Methylene Blue Research Articles

Photosensitizer conjugated carbon dots@dopamine-copper sulfide nanocomposites: Advanced photoactive agents for antibacterial applications through experimental and theoretical insights

The massive use and abuse of antibiotics has given birth to drug-resistant bacteria and emergence of severe bacterial infections in people. Intriguingly, light activated antimicrobial activity i.e. antimicrobial photodynamic therapy has gained enhanced therapeutic potential and efficacy in killing the bacterial cells. Therefore, the present study investigates the efficacy of employing advanced nanocomposites for biocidal inhibition of bacterial growth through enhanced sterilization capabilities. Specifically, dopamine functionalized CuS NPs combined with carbon dots (CDs@Dop-CuS) were selected for their remarkable photodynamic potential when used in conjunction with methylene blue (MB). Comparative and synergistic application of Dop-CuS, CDs, and MB revealed the superior singlet oxygen generation potency of MB/CDs@Dop-CuS. Furthermore, the structural changes in the E. coli bacterial cells membrane were elucidated through scanning electron microscopy imaging, demonstrating superior inhibition rates of MB/CDs@Dop-CuS compared to MB alone under 660 nm irradiation. The commendable docking score and binding potential of CDs@Dop-CuS nanocomposites obtained via molecular docking simulations further validate their efficacy as photosensitizers against E. coli bacterial cells. Thus, this novel MB/CDs@Dop-CuS photosensitizer provides enhanced efficacy as an alternative to traditional antibiotic treatments, offering a superior disinfection for public utility services and addressing the growing issue of drug-resistant bacterial infections.

Characterization, biological activity and photodegradation efficacy of synthesized tryptophan capped silver nanoparticles

Tryptophan capped Silver nanoparticles (AgNPs) were synthesized through a sonochemical method, utilizing tryptophan as a biocompatible and non-toxic capping agent. Based on UV–visible spectra, the optical band gap of the nanoparticles was found to be roughly 3.01 eV. The TEM and XRD measurements of the particle sizes showed a range of 10–22 nm. Under sun irradiation, these nanoparticles showed notable photocatalytic activity, destroying Methylene Blue (MB) dye by more than 79.4 %. With a pseudo-first-order apparent rate constant of 1.5×10−2min-1, the degradation kinetics were observed. The photocatalysis of MB dye was investigated using liquid chromatography in conjunction with electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOF-MS) to determine the products generated and to clarify the degradation processes. Additionally, the antibacterial, anticancer potential showed thate the nanoparticles exhibited good antibacterial and notable anticancer properties. Furthermore, the antidiabetic activity was investigated through α-glucosidase inhibition, demonstrating a significant inhibition rate of 53.98 %. Antioxidant capabilities were also tested using ABTS and DPPH assays, revealing antioxidant activities of 73.9 % and 52.04 %, respectively. Overall, the synthesized tryptophan-capped AgNPs show promising applications in environmental remediation, as well as potential therapeutic uses.

Spent coffee to carbon: blending with manganese zinc ferrite as a plasmonic photocatalysis for degradation of organic dyes

ABSTRACT In this work, we introduce a new composite material consisting of Mn(1-x)ZnxFe2O4 (MZF) and wasted coffee grounds carbon (C). Crucially, the surface chemistry of the ‎composite, which lacks Zn2+ ions in octahedral locations, highlights its distinctive structural ‎characteristics. Before the integration of the carbon composite, the saturation magnetisation ‎of the sample was recorded as 53.073 emu/g. However, it decreased to 45.49 emu/g ‎after the composite was formed and the reaction processes occurred. UV-spectroscopy ‎enabled the measurement of band gap energies, which showed that the band gap energies for ‎ferrite were 2.93 eV and for the MZF/C composite were 2.12 eV. By utilising plasmonic ‎photocatalysis, the MZF/C composite has shown exceptional effectiveness as a high-temperature photocatalyst, specifically in the breakdown of methylene blue (MB) and Eosin (EO) dyes, ‎which are representative of basic and acidic dyes, respectively. The study demonstrated enhanced photocatalytic degradation kinetics under both visible light and sunlight, with sunlight showing superior performance. Over a 120-min period, the ferrite composite achieved a removal efficiency of 89% under sunlight, compared to 68% under artificial light. By utilising plasmonic photocatalysis principles, this work clarifies the structural and optical ‎properties of the MZF/C composite and emphasises its capacity to tackle environmental ‎issues through effective dye degradation mechanisms.‎

