerisation Synthesis of g-C3N4 for Photocatalytic Degradation of Rhodamine B Dye under Natural Sunlight

The photocatalytic performance of g-C3N4 materials prepared by different precursors for Rhodamine B (RhB) dye degradation was studied. Their crystal structure, morphologies, chemical compositions, functional groups, and optical and photoelectrochemical performances of prepared g-C3N4 were analysed and characterised using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectra, photoluminescence, and electrochemical workstations. The degradation of RhB dye in the presence of visible light and sunlight was utilised to assess the photocatalytic efficiency of the g-C3N4 photocatalyst. The results of the photocatalytic comparison experiment showed that the g-C3N4 photocatalyst prepared with urea as a precursor (UCN) has the best photocatalytic performance, achieving 99.61% removal in 40 min. In addition, the photocatalyst UCN can completely degrade 10 mg/L RhB dye within 20 min under sunlight, demonstrating its potential for practical applications under natural sunlight conditions. After four cycles, the degradation rate remains above 99%, demonstrating excellent stability and reusability. Due to its lower average pore number, larger BET-specific surface area and volume of pores, UCN provides more activity spaces and facilitates the adsorption of pollutant molecules, thereby enhancing photocatalytic activity. It was established through the active substance trapping studies that the main reactive species involved in the photocatalytic degradation process of RhB dye is •O2−. This study showed that g-C3N4 synthesised with urea as the precursor has better photocatalytic performance in the degradation of RhB dye.

A smart and sustainable pathway for abatement of single and binary mixtures of dyes through magnetically retrievable Ca4Fe9O17 anchored on Biochar matrix

In this work, the author developed Ca4Fe9O17/biochar (CFB) via a green method through a facile co-precipitation procedure involving egg shells as calcium precursor and investigating its performance in single as well as binary solution of methylene blue (MB) and rhodamine B (RhB). The CFB nanocomposite was characterized by XRD, SEM, TEM, XPS, Raman, FTIR, BET, and VSM. ESR studies show the presence of hydroxyl (·OH) and superoxide (O2·¯) radicals, which are primary radical species for pollutant degradation. The average crystalline size of CFB nanocomposites was found to be 32.992 nm using XRD, whereas TEM analysis indicates a particle diameter of 35–36 nm. The degradation efficacy of MB and RhB dyes was achieved at 99.2% and 98.6%, respectively, in a single solution, whereas 99.4% and 99.2%, respectively, in a binary solution within 36 min. Additionally, an iron cluster was formed during the degradation process of MB dye. The degradation of organic contaminants and generation of iron clusters from the degraded dye products were both expedited by the remarkable extension effect of the Ca4Fe9O17 in the CFB nanocomposites. The three processes were achieved using CFB nanocomposite: (1) the advanced oxidation process; (2) degradation of MB and RhB dye in single as well as binary solution with enhanced efficiency, (3) the production of the iron cluster from degraded products. Thus, these three steps constitute a smart and sustainable way that leads to an effective effluent water treatment system and the generation of iron clusters preventing secondary pollution.

A new coordination polymer assembled by one rigid coligand for the photocatalytic degradation of rhodamine B

The perturbation in the environment by the discharge of toxic dyes in wastewater is a matter of concern and there is an urgent need to impart the balance. These organic dyes can be removed via catalytic degradation, adsorption or membrane filtration. In this study, we have developed a Zn(II)-based coordination polymer (CP) [Zn(bpyp)(HL-NO2)2]n(1) by solvothermal method using 2,5-bis(pyrid-4-yl)pyridine (bpyp) and 4-nitrobenzoic acid (HL-NO2) as organic linkers. The single crystal X-ray diffraction depicts that the Zn(II) adopts a tetragonal coordination environment and 1D linear chains are linked together to form a 2D framework via hydrogen bonding and π-π interactions. Methyl orange (MO), methyl violet (MV), methyl blue (MB) and rhodamine B (RhB) were investigated for photocatalytic degradation in the presence of visible light. Synthesized 1 shows 82% degradation of RhB dye. The Hirshfeld surfaces study demonstrated that these synthesized coordination polymers contain various forms of intermolecular contacts (C⋯C, H⋯C, H⋯H, and O⋯H).

