Methyl Orange Research Articles

Enhanced photocatalytic and antimicrobial properties of nickel-doped barium M-type hexaferrites synthesized via citrate sol-gel method

Industrial activities release waste into aquatic sources, which is hazardous because of the pathogenic and cytotoxic behaviour of the contaminants present in the effluent. To address this issue, the citrate sol-gel auto-combustion method synthesized nickel-substituted barium M-type hexaferrites BaNixFe12−xO19 (x = 0.0, 0.1, 0.2) nanoparticles. The nanoparticles show the single-phase hexaferrite structure having a crystallite size of 52.47 to 49.30 nm with the space group P63/mmc. Magnetic study of nanoparticles indicates that increased nickel ions give rise to saturation magnetization, whereas coercivity decreases. The band gap values of the pure and Ni-doped barium hexaferrites determined by Tauc plots have been noticed to range from 1.42 eV to 1.26 eV. The photocatalytic activity of nanoparticles for methyl orange (MO) dye has been investigated. The nanoparticles have shown a dye degradation efficiency of 84.5 % within 100 min. The antimicrobial properties of the synthesized nanoparticles have also been studied. The effectiveness of synthesized nanoparticles against two types of bacteria, gram-positive Staphylococcus aureus and gram-negative Escherichia coli, as well as against two pathogenic fungi, Candida albicans and Aspergillus niger, has been investigated. The antibacterial effect has been demonstrated by all samples at all concentrations, with MIC values ranging from 1 to 4 mg/ml. Therefore, this study investigates the potential applications of nickel-doped barium M-type hexaferrites nanoparticles in real-world biological settings, suggesting their promising role in fighting against bacterial and fungal infections.

Controllable preparation of red phosphorus nanoribbons for enhanced photocatalytic degradation of Methyl Orange and Tetracycline.

Nanoribbons (NRs), leveraging the flexibility of one-dimensional materials and the expansive surface area of two-dimensional materials, offer heightened exposure to edge sites and superior charge transfer rates. Consequently, they present promising prospects within the domain of photocatalysis. Crystalline red phosphorus (cRP), dcharacterized by its layered and fibrous structure, lends itself readily to the production of nanoribbons. Our study demonstrates a robust method for achieving high-yield, high-quality cRP by concurrently introducing mineralizing agent I2 and Si wafers into the Chemical Vapor Transport (CVT) synthesis process. Through ultrasound assistance, we transformed high-quality cRP into crystalline red phosphorus nanoribbons (cRP NRs) with an average thickness ranging from 7.5 to 17.5nm and an average width between 75 and 175nm. cRP NRs (I2 and Si) showcased impressive degradation capabilities towards Methyl Orange (MO) and Tetracycline (TC), achieving a remarkable 99% degradation of MO within 18min under the simulated visible-light irradiation. The reactive species capturing experiments confirmed that ·O2- was the primary active agent responsible for the photocatalytic degradation of MO.

Magnetic Silver Nanoparticles Stabilized by Superhydrophilic Polymer Brushes with Exceptional Kinetics and Catalysis.

