Sonocatalytic Process Research Articles

Preparation of CuWO4/Bi2WO6 composite and its sonocatalytic removal of tetracycline by combined persulfate

In this study, CuWO4/Bi2WO6 composites were prepared by the one-pot method and characterized. The sonocatalytic performance of the CuWO4/Bi2WO6 composites was investigated using tetracycline (TET) as a model of organic pollutant, in which the best catalytic performance was achieved by CB-10. When the addition of CB-10 was 1.0 g/L, the ultrasonic power was 500 W, the concentration of TET was 20 mg/L, and the addition of K2S2O8 was 2.7 g/L, the removal rate of TET was achieved 98.77 ± 1.55% after 60 min of ultrasonic irradiation time. The results indicated that the construction of CuWO4/Bi2WO6 Type-II heterojunction could effectively separate the e--h+ pairs generated in the CuWO4/Bi2WO6 composite during the sonocatalytic process, which could significantly enhance the sonocatalytic performance of Bi2WO6. The combination of this sonocatalytic system and K2S2O8 could effectively remove TET. The results of the present paper provide a good basis for the development of novel sonocatalysts and the practical application of sonocatalytic degradation technology in pharmaceutical wastewater purification.

Dual-functional MnS nanomaterials: Efficient adsorbent for phosphate removal and sonocatalyst for textile dye degradation

Naturally abundant, environmentally friendly alternatives for replacing the expensive lanthanum-based phosphate removal technique are sought after. Solocatalysis is an emerging area for water remediation. This study introduces a dual-functional MnS nanomaterial for removing phosphate ions and Congo Red textile dye. MnS nanomaterials were synthesized via a hydrothermal route. Batch adsorption experiments revealed a phosphate adsorption capacity of 160.73 mg P/g, commendable for adsorbent in its bare form. Thermodynamic parameters of the process indicated a spontaneous, exothermic process, confirming favourable adsorption. FTIR analysis confirmed the adsorption mechanism, which includes electrostatic attraction, surface complexation, and ion exchange. MnS maintained its adsorption capacity despite competing ions, demonstrating a selective affinity for phosphate ions. MnS showed high sonocatalytic efficiency, degrading Congo Red dye within 10 min of ultrasonic irradiation. The degradation mechanism of Congo Red dye in the sonocatalytic process is proposed. This novel metal chalcogenide material exhibits exceptional affinity for phosphate ions and Congo Red dye molecules, surpassing La-based adsorbents in efficacy. The results suggest that MnS nanomaterials are promising for practical applications in phosphate removal and textile dye degradation from wastewater.

Synthesis of biomass-based BiOI@Hydrochar heterogeneous catalyst and investigation of its activity in sonocatalytic process

Innovative studies in recent years to remove pollutants discharged into water resources through various means are critically important for protecting existing water resources. An important part of these studies is heterogeneous catalysis-based AOPs, where new generation composite materials are used and high organic pollutant degradation has been achieved. This study used the solvothermal approach to produce a BiOI@BH sonocatalyst doped with hydrochar (BH). A variety of analysis techniques, including XRD, FESEM, EDS, FTIR, DRS, and BET surface analysis, were used to assess changes in the physico-chemical properties of the BiOI@BH structure in comparison to BiOI. Both the adsorption and sonocatalytic degradation processes for the methylene blue aqueous solution were found to be more successful with the BiOI@BH structure. The following order of oxidative species activity was observed in sonocatalytic degradation: •OH > h+ > O2•–. Recovery studies showed that the decrease in the efficiency of the catalyst after 5 cycles in MB degradation was 10 %. It was determined that the MB degradation efficiency increased significantly with the use of persulfate oxidant at pH> 5. Finally, MB solution (20 mg L−1) was degraded by 99 % in the presence of 5 mM persulfate and 0.5 g L−1 BiOI@BH at 90 min

Fabrication of MoS2 nanopetals on honeycomb-like biochar with enhanced sonocatalytic activity for degradation of acid blue 7 and pharmaceutical pollutants

Organic dyes constitute an integral part of industrial effluents. Advanced oxidation processes are efficient methods for the degradation of organic pollutants, one of the most promising of which is sonocatalysis. In this study, we aimed to immobilize MoS2 nanopetals on honeycomb-like biochar through a one-step hydrothermal method and evaluate its sonocatalytic performance in the degradation of acid blue 7 (AB7). The MoS2-Biochar composite demonstrated enhanced sonocatalytic activity, approved by its larger specific surface area (5.0 m2/g) and narrower bandgap (1.25 eV) compared with those of pure MoS2. Application of 1.5 g/L MoS2-Biochar (10:1) led to a 95 % decolorization of AB7 (20 mg/L) within 40 min of reaction time. Moreover, considerable degradation efficiencies were achieved for various organic pollutants, including hydroxychloroquine (96 %), levofloxacin (81 %), phenazopyridine (80 %), and tilmicosin (67 %) with initial concentration of 20 mg/L within 120 min of treatment. The synergy factor and degradation turnover value of the sonocatalytic process for decolorization of AB7 were calculated to be 4.88 and 27.37 µmol/h.gcat, respectively. Trapping experiments were conducted to determine the roles of various reactive species in the sonocatalytic degradation process, and holes were found to be the dominant species. Furthermore, the generated intermediates were identified using gas chromatography–mass spectrometry (GC–MS) analysis, which suggested a possible mechanism for the degradation process. A stable structure and acceptable reusability with a 16 % reduction in the decolorization efficiency after four consecutive sonocatalytic runs were observed for the 10:1 composite, suggesting a promising perspective for the application of the studied system in the efficient treatment of organic pollutants.

Persulfate assisted sonocatalytic process for the degradation of Reactive Yellow 145 dye in aqueous solution

Persulfate assisted sonocatalytