Degradation Of Crystal Violet Research Articles

Photocatalytic application of nickel oxide/zinc oxide nanoparticles decorated kaolinite nanocomposite for the degradation of crystal violet

The photocatalysis process, which is effective, economical, and environmentally friendly can overcome rapidly increasing environmental problems, has shown rapid development in recent years. Nontoxic, low-cost natural minerals are often used in photocatalysis processes that remove organic pollution from wastewater. In this study, a selective method for the removal of crystal violet (CV) from aqueous solutions using nanocomposite of nickel oxide/zinc oxide nanoparticles (NiO/ZnO) supported on kaolinite photocatalyst was investigated. The raw kaolinite, bare NiO, bare ZnO and nanocomposite samples were characterized by the XRD, TEM, SEM-EDX, XPS and FTIR techniques. The photocatalytic performances of kaolinite-NiOZnO (K-NiO/ZnO) nanocomposite and bare samples were also investigated and comparatively evaluated by the photodegradation of CV (cationic dye) dye under visible light irradiation. The effects of various parameters such as the dosage of photocatalysis, contact time, and initial dye concentration on the rate of removal of dye were investigated and optimized. The kinetics of decolorization by samples can be well described by the pseudo-first-order model. Finally, it can be used in advanced oxidative processes for the degradation of organic pollutants.

Assembly of Fe@Zn-Coordination Polymer Composite: Iron Doping Foster the Luminescent Detection for Tetracycline, Uric Acid and Cr2O72− and Crystal Violet Degradation Efficiency

Coordination polymers exhibit a diverse array of applications across various fields, and through the development of composite materials, their utility and versatility are further enhanced, broadening their impact on our world. In this work We synthesized the first coordination polymer (CP) based on Zn and doped with Fe composites (Fe@Zn-CP Composite), which exhibit enhanced photocatalytic activity triggered by visible light. Using mixed ligands orotic acid potassium salt, 1,3 di (4-pyridyl) propane (dpp), and FeSO4 in a simple method at ambient temperature, the Zn-CP [Zn8(Or)8(dpp)4(H2O)8] was resynthesized here to form the Fe@Zn-CP composites. Zn-CP and Fe@Zn-CP Composite were both characterized by powder X-ray diffraction, FT-IR spectra analysis, and SEM-EDX analysis and elemental mapping analysis. It has been observed that Fe@Zn-CP Composite is as multi-functional luminescence sensor for MnO4−, Cr2O72− and Tetracycline with high sensitivity. In-depth research has also been done on the recyclable nature, and photocatalytic efficiency of Zn-CP and Fe@Zn-CP Composite for the decomposition of organic dyes Crystal Violet and Rose Bengal (RB) in contaminated water under the sunlight irradiation.

Sonication supported green modulation of Fe:MoO3/g-C3N4 heterojunction as solar light sensitive photocatalyst for dye degradation and photoelectrochemical water splitting