Stimuli-responsive catalysts with exceptional kinetics and complete recoverability for efficient recyclability are essential in, for example, converting pollutants and hazardous organic compounds into less harmful chemicals. Here, we used a novel approach to stabilize silver nanoparticles (NPs) through magneto/hydro-responsive anionic polymer brushes that consist of poly (acrylic acid) (PAA) moieties at the amine functional groups of chitosan. Two types of responsive catalyst systems with variable silver loading (wt.%) of high and low (PAAgCHI/Fe3O4/Ag (H, L)) were prepared. The catalytic activity was evaluated by monitoring the reduction of organic dye compounds, 4-nitrophenol and methyl orange in the presence of NaBH4. The high dispersity and hydrophilic nature of the catalyst provided exceptional kinetics for dye reduction that surpassed previously reported nanocatalysts for organic dye reduction. Dynamic light scattering (DLS) measurements were carried out to study the colloidal stability of the nanocatalysts. The hybrid materials not only showed enhanced colloidal stability due to electrostatic repulsion among adjacent polymer brushes but also offered more rapid kinetics when compared with as-prepared Ag nanoparticles (AgNPs), which results from super-hydrophilicity and easy accumulation/diffusion of dye species within polymer brushes. Such remarkable kinetics, biodegradability, biocompatibility, low cost and facile magnetic recoverability of the Ag nanocatalysts reported here contribute to their ranking among the top catalyst systems reported in the literature. It was observed that the apparent catalytic rate constant for the reduction of methyl orange dye was enhanced, PAAgCHI/Fe3O4/Ag (H) ca. 35-fold and PAAgCHI/Fe3O4/Ag (L) ca. 23-fold, when compared against the as prepared AgNPs. Finally, the regeneration and recyclability of the nanocatalyst systems were studied over 15 consecutive cycles. It was demonstrated that the nanomaterials display excellent recyclability without a notable loss in catalytic activity.

A Comprehensive Comparison of the Structural, Ferroelectric, Energy Storage, and Photocatalytic Properties of Chemical Composition-Tailored Perovskite Ceramics

This article reports on the structural, ferroelectric, energy density, and photocatalytic properties of (Pb0.50Ba0.35Ca0.15)(Fe0.25Nb0.25Ti0.50)O3 [PBCTO] and (Pb0.50Ba0.50)(Fe0.25Nb0.25Zr0.1Ti0.40)O3 [PBZTO] ceramics synthesized by the solid synthesis route. X-ray diffraction and Raman spectra confirmed peaks corresponding to perovskite crystalline structure with tetragonal phase for both PBCTO and PBZTO ceramics. Slim ferroelectric hysteresis was observed in polarization-electric field measurements. Remnant polarization (Pr), and coercive field (Ec) values are ∼3.63 μC cm−2, ∼25.4 kV cm−1, and ∼1.39 μC cm−2 and 17.9 kV cm−1 for PBCTO and PBZTO, respectively. Energy densities were obtained from ferroelectric hysteresis loops. For PBCTO ceramics, the largest unreleased energy density is 0.72 J cm−3 @ 200 kV cm−1; for PBZTO ceramics, the largest unreleased energy density is 0.60 J cm−3 @200 kV cm−1. Photocatalytic performance was studied on methylene blue (MB) and methyl orange (MO) dyes under visible irradiation. The degradation percentage of MB dye in the presence of PBCTO and PBZTO was found to be 56% and 98% in 80 min with irradiation. The degradation percentage of MO dye in the presence of PBCTO and PBZTO at their respective wavelength was 48% and 97% in 120 min with irradiation. These bulk ceramics under study have shown interesting multifunctional properties useful for various potential applications.

Mechanistic studies on bioremediation of dye using Aeromonas veronii immobilized peanut shell biochar

Recalcitrant chemicals in the environment not only present obstacles to living organisms but also contribute to the degradation of natural resources. One contribution to environmental pollution is the discharge of synthetic dyes from the textile sector. This study investigates the combined effect of microbial cells and biochar on eliminating methyl orange (MO) dye. The immobilization of Aeromonas veronii on peanut shell biochar (APSB) was conducted to investigate its efficacy in removing MO dye from water. PSB synthesized by pyrolysis at 300 °C for 120 min showed maximum bacterial immobilization potential. The highest degradation rate of 96.19 % was achieved in APSB within 96 h using MO dye concentration of 100 mg L−1, incubation temperature of 37 °C, pH 7, and biocatalyst dosage of 1g L−1. In comparison, free cells achieved degradation rates of 72.53 % and 61.56 % for PSB. Moreover, the adsorption process was primarily controlled by PSB, with subsequent dye mineralization by A. veronii, as supported by FTIR and LC-MS studies. Moreover, this innovative approach exhibited the reusability of the biocatalyst, giving 76.23 % removal after fifth cycle, suggesting sustainable alternative in dye remediation and potential option for real-time applications.

