Sonophotocatalytic Degradation Research Articles

Effective sonophotocatalytic degradation of tetracycline in water: Optimization, kinetic modeling, and degradation pathways

Hybrid advanced oxidation processes (AOPs) are gaining interest in degradation of variety of recalcitrant compounds for water and wastewater treatment, due to possible synergistic effects. The present study systematically evaluated the degradation of tetracycline (TC) with a sonophotocatalytic process combining acoustic cavitation (sonocavitation) and photocatalysis based on N-doped TiO2 catalyst. The TC degradation rate constant was 2.4 × 10−2 min−1, i.e., much higher than individual sonocatalytic (0.5 × 10−2 min−1) and photocatalysis (0.6 × 10−2 min−1) processes at the optimized conditions. The synergy index was 2.14, which reveals a significant improvement in the process performance. Maximum TC degradations of 55.5 ± 1.8 % for photocatalysis, 66.4 ± 1.8 % for sonocatalysis, and 79.5 ± 0.3 % for sonophotocatalysis were observed for 10 mg L−1 initial TC concentration after 90 min of treatment. The photocatalytic experiments were extended further to 210 min to achieve a maximum degradation of 78.9 ± 0.2 % at the optimized condition. Scavenging experiments confirmed that hydroxyl radicals (•OH), electron holes (h+), and superoxide radical anions (O2−•) played a significant role in the degradation of TC. Further, the degradation intermediates for each process were identified and degradation pathways were proposed. Empirical kinetic models based on operational parameters were also developed and validated.

Novel synthesis of Ti3C2 MXene/ZnO/CdSe for sonoelectron and photoelectron triggered synergetic sonophotocatalytic degradation with various antibiotics

A straightforward and precise method was employed to generate Ti3C2 MXene/ZnO/CdSe photocatalysts by a simple synthesis process involving calcination at a temperature of 400 °C. Optical, structural, morphology, microstructure, and compositional properties of these catalysts were characterized. Results demonstrated that the presence of ZnO and CdSe doping sustained their existence inside the Ti3C2 MXene structure. Effects of catalyst powder, pollutant powder, and different degrading methods such as sonophotocatalytic, sonocatalytic, and photocatalytic methods on various antibiotic pollutants were then compared. The degradation efficiencies of sonophotocatalytic method were found to be highly efficient, resulting of 99.99, 99.98, and 99.90 % for ciprofloxacin, amoxicillin, and ofloxacin, respectively. Analysis of scavenger effect also illustrated the deterioration of ciprofloxacin and amoxicillin, suggesting that superoxide radicals (O2−) had a substantial role in the sonophotocatalytic degradation process. Based on data obtained for ofloxacin, it was clear that the existence of holes (h+ quencher) affected the deterioration of ofloxacin in the system. Ti3C2 MXene/ZnO/CdSe had a performance in electrochemical sensing. Limits of detection (LODs) for ciprofloxacin, amoxicillin, and ofloxacin were 39.29, 4.49, and 13.04 ppm, respectively. Limits of quantification (LOQs) for ciprofloxacin, amoxicillin, and ofloxacin were 119, 13.61, and 39.52 ppm, respectively. Efficient degradation of pollutants using visible light can be achieved by employing straightforwardly manufactured Ti3C2 MXene/ZnO/CdSe photocatalysts, making them a practical and promising option.

Optimization of cerium-based metal–organic framework synthesis for maximal sonophotocatalytic tetracycline degradation