The concerns of dye in an aquatic system associated with acute toxicity and carcinogenicity, and the increase in demand for hydrogen production has led to a keen interest in advancing solar driven methodologies utilizing potent photocatalysts to address environmental concerns through sustainable remediation practices. In this pursuit, we synthesized a heterostructure comprised of Fe doped MoO3 (Fe:MoO3), anchored on g-C3N4 sheet as a photocatalyst denoted as Fe:MoO3/g-C3N4, employing a sonication supported green synthesis method with the aid of Murraya paniculata leaf extract. We explored structural, morphological, and surface characteristics using various analytical techniques, including X-Ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, Field emission scanning electron microscopy (FE-SEM) and High-resolution transmission electron microscopy (HR-TEM), X-Ray photoelectron spectroscopy, and BET for a comprehensive surface analysis. The outcomes highlighted the exquisitely oriented and interconnected arrangement of MoO3 nano rods ensconced within a piled layer of g-C3N4. The XRD patterns unveiled the coexistence of g-C3N4 and Fe:MoO3 within the heterojunction structure. FESEM and HRTEM image analysis of Fe:MoO3/g-C3N4 heterojunction reveals a g-C3N4 nanosheet wrapping the Fe:MoO3 nanoparticles with the formation of nanorods of MoO3 with an average thickness of 9.46 nm containing circular Fe nanoparticles with a mean diameter of 8.97 nm. This intricate configuration resulting in a decrease of the size of the nanoparticle caused by effective sonication-supported green modulation configuration facilitated an optimized charge flow, contributing to the elevated photo assisted catalytic performance of the heterojunction. The Fe:MoO3/g-C3N4 semiconductor heterojunction exhibited a considerable surface area and pore volume, inherently amplifying the sites of the activity on the surface and thereby enhancing photoactivity. As opposed to both g-C3N4 and the Fe:MoO3 nanoparticles, the Fe:MoO3/g-C3N4 semiconductor heterojunction showcased enhanced photocatalytic effectiveness in the degradation of dye Crystal violet (CV). Under optimized circumstances, the photo assisted degradation of dye CV by the semiconductor heterojunction adhered to pseudo-first-order kinetics. The active species responsible for the photo assisted degradation process is identified as •O2−. These findings not only emphasize the enhanced efficacy of the developed semiconductor heterojunction but also reveal its potential for addressing the environmental challenges posed by dye CV contamination through prolonged and efficient photocatalytic remediation practices. A marked improvement in both photo assisted catalytic and photoelectrochemical (PEC) water splitting activities under visible light exposure was showcased. The augmented performance of the Fe:MoO3/g-C3N4 semiconductor heterojunction in photodegradation and PEC water splitting activities can be attributed to the extended absorption of visible light. Additionally, the synergistic influence of g-C3N4, contributes positively to the separation of charges and expedites the transfer efficiency of photogenerated charge carriers. This synergy enhances the overall effectiveness of the nanoparticles in harnessing visible light for efficient water-related processes.

Decolorization and degradation of crystal violet dye by electron beam radiation: Performance, degradation pathways, and synergetic effect with peroxymonosulfate

Ionizing radiation (mainly including gamma ray and electron beam) technology provides a more efficient and ecological option for dye-containing wastewater treatment, which is supported by its successful achievements in industrial-scale applications. However, the degradation pathway of triphenylmethane dyes by radiation technology is still unclear. In this study, crystal violet (CV) was selected as representative cationic triphenylmethane dye, the decolorization and degradation performance by electron beam radiation technology was systematically evaluated. The results showed that CV can be efficiently decolorized and mineralized by radiation, and its degradation kinetics followed the first-order kinetic model. The effect of inorganic anions and chelating agents commonly existed in dye-containing wastewater on CV decolorization and total organic carbon (TOC) removal was explored. Quenching experiments, density functional theory (DFT) calculation and high performance liquid chromatography mass spectrometry (HPLC-MS) analysis were employed to reveal CV decolorization and degradation mechanism and pathway, which mainly included N-demethylation, triphenylmethane chromophore cleavage, ring-opening of aromatic products and further oxidation to carboxylic acid, and mineralization to CO2 and H2O. Additionally, electron beam radiation/PMS process was explored to decrease the absorbed dose required for decolorization and degradation, and the synergetic effect of radiation with PMS was elucidated. More importantly, the findings of this study would provide the support for treating actual dyeing wastewater by electron beam radiation technology.

Photocatalytic Degradation of Crystal Violet on Cu, Zn Doped BiVO4 Particles.

Fabrication of codoped photocatalysts is a developing area of research. Herein, we explore the visible light photocatalytic properties of Cu, Zn codoped BiVO4 particles. Doping lower valent cations (Cu and Zn) makes the BiVO4 surface more acidic and enables us to target the basic crystal violet (CV) dye. The adopted hydrothermal protocol of synthesis results in the formation of Cu-Zn codoped monoclinic BiVO4 particles. Undoped monoclinic BiVO4, prepared by the same protocol, showed significant formation of oxygen vacancies. XPS analyses confirm the coexistence of Cu2+/Cu+ and Zn2+ dopants. Increased dopant percentage reduced oxygen vacancies. XRD indicates that Cu2+/Cu+ or Zn2+ dopants generally substitute Bi3+ in BiVO4. All photocatalysis activities for CV degradation are reported under near-neutral pH conditions. A typical codoped BiVO4 photocatalyst with 1% Zn and 2% Cu demonstrated the best CV degradation photocatalytic activity. The activity of this Zn, Cu codoped photocatalyst is better than that of pure, Zn-doped, and Cu-doped BiVO4 samples. Active species trapping experiments indicated the possible photocatalysis mechanism. The photocatalysts exhibited appropriate recyclability and photostability.