Ultrasonic assisted removal of methyl orange and bovine serum albumin from wastewater using modified activated carbons: RSM optimization and reusability

Abstract The removal of industrial pollutants from water remains a significant challenge in water treatment processes. This study investigated the efficacy of powder-activated carbon (PAC), thermally modified PAC (TPAC), and chemically modified PAC (CPAC) for removing bovine serum albumin (BSA) and methyl orange (MO) from simulated wastewater. After undergoing treatment, the BET surface area of TPAC increased to 823 m2/g, while that of CPAC increased to 657 m2/g compared to the initial surface area of pristine PAC, which was 619 m2/g. Batch adsorption experiments assisted by ultrasonication were conducted to evaluate the impact of solution pH, initial concentration, and contact time on the adsorption capacities (qmax) of BSA and MO. TPAC demonstrated superior performance, achieving qmax values of 152 mg/g for MO and 133 mg/g for BSA, compared to PAC, which provided qmax values of 124 mg/g and 112 mg/g for BSA, respectively. Furthermore, pH levels of 3 and 5 were identified as highly effective for the removal of MO and BSA from water, respectively. The adsorption kinetics of both MO and BSA followed pseudo2nd-order (R2 > 0.99) reaction kinetics under both batch and ultrasonic conditions, confirming the removal of contaminants through chemisorption. The adsorption trends also satisfied the Langmuir isothermal model, indicating the formation of a uniform monolayer during the adsorption process of these contaminants. To understand the simultaneous effect of all the variables, response surface methodology (RSM) using central composite design (CCD) was used to predict the adsorption capacities of CPAC. After five adsorption cycles, the removal efficiencies of MO (from 98% to 80%) and BSA (from 55% to 40%) decreased in the CPAC system. The results suggested that CPAC can be effectively utilized to remove MO from wastewater.

Biogenic PAG-FeNPs from Prunus armeniaca (Gum) as robust colorimetric sensors for methyl orange detection

Biogenic synthesis of nanoparticles is an emerging research area of the scientific community holding versatile and potential applications. The nanoscaled iron nanoparticles (FeNPs) have unique chemical and physical properties. Beside the available physical and chemical methods, the aqueous extract of the Prunus armeniaca Gum (PAG) was employed to promote a green and sustainable approach for the synthesis of FeNPs. The structure and morphology of the FeNPs were characterized by SEM, FTIR, and XRD techniques. And UV–Vis spectrophotometry is employed to study optical properties, time, temperature, and pH dependent stability. Herein PAG-FeNPs has been employed as efficient and cost-effective colorimetric probe for the sensing of methyl orange (MO) for the first time displaying a color change from light orange to dark voilet on exposure to MO. The selectivity of the detection method for MO against various interferences including heavy metals, and organic dyes was examined and sensor’s signal remained unaffected by common interferences. Under ideal detection conditions, the proposed method demonstrates an excellent linear correlation (R2 = 0.992) in the concentration range of 10–350 µM methyl orange. The limits of detection and limit of quantification are 13 µM and 40 µM, respectively. Moreover, the technique has been successfully employed for detecting methyl orange in self-contaminated tape water samples.

Facile preparation of magnetic activated carbon from Peltophorum pterocarpum flowers for persulfate activation in methyl orange treatment

Herein, Peltophorum pterocarpum flowers (PPFs) were used to fabricate magnetic activated carbon (MAC) through one-pot pyrolysis with the addition of FeCl3 and KOH. XRD results proved that zero-valent iron crytals were formed in activated carbon (AC) bases. With 16.0 wt% Fe, MAC possessed a specific saturation magnetization of 35.6 emu/g, indicating its sufficient strength for magnetic separation. Furthermore, MAC had hierarchical porosity, characterized by a specific surface area of 69 m2/g and a total pore volume of 0.104 cm3/g. Subsequently, MAC was explored for activating persulfate (PS) in methyl orange (MO) decolorization. At pH 3.0, 30 °C, 5.00 mM PS, and 1.00 g/L MAC, 93.3 % MO (0.100 mM) vanished after 120 min. In reuse experiments, only 10.6 % of iron was leached from the MAC activator, and MO removal still remained at 77.7 % after five cycles. In summary, PPF-derived MAC showed effective potential in activating PS for MO elimination.