Wastewater treatment is inevitably required to alleviate the pollution of water resources by various contaminants such as antibiotics. MOFs are novel materials with photocatalytic activities. In this study, sonophotocatalytic degradation of tetracycline (TC) by the Cerium-based MOF (Ce-MOF) is optimized by modification of its synthesis route. Ce-MOF synthesis by room temperature (RT), hydrothermal (HT), and sonochemical synthesis (SC) are studied. TC degradation experiments revealed the superiority of SC synthesis. The interplay of main synthesis parameters, namely, initial ligand concentration, ultrasound (US) power and time on sonophotocatalytic activity of Ce-MOF, were investigated by response surface methodology model (RSM) utilizing the central composite experimental design (CCD). The optimum SC synthesis conditions are an initial ligand concentration of 8.4 mmol/L, a sonication power of 50 amplitude, and a US time of 60 min. The optimally synthesized Ce-MOF was characterized by infrared spectroscopy, FTIR, XRD, FE-SEM, TEM, zeta potential analysis, diffuse reflectance spectroscopy, particle size analysis, Mott-Schottky analysis, photocurrent analysis, electrochemical impedance spectra, and photoluminescence spectroscopy. The findings indicate that the removal efficiency of TC can reach up to 81.75% within 120 min in an aqueous solution containing an initial TC concentration of 120 ppm and 1 g/L Ce-MOF at pH of 7. Mineralization efficiency of the process is 71% according to COD measurements. The Ce-MOF catalyst retained its chemical stability and remained active upon TC degradation which makes it a promising candidate for wastewater treatment.

Sonophotocatalytic degradation of sulfamethoxazole using lanthanum ferrite perovskite oxide anchored on an ultrasonically exfoliated porous graphitic carbon nitride nanosheet.

The lanthanum ferrite perovskite (La0.8FO) was synthesized using a citric combustion route and then modified with a porous graphitic nitride nanosheet via the wet impregnation-assisted ultrasonic method to produce La0.8FO@PgNS. Various techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet diffuse reflectance spectroscopy (UV-DRS), and Tauc plot analysis were employed to confirm the functional moieties, crystallinity, phase change, morphology, composition, and bandgap of La.0.8FO and La0.8FO@PgNS. La0.8FO and La0.8FO@PgNS were used for the sonophotocatalytic oxidative degradation of sulfamethoxazole (SMX) under low energy and ultrasound wave frequency in the presence of visible light. La0.8FO and La0.8FO@PgNS exhibited a sonophotocatalytic degradation capacity of 52.06 and 99.60%, respectively. Furthermore, the rate constant at the optimum condition of pH 7 and 5 mg L-1 concentration was 0.01343 and 0.01494 min-1 for La0.8FO and La0.8FO@PgNS, respectively. The integration of sonolysis and photocatalysis in the remediation process of SMX resulted in a synergy of 2.5-fold. Ultrasonic waves and hydroxyl and superoxide radicals are the main species governing the degradation process while La0.8FO@PgNS was stable over 8 cycles, proving to be a sustainable material for environmental remediation.

Sono-photocatalytic degradation of Tetracycline and Ciprofloxacin antibiotics using microwave-reflux of NiO-MoS2/rGO ternary nanocomposite

In this study, NiO-MoS2/rGO nanocomposites were synthesized successfully by a simple microwave assisted refluxing method by varying the mass ratios of rGO. The NiMG-50 ternary nanocomposite has been applied by sonocatalytic, photocatalytic and sono-photocatalytic degradation for the removal of tetracycline (TTC) and ciprofloxacin (CIP) antibiotics. Physicochemical properties of the synthesized samples were characterized by Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray Spectroscopy (EDAX) and X-ray Photoelectron Spectroscopy (XPS) corroborated the phase purity of NiMG-50 nanocomposite. The High Resolution Scanning Electron Microscopy (HR-SEM) image reveals the zigzag arrangements of NiO nanoflakes over MoS2 and rGO sheets. The tight contact of platelet shaped-NiO NP’s and curled layer-MoS2 on the sheets of rGO results in the separation of photo-induced e--h+ pairs as demonstrated by the High Resolution Transmission Electron Microscopy (HR-TEM) analysis. Optical properties reveal a reduced band gap and enhanced separation efficiency with fast charge transfer rate, improving the organic pollutant degradation efficiency. NiMG-50 demonstrated a good catalytic activity against TTC and CIP in sono-photocatalytic process with an efficiency of 94.10 % and 83.96 % at 35 and 90 min, respectively. Simultaneously, the experimental results showed that the NiMG-50 composite follows the pseudo-first order reaction kinetics with a rate constant (KSP) value of 0.077 min−1 and 0.015 min−1 for TTC and CIP. The radical trapping test and degradation mechanism indicated that the continuous contribution of ̇OH and ̇O2– reactive radicals are the major ones responsible for the active involvement in the degradation reaction. This research work gives a fresh prospects to the as prepared NiMG catalyst as an efficient composite with a good applicability for the sono-photocatalytic degradation of pharmaceutical products.