TiO2 / Graphitic carbon nitride Z-scheme catalyst for binary dye degradation by persulphate activation

In this work, we describe the preparation of the TiO2 (P25) / Graphitic Carbon Nitride composite and the degradation of pollutants using this composite with persulphate activation. The materials are characterized by XRD, FTIR analysis, etc. XRD analysis confirms the presence of TiO2 anatase and GCN and the characteristic functional groups of both TiO2 and GCN are determined with the help of FTIR. The degradation of crystal violet and Rhodamine B in binary mixtures over this synthesized catalyst is easier than individual catalysts separately. The degradation efficiency of crystal violet over TiO2/GCN composite is 1.5 times higher than GCN and 3 times higher than TiO2 alone and the degradation efficiency of Rhodamine B over TiO2/GCN composite is 1.1 times higher than GCN and 2.4 times higher than TiO2 alone. In flat band analysis, a Z-Scheme catalyst is formed between TiO2 and GCN. The electron transfer between the bands of TiO2 and GCN occurs because of proper band alignment between these materials.

Recycled gold-reduced graphene oxide nanocomposite for efficient adsorption and photocatalytic degradation of crystal violet

In this study, gold-reduced graphene oxide (Au@rGO) nanocomposite has been synthesized by repurposing electronic waste and dry batteries. This innovative approach involved utilizing the graphite rod from dry batteries to produce reduced graphene oxide (rGO), which was subsequently modified through the incorporation of gold nanoparticles obtained from recycled electronic waste. This methodology marks a significant breakthrough in electronic waste recycling, presenting a cost-effective and sustainable means of creating novel nanocomposites for applications in photocatalysis and adsorption, particularly in the removal of crystal violet (CV) from aqueous media. The synthesized Au@rGO nanocomposite was characterized using X-ray diffraction, scanning electron microscopy, energy dispersed X-ray, and N2 adsorption/desorption. Parameters that affect the adsorption and photocatalytic degradation of CV dye have been studied in detail. The optimal conditions for CV adsorption and photocatalytic degradation were pH of 10, equilibrium time of 30 min, CV concentration of 10 mg/L and adsorbent dosage of 40 mg. Furthermore, the isotherm and kinetics of CV removal were also studied. The removal of CV dye using adsorption and photocatalytic degradation techniques reached 95% and 99%, respectively. Consequently, the results showed that photocatalytic degradation of CV dye onto the mesoporous Au@rGO nanocomposite is more proper way than the adsorption technique for removing the CV dye from aqueous media. The designed photocatalyst has high efficiency and it can be reused and activated several times so it can be used in real water treatment applications.

A Photocatalysis of CV Dye Under UV Light Degradation using Laboratory Prepared In(OH)3 And In2O3 By Hydrothermal Method: Nano-Matrrials For Dye Sensitive Solar Cell

Hollow microcubes with nanorods of Indium oxide (In2O3) are synthesized using hydrothermal followed by decomposition process. Synthesized materials are characterized with XRD, SEM, and FTIR spectroscopy for esteeming phase compositions and morphologies. The photocatalytic performances of two materials are evaluated by the degradation of crystal violet dye in an aqueous solution under UV light. The photocatalytic activity of prepared In(OH)3 shows ~60% degradation of crystal violet after 5 h reaction, whereas In2O3 shows ~92% degradation under same conditions.

New Y0.045Ni0.045Fe2.91O4 nanowires decorated over mesoporous silica for crystal violet removal: Response surface methodology optimization, kinetics, and isothermal studies

