Degradation Rate Of Methyl Orange Research Articles

The Synthesis of Ag/TiO2 via the DC Magnetron Sputtering Method and Its Application in the Photocatalytic Degradation of Methyl Orange in Na2SO4 Solution

TiO2 and TiO2 films modified with Ag (Ag/TiO2) were prepared via the DC magnetron sputtering method and the degree of modification was controlled via the sputtering power and time of Ag. The microstructures and properties of these films were characterized using field emission scanning electron microscopy, X-ray diffractometry, ultraviolet–visible diffuse reflectance spectrometry, atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). The results show that the prepared films have an anatase structure. Compared with pure TiO2, Ag deposition can improve the utilization of light. The three-dimensional images of Ag/TiO2 clearly show that with the increase in Ag sputtering power and sputtering time, Ag particles on the surface of the film gradually increase, and the structure of the film is relatively dense. The photocatalytic effect of Ag/TiO2 films is the best when the Ag sputtering power is 5 W and the sputtering time is 50 s. Under high-pressure mercury lamp irradiation, the photocatalytic degradation rate of methyl orange (MO) in pure MO solution with Ag/TiO2-5 W-50 s can reach 100% within 55 min, whereas that in MO-Na2SO4 mixed solution can reach 99.55% within 65 min. The results suggest that the presence of Na2SO4 in MO solution can inhibit the degradation of MO using Ag/TiO2, the result of XPS suggests that Na2SO4 accelerates the oxidation of Ag, which may lead to an increase in the recombination rate of photogenerated electron–hole pairs and a decrease in the degradation rate. During the process of recycling photocatalysts, the degradation rate of MO was apparently reduced. A possible reason is that the Ag particles have been oxidized and products of photocatalytic degradation are on the surface of the photocatalyst. The photocatalytic degradation mechanism was studied.

Efficient Catalytic Degradation of Methyl Orange by Various ZnO-Doped Lignin-Based Carbons.

Herein, a series of ZnO-doped lignin-based carbons (LC/ZnO) were successfully prepared from different types of lignin and used for methyl orange (MO) photocatalytic degradation. The apparent morphology, internal structure, and photoelectric properties of prepared LC/ZnO composites and their effects on subsequent MO photocatalytic degradation were investigated by various characterization techniques. The results showed that the LC/ZnO composites that were prepared in this work mainly consisted of highly dispersed ZnO nanoparticles and lignin-based carbon nano-sheets, which were beneficial for subsequent photogenerated electrons and holes formation, dispersion, and migration. The MO could be significantly degraded with various ZnO-doped lignin-based carbons, especially over the LCSL/ZnO, and the maximum degradation rate was 96.9% within 30 min under the simulated 300w sunlight exposure. The experiments of free radical elimination showed that the photocatalytic degradation of MO over LC/ZnO were a result of the co-action of multiple free radicals, and h+ might play the predominant roles in MO degradation. In addition, the pH of the solution had little effect on MO degradation, and the MO could be effectively degraded even in an alkaline solution of pH = 12.0. The cycling experiments showed that the prepared LC/ZnO had a good stability for MO photodegradation, especially for LCSL/ZnO, even after 5 times recycling, and the degradation rate of MO only dropped from 97.0% to 93.0%. The research not only provided a fundamental theory for the efficient photocatalytic degradation of MO by LC/ZnO composites, but also offered a new insight into lignin valorization.

Efficient removal of amoxicillin and methyl orange with antibacterial activity assessment via nanostructured ZnO coatings synthesized by ultrasonic spray pyrolysis method

Our study explores the potential of ZnO nanostructured coatings synthesized through ultrasonic spray pyrolysis and focuses on the dual functionality of these coatings: efficiently removing amoxicillin and methyl orange, while also assessing their antibacterial activity. The characterization techniques used in this work include Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Photoluminescence spectroscopy (PL), X-ray Photoelectron Spectroscopy (XPS) and UV–visible spectroscopy. The degradation rates of amoxicillin and methyl orange were studied through the decrease in absorption bands at 228 nm and 436 nm, respectively, under UV irradiation. By closely analyzing the responses of Pseudomonas Aeruginosa, Bacillus Cereus and Bacillus Subtilis bacteria, zinc oxide thin films demonstrate antibacterial efficacy due to the attraction of opposite charges to the bacterial surface, which influences the oxidation process of the membrane, ultimately resulting in cellular death.