Polyethylenimine functionalized graphene oxide and cellulose nanofibril composite hydrogels: Synthesis, characterization and water pollutants adsorption

A stable 2,2,6,6-tetramethylpiperidine-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibril (TCNF)/graphene oxide (GO)/polyethylenimine (PEI) composite hydrogel was synthesized by self-assembly instead of chemical crosslinking. Their chemical, morphology, surface, and mechanical properties were characterized and adsorption behavior for methyl blue (–) was systematically investigated in terms of the optimal GO content, pH effect, kinetics, and isotherm models. Additionally, to assess the adsorption capability of the TCNF/GO/PEI hydrogel for various contaminants, its effectiveness was also tested for methylene blue (+), Cu (II), and soybean oils. The maximum adsorption capability for the methyl blue (−) dyes increased from 3125 to 3962 mg/g when 13.3 % of GO was added. The adsorption capability for Cu (II) and soybean oils rose from 205.3 to 218.5 and 2.1 to 7.2 mg/g, respectively. The adsorption capability of optimized TCNF/GO/PEI hydrogel for a variety of contaminants was improved overall based on the increase of surface area, electrostatic interactions, and hydrophobic domains. Moreover, adding GO did not impact the adsorption mechanism but increased the external diffusion rate in the intraparticle diffusion model. This work provides a self-assembling route to TCNF/GO/PEI hydrogels with great potential for the removal of multiple water pollutants.

Mesoporous Fe3O4@SiO2@La nanocomposite for efficient methylene blue removal from wastewater

This study investigates the synthesis and application of Fe3O4@SiO2@La mesoporous nanocomposites for methylene blue (MB) removal from wastewater. The successful synthesis of the nanocomposite was confirmed by various characterization techniques including FE-SEM, XRD, BET/BJH, and FT-IR. The adsorption efficiency of the nanocomposite for MB removal was evaluated under different operating conditions, including initial solution pH, adsorbent dosage, contact time, and temperature. The results revealed that the nanocomposite demonstrated optimal performance at neutral pH (pH=7), with an adsorbent dosage of 0.01 g, a contact time of 5 min, and 25 °C. Kinetic studies revealed pseudo-second-order kinetics, indicating chemisorption as the rate-limiting step. Langmuir and Freundlich isotherms were applied to describe the adsorption process. The nanocomposites demonstrated excellent reusability and high removal efficiency in real wastewater samples. The enhanced MB removal efficiency of the Fe₃O₄@SiO₂@La nanocomposites is attributed to electrostatic interactions, π-π stacking, and hydrogen bonding between MB and the adsorbent surface. Overall, the synthesized nanocomposites offer a promising and efficient solution for MB removal from wastewater, demonstrating potential for practical applications in environmental remediation.

Band gap engineering of ADG/NiO nanocomposite and applications for photocatalytic reduction of nitrogen and photo-oxidation of dyes

The use of solar-driven semiconductor photocatalysis to solve energy and environmental issues is an intriguing and difficult subject. As a consequence, various types of photocatalysts have been developed subsequently to fulfill the requirements of photocatalysis.Since graphene was discovered, materials based on graphene have garnered considerable interest. The aloe-vera derived (ADG)/nickel oxide (NiO) nanocomposite is a notable example of a graphene derivative.The uniform structure of graphene fibre is altered by nickel oxide(NiO) which tunes its band gap and causes electronic arrangements within graphene that is requiste for photocatalysis. Herein, we have used a one-pot chemical approach to design aloe vera-derived graphene/nickel oxide nanocomposites (ADG/NiO), a novel photocatalyst that show high molar absorbance, suitable band gap of 2.68 eV, good photo-stability and reusability. Under solar light irradiation, the ADG/NiO nanocomposite exhibited remarkable photocatalytic activity. It effectively fixed nitrogen into ammonia with an apparent quantum efficiency(AQE) of 0.64% and efficiently photo-oxidized dyes. Specifically, it achieved a dye removal efficiency of 94.2% for methylene blue (MB) and 86.41% for Eosin-B, converting them into harmless inorganic species like CO2 and H2O within just 90 minutes. The cost-effective ADG/NiO nanocomposite shows significant potential as a photocatalyst activated by solar light for practical applications such as the selective generation of NH3 and the purification of industrial wastewater containing dyes.