Ingenious development of bandgap engineered MIL-101(Fe) core-shell supported on SnO2/ZnO heterojunction and its photocatalytic activity towards azo dye degradation: Process optimization and mechanistic insight

Water pollution is a pressing global concern, exacerbated by industrial effluents containing hazardous azo-dyes such as Trypan blue (TB) and Methyl orange (MO), which contaminate water bodies and threaten ecosystems. The scarcity of pure water intensifies the urgency to develop effective remediation strategies to tackle the toxic dye pollutants. In the present work, an attempt has been made to fabricate and utilize a novel ternary MOF-based SnO2/ZnO@MIL-101(Fe) photocatalyst for the removal of TB and MO dyes from an aqueous medium. The photocatalyst was characterized using various analytical techniques, like XRD, FTIR, UV–vis DRS, PL, SEM, TEM, and XPS, which provide insights into the composites’ crystal structure, morphology, and optical properties, which are crucial for understanding their photocatalytic behavior. The photocatalytic performance of the heterojunction was investigated under various reaction parameters such as catalyst dosage, initial concentration of dyes, and light irradiation time. The results demonstrated the superior performance of the SnO2/ZnO@MIL-101(Fe) composites in degrading the mono-azo and di-azo dyes under visible light irradiation via a photo-fenton process. The maximum degradation efficiency of 97.44 % and 98.8 % were obtained for TB and MO within 30 and 55 min, respectively. Furthermore, the change in the total organic carbon (TOC) was monitored to verify the degree of mineralization of the azo dyes. The extremely high dye degradation activity and TOC removal can be attributed to the formation of a suitable heterojunction interface between the components of the photocatalyst, leading to effective charge carrier transport and the generation of active radicals. Finally, based on the radical scavenging experiments, ESR, and VB-XPS analysis, a plausible mechanism for the photodegradation process was derived. This research contributes to the advancement of sustainable water treatment technologies by providing insights into the design, fabrication, and utilization of novel composites for efficient remediation of dye-contaminated wastewater.

Construction of ZnCo2O4/Ag3PO4 composite photocatalyst for enhanced photocatalytic performance

AbstractIn this study, ZnCo2O4/Ag3PO4 composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, selected area electron diffraction, X‐ray photoelectron spectroscopy, and UV‐Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo2O4/Ag3PO4 composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo2O4/Ag3PO4 was 0.05301 min−1, which is 3 times and 52 times the rate constant of pure Ag3PO4 and pure ZnCo2O4, respectively. In catalyst recycling experiments, 0.1 ZnCo2O4/Ag3PO4 still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo2O4/Ag3PO4 is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo2O4/Ag3PO4 demonstrated the best photocatalytic performance.

Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticleswas accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0min and 3.0min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14min-1 and 2.15min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17s-1 for RhB, MG and 0.05s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

A maghemite (γ-Fe2O3) incorporated activated carbon photocatalytic nanocomposite fabricated via Co-precipitation utilized against degradation of methyl orange