Chitosan derived N-doped carbon anchored Co3O4-doped MoS2 nanosheets as an efficient peroxymonosulfate activator for degradation of dyes

Peroxymonosulfate (PMS), which is dominated by non-free radical pathway, has a good removal effect on organic pollutants in complex water matrices. In this article, a biodegradable cobalt-based catalyst (Co3O4/MoS2@NCS) was synthesized by a simple hydrothermal method with chitosan (CS) as nitrogen‑carbon precursor and doped with Cobaltic‑cobaltous oxide (Co3O4) and Molybdenum disulfide (MoS2), and was used to activate PMS to degrade dye wastewater. Electrochemical tests showed that Co3O4/MoS2@NCS exhibited higher current density and cycling area than MoS2@NCS and MoS2. In the Co3O4/MoS2@NCS/PMS system, the degradation rate of 30 mg·L−1 rhodamine B (RhB) reached 97.75 % within 5 min, and kept as high as 94.34 % after 5 cycles. Its rate constant was 1.91 and 8.37 times that of MoS2@NCS/PMS and MoS2/PMS, respectively. It had good complex background matrices and acid-base anti-interference ability, and had good universality and reusability. The degradation rate of methyl orange (MO) and methylene blue (MB) were more than 91 % within 5 min at pH 4.8. The experimental results demonstrated that MoS2-modified CS as a carrier exposed a large number of active sites, which not only dispersed Co3O4 nanoparticles and improved the stability of the catalyst, but also provided abundant electron rich groups, and promoted the activation of PMS and the production of reactive oxygen species (ROS). PMS was effectively activated by catalytic sites (Co3+/Co2+, Mo4+/Mo5+/Mo6+, CO, pyridine N, pyrrole N, hydroxyl group and unsaturated sulfur), producing a large number of radicals that attack RhB molecules, causing chromophore cleavage, ring opening, and mineralization. Among them, non-free radical 1O2 was the main ROS for RhB degradation. This work is expected to provide a new idea for the design and synthesis of environmentally friendly and efficient MoS2-modified cobalt-based catalysts.

Catalytic wet peroxide oxidation of organic dye with in-situ generated H2O2 over bifunctional Fe-Pt@Pd/SiO2 catalyst prepared by double-metal complex salt approach

While the Fenton reaction is efficient in wastewater treatment, the intrinsic problem of the dosage-dependent process poses another burden on ecosystem. Herein, we propose a highly efficient and environmentally-benign catalytic wet peroxide oxidation (CWPO) of methyl orange (MO) using in-situ generated H2O2 from hydrogen and air instead of ready-made H2O2. Pt@Pd/SiO2 and Pd@Pt/SiO2 catalysts were prepared by double-metal complex salt approach, and they were combined with soluble Fe salt (CWPO-I) or impregnated Fe (CWPO-II). The MO degradation rate of Pt@Pd/SiO2 for CWPO-I was 2.5 times faster than that of the conventional PdPt/SiO2. This can be rationalized in terms of Pd-enriched surface with strong interaction between Pt and Pd. Moreover, bifunctional Fe-Pt@Pd/SiO2 catalyst demonstrated outstanding activity in promoting CWPO-II with in-situ generated H2O2, even outperforming its counterpart with ready-made H2O2. This new approach offers an efficient water remediation method free from addition and generation of any undesirable chemicals affecting environment.