Synergistic effect of Sonophotocatalytic degradation of crystal violet and alizarin red S dyes using Ag-doped ZnSnO3 nanoparticles

This study proposes an environmentally conventional sonophotocatalytic method that uses silver (Ag)-doped ZnSnO3 nanoparticles (NPs) to effectively eliminate industrial dye-polluted wastewater. This study was conducted to investigate the effect of the Ag doping ratio of the synthesized ZnSnO3 NPs on the removal of dye molecules. We used crystal violet (CV) and alizarin red S (AR) dyes as test pollutants to examine the catalytic activity of the synthesized Ag-doped ZnSnO3 NPs in response to the ultrasound and visible light stimulation. The most effective photocatalytic performance was exhibited by 4 % Ag-ZnSnO3 NPs, which degraded 95 % of the CV and 52 % of the AR dye in 100 min. Surprisingly, using sonophotodegradation to combine ultrasound with visible-light irradiation has resulted in almost complete degradation of the CV dye in 100 min, demonstrating a strong beneficial synergy between the sonocatalytic and photocatalytic processes. Additionally, the sonophotocatalytic degradation of the CV and AR dyes was examined at various pH values. It shows to have high stability across several cycles of dye treatment, indicating that this method can be used for industrial effluents. Scavenger tests demonstrated that the primary active species in the dye degradation is O2•−. Ultimately, the prepared Ag-ZnSnO3 NPs and sonophotocatalytic processes may offer a promising path toward a variety of environmental uses, including the remediation of water and the removal of other organic contaminants.

Sonophotocatalytic Degradation of Reactive Black 5 in Simulated Dye Wastewater Using ZnO and Activated Red Mud Sonophotocatalyst

Sonophotocatalytic Degradation of Reactive Black 5 in Simulated Dye Wastewater Using ZnO and Activated Red Mud Sonophotocatalyst

Facile hydrothermal synthesis and continuously improved sonophotocatalytic performance of PO4-doped Bi2WO6 nanoplates

The doping of ionic group composed of various atoms can play a great role in regulating electronic structure, optimizing light absorption capacity, and enhancing the catalytic performance of semiconductor catalysts. Herein, we took a urea-precipitate assisting hydrothermal route for preparing PO4-doped Bi2WO6 nanoplates and discussed the effect of the ionic group doping on the sonophotocatalytic performance toward the degradation of pollutant. The result of the X-ray photoelectron spectrometer (XPS) measurements revealed that abundant oxygen vacancies were formed in PO4-doped Bi2WO6 owing to the incorporation of the ionic group, which would contribute to the regulation of electronic structure and activated carriers’ migration rate. The sonophotocatalytic activity toward the removal of tetracycline hydrochloride (TCH) was investigated under visible-light coupling with ultrasonic irradiation. The results showed that PO4-doped Bi2WO6 nanoplates possessed higher sonophotocatalytic degradation rate than pure Bi2WO6. More interestingly, the TCH removal efficiency was continuously improved over PO4-doped Bi2WO6 nanoplates with the assistance of the sulfate radical-mediated technique. Based on the comprehensive discussion and analysis, a possible enhancement mechanism of the sonophotocatalytic behavior was proposed for PO4-doped Bi2WO6 nanoplates catalyst in the presence of peroxymonosulfate.