Recently, there has been considerable interest in developing an efficient, easily separable, cost-effective, and environmentally friendly catalyst for treating toxic environmental pollutants. In this study, we successfully designed yttrium–nickel-doped magnetite nanowires (Y0.045Ni0.045Fe2.91O4) and their mesoporous silica (MS)-coated composite (Y0.045Ni0.045Fe2.91O4/MS) using a simple coprecipitation method. The resulting composite demonstrated effective adsorption and photocatalytic degradation of crystal violet (CV) dye under sunlight. Various instrumental characterization techniques were employed to assess the nanowires' morphological, chemical, and surface functional properties and their composite. The existence of metal–oxygen bonds in Y0.045Ni0.045Fe2.91O4 within the 500–800 cm−1 range was verified through FTIR analysis. According to the Brunauer–Emmett–Teller analysis, the composite exhibited a surface area of 285 m2/g, a pore volume of 0.436 cm³/g, and an average pore width of 5 nm. The composite's high surface area and mesoporous nature underscored its porous structure, confirming its enhanced adsorption capacity for contaminants. High resolution XPS spectrum justified the presence of surface silanol groups (Si–OH) which are responsible for adsorption phenomena. Photocatalytic experiments revealed that Y0.045Ni0.045Fe2.91O4 nanowires and their composites achieved 89% and 90% degradation rates for CV dye within 60 and 10 min, respectively. The removal efficiency was assessed under optimized conditions of pH (8), dose (15 mg), time (60 and 10 min), and concentration (10 mg/L). Statistical analysis revealed that pH significantly impacted CV dye removal because functional group activation varied at different pH values. To elucidate the adsorption mechanism and kinetics, the Temkin isotherm model and pseudo-second-order kinetics model (R2 = 1.996 mg min−1) were the best fit for the composite. Furthermore, approximately 99% of the nanowires were magnetically separated from the reaction mixture in an external magnetic field. The demonstrated synergy of efficient adsorption–photocatalysis, coupled with easy recovery, suggests that innovatively designed nanomaterials are optimal for the water remediation of organic pollutants in wastewater.

Photodegradation of cationic and anionic dyes by ZnO and S/ZnO biosynthesized nano‐photocatalysts

Photocatalysis is considered a promising and efficient oxidation technique for wastewater treatment. Developing more environmentally biocompatible, simple, effective, and inexpensive photocatalysts enables photocatalysis technology to be at the forefront of wastewater treatments. As an alternative to harmful chemicals, this work focused on the biosynthesis of a variety of ZnO and doped ZnO based on the extract of the brown alga Cystoseira crinite. X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform‐infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–vis) spectroscopy were used to characterize the structure, phase, morphology, and UV–vis properties of the biosynthesized samples. XRD showed the crystalline structure of ZnO and S‐doped ZnO. SEM analysis revealed agglomerated spherical particles of the prepared samples. EDX analysis confirmed the formation of S‐doped ZnO. FTIR spectra exhibited that phenolic compounds and protein molecules are present in the Cystoseira crinite extract. The photocatalytic efficiency of biosynthesized materials was examined by monitoring the degradation of crystal violet (CV) and methyl orange (MO) dyes, which serve as cationic and anionic dye models, respectively. The various factors that influence the efficacy of the photodegradation process were investigated. In total, 5% S‐doped ZnO decomposed 97.40% and 89.18% of CV and MO dyes, respectively. The dye degradation was most efficient in samples calcined at 500 °C. The photodegradation of CV dye was enhanced at high pH, while the highest photocatalytic activity of MO dye was observed at low pH values. The kinetic study confirmed that the photodegradation follows the first‐order reaction.

Starch-assisted precipitation synthesis of molybdenum-doped WO3 nanoparticles for degradation of crystal violet and rhodamine-B dye under direct sunlight irradiation

Starch-assisted precipitation synthesis of molybdenum-doped WO3 nanoparticles for degradation of crystal violet and rhodamine-B dye under direct sunlight irradiation

Increase of the degradation activity of Phanerochaete chrysosporium by hybridization with silica nanoparticles

Silica nanoparticle–hybridized Phanerochaete chrysosporium mycelium pellets were prepared by a simple one-step composite technology–based approach, involving co-culturing of silica nanoparticles with this fungus under mild culture conditions. The hybrid generated displays a significant increase in peroxidase activity, which reaches a maximum on the fifth day of culturing. Hybridization causes a morphology change and significantly increases the rate of crystal violet degradation, the amounts of excreted extracellular manganese peroxidase and hydrogen peroxide, and the rate of glucose consumption. The results show that hybridization with silica nanoparticles significantly increases of the degradation activity of P. chrysosporium cells.