Degrade Methyl Orange by Combining Cu2O/Al2O3 and H2O2 as Catalyst

To efficiently degrade printing and dyeing wastewater at low costs, Cu2O/Al2O3 catalyst was prepared by electrochemical method. Under its combined action with H2O2, photocatalytic degradation of methyl orange solution, as simulated wastewater, was carried out. With the aid of X-ray diffractometer, X-ray microanalysis system and scanning electron microscope, the structure and composition of catalyst film were designed by adjusting the electrochemical parameters, and the performance of photocatalyst was evaluated by the degradation rate of methyl orange. It was found that after anodizing aluminum alloy for 2 h in a 2 mol/L H2SO4 solution under a voltage of 15 V, alumina film with reasonable pore size distribution could be prepared on the alloy surface. By electroplating the film in a 0.01 mol/L CuSO4 solution at 5°C, and then hydrothermally treating it at 200°C, the Cu2O/Al2O3 photocatalyst could be obtained. The prepared Cu2O/Al2O3 and 10% H2O2 were used jointly as photocatalyst to degrade 10 mg/L methyl orange solution for 480 min, which achieved a methyl orange degradation rate of up to 82.1%.

Research Progress on Photocatalytic Degradation of Methyl Orange Dye Wastewater by Light‐assisted Composite‐modified Ag3PO4

AbstractA new type of modified catalyst was prepared by a silver ammonia‐assisted precipitation method through a custom‐built electrochemical reactor, and the catalytic degradation of the azo dye methyl orange was studied under the synergistic effect of visible light. The optimum doping ratio for the loading of graphene oxide (GO) is 1.0 %. Under the optimum conditions, the degradation rate of Ag3PO4/GO/NiFe2O4 to methyl orange is 97.56 % when the light reaction time is 50 min. After three cycles, the degradation rate of methyl orange by Ag3PO4/GO/NiFe2O4 is 94.47 %. Through the free radical capture experiment, it is known that the contribution degree of the main active substances in the photocatalytic degradation of methyl orange is h + >⋅O2− >⋅OH. By forming a Z‐type heterojunction between Ag3PO4 and NiFe2O4, the recombination probability of photogenerated carriers is greatly reduced, and the stability of Ag3PO4 is improved.

Dodecahedral hollow multi-shelled Co3O4/Ag:ZnIn2S4 photocatalyst for enhancing solar energy utilization efficiency.

Employing semiconductor photocatalysts featuring a hollow multi-shelled (HoMs) structure to establish a heterojunction is an effective approach to addressing the issues of low light energy utilization and severe recombination of photogenerated charge carriers. To take advantage of these key factors in semiconductor photocatalysis, here, a dodecahedral HoMs Co3O4/Ag:ZnIn2S4 photocatalyst (denoted as Co3O4/AZIS) was firstly synthesized by coupling Ag+-doped ZnIn2S4 (AZIS) nanosheets with dodecahedral HoMs Co3O4. The unique HoMs structure of the photocatalyst can not only effectively promote the separation and transfer of photo-induced charge, but also improve the utilization rate of visible light, exposing rich active sites for the photocatalytic redox reaction. The photocatalytic experiment results showed that the Co3O4/90.0 wt% AZIS photocatalyst has a high hydrogen (H2) production rate (695.0 μmol h-1 g-1) and high methyl orange (MO) degradation rate (0.4243 min-1). This work provides a feasible strategy for the development of HoMs heterojunction photocatalysts with enhanced H2 production and degradation properties of organic dyes.

Application of 3D printing technology for green synthesis of Fe2O3 using ABS/TPU/chlorella skeletons for methyl orange removal.