Efficient Dye Degradation and Antibacterial Activity of Carbon Dots/Chitosan-Doped La2O3 Nanorods: In Silico Molecular Docking Analysis.

This work demonstrates the degradation of toxic RhB (rhodamine B) dye from polluted water in various pH environments. It assesses the antibacterial action of CDs (carbon dots)/CS (chitosan)-doped La2O3 (lanthanum oxide) NRs (nanorods). CS and CDs have been introduced as dopants to modify the characteristics of La2O3 to achieve efficient outcomes. The influence of doping on the structural, morphological, optical, and elemental properties of synthesized La2O3 NRs was investigated through a number of analytical techniques. The structural analysis of XRD revealed a hexagonal phase. The rod-like structure of pure La2O3 and reduction in the size of NRs upon doping were exhibited by TEM micrographs. From UV-vis spectroscopy, increased absorption upon doping and introduction of redshift that led to reduced bandgap energy were observed. The FTIR spectra indicate the presence of functional groups of pure and integrated samples. The catalytic activity of specimens in basic medium toward dye showed excellent results (94.57%). The inhibition zone of diameter 4.15 mm was evaluated by 6 mL of CDs/CS-doped La2O3 NRs against Escherichia coli once the surface area increased by dopants. In silico experiments were performed for enoyl-[acyl-carrier-protein] reductase (FabI) and DNA gyrase enzymes to assess the potency of CS-doped La2O3 and CDs/CS-doped La2O3 as their inhibitors and to justify their possible mechanism of action.

Hydrothermally Synthesized Cu<sub>2</sub>ZnSnS<sub>4</sub> Nanoparticles for Photocatalytic Degradation of Rhodamine B Dye

Industrial dyes contained a wide range of organic compounds that could affect the environment and high dimensional challenges to humans. In recent years, the environmentally safe and inexpensive quaternary copper-based chalcogenide Cu2ZnSnS4 (CZTS) has emerged as a material for photovoltaics and photocatalysis. CZTS nanoparticles were prepared in this investigation using the hydrothermal route at 210 °C for 24 h without the addition of a surfactant or capping agents. Rhodamine B (RhB), a carcinogenic dye, was degraded using the synthesized material through a photocatalytic process. The structural, morphological, optical, and photocatalytic characteristics of CZTS nanoparticles were examined using X-ray diffraction (XRD), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), and UV-vis spectroscopy. The average particle size of CZTS is found to be 31 nm with crystalline nature have been characterized by XRD. The results demonstrate that the synthesized sample has mixed morphological structures such as clew-like and flower-like structures and a bandgap of 1.50 eV. CZTS nanoparticles were used as photocatalysts under direct sunlight for Rhodamine B degradation, with the fastest degradation efficiency of 72% at 50 minutes. The results show that surfactant-free hydrothermally synthesized CZTS nanoparticles are a very promising material for the degradation of RhB dye due to the rapid degradation rate and high degradation efficiency.

Sonophotocatalytic degradation of Rhodamine B dye on MgWO4 crystals modified with AgNPs

In recent years, environmental problems caused by organic pollutants, especially industrial organic dyes, have caused severe environmental issues because they are potentially toxic and non-biodegradable carcinogens. Therefore, in this work, the magnesium tungstate (MgWO4) crystals were synthesized by the polymeric precursor method, followed by heat treatment at 900 °C for 2 h. Then, the obtained crystals were modified with silver nanoparticles (AgNPs) by the photoreduction method using silver nitrate solutions at ratios (m/m%) of 0.5%, 2%, and 4%. X-ray diffraction patterns and Rietveld refinement confirmed the presence of MgWO4 crystals with a wolframite-type monoclinic structure, emphasizing that the modification did not promote structural changes, only superficial ones. Raman and Fourier-transform infrared spectroscopies showed twenty-four active vibrational modes overall, seventeen active Raman modes, and seven IR-active modes. X-ray photoelectron spectroscopy (XPS) identified the peaks related to Mg, W, and O elements in all samples, and ascribed to Ag in the modified samples. In addition, field emission scanning electron microscopy (FE-SEM) images showed that both materials present a set of small aggregated particles with irregular shapes. Moreover, the UV–Vis absorption spectra showed a shift of the maximum band to a higher wavelength value from the modification with 2% and 4% of AgNPs with direct forbidden band energy between 3.87 and 4.00 eV. The crystals modified with 2% AgNPs present improved the catalytic properties that pristine MgWO4 crystals since they showed the best sonophotocatalytic (SPC) activity with the 92% degradation rate of Rhodamine B (RhB) dye in 240 min. Finally, we demonstrate for the first time that SPC activity in these crystals enables 74% RhB degradation even after four reuse cycles, while the radical scavengers assays indicated that holes (h) and hydroxyl (OH) radicals are the main ones responsible for the chemical reactions to RhB dye degradation.