Cadmium oxide nanoparticles doped with nickel and silver: Photocatalytic activity for environmental remediation

In this work, we used a co-precipitation approach to create CdO nanoparticles that were co-doped with nickel (Ni) and silver (Ag). X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were employed to assess the structural attributes of the nanoparticles that were synthesized. Co-doping with Ni and Ag resulted in a steady rise in nanoparticle crystallite size, increasing from 20.97 nm to 32.16 nm. Following the co-doping procedure, FESEM pictures demonstrated a morphological shift from tiny, rock-like formations in pure CdO to bigger rock-like structures. Energy-dispersive X-ray spectroscopy (EDX) was utilised to explore the compositional characteristics of Ni and Ag-doped CdO nanoparticles. The existence of particles’ agglomerations was observed, which may have limited the real surface area available for gas adsorption and resulted in smaller apparent pore sizes in the Brunauer-Emmett-Teller (BET) investigation. Diffused Reflectance Spectroscopy (DRS) revealed a decline in the band gap from 2.45eV to 2.30eV, which was most likely caused by structural changes caused by cadmium ion replacement or the occupancy of interstitial spaces within the lattice by nickel and silver ions. The chemical and electronic states of the atoms were assessed using X-ray photoelectron spectroscopy (XPS), which examined the formation of defects in the form of oxygen vacancies, which contributed to accelerated photocatalytic performance. The deterioration of Crystal Violet (CV) dye during sunlight exposure utilising co-doped CdO nanoparticles vs pristine CdO is being evaluated in the evaluation of photocatalytic activity. Notably, co-doped nanoparticles improved photocatalytic activity significantly, with CV degradation reaching up to 95 % within 180 min of exposure. The potential of Ni and Ag impregnated CdO nanoparticles as effective photocatalysts for environmental remediation applications is highlighted in this study.

Optical, Dielectric, Magnetic, Photocatalytic, and Antibacterial Properties of Ga-Doped BiGaxFe1-xO3 Synthesized by the Microemulsion Approach.

The effect of Ga-substitution on bismuth ferrite BiGaxFe1-xO3 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25) properties was investigated, which was fabricated using a microemulsion route. X-ray diffraction analysis confirmed that specimens had a single-phase rhombohedral structure with space group R3̅c. The concentration of Ga had an impact on various properties such as structural parameters, crystalline size, porosity, and unit cell volume. The samples exhibited notable values for the dielectric constant, tangent loss, and dielectric loss in the low-frequency range, which declined as the frequency increased due to different polarizations. The increment in the AC conductivity was associated with rise in frequency. The P-E loops demonstrated that the samples became more resistive as the Ga concentration increased. The retentivity (Mr) and saturation magnetization (Ms) values reduced as the Ga content increased, although all samples had Hc values within the range for electromagnetic materials. The Ga-substitution had a synergistic effect on the electrochemical characteristics of BiGaxFe1-xO3, resulting in greater conductivity than that of undoped BiFeO3. These enhanced properties contributed to their higher photocatalytic activity in the degradation of crystal violet under visible light irradiation. The doped BiGaxFe1-xO3 exhibited 79% dye degradation after 90 min of illumination compared to 54% for pure BiFeO3. Recycling experiments confirmed the stability and reusability of the synthesized nanoparticles. The antibacterial activity of the samples was certified against various microbes, and the doped BiGaxFe1-xO3 showed promising activity. Thus, doped materials are good candidates for memories, dielectric resonators, and photovoltaics because of their high dielectric constant and AC conductivity, while their higher photocatalytic activity under visible light makes them promising photocatalysts for removing noxious and harmful effluents from wastewaters.

Modeling and Optimization of Hybrid Fenton and Ultrasound Process for Crystal Violet Degradation Using AI Techniques