Photocatalysis is widely acknowledged as an efficient and environmentally friendly method for treating dye-contaminated wastewater. However, the utilization of powdered photocatalysts presents significant challenges, including issues related to recyclability and the potential for secondary pollution. Herein, a novel technique based on 3D printing for the synthesizing of iron oxide (Fe2O3) involving chlorella was presented. Initially, chlorella powders were immobilized within acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) substrate plastics using melt extrusion technology. Subsequently, these composite materials were transformed into ABS/TPU/chlorella skeletons (ATCh40), through fused deposition molding (FDM) technology. The integration of Fe2O3 onto the ATCh40 (ATCh40-Fe2O3) skeletons was accomplished by subjecting them to controlled heating in an oil bath. A comprehensive characterization of the synthesized materials confirms the successful growth of Fe2O3 on the surface of 3D skeletons. This strategy effectively addresses the immobilization challenges associated with powdered photocatalysts. In photocatalytic degradation experiments targeting methyl orange (MO), the ATCh40-Fe2O3 skeletons exhibited a remarkable MO removal rate of 91% within 240 min. Under conditions where the pH of MO solution was maintained at 3, and the ATCh40-Fe2O3 skeletons were subjected to a heat treatment in a 150 °C blast drying oven for 2 hours, the degradation rate of MO remained substantial, achieving 90% removal after 6 cycles. In contrast, when the same synthetic procedure was applied to ABS/TPU (AT) skeletons, the resulting product was identified as α-FeOOH. The MO removal rate by the AT-α-FeOOH skeletons was considerably lower, reaching only 49% after 240 min. This research provided a practical approach for the construction of photocatalytic devices through the use of 3D printing technology.

Preparation and photocatalytic properties of g-C3N4/WO3–SiO2 composite photocatalyst for methylene blue and methyl orange degradation

WO3–SiO2 gel was prepared by sol-gel method using ethyl orthosilicate and sodium tungstate dihydrate as raw materials, and a series of g-C3N4/WO3–SiO2 composite photocatalysts with different g-C3N4 loading loads were prepared on WO3–SiO2 gel. The photocatalytic degradation performance of methylene blue (MB) and methyl orange (MO) was investigated under 464 nm light source. According to the findings, the degrading effect of the g-C3N4/WO3–SiO2 composite catalyst is optimum when the load of g-C3N4 is 1.3 wt%, and the degradation rates of MB and MO are 95.62 % and 98.09 %, respectively. The characterization results show that the excellent photocatalytic performance is due to the formation of g-C3N4/WO3 heterojunction by the introduction of g-C3N4, which effectively promotes the migration and separation of photogenerated carriers, increases the number of active electrons and holes, and thus enhances its photocatalytic activity. In addition, according to the analysis of the energy band structure of the catalyst, the possible mechanism of g-C3N4/WO3–SiO2 degradation of MB (MO) is proposed as S-type heterojunction mechanism.

Synthesis of Fe2O3/g-C3N4 composite with efficient photocatalytic degradation for methyl orange

g-C3N4 is a metal-free photocatalytic material, but it has poor photocatalytic activity due to its fast e-/h+ recombination rate. In this paper, Fe2O3/g-C3N4 composite was constructed to improve the photocatalytic property of g-C3N4. The photocatalytic performance of Fe2O3/g-C3N4 composite was evaluated for the methyl orange (MO) degradation under simulate visible light. The results showed that Fe2O3 combined with g-C3N4 can obviously decline the e-/h+ recombination rate, which was attributed to the synergistic effect in Fe2O3/g-C3N4 composite that increased the lifetime of photogenerated carriers. What’s more, the degradation rate of MO by 1 %-Fe2O3/g-C3N4 composite can reach 92.2 % within 60 min. Furthermore, 1 %-Fe2O3/g-C3N4 composite also had excellent photocatalytic stability.

Enhanced Photocatalytic Activity of π-Conjugated Pyridine Rings-Modified C3N4/Bi@BiOCl Z-Scheme Heterogeneous Material.