Garlic Peel-Based Biochar Prepared under Weak Carbonation Conditions for Efficient Removal of Methylene Blue from Wastewater

Background: Due to it containing cellulose, hemicellulose, and lignin with abundant specific functional groups which could interact with organic dyes, garlic peel (GP) might be used as an efficient biosorbent. The aim of this study is to evaluate the adsorption performances of GP-based bio-adsorbents and obtain optimum preparation conditions. Methods: GP-based bio-adsorbents were prepared by thermal pyrolysis under different temperatures (150–400 °C). The morphologies, chemical states, and surface functional groups of the adsorbents were analyzed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Batch experiments were conducted to investigate the adsorption of methylene blue (MB) under various conditions, including contact time, contact temperature, initial dye concentration, and initial pH value. The equilibrium adsorption data were fitted to different kinetic and isothermal models, and the adsorption thermodynamics were also calculated. Significant Findings: The physicochemical properties of the GP-based bio-adsorbents were primarily dominated by the pyrolysis temperature, because their morphologies and surface functional groups of GP-based bio-adsorbents significantly varied with the changes in pyrolysis temperature. The adsorption capacity of GP materials for MB decreased as the pyrolysis temperature increased. At an initial concentration of 50.00 mg L−1, GP150 possessed a higher adsorption capacity of 167.74 mg g−1 toward MB. The possible adsorbate–adsorbent interactions, including electrostatic attraction, hydrogen bonding, and π-π stacking, were recognized. After 10 consecutive adsorption–desorption cycles, GP150 maintained a high removal rate (88%) for MB, demonstrating its excellent adsorption performance, good reusability, and potential application in the treatment of MB-contaminated water.

Advanced nano modification of ecofriendly glauconite clay for high efficiency methylene blue dye adsorption

This research focuses on the utilization of nano glauconite clay as an environmentally friendly sorbent for the removal of cationic dyes, particularly Methylene Blue (MB), from polluted water. The glauconite clay was sourced from the El Gidida region of Egypt and subjected to grinding in a laboratory-type ball mill to ensure homogeneity and increase the active sites available for the adsorption process. The resulting ball milled nano clay (BMNC) was characterized using techniques such as X-ray fluorescence (XRF), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The concentration of MB dye was monitored using UV–Vis spectroscopy to assess the adsorption capacity of BMNC under various conditions including pH, time, dose, and temperature. The optimal conditions for the adsorption process were determined to be a pH range of 7–8, a contact time of 60 min, and a dose of 200 ppm, resulting in an adsorption capacity of 128 mg/g. This process demonstrated both low cost and high speed. The adsorption mechanism of MB on the BMNC surface was evaluated through kinetics, adsorption isotherms, and thermodynamics. The experimental data indicated an endothermic, spontaneous, and thermodynamically favourable adsorption process, which was further supported by simulated modelling results using Forcite program. The in-silico data aligned well with the experimental findings. Additionally, the study assessed the interference of salts, metal ions, and other dyes on MB adsorption onto BMNC, showing promising results. These findings strongly support the effectiveness of our sorbent substrate under challenging conditions.

Selective adsorption of cationic dye by κ-carrageenan-potato starch bio-hydrogel: Kinetics, isotherm, and thermodynamic studies

An eco-friendly κ-carrageenan/potato starch bio-hydrogel is designed for the efficient removal of methylene blue (MB) dye from water. The incorporation of potato starch was successfully confirmed through XRD, FT-IR, and SEM analysis, while TGA highlighted the hydrogel's thermal stability. Batch adsorption experiments demonstrated excellent MB removal efficiency, with a maximum adsorption capacity of 116.1 mg/g under optimal conditions (initial dye concentration: 100 mg/L, contact time: 180 min, temperature: 20 °C, adsorbent dosage: 1.6 g/L, and pH: 11). FT-IR analysis indicated that electrostatic interactions and hydrogen bonding primarily govern the adsorption process. The adsorption followed pseudo-second-order kinetics and fitted well with the Langmuir isotherm model. Thermodynamic studies revealed that the adsorption was exothermic and spontaneous. A key feature of this bio hydrogel is its selective affinity for the cationic dye MB, in a mixture with Acid Orange (AO) and other cationic dyes (Rhodamine B (Rh B) and crystal violet (CV)). The adsorbent also demonstrated impressive reusability, maintaining 93 % of its efficiency after five cycles, highlighting its potential for sustainable and cost-effective water treatment.