This study conducts a comprehensive investigation to optimize the degradation of crystal violet (CV) dye using the Fenton process. The main objective is to improve the efficiency of the Fenton process by optimizing various physicochemical factors such as the Fe2+ concentration, H2O2 concentration, and pH of the solution. The results obtained show that the optimal dosages of Fe2+ and H2O2 giving a maximum CV degradation (99%) are 0.2 and 3.13 mM, respectively. The optimal solution pH for CV degradation is 3. The investigation of the type of acid for pH adjustment revealed that sulfuric acid is the most effective one, providing 100% yield, followed by phosphoric acid, hydrochloric acid, and nitric acid. Furthermore, the examination of sulfuric acid concentration shows that an optimal concentration of 0.1 M is the most effective for CV degradation. On the other hand, an increase in the initial concentration of the dye leads to a reduction in the hydroxyl radicals formed (HO•), which negatively impacts CV degradation. A concentration of 10 mg/L of CV gives complete degradation of dye within 30 min following the reaction. Increasing the solution temperature and stirring speed have a negative effect on dye degradation. Moreover, the combination of ultrasound with the Fenton process resulted in a slight enhancement in the CV degradation, with an optimal stirring speed of 300 rpm. Notably, the study incorporates the use of Gaussian process regression (GPR) modeling in conjunction with the Improved Grey Wolf Optimization (IGWO) algorithm to accurately predict the optimal degradation conditions. This research, through its rigorous investigation and advanced modeling techniques, offers invaluable insights and guidelines for optimizing the Fenton process in the context of CV degradation, thereby achieving the twin goals of cost reduction and environmental impact minimization.

Catalytic activity of Co (II)-porphyrin anchored onto polymeric support of electrospun polyacrylonitrile nanofiber: synthesis and efficient green oxidation of crystal violet dye with hydrogen peroxide

AbstractA novel method was explored in this study to address water contamination challenges by utilizing nanofiber mat-supported metalloporphyrin materials. Specifically, electrospinning was employed to create various compositions of polyacrylonitrile (PAN) mixed with different concentrations of Co(II) complex of tetrakis-5, 10, 15, 20 (4-hydroxyphenyl)porphyrin Co(II)TPHPP 1 anchored to chloroacetylated poly (p-hydroxy styrene) CAPS. These resulting nanofiber mat-supported metalloporphyrin materials were comprehensively analyzed using UV, FTIR spectrum, SEM, and TGA thermographs. The study found that the designed nanofibers acted as efficient catalysts for the oxidative breakdown of crystal violet (CV) dye using H2O2 in aqueous solutions. Among these materials, the nanofiber composed of a 1:1 ratio of PAN to Co(II)TPHPP/CAPS with a lower Co(II)TPHPP loading (NF6), demonstrated the highest catalytic activity, decomposing CV completely within 60 min. Various experiments were conducted to explore the effects of H2O2 concentration, catalyst dosage, and temperature on the catalytic degradation of CV with the NF6 nanofiber mat-supported metalloporphyrin. An interesting finding was the enhanced recovery and recyclability of the catalyst due to the immobilization of metalloporphyrin on chloroacetylated polymer-supported nanofiber mats. Remarkably, even after five cycles of reuse, there was no significant degradation in the catalytic activity of the recycled catalyst. This breakthrough highlights the potential of these materials in addressing water pollution challenges efficiently and sustainably.

Crystal violet degradation in the ozone/persulfate/ferroferric oxide system: A heterogeneous catalytic process for simultaneous catalysis of ozone and persulfate

Crystal violet (CV) is a widely used cationic triphenylmethane dye, mostly from textile, leather and other industrial manufacturing companies. The carcinogenicity, teratogenicity and mutagenicity of crystalline violet have received widespread attention, but due to the toxicity of crystalline violet itself, the It is difficult to degrade crystal violet by conventional wastewater biological treatment system. In this study, Fe3O4 was used to activate ozone and persulfate to degrade crystal violet in water. The results showed that the degradation of crystal violet followed a pseudo-second-order kinetic model and logistic model in the O3/PDS/Fe3O4 system, there was an obvious synergistic effect among ozone, persulfate, and Fe3O4. The effect of chelating agents and background components in aqueous solution on the degradation of crystalline violet in the O3/PDS/Fe3O4 system was investigated. The Radical quenching experiments and electron spin resonance spectra show that the generation of SO4•-, •OH, and 1O2 is the main cause of crystal violet degradation. After eight reuses of ferroferric oxide, the catalytic activity of Fe3O4 slightly decreased, but it still showed a high removal effect on crystal violet. The catalysis of Fe3O4 in O3/PDS/Fe3O4 system is mainly carried out by heterogeneous catalytic process, including electron transfer in Fe(Ⅱ)/Fe(Ⅲ) redox and lattice oxygen, catalytic ozonation process of surface hydroxyl groups. The O3/PDS/Fe3O4 system has an EE/O of 139.23 kWh·m−3 per order, indicating a higher energy efficiency compared to the other process. Intermediate products of CV degradation were identified by ultraviolet absorption spectrometry and liquid chromatography-mass spectrometry (LC-MS), and the degradation pathways of CV were determined.