The enhanced photocatalytic properties of Z-Scheme Bi@BiOCl/C3N4-DPY heterojunction materials were successfully prepared by the ultrasonic-assisted coprecipitation method. The Bi@BiOCl/C3N4-DPY heterojunction exhibited remarkable photocatalytic activity under visible light irradiation, and the degradation rate of methyl orange (MO) was about 90.6% in 180 min. This impressive efficiency is mainly due to the Z-Scheme charge transfer mechanism in Bi@BiOCl/C3N4-DPY, resulting in the efficient separation of charge carriers and an increase in the REDOX potential of photogenerated electrons and holes. C3N4 was modified with a π-deficient conjugated pyridine ring, which caused the light absorption redshift, promoted the formation of oxidizing •O2-, and improved the photocatalytic activity. At the same time, a well-aligned heterojunction is formed at the interface between C3N4-DPY and BiOCl, facilitating the seamless transfer of light-induced electrons from the LUMO of C3N4-DPY to the CB of BiOCl. In addition, the addition of Bi introduces a unique band gap reduction effect, resulting in a change in the density of the band states, which further promotes charge transfer and separation. It is worth noting that the introduction of metallic bismuth (Bi) brings about a unique band gap reduction effect, resulting in a change in the density of states within the band, which ultimately promotes charge transfer and separation. The Z-scheme charge migration inside Bi@BiOCl/C3N4-DPY further promotes the efficient separation of photogenerated electron-hole pairs, greatly improving the overall efficiency of the material. The Z-structured photocatalyst developed in this study has great application potential in various fields of photocatalysis.

Polyvinyl alcohol stabilized ZnS nanoaggregates using organosulfur source for photocatalytic disintegration of methyl orange dye

ZnS nanoaggregates surface-passivated by a hydroxyl-based polymer matrix, polyvinyl alcohol (PVA), have been synthesized using a wet chemical method and an organosulphur precursor. The nanocomposite was characterized by XRD, SEM, and FTIR. XRD patterns revealed wurtzite structure. FTIR spectrum confirmed the interaction of hydroxyl group of PVA with the ZnS. We proposed a probable pathway for the precipitation of zinc sulfide by alkaline hydrolysis of complex formed from (NH2)2CS and Zn2+-polymer complex. The optical properties were monitored using UV–Vis spectroscopy and photoluminescence (PL) spectroscopy. Quantum confinement of electrons is confirmed by increase in the optical band gap and determined to be 3.91 eV. The photocatalytic activity of the ZnS/PVA nanoaggregates particles was examined using methyl orange (MO). After 3 h of illumination, the photocatalytic degradation rate of methyl orange (MO) is about 94.20 %.

Composites of W18O49 Nanowires with g-C3N4/RGO Nanosheets for Broadband Light-Driven Photocatalytic Wastewater Purification.

Developing a photocatalyst that can effectively utilize the full solar spectrum remains a high-priority objective in the ongoing pursuit of efficient light-to-chemical energy conversion. Herein, the ternary nanocomposite g-C3N4/RGO/W18O49 (CN/RGO/WO) was constructed and characterized by a variety of techniques. Remarkably, under the excitation of photon energies ranging from the ultraviolet (UV) to the near-infrared (NIR) region, the photocatalytic performance of the CN/RGO/WO nanocomposite exhibited a significant enhancement compared with single component g-C3N4 or W18O49 nanosheets for the degradation of methyl orange (MO). The MO photodegradation rate of the optimal CN/1.0 wt% RGO/45.0 wt% WO catalyst reached 0.816 and 0.027 min-1 under UV and visible light excitation, respectively. Even under low-energy NIR light, which is not sufficient to excite g-C3N4, the MO degradation rate can still reach 0.0367 h-1, exhibiting a significant enhancement than pure W18O49. The outstanding MO removal rate and stability were demonstrated by CN/RGO/WO nanocomposites, which arise from the synergistic effect of localized surface plasmon resonance effect induced by W18O49 under vis-NIR excitation and the Z-scheme nanoheterojunction of W18O49 and g-C3N4. In this work, we have exploited the great potential of integrating nonmetallic plasmonic nanomaterials and good conductor RGO to construct high-performance g-C3N4-based full-solar spectral broadband photocatalysts.