The γ−Fe2O3/ACP has been synthesized in different ratios by facile co-precipitation method to degrade the methyl orange dye. In order to check the stability and potential of photo activated catalyst, UV, PL, SEM, XRD, EDX, FTIR and Zeta Potential are discussed here. The bandgap has been reduced from 2.06 eV to 1.86eV. Here, 1:3 γ−Fe2O3/ACP sample showed maximum reduced bandgap of 1.86 eV. The PL spectroscopy showed that 1:3 sample has less intensity, which in turn have 94 % photo degradation of methyl orange dye in 180min. The 1:3 sample showed 87 % degradation of methyl blue dye at 125mins light irradiation and proved as an optimal concentration of ACP in maghemite at pH of 11. The inclusion of carbon into maghemite enhances the overall properties by reducing the charge recombination rate. No impurity has been found in the final synthesized samples confirmed through EDX. The XRD and SEM revealed that size of crystallites and particle size increases, which confirms that bandgap is reduced. While trapping techniques and recycling techniques has been employed on the optimal concentration sample to check its stability towards degradation of methyl orange (MO) dye. The photo catalysis through such nanocomposite is not reported before. The 1:3 sample showed promising potential towards pollutants degradation in waste water treatment.

Solvothermal synthesis of Zr-based MOFs with mixed linker as adsorbent for methyl orange in water

Abstract UiO-66 is one type of Zr-based MOF consisting of ZrO4(OH)4 polyhedral. Synthesis of materials UiO-66 mixed linker with additional acetic acid modulator was successfully carried out by the solvothermal method at 120°C. UiO-66 modified with mixed linker can improve stability in water that has systematically and functionally modulated pores. When the concentration of each linker increases, the linkers merge in one place and produce cluster defects. UiO-66 mixed linker was synthesized with a ratio of adding H2BDC and NH2BDC of 3:1 to moles of ligand. The X-ray diffraction (XRD) pattern and Fourier transform infrared (FTIR) spectra of the synthesized material have the same pattern with the peak characteristics of UiO-66 and UiO-66-NH2. The synthesized material has a spherical morphology with a rough surface. The performance of the materials as an adsorbent for methyl orange (MO) dyes in water reached a maximum adsorption capacity of 202.82 mg/g for materials UiO-66 mixed linker (75% H2BDC and 25% NH2BDC). The adsorption results for all the synthesized materials followed the apparent pseudo-second-order kinetics and Langmuir isotherm. The adsorption mechanism between the adsorbent and methyl orange dyes consists of π-π interactions, hydrogen bonds, and electrostatic interactions.

Green approach for fabricating hybrids of food waste-derived biochar/zinc oxide for effective degradation of bromothymol blue dye in a photocatalysis/persulfate activation system

This study presents novel composites of biochar (BC) derived from spinach stalks and zinc oxide (ZnO) synthesized from water hyacinth to be used for the first time in a hybrid system for activating persulfate (PS) with photocatalysis for the degradation of bromothymol blue (BTB) dye. The BC/ZnO composites were characterized using innovative techniques. BC/ZnO (2:1) showed the highest photocatalytic performance and BC/ZnO (2:1)@(PS + light) system attained BTB degradation efficiency of 89.47% within 120 min. The optimum operating parameters were determined as an initial BTB concentration of 17.1 mg/L, a catalyst dosage of 0.7 g/L, and a persulfate initial concentration of 8.878 mM, achieving a BTB removal efficiency of 99.34%. The catalyst showed excellent stability over five consecutive runs. Sulfate radicals were the predominant radicals involved in the degradation of BTB. BC/ZnO (2:1)@(PS + light) system could degrade 88.52%, 84.64%, 81.5%, and 77.53% of methylene blue, methyl red, methyl orange, and Congo red, respectively. Further, the BC/ZnO (2:1)@(PS + light) system effectively activated PS to eliminate 97.49% of BTB and 85.12% of dissolved organic carbon in real industrial effluents from the textile industry. The proposed degradation system has the potential to efficiently purify industrial effluents which facilitates the large-scale application of this technique.