Peroxymonosulfate activation with an α-MnO2/Mn2O3/Mn3O4 hybrid system: parametric optimization and oxidative degradation of organic dye.

The present study proposed the synthesis of low-toxicity and eco-friendly spherically shaped manganese oxides (α-MnO2, Mn2O3, and Mn3O4) by using the chemical precipitation method. The unique variable oxidation states and different structural diversity of manganese-based materials have a strong effect on fast electron transfer reactions. XRD, SEM, and BET analyses were used to confirm the structure morphology, higher surface area, and excellent porosity. The catalytic activity of as-prepared manganese oxides (MnOx) was investigated for the rhodamine B (RhB) organic pollutant with peroxymonosulfate (PMS) activation under the condition of control pH. In acidic conditions (pH = 3), complete RhB degradation and 90% total organic carbon (TOC) reduction were attained in 60 min. The effects of operating parameters such as solution pH, PMS loading, catalyst dosage, and dye concentration on RhB removal reduction were also tested. The different oxidation states of MnOx promote the oxidative-reductive reaction under acidic conditions and enhance the SO4•-/•OH radical formation during the treatment, whereas the higher surface area offers sufficient absorption sites for interaction of the catalyst with pollutants. A scavenger experiment was used to investigate the generation of more reactive species that participate in dye degradation. The effect of inorganic anions on divalent metal ions that genuinely occur in water bodies was also studied. Additionally, separation and mass analysis were used to investigate the RhB dye degradation mechanism at optimum conditions based on the intermediate's identification. Repeatability tests confirmed that MnOx showed superb catalytic performance on its removal trend.

Comparative investigation on physicochemical and photocatalytic properties of CuS and Al3+ doped CuS thin films

By using the chemical bath approach, CuS, and Al-doped CuS thin films were formed onto glass substrates. To enhance the photocatalytic capabilities of the traditional CdS thin film, Al3+ ions were used as doping element. Investigations were done into how the amount of Al doping affected the physical characteristics of CuS films by varying Al content as 2 wt%, 4 wt%, 6 wt%, and 8 wt%). The bandgap energy, thickness, morphology, and crystalline structure of CuS and Al-doped CuS thin films were examined. By using FTIR and FT-Raman studies, the functional groups contained in the CuS and Al-doped CuS thin films were observed. EDS was used to estimate the elemental components that are present in the prepared thin films. Degradation of the textile dyes rhodamine B (RhB) and methylene blue (MB) was used to examine the photocatalytic characteristics of the produced films. Among the produced films 8 wt% Al-doped CuS thin film showed high efficiency in degradation of both MB (98 %) and RhB (98 %) dyes.

Ag2O-adorned ZnO nanostructures: cooperative and sustainable nanomaterial system for effective reduction and mineralization of hazardous water pollutants

Organic water pollutants like nitroaromatics and synthetic dyes are causing serious threats to water. Ever-growing urban and industrial activities along with population explosion are rapidly contributing severe level of water contamination. Semiconducting nanomaterial-based photocatalysis has been proven to be an effective process for degradation of organic water pollutants. In the current study, visible light active Ag2O-adorned ZnO nanostructures were fabricated by a simple two-step hydrothermal method and the prepared nanostructures were utilized for the photocatalytic mineralization of rhodamine B (RhB) dye with visible light radiation. The catalytic potential of as-synthesized nanostructures was also investigated for the reduction of nitroaromatics (4-NP and 4-NA) and RhB dye in the presence of NaBH4. The Ag2O-adorned ZnO nanostructures prepared with 5% of silver nitrate denoted as ZnO/Ag2O (5%) demonstrated stupendous photomineralization activity against RhB dye as almost 100% degradation of RhB dye was achieved within 100min of reaction time at pH = 6. The kinetic study revealed that the degradation reaction followed the pseudo-first-order kinetics and the kinetic rate constant (k) of photodecolorization reaction for optimal catalyst was calculated to be 61.4 × 10-3min-1. The nanostructures revealed excellent recyclability and photostability as 95% activity of the catalyst was preserved even after the fifth cyclic run. The catalytic reduction of the 4-NP, 4-NA, and RhB dye was completed in 21, 12, and 40min, respectively, in the presence of ZnO/Ag2O (5%) and NaBH4 solution. The kinetic rate constant values for the reduction reactions were determined to be 229.6 × 10-3, 454.2 × 10-3, and 105.5 × 10-3min-1 for 4-NP, 4-NA, and RhB dye, respectively. Thus, the obtained results suggest that the components of the prepared nanosystem help in mutually strengthening the catalytic and photocatalytic abilities of each other, indicating the development of a cooperative and sustainable nanomaterial system in the current study.