Sonophotocatalytic degradation of methylene blue with magnetically separable Zn-Doped-CoFe2O4/α-Fe2O3 heterostructures

Sonophotocatalytic degradation of methylene blue with magnetically separable Zn-Doped-CoFe2O4/α-Fe2O3 heterostructures

Decoration of viscose fibers with silver nanoparticle-based titanium-organic framework for use in environmental applications.

To effectively remove pharmaceuticals, nitroaromatic compounds, and dyes from wastewater, an efficient multifunctional material was created based on silver nanoparticles (Ag) and MIL-125-NH2 (MOF) immobilized on viscose fibers (VF) as a support substrate. Firstly, silver nanoparticles (Ag) were immobilized on the surface of viscose fibers (VF) via in situ synthesis using trisodium citrate (TSC) as a reducing agent to create (VF-Ag). Then, VF and VF-Ag were decorated with the titanium metal-organic framework MIL-125-NH2 (MOF) to create VF-MOF and VF-Ag-MOF. The influence of VF-Ag, VF-MOF, and VF-Ag-MOF on the sonocatalytic or sonophotocatalytic degradation of sulfa drugs was investigated. The results show that VF-Ag-MOF showed excellent sonocatalytic and sonophotocatalytic activity towards the degradation of sulfa drugs compared to VF-Ag and VF-MOF. Furthermore, sonophotodegradation showed a dramatic enhancement in the efficiency of degradation of sulfa drugs compared to sonodegradation. The sonophotodegradation degradation percentage of sulfanilamide, sulfadiazine, and sulfamethazine drugs in the presence of VF-Ag-MOF was 65, 90, and 95 after 45min of ultrasonic and visible light irradiation. The catalytic activity of VF-Ag, VF-MOF, and VF-Ag-MOF was evaluated through the conversion of p-nitrophenol (4-NP) to p-aminophenol (4-AP). The results demonstrate that VF-Ag-MOF had the highest catalytic activity, followed by VF-Ag and VF-MOF. The conversion percentage of 4-NP to 4-AP was 69%. The catalytic or photocatalytic effects of VF-Ag, VF-MOF, and VF-Ag-MOF on the elimination of methylene blue (MB) dye were investigated. The results demonstrate that VF-Ag-MOF showed high efficiency in removing the MB dye through the reduction (65%) or photodegradation (71%) after 60min. VF-Ag-MOF composites structure-activity relationships represent that doping within silver NPs enhanced the photocatalytic activity of MIL-125-NH2, which could be explained as follows: (i) Due to the formation of a Schottky barrier at the junction between MIL-125-NH2 and Ag NPs, the photogenerated electrons in the conduction band of MIL-125-NH2 were supposed to be quickly transferred to the valence band of the Ag NPs, and subsequently, the electrons were transferred to the conduction band of Ag NPs. This considerable electron transferring process, which is reported as Z scheme heterojunction, can efficiently suppress the recombination of electron/hole pairs in VF-Ag-MIL-125-NH2 composites. (ii) Sufficient separation between the photogenerated charge carriers (holes and electrons) and avoiding their recombination enhanced the photocatalytic activity of composites.

Intensification of Sonophotocatalytic Degradation of Ponceau S using Fe - Doped and Undoped ZnO Nano Catalyst

Fe-doped ZnO nano catalyst was synthesized by co-precipitation method. The intrinsic characteristics of a prepared nano Fe-doped ZnO catalyst were studied using a variety of techniques including powder X-ray diffraction (XRD), scanning electron microscope (SEM), electron dispersive X-ray spectroscopy (EDS). In this study, degradation of Ponceau S as a dye pollutant was investigated in the presence of ZnO and Fe-doped ZnO nano catalyst using sonolysis, photocatalysis, sonocatalysis and sonophotocatalysis. The UV light and ultrasonic probsonicator at 20 kHz and 150 W powers were used as an irradiation source. The effect of H2O2 on sonocatalytic, photocatalytic and sonophotocatalytic degradation was investigated. At optimum conditions the dye degradation efficiency was influenced by addition of H2O2, the highest dye degradation was obtained as 98 % by US+UV+Fe-doped ZnO+H2O2 for 40 mg/L dye concentration after 90min. The experimental kinetic data followed the pseudo-first order model in doped and undoped sonocatalytic, photocatalytic and sonophotocatalytic processes but the rate constant of sonophotocatalysis is higher than sonocatalysis and photocatalysis process. The sonophotocatalysis was always faster than the respective individual processes due to the more formation of reactive radicals as well as the increase of the active surface area of nano catalyst.