Using natural antioxidant Rhubarb extracts in PVA/chitosan bio-adsorbent films for efficient removal of cationic and anionic dyes from polluted water

In this research, sustainable membrane films were developed for removal of cationic and anionic dyes from wastewater based on polyvinyl alcohol/chitosan (PVA/CS) incorporated with natural antioxidant Rhubarb dye (Rh) extracts. Rh dye was extracted from Rhubarb roots by a green method. Three different quantities of Rh dye extracts (i.e., 2.5, 5, and 10 %) were used to fabricate crosslinked PVA/CS films by solvent-casting approach. The fabricated films subjected to different techniques such as X-ray diffraction (XRD), scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDX), dynamic mechanical analysis (DMA), as well as antioxidant activity. In all cases, the incorporation of Rh dye extracts inside the composite improved the crystallinity, biocompatibility, stress–strain properties, besides the DPPH scavenging activity reached 42.50 % for PVA/CS-10 % Rh membrane compared to PVA/CS blank (i.e., ∼ 2.10 %). Dyes adsorption including different cationic and anionic dyes implemented for all selected membranes. The data revealed that the membrane containing 10 % Rh dye was the optimum for removal of malachite green oxide (MG, 93 %) as cationic dye and methyl orange (MO, 95.70 %) as anionic dye. Moreover, the kinetics of the removal process exhibited that this process followed the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models, and the pseudo-1st order kinetic model, with an R2 of 0.998 and 0.943 for MG and MG, respectively. Whereas, the adsorption process corresponded to the Freundlich isotherm model, with coefficients R2 was of 0.989 and 0.988 for MO and MG, respectively. Other parameters including dye concentration, contacting time, pH media, and kinetic studies were also applied on PVA/CS-10 % Rh membrane.

Excellent Catalytic Performances of Embedded CoFe2O4 and TiO2 Nanoparticles on the Surface of Silica Matrix Toward Reduction of Toxic Cr (VI), Dyes, and Nitroaromatic Compounds

ABSTRACTA novel TiO2/CoFe2O4/SiO2 magnetic nanocomposite was successfully synthesized using sol–gel and hydrothermal methods. This nanocomposite consists of highly dispersed CoFe2O4 and TiO2 nanoparticles on the surface of the SiO2 matrix. The synthesis process involved the utilization of activated carbon, which played a dual role as a support for depositing the CoFe2O4 and TiO2 nanoparticles and as a rigid pattern for producing the silica matrix that enmeshed the nanoparticles. To study the unique characteristics of the samples, a range of analytical techniques, such as FT‐IR, VSM, XRD, SEM, N2 adsorption–desorption analysis, BET and EDX were employed. We carried out a complete examination of the catalytic performance of the TiO2/CoFe2O4/SiO2 nanocomposite for the reduction of different substances, including methyl orange (MO), safranin O (SO), methylene blue (MB), rhodamine B (RhB), chromium (VI) ions, and nitroaromatic compounds such as 2‐nitrophenol (2‐NP), 4‐nitroaniline (4‐NA), 2‐nitroaniline (2‐NA), and 4‐nitrophenol (4‐NP). The findings of our study demonstrate the remarkable efficacy of the TiO2/CoFe2O4/SiO2 nanocomposite in efficiently reducing dyes, Cr (VI), and nitroaromatic compounds to their desired forms in environmentally friendly aqueous solutions. Notably, the nanocomposite stands out due to its simple synthesis process, effortless recyclability, and its convenient separation by a magnet.

Ni-doped ZnO nanorods/Ti3C2 MXene composites and their photocatalytic performance

Herein, composites based on Ni-doped ZnO nanorods and Ti3C2 MXene structure (Ni-ZnO NR/Ti3C2) were produced via a simple hydrothermal method for photocatalytic applications. Special attention was paid to their structural and optical properties. The composite exhibited a photocatalytic effectiveness of 88.2% in degrading methyl orange (MO) within a duration of 75 minutes when exposed to a xenon lamp. The enhancement of the catalytic activity was due to the one-dimensional ZnO nanostructure, the Ni doping, and the Schottky heterojunction is formed by the interface within ZnO and Ti3C2. Therefore, this work provides an effective strategy to fabricate metal oxide/MXene photocatalysts.