Photocatalytic degradation of Rhodamine B dye using low‐cost pyrofabricated titanium dioxide quantum dots‐kaolinite nanocomposite

In this study, we report a simple technique for the pyrofabrication of a novel photocatalyst of titanium dioxide quantum dots‐kaolinite nanocomposite (TiO2‐QDs‐Kao) used for rhodamine B (RhB) dye degradation. The photocatalyst was characterized by using different analytical techniques, including XRD, XRF, XPS, FTIR, DTA/TGA, SEM–EDX, TEM, BET, BJH, ZP and UV–Vis DRS. The photocatalytic degradation of RhB was performed in aqueous solutions using the sustainable sunlight energy under atmospheric conditions and fixed neutral medium (pH = 7). The produced photocatalyst exhibited optical band gap energy of 2.85 eV, an improved large specific surface area of 107.724 m2/g with pore radius of 1.45 nm and total pore volume of 0.123 cm3/g. The study indicated a maximum 91% degradation efficiency of RhB after 120 min using the optimum dose 1,400 mg/l of the TiO2‐QDs‐Kao photocatalyst. The degradation of RhB dye fitted the Langmuir first‐order kinetics with rate constant 0.0151 min−1. The radical trapping experiments based on scavengers confirmed that the mechanism of photocatalytic degradation activity was potentially based on electron (e−) and hole (h+) conduction band. The potential energy of the valence and conduction bands EVB and ECB were calculated 2.73 and −0.12 eV, respectively. A triple reusability study confirmed a high stability of TiO2‐QDs‐Kao photocatalyst with detected degradation efficiencies of 91.0, 89.9, 88.8 and 87.5%, respectively.

Solar photocatalytic performance of glass substrates coated with Ag3PO4 thin films

Silver-orthophosphate (Ag3PO4) photocatalysts exhibit excellent photo-oxidative capabilities under visible light irradiation, especially in their powders form. However, Ag3PO4 in the form of thin films has not been explored that much and very little is known about their performance under solar irradiation. In the present study, glass substrates were coated with Cu-doped Ag3PO4 (Cu-Ag3PO4) and Ag3PO4 thin films using successive ionic layer adsorption and reaction (SILAR) due to its simplicity, relatively low-cost and ability to be performed at low temperatures with low time requirements. The as-deposited thin films were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV–Visible spectrophotometry, while their photocatalytic performances were evaluated on Rhodamine-B (Rh-B) dye degradation under real solar light irradiation. The adopted coating protocol resulted in regular thin films that crystallize in the desired P4̅3n cubic phase, where doping with Cu was shown to be responsible of a crystallite size reduction within the film. From the optical point of view, a broad absorbance in the entire visible range was obtained with bandgap energies of about 2.2 eV in the case of Ag3PO4 thin films, and around 1.65 eV in the case of Cu-Ag3PO4 thin films. Such optical features were exploited to test the photocatalytic performance in the degradation of Rh-B dye. After 4 h of solar irradiation, the variation of the relative concentration of Rh-B solution relative to the degradation efficiency of the photocatalysts was of 54% in the case of Cu-Ag3PO4 thin films and of 89% in the case of Ag3PO4 thin films. So, exploration of a wide area of the solar visible spectrum is made possible under doping, a finding that would improve the overall photocatalytic activity which is very promising for the degradation of other organic pollutants under solar irradiation.