Assembling BiOBr nanoplates on MIL-125(Ti)–NH2 via group linkage towards effective dye-contaminated water purification

BiOBr-based photocatalysts have drawn a lot of interests for their favorable properties. However, the limitations in terms of active site accessibility and electron-hole separation hinder their practical applications. In this work, BiOBr was in situ synthesized in the presence of MIL-125(Ti)–NH2 under room temperature, constructing a series of BiOBr/MIL-125(Ti)–NH2 composites. The MIL-125(Ti)–NH2 which is rich in carboxyl and amino groups, facilitates the nucleation of BiOBr nanoplates to induce the formation of 3D flower-like structure, thus promoting the contact between photocatalysts and pollutants. What's more, heterojunction structures fabricated from BiOBr and MIL-125-NH2 can realize the rapid transfer of charge carriers. In comparison to bare components, the resultant composites presented boosted methyl orange (MO) removal efficiency, in which 91 % degradation rate of MO was achieved over the optimal sample BTN-4 and maintained at 84 % after four cycles. Finally, a reasonable photocatalytic mechanism was put forward to illustrate the superior effectiveness.

Preparation and photocatalytic degradation performance of AgI/4A molecular sieves

AgI/4A molecular sieves photocatalysts with different mass ratios were prepared by depositing the silver iodide on the 4A molecular sieve by ion exchange method. When the mass ratio of silver iodide and 4A molecular sieve was 2:1, AgI/4A molecular sieves exhibited enhancing photocatalytic activity than pure AgI and 4A molecular sieves. The degradation rate of methyl orange (MO) dye reached 96.4% at 20 min. The possible mechanism of photodegradation by AgI/4A molecular sieves was proposed.

Understanding the Plasmonic Effect of Enhanced Photodegradation with Au Nanoparticle Decorated ZnO Nanosheet Arrays under Visible Light Irradiation.

Plasmonic-enhanced photocatalysis using visible light is considered a promising strategy for pollution photodegradation. However, there is still a lack of comprehensive and quantitative understanding of the underlying mechanisms and interactions involved. In this study, we employed a two-step process to fabricate arrays of ZnO nanosheets decorated with Au nanoparticles (Au-ZnO NS). Various characterization techniques were used to examine the morphological, structural, and chemical properties of the fabricated Au-ZnO NS array. Furthermore, we systematically investigated the photocatalytic degradation of methyl orange under visible light irradiation using Au-ZnO NS arrays prepared with varying numbers of photochemical reduction cycles. The results indicated that as the number of photochemical reduction cycles increased, the photodegradation efficiency initially increased but subsequently decreased. Under visible light irradiation, the Au-ZnO NS array obtained via four cycles of photochemical reduction exhibits the highest photocatalytic degradation rate of methyl orange 0.00926 min-1, which is six times higher than that of the ZnO NS array. To gain a better understanding of the plasmonic effect on photodegradation performance, we utilized electromagnetic simulations to quantitatively investigate the enhancement of electric fields in the Au-ZnO NS array. The simulations clearly presented the nonlinear dependencies of electric field intensity on the distribution of Au nanoparticles and the wavelength of radiation light, leading to a nonlinear enhancement of hot electron injection and eventual plasmonic photodegradation. The simulated model, corresponding to four cycles of photochemical reduction, exhibits the highest electric field intensity at 550 nm, which can be attributed to its strong plasmonic effect. This work provides mechanistic insights into plasmonic photocatalysts for utilizing visible light and represents a promising strategy for the rational design of high-performance visible light photocatalysts.