Ti3C2TX MXene/loofah-derived carbon aerogel for high-efficiency adsorption of organic pollutants in wastewater

The contamination of wastewater by organic pollutants significantly impacts human health and the environment due to their carcinogenic nature and various adverse effects. To address this issue, this study offers a high-efficiency and low-cost biomass-based carbon aerogel adsorbent, which was prepared through the hydrothermal carbonization of loofah, followed by Ti3C2TX MXene impregnation. The aerogel features a porous three-dimensional network structure and a substantial specific surface area, facilitating broad-spectrum adsorption capabilities for various dyes and drugs. The aerogel achieved impressive adsorption capacities of 175.29 and 75.73 mg/g for cationic methylene blue and Rhodamine B dyes, and 106.33 and 93.29 mg/g for anionic methyl orange and Congo red dyes, as well as 86.25 mg/g for tetracycline hydrochloride, surpassing other reported biomass-based aerogels. Furthermore, it demonstrated effective decolorization ability for wastewater containing mixed dyes. Notably, it exhibited excellent recycling and regeneration properties, maintaining a high removal rate after multiple cycles of adsorption–desorption. The adsorption process of dye/drug by the aerogel followed Langmuir’s monomolecular layer adsorption model, exhibiting spontaneous, endothermic, and disorder-increasing behavior in alignment with the pseudo-second-order kinetic model. This study presents an efficient biomass-based aerogel for the removal of organic pollutants from wastewater.

Binary nano-systems TiO2-ZnO and TiO2-Cu in the chitosan matrix: synthesis and photocatalytic properties

Abstract Binary TiO2-ZnO and TiO2 - nanoparticles (NPs) Cu in a chitosan stabilizer matrix were obtained and studied as photocatalysts at their content relative to the mass of the dry polymer of 10 wt.%. The effect of the mass ratio of TiO2:ZnO, TiO2:Cu NPs was revealed on the photocatalytic properties of materials in the decomposition reaction of methylene orange when exposed to UV and visible light. It is shown that the greatest depth of decomposition of the azo dye - 98% – in an aqueous solution is achieved in 60 minutes of light exposure using the system TiO2:ZnO with a mass ratio of 1:1 and 2:1 components. The same level of photocathaitic activity – a decrease in the concentration of methylene orange by 95-98 % is achieved when using the system TiO2: Cu NPs at a mass ratio of 10:1 and 5:1 components.

Synthesis and catalytic activity of core-shell gold-palladium nanoworms towards the catalytic reduction of 4-nitrophenol and methyl orange

The Au-Pd core–shell nanostructures have gained attention as a promising catalyst and exhibit outstanding stability and selectivity in pivotal chemical reactions. This work demonstrates a facile seed-mediated approach for depositing the shell of Pd on worm-shaped Au nanostructures. The control over Pd content on Au nanoworms (NWs) was achieved by adjusting the concentration of tetrachloropalladic acid (H2PdCl4) in the deposition solution. The bent morphology, surface roughness, and polycrystalline structure of the Au NWs ensured that at lower H2PdCl4 concentrations, Pd formed an island-like structure on the Au NWs’ surface. In contrast, increasing the H2PdCl4 concentration led to the formation of a complete Pd shell encasing the Au NWs. The catalytic activity of the Au-Pd core–shell (Pd@Au) NWs exhibited a significant improvement compared to uncoated Au NWs, which has been attributed to the synergetic effect of the two metals. However, it was observed that an optimum Pd-coating was necessary to obtain the best catalytic performance and a further increase in Pd content led to the degradation of the catalytic activity. Specifically, the rate constant of the reduction reactions of 4-nitrophenol (4-NP) and methyl orange (MO) was increased by 6.3 and 3.1 folds, respectively, for the optimized Pd@Au NWs.