Laser-induced the enhancement of Raman scattering performance in WO3-x/Ag composite films

Non-stoichiometric tungsten oxide (WO3-x) has controllable defects, high charge density, and good synergy with other materials to exhibit good surface-enhanced Raman scattering (SERS) properties. Its heterojunction structure provides an opportunity to develop high-quality and low-cost SERS substrates. This study obtained WO3-x/Ag composite thin films were obtained by Nd: YAG fiber pulsed laser modification at ambient conditions. The effects of interactions between heterojunctions and laser modification on the samples’ morphology, composition, and optical properties were investigated. The absorption peaks exhibited a red shift by varying the laser scan speeds, and the SERS properties of the sample were evaluated by methylene blue (MB) dye. The results show that the laser-modified WO3-x/Ag films have good stability as SERS substrates. The characteristic peaks of MB can still be detected after 90 days in the air. The WO3-x/Ag films also have good homogeneity and a low detection limit, with a limit of detection (LOD) as low as 10−7 M, and an enhancement factor as high as 1.34 × 104. The simulated results by the finite difference in time domain (FDTD) showed substantial agreement with those of the experimental ones.

Enhancement of visible light adsorption and photocatalytic degradation activity of organic dye by coating semiconducting TiO2 shell on plasmonic Au particles

The plasmonic effect enhances light absorption in semiconductor photocatalysts, while the noble metal-semiconductor interface promotes charge carrier transfer and separation, boosting photocatalytic activity. However, current methods for synthesizing metal-core TiO2-shell nanoparticles face challenges, such as keeping stable and preventing aggregation. This study presents a simple and moderate synthesis method for Au@TiO2 core-shell nanoparticles, enabling precise control over the TiO2 shell thickness and stable photocatalytic performance. Various characterization techniques were employed to assess the optical and structural properties of the synthesized Au@TiO2 core-shell nanostructures. The results demonstrated that increasing the Au core concentration led to a gradual decrease in TiO2 shell thickness. The adsorption properties and photocatalytic degradation efficiency of the synthesized Au@TiO2 core-shell nanostructured catalysts were thoroughly examined, particularly focusing on their performance with methyl orange (MO) and methylene blue (MB). Au@TiO2 achieved excellent adsorption performance for MO, with a maximum capacity of 231±6 mg/g. Furthermore, Au@TiO2 exhibited higher photocatalytic degradation activity of both MO and MB than pure TiO2. The mechanism study indicated that it attributed to enhanced visible light absorption, reduced bandgap, and higher valence band energy. Additionally, the Au@TiO2 catalysts showed good cyclic stability, making them promising for future applications. This research offers insights into designing efficient photocatalysts, addressing existing synthesis challenges, and contributing valuable references for future advancements.

A novel BiVO4/vermiculite Z-scheme heterojunction with enhanced removal rate of dyes through adsorption photodegradation synergistic mechanism

Water pollution, exacerbated by industrialization, poses severe threats to aquatic ecosystems and human health, particularly due to persistent organic pollutants like dyes. To mitigate this issue, the development of effective and sustainable water treatment technologies is essential. This study presents the synthesis of a novel bismuth vanadate (BVO)/vermiculite (Vt) adsorption-photocatalytic self-cycling composite using a simple hydrothermal method. The composite's Z-scheme heterojunction structure, along with the introduction of surface oxygen vacancies, significantly reduces electron-hole recombination and enhances charge separation. These modifications lead to a 1.64-fold increase in adsorption capacity compared to Vt and a 6.4-fold improvement in photocatalytic efficiency over BVO. The material maintained a 76 % removal efficiency after five usage cycles and demonstrated high efficacy in methylene blue (MB) solutions, even at concentrations up to 300 mg/L. Moreover, the composite displayed stable performance under repeated use and in high-pollutant environments, highlighting its durability and practicality. These characteristics underscore its strong potential for widespread application in environmental remediation and sustainable water resource management, offering an innovative solution to the global challenge of water pollution.