Graphene oxide-modified polythiophene nanohybrids: antibacterial properties and sonophotocatalytic degradation of dyes under visible-light irradiation

The present work highlights the synthesis of graphene oxide (GO) modified polythiophene (PTh) for its application as an antibacterial agent as well as a visible light active photocatalyst. PTh was synthesized via the interfacial polymerization method using FeCl3 as initiator and then formulated as nanohybrids by mixing it in different weight ratios with graphene oxide (GO) i.e., 1 wt.%,3 wt.% and 5 wt. %. PTh and GO/PTh nanohybrids were characterized using FTIR, UV-visible, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The polymerization of PTh as well as modification of PTh with GO was confirmed by IR studies, while the shifting of electronic transitions of PTH upon modification with GO were confirmed by the UV-visible studies. The degradation of dyes, Alizarin Yellow (AY), Basic Blue (BB) and Congo Red (CR) was carried out via sonophotocatalysis under visible light using PTh and GO/PTh as catalysts for a period of 60 min. The GO/PTh revealed higher degradation efficiency as compared to PTh. To evaluate its effectiveness as an antibacterial agent against Bacillus subtilis, disk diffusion inhibitory assay was carried out under dark and light conditions. The results showed that PTh and GO/PTh nanohybrids had bactericidal properties, regardless of light exposure. The results of the minimal inhibitory concentration (MIC) assay indicated the nanohybrid of 3-GO/PTh had the lowest MIC, followed by 1-GO/PTh and 5-GO/PTh.

Proficient sonophotocatalytic degradation of organic pollutants using Co3O4/TiO2 nanocomposite immobilized on zeolite: Optimization, and artificial neural network modeling

The health of all living organisms is greatly influenced by the quality of the water. Therefore, developing cost-effective, eco-friendly, and easily accessible methods is desperately needed to meet the high global demand for clean water. Recently, nanozyme-based dye degradation methods have been promising for the remediation of water pollution. In this work, peroxidase-mimic Co3O4/TiO2 nanocomposite was synthesized and characterized for its size, morphology, and crystalline structure. Colorimetric assay results showed that the peroxidase-like activity of the Co3O4/TiO2 nanocomposite was considerably enhanced compared to the pure Co3O4 NPs and TiO2 NPs. Besides excellent enzyme-mimic activity, the higher sonophotocatalytic dye degradation capability of the nanocomposite after immobilization on zeolite (Co3O4/TiO2@Ze) was also demonstrated. Under optimal conditions (pH = 5.0, 25 °C), 0.1 g/L of catalyst was able to degrade 100 % of methylene blue (MB) with 600 μM in the presence of 30 μM H2O2 within 12 min. GC/MS analysis and toxicity studies revealed less toxic metabolite production after treatment of MB with sonophotocatalytic Co3O4/TiO2@Ze. Modeling of MB degradation using artificial neural networks (ANN) with a 5:6:1 topology was successfully performed, and the results confirmed the fitness of theoretical and experimental outputs according to the calculated correlation coefficient values. The prepared nanocomposite could thus be used as a promising and highly effective catalyst for the removal of organic dyes from polluted water.