Synthesis, structure, and improved photo/electrocatalytic performance of Co- and Ni-based metal-organic frameworks (MOFs) by using mixed ligands of 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpd) and 1,3-dicarboxyadamantane (H2adc)

Four MOFs with two identical structures were constructed by using 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpd) and 1,3-dicarboxyadamantane (H2adc) as linkers, and Co2+, Ni2+ as metal nodes by solvothermal method. Single-crystal X-ray diffraction revealed that complexes [Co2(adc)2(4-bpd)]n (1) and [Ni2(adc)2(4-bpd)]n (2) have the same two-dimensional molecular structure, while complexes [Ni(Hadc)2(H2O)2]n (3) and [Co(Hadc)2(H2O)2]n (4) exhibit identical one-dimensional chain-like molecular structures. The photo/electrocatalytic performances and thermal stability of four complexes were investigated. Introducing 4-bpd to form mixed-ligand complexes 1 and 2 enables the degradation of crystal violet (CV) dye in a Fenton-like system. Furthermore, there is an improvement in the oxygen evolution reaction (OER) catalytic performance among the MOFs of the same metal nodes. It is worth mentioning that in this study, Co-based MOFs showed better catalytic performance than Ni-based MOFs, which is mainly attributed to the distinctive electronic structure of Co2+ and Ni2+d orbitals.

Photocatalytic removal of crystal violet by C–MIL–53(Fe)@BiOI heterojunction: Process modeling and optimization

A facile synthesize protocol was utilized to prepare C–MIL–53(Fe)@BiOI photocatalyst with exceptional performance under 5-watt visible light irradiation. The prepared material was characterized for physio-chemical and optical properties. The EDX and N2 adsorption–desorption analysis revealed the heterojunction surface contained ∼ 71.48 % bismuth by weight, and a BET surface area of 12.96 m2/g. Box-Behnken design (BBD) was applied for the experimental study to optimize the process of crystal violet (CV) removal by low-powered LED irradiation. BBD also provided essential information on the effect of independent parameters i.e., pH, photocatalyst dose, CV concentration, reaction time, their interactions, and dye removal prediction under determined operating conditions. Screening tests indicated a significant improvement in catalytic performance for C–MIL–53(Fe)@BiOI composite compared to parent materials, MIL–53(Fe), and C–MIL–53(Fe). Maximum removal of 96.8 % was achieved for CV degradation at pH = 4, photocatalyst dosage = 0.55 g/L, CV concentration = 10 mg/L, and irradiation time = 38 min. Mechanistic study nominated OH. radicals as the most active species participate in CV degradation. C–MIL–53(Fe)@BiOI represents a viable material owing to the promising removal performance against cationic dye under low-energy irradiation.

Constructing a novel Ag2MoO4/MIL-101(Fe)/Ag composite for efficient crystal violet degradation via photo-Fenton-like process

This study presents a novel ternary Ag2MoO4/MIL-101(Fe)/Ag catalyst for efficient crystal violet (CV) degradation under visible light. Silver nanoparticles were in-situ generated on Ag2MoO4/MIL-101(Fe) through Ag2MoO4 reduction with NaBH4. Extensive characterization (XRD, FT-IR, FE-SEM, EDX, TEM, UV–Vis DRS, BET, PL spectroscopy) confirmed the catalyst's structure. The ternary composite exhibited significantly enhanced photo-Fenton catalytic activity, with reaction rates approximately 3.5 and 5 times faster than those observed with the Ag2MoO4/MIL-101(Fe) and pristine catalysts, respectively. Optimal conditions (H2O2 concentration of 50 mM, catalyst dosage of 2 g/L, pH 7, CV concentration of 25 mg/L, and temperature of 25 °C) were determined. Hydroxyl radicals dominated CV degradation, with minor contributions from electrons, holes, and superoxide radicals. The ternary composite showed excellent reusability, retaining over 92 % CV degradation efficiency after five cycles. The Ag2MoO4/MIL-101(Fe)/Ag composite demonstrates great potential for efficient and stable organic dye degradation, promising advancements in water treatment applications.