Using zero nano-valent iron/thin film composite (ZNVI/TFC) membrane for brackish water desalination and purification

This study looked at the use of synthetic Zero Nano-valent Iron (ZNVI) particles in a unique interfacial polymerization technique on a polyamide thin film PA(TF) composite membrane for the treatment and desalination of brackish wastewater. Zero nano-valent iron (ZNVI) particles were created utilizing chemical reduction technique. ZNVI/PA(TF) NCs membrane is the outcome of advancing the PA(TF) membrane by combining with different concentration of ZNVI particles into the organic phase 1,3,5-benzenetricarbonyl trichloride (TMC). ZNVI/PA(TF) NCs membranes and ZNVI particles' surface properties were examined by the use of mechanical activity, contact angle, BET, FTIR, SEM, XRD, zeta potential, TEM analysis, and EDX studies. Using a variety of salt solutions, such as NaCl, Na2SO4, MgSO4, NaHCO3, CaSO4, CaCl2, and MgCl2, the ZNVI/PA(TF) NCs membrane performance towards salt rejection, flux (at varying pressure), anti-fouling activity, and ZNVI particles stability was assessed. This work investigated the removal efficiency of four dyes: methylene blue (MB), methyl orange (MO), Congo red (CR), and malachite green oxalate (MG). The water flux of the pristine PA(TF) membrane improved from 22 to 35 L/m2.h at 15 bar, indicating a 63% flux enhancement and the NaCl rejection was improved from 88.5 to 98.6%, indicating an 11.4% rejection improvement by incorporation of 0.3 wt.% of ZNVI particles into PA(TF) matrix. The ZNVI/PA(TF) NCs membrane's separation performances were evaluated using 5000 mg/L feed solutions of various salts at 15 bar. It was discovered that the water flux and salt rejection are, respectively, 33.4, 33, 32.7, 32, 31, 30 and 29 L/m2.h for CaSO4, MgSO4, Na2SO4, NaCl, CaCl2, MgCl2, and NaHCO3, and 97.4, 97, 96.5, 96, 94, 93.2, and 92.8%. It demonstrates that the flux recovery ratio (FRR) of the ZNVI/PA(TF) NCs membrane is greater than that of pristine PA(TF) (78%), coming in at 87%. High stability and fixing of the ZNVI particles on the modified membrane surface is indicated by the low overall ZNVI particles release rate over the course of the 10-day experiment.

Exceptional stability and reusability of Cu-doped ZnO:SnO2 nanocomposites for photocatalysis under visible light

In the present work, synthesis of Cu-doped ZnO–SnO2 nanocomposites was done by the hydrothermal method, to examine the photodegradation of methyl blue (MB) dye molecules under the exposure of visible light irradiation. Five samples were prepared with 0, 0.25, 0.50, 0.75, and 1 at.% of Cu, coded as CuZS0, CuZS1, CuZS2, CuZS3, and CuZS4, respectively. XRD and FTIR characterization techniques were used to analyse the structural properties and chemical bonding. FE-SEM confirms the gradual change in the morphology as CuZS3 shows the nano-capsule/rod-like morphology. The optical bandgap for the samples varied from 3.10 eV to 3.19 eV with Cu-doping. Photocatalytic activity of the samples show dependency on morphology as the degradation for CuZS0, CuZS1, CuZS2, CuZS3, and CuZS4 was found 60.5, 73.8, 79.6, 99.6, and 99.2 %, respectively. Optimized samples exhibit exceptional stability and reusability after five cycles, which was confirmed by post application characterization. Thus, prepared nanocomposites were found to be promising photocatalysts for organic pollutants.

Optimizing drying time of lacquer-based MTCS-modified SiO2-TiO2 coatings for enhanced mechanical durability, superhydrophobicity and photocatalytic activity

This research successfully improved the mechanical durability of a superhydrophobic coating on wet lacquer. Methyltrichlorosilane (MTCS) modified SiO2-TiO2 nanoparticles (NPs) were applied to a wet lacquer layer with various drying times using a simple spraying technique. The optimal coating exhibited superhydrophobicity with a water contact angle of 157° and a sliding angle of 2°. Additionally, the superhydrophobic surface could withstand over 100,000 water drops, 200 g of sand, and 40 tape-peeling repetitions, indicating high mechanical stability. Moreover, the superhydrophobic surface demonstrated photocatalytic activity by degrading methylene blue (MB) solution. The coating showed excellent adaptability to different substrates, including automotive body panels, with self-cleaning properties. This simple and effective strategy has potential for large-scale fabrication for practical applications in various industrial fields.