Remarkably enhanced catalytic performance in CoOx/Bi4Ti3O12 heterostructures for methyl orange degradation via piezocatalysis and piezo-photocatalysis

A novel heterojunction composite of CoOx/Bi4Ti3O12 was synthesized through a combination of molten salt and photodeposition methods. The optimal sample exhibited superior performance in the piezocatalytic degradation of methyl orange (MO) dye with a degradation rate of 1.09 h−1, which was 2.4 times higher than that of pristine Bi4Ti3O12. Various characterizations were conducted to reveal the fundamental nature accountable for the outstanding piezocatalytic performance of CoOx/Bi4Ti3O12. The investigation of the band structure indicated that the CoOx/Bi4Ti3O12 composite formed a type-I p-n heterojunction structure, with CoOx acting as a hole trapper to effectively separate and transfer piezogenerated carriers. Significantly, the MO degradation rate of the best CoOx/Bi4Ti3O12 sample further increased to 2.96 h−1 under combined ultrasonic vibration and simulated sunlight. The synergy between piezocatalysis and photocatalysis can be ascribed to the following factors. The photoexcitation process ensures the sufficient generation of charge carriers in the CoOx/Bi4Ti3O12, while the piezoelectric field within Bi4Ti3O12 promotes the separation of electron-hole pairs in the bulk phase. Furthermore, the heterojunction structure between Bi4Ti3O12 and CoOx significantly facilitates the surface separation of charge carriers. This increased involvement of free electrons and holes in the reaction leads to a remarkable enhancement in catalytic MO degradation. This work contributes to the understanding of the coupling mechanism between the piezoelectric effect and photocatalysis, and also provides a promising strategy for the development of efficient catalysts for wastewater treatment.

The effect of individual factors, their binary and ternary interactions on photodegradation rate of organic contaminants using photocatalysts based on multi-walled carbon nanotubes (MWCNTs): statistical analysis based on ANOVA and RSM.

The influence of three main parameters including irradiation time, weight fraction of photocatalysts including multi-walled carbon nanotubes and different amount of TiO2 (MCT#1 and MCT#2) and pH is investigated for the degradation rate of methyl orange (MO). Analysis of variance (ANOVA) and response surface methodology (RSM) have been applied to study the binary and ternary interactions of the main parameters on the degradation rate. The ANOVA results confirm that all of three studied factors have a considerable efficacy on degradation rate of MO at 5% level of probability. Meanwhile, the results show that the degradation rate is enhanced with increasing the weight fraction in range of 0.1 to 0.3%wt and irradiation time in a period of 5 to 35min.The lowest and highest degradation are observed at pH=7 and pH=3, respectively. The normality of residue distribution can be confirmed using graphical analysis. The RSM results reveal that the degradation rate dependency on irradiation time is higher than the weight fraction of photocatalysts.

Construction of R-TiO2/n-TiO2 heterophase photocatalysts for efficient degradation of organic pollutants

In this study, a commercial rutile titanium dioxide (R-TiO2) with a particle size of 200–300 nm was used as a carrier to prepare R-TiO2/n-TiO2 photocatalysts through wet co-grinding in a stirred grinder, along with commercial TiO2 (n-TiO2). The structure of R-TiO2/n-TiO2, its photocatalytic degradation performance towards methyl orange, and the enhancement mechanism were investigated. The results demonstrated that under the optimized conditions of grinding time and n-TiO2 loading ratio, the prepared R-TiO2/n-TiO2 composite (with a n-TiO2 ratio of 30%) exhibited excellent photocatalytic degradation and recyclability. After 30 min of UV irradiation, the removal rate of methyl orange was 99%, which was comparable to that of pure n-TiO2 (degradation rate of 99.5%). The degradation rate of methyl orange using R-TiO2/n-TiO2 was 4.5 times higher than that of an equivalent proportion of n-TiO2, and the degradation performance remained nearly unchanged after five cycles of recycling. R-TiO2/n-TiO2 exhibits features such as effective dispersal and even distribution of n-TiO2 onto the surface of R-TiO2, coupled with the establishment of chemical bonding at the interface between the two constituents. The existence of R-TiO2 improved the dispersion of n-TiO2 and promoted the formation of an interfacial anatase/rutile heterophase junction, which are intrinsic mechanisms for enhancing the efficiency of TiO2 photocatalysis and achieving a reduction in the application process.