Decorating 2D graphene oxides sheets with spherical shaped Fe3O4 for the applications of supercapacitors and sunlight induced sonophotocatalytic degradation of methylene blue dye

This study introduces a versatile nanocomposite material composed of Fe3O4 and GO/Fe3O4, demonstrating remarkable enhancements in sonication involved sonophotocatalytic and supercapacitor applications. The GO/Fe3O4 nanocomposite (NCs) were synthesized through a facile chemical precipitation method and subjected to comprehensive characterization using diverse techniques, including Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, UV-Visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The successful synthesis of both Fe3O4 and GO/Fe3O4 NCs was confirmed through XRD analysis, while UV-Vis measurements indicated a reduced bandgap for the nanocomposites. FESEM and TEM examinations unveiled a uniform distribution of Fe3O4 nanoparticles over the GO nanosheets, reinforcing the meticulous design of the nanostructure. Leveraging their unique properties, the synthesized nanocomposites were employed as efficient sonication and sun-light driven photocatalysts for the degradation of methylene blue (MB) dye. Impressively, the GO/Fe3O4 NCs exhibited exceptional sonophotocatalytic process, achieving rapid degradation rates (98.68% in 30 min) for MB dye under direct sunlight exposure. Furthermore, the engineered nanocomposites demonstrated outstanding suitability as electrode materials for supercapacitor applications. The GO/Fe3O4 NCs showcased a peak specific capacitance of 690.03 Fg−1 at a current density of 1 Ag−1 was achieved, with the cyclic stability remaining at 91% after 8000 cycles. The enhanced catalytic and the specific capacitance is due to the synergistic effect create between the Fe3O4 NPs and GO via the effective bonding of Fe-O-C. These findings reveals that the prepared nanohybrid is effective material for the dye degradation and the energy storage applications.

Enhancement of photocatalytic and sonophotocatalytic degradation of chitosan-ZnSnO3 nanocomposite for environmental remediation of emerging pollutants

In this study, the sonocatalytic, photocatalytic, and sonophotocatalytic activity of chitosan-ZnSnO3 nanocomposites (CS-ZnSnO3 NCs) against crystal violet dye were investigated. By using a variety of contemporary techniques, the crystalline phase, purity, crystal structure, shape, elemental composition, particle size, thermal properties, functional groups, and optical absorption properties of the synthesized CS-ZnSnO3 NCs were studied. By examining the variation in dye absorbance under a UV spectrophotometer, the catalytic activity of CS-ZnSnO3 NCs on crystal violet dye has been observed. The degradation efficiency of crystal violet dye was found to be 43 %, 80 %, and 97 % for sonocatalytic, photocatalytic, and sonophotocatalytic activity of CS-ZnSnO3 NCs after 75 min, respectively. The effect of pH analysis demonstrates that maximum degradation is obtained at pH 10 and the reusability study reveals the stability of the CS-ZnSnO3 catalyst. The degradation of crystal violet dye follows the pseudo-first-order kinetics and the rate constant for the sonophotocatalysis is higher than the individual catalysis processes. The prepared CS-ZnSnO3 can be utilized as a sonophotocatalyst for the degradation of crystal violet dye in an environmental remediation procedure to treat wastewater.

Capability of TiO2 and Fe3O4 nanoparticles loaded onto Algae (Scendesmus sp.) as a novel bio-magnetic photocatalyst to degration of Red195 dye in the sonophotocatalytic treatment process under ultrasonic/UVA irradiation

In this study, the magnetic photocatalyst Scendesmus/Fe3O4/TiO2 was synthesized, and its sonophotocatalytic properties in relation to the degradation of the Red195 dye were evaluated. Particles were characterized using a scanning electron microscope (SEM), Fourier's transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and a vibrating-sample magnetometer (VSM). At a pH of 5, a photocatalyst dosage of 100 mg, an initial R195 concentration of 100 mg/l, an ultrasound power of 38W, and an exposure time of 20 min, the maximum Red195 removal efficiency (100%) was achieved. After five cycles of recycling, the composite's sonophotocatalytic degradation stability for R195 remains above 95%. Experiments on scavenging indicate that electrons (h+) and hydroxyls (OH-) are indispensable decomposition agents. The removal of R195 by Scendesmus/Fe3O4/TiO2 is consistent with the pseudo-first-order kinetic, Freundlich, and Henderson's isotherm models, as determined by kinetic and isotherm investigations. The negative activation enthalpy of the standard (ΔH°) illuminates the exothermic adsorption mechanism. The increase in standard Gibbs activation free energy (ΔG°) with increasing temperature reveals the process is not spontaneous. As indicated by the negative value of the standard entropy of activation (ΔS°), activation of the reactants resulted in a loss of freedom.