Carboxymethyl cellulose grafted poly(acrylamide)/magnetic biochar as a novel nanocomposite hydrogel for efficient elimination of methylene blue

Carboxymethyl cellulose grafted poly(acrylamide)/magnetic biochar as a novel nanocomposite hydrogel for efficient elimination of methylene blue

Sustainable and Reusable Modified Membrane Based on Green Gold Nanoparticles for Efficient Methylene Blue Water Decontamination by a Photocatalytic Process.

Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV-vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min-1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively.

Adsorption behavior of cationic dyes on starch nanocrystals: Kinetic, isotherm, and thermodynamic insights from single to multi-component systems

The adsorptive potential of starch nanocrystals (SNCs) was evaluated for the elimination of methylene blue (MB), crystal violet (CV), and malachite green (MG) from aqueous media in single, binary, and ternary dye systems using batch mode experiments. SNCs were extracted using mild acid hydrolysis to remove the amorphous parts of native granular starch, and they were characterized using different physicochemical methods, such as FESEM, XRD, FTIR, BET, TGA, and pHZPC. The results revealed that the optimal pH for dye removal in both single and mixed dye systems was found to be 9.0. The equilibrium time increased from 5 to 20 min when the system was changed from single to binary, and then further increased to 30 min when the system was changed to ternary. The equilibrium data for single-dye systems exhibited a good fit with the Langmuir isotherm model (R2 > 0.98, SEE <3.52 mg g−1), whereas for binary and ternary dye mixtures, the extended Langmuir model provided an accurate representation of the experimental data (R2 > 0.99, SEE <1.33 mg g−1). Among the single, binary, and ternary systems, the highest adsorption capacities were observed for MB, MB in the (MB + MG) binary system, and MB in the (MB + CV + MG) ternary system. The respective adsorption capacities were recorded as 79.55 mg g−1, 61.91 mg g−1, and 43.59 mg g−1. The adsorption of dyes onto the SNCs was inherently spontaneous and endothermic, and adhered to the pseudo-second-order kinetic model in single dye systems as well as mixed dye systems. It can be concluded that the SNCs are capable of being utilized for five consecutive cycles in the adsorption-desorption process for single dye systems and three consecutive cycles for mixed dye systems. This suggests that the SNCs have potential as a sustainable and efficient option for dye removal in mixture systems.

Solar driven highly efficient photocatalyst based on Dy2O3 nanorods deposited on reduced graphene oxide nanocomposite for methylene blue dye degradation.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution - transmittance electron microscopy (HR-TEM), field emission-electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV-visible diffusive reflectance spectroscopy (UV-Vis-DRS) studies revealed a band gap energy of 3.18eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10ppm. The remarkable photocatalytic performance was achieved within 60min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation.

Easy fabrication of PVA-CaO-CuO composite films for efficient photocatalyst: Towards distinct luminescence property, morphology and thermal stability

PVA-CuO-CaO composites in the film form were synthesized by loading the different compositions of metal oxides (CuO and CaO) ranging from 5 to 25 wt% via solvent casting approach. The applications of the prepared composites as photocatalysts were assessed together with the findings of photoluminescence (PL) characteristics, optical clarity, morphological features, and thermal properties. Fourier-transformed infrared (FTIR), ultraviolet–visible (UV–vis), and photoluminescence (PL) spectra exposed the systematic and viableintegration of metal oxides (CuO-CaO) into the PVA matrix in PVA-CuO-CaO composites. The modifications of PL property of PVA-CuO-CaO composites were recognized rather than bare PVA. The prepared composite films exhibited excellent optical transparency irrespective of the addition of metal oxides. Both TGA and DSC data showed that the thermal properties of the composites could be significantly enhanced by incorporating CuO and CaO. DSC measurements demonstrated that the Tm of PVA-CuO-CaO composites is improved substantially (∼7 to 38 °C) than PVA. The distinct morphological structures of the obtained composites were identified with variations in CuO and CaO addition remaining diameter in the 30–200 nm range. The photocatalytic assessments revealed the better photocatalytic performance of PVA-CuO-CaO composites for removing methylene blue (MB) than bare PVA. By eliminating organic pollutants, the current study may provide a new perspective on the preparation of water-processable PVA-CuO-CaO photocatalysts for wastewater management.