Boosted ultrasound-sunlight-driven removal of organic pollutant over double Z-scheme plasmonic ZnO–Cu–CuO/g-C3N4 nanophotocatalyst: design via in-situ co-precipitation hybrid with various sonication powers

Herein, the sonophotocatalytic degradation of the organic pollutant is studied over double Z-scheme plasmonic ZnO–Cu–CuO hybridized two-dimensional C3N4, which is designed with an in-situ co-precipitation manner hybrid with sonicated irradiation. The sonication power effect on semiconductor properties is studied at P = 0, 30, 60, and 90 W, and the sonophotocatalysis test is done at constant power (P = 60 W) and simulated sunlight irradiation in order to find optimal properties. XRD, FESEM, 3D texture, TEM, EDX, BET–BJH, and DRS were used to determine the physicochemical characteristics and ultrasound effect on nano semiconductors. XRD analysis shows that Cu nanoparticles have been observed in heterostructured catalysts synthesized by ultrasound waves, except ZnO–Cu–CuO/C3N4 (P = 0). And with an increase in sonication power, the intensity of plasmonic Cu particles decreased. According to FESEM and 3D texture analysis, the surface roughness is reduced, which shows nanoparticles' good-fit nucleation and dispersion. More importantly, the total pore volume for ZnO–Cu–CuO/g-C3N4 (P = 0) and ZnO–Cu–CuO/g-C3N4 (P = 90) is 0.076 and 0.096 cm3/g, respectively in which the mesopores volume for ZnO–Cu–CuO/g-C3N4 (P = 90) sample (0.0622cm3/g) is more, facilitating the penetration of pollutants and products. DRS revealed that by increasing Cu nanoparticles, the band gap of ZnO–Cu–CuO/C3N4 (P = 90) is tuned in the visible-light region (Eg = 1.54 eV). The highest sonophotocatalytic degradation of 20 mg/L of methylene blue was obtained at 97.9% over ZnO–Cu–CuO/C3N4 (P = 90) and 60 W ultrasound irradiation, after 120 min of sonophotocatalysis treatment.

Cu:TiO2 nanoparticles prepared by planetary ball mill with enhanced sonophotocatalytic performance with visible light

AbstractIn this research, pure and Cu(II)‐doped TiO2 nanoparticles (NPs) were synthesized via a simple and nontoxic approach to fabricate a nanocatalyst for the oxidative sonophotocatalytic degradation of phenol. TiO2 NPs were prepared using a solvothermal method and doped with Cu(II) by high‐energy planetary ball mill. The as‐synthesized NPs were identified and characterized by X‐ray diffraction, energy‐dispersive X‐ray, and transmission electron microscopy techniques. The doped NPs were used for the first time in pollutant decomposition using phenol as a model pollutant in low‐energy and low‐frequency ultrasound at room temperature and pH = 7 in the presence of visible light. The progress of the pollutant degradation was followed by UV–Vis spectrophotometry. After about 60 min of sonophotocatalytic process (dual irradiation [visible light + ultrasound] in the presence of doped NPs), around 75% of the phenol degraded, with a rate constant of about 0.024 min−1. The sonophotocatalytic process was compared with photocatalysis and sonocatalysis processes conducted in the same conditions. Importantly, the combination of visible light and ultrasound irradiation in a sonophotocatalytic decomposition reaction represented about 58% of the synergy effect, demonstrating a positive synergy between the photocatalytic and sonocatalytic processes. The optimum condition was used to degrade the commercial sample (amoxicillin) with excellent performance. The reusability test represented the excellent stability of doped catalysts within four consecutive runs with less fading in their sonophotocatalytic reaction. This feature proves the reusability potential of the doped catalyst to be used in the commercial and industrial directions. The performance of the doped catalyst was affected severely by the addition of different scavengers, and based on the results, the sonophotocatalytic mechanism was discussed.

Highly efficient ultrasound-driven Cu-MOF/ZnWO4 heterostructure: An efficient visible-light photocatalyst with robust stability for complete degradation of tetracycline

Metal-organic frameworks (MOFs) are a significant class of porous, crystalline materials composed of metal ions (clusters) and organic ligands. The potential use of copper MOF (Cu-BTC) for the sonophotocatalytic degradation of Tetracycline (TC) antibiotic was investigated in this study. To enhance its catalytic efficiency, S-scheme heterojunction was created by combining Cu-BTC with Zinc tungstate (ZnWO4), employing an ultrasound-assisted hydrothermal method. The results demonstrated that the Cu-BTC/ZnWO4 heterojunction exhibited complete removal of TC within 60 min under simultaneous irradiation of visible light and ultrasound. Interestingly, the sonophotocatalytic degradation of TC using the Cu-BTC/ZnWO4 heterojunction showed superior efficiency (with a synergy index of ∼0.70) compared to individual sonocatalytic and photocatalytic degradation processes using the same heterojunction. This enhancement in sonophotocatalytic activity can be attributed to the formation of an S-scheme heterojunction between Cu-BTC and ZnWO4. Within this heterojunction, electrons migrated from Cu-BTC to ZnWO4, facilitated by the interface between the two materials. Under visible light irradiation, the built-in electric field, band edge bending, and coulomb interaction synergistically inhibited the recombination of electron-hole pairs. Consequently, the accumulated electrons in Cu-BTC and holes in ZnWO4 actively participated in the redox reactions, generating free radicals that effectively attacked the TC molecules. This study offers valuable perspectives on the application of a newly developed S-scheme heterojunction photocatalyst, demonstrating its effectiveness in efficiently eliminating diverse recalcitrant pollutants via sonophotocatalytic degradation.

Ultrasound assisted fabrication of InVO4/In2S3 heterostructure for enhanced sonophotocatalytic degradation of pesticides

A cost effective and environmentally benign ultrasonic method has been developed for the synthesis of InVO4 (InV), In2S3 (InS) and the InVO4/In2S3 heterostructure (InV/InS). All the designed materials were evaluated for their structural, morphological, spectroscopic, and electrochemical characterizations. Materials were examined for photocatalytic, sonocatalytic, and sonophotocatalytic degradation of carbofuran (CBF) and diazinon (DZN) pesticides under visible light. InV/InS showed enhanced degradation of CBF and DZN when compared to InV and InS. Photocatalytic degradation was accelerated by ultrasonication and found to degrade 97 and 98 % of CBF and DZN in 60 and 70 min, respectively. The reaction conditions, like pH, catalyst dosage, acoustic intensity, and ultrasound power, were carefully optimized. Electron spin resonance (ESR) spectroscopy shows the generation of superoxide radical anion and hydroxyl radicals as reactive species during photoredox reaction. The CBF and DZN degradation intermediates were analyzed using liquid chromatography mass spectroscopy (LC-MS) that shows the mineralization of the CBF and DZN to CO2 and H2O. The effect of Cl−, and PO43− were examined towards degradation of CBF and DZN under optimal conditions in the presence of InV/InS. The degradation of CBF and DZN is decreased in presence of Cl−, CO32– and NO3– but PO43− ions does not show any effect on degradation. The bandgap and Mott-Schottky results suggest the existence of type-II heterostructure between InV and InS through the interface. The synthesis of heterostructure and degradation of pesticides utilizes ultrasonic waves, which prove their multiple applications and attract researchers towards the effective use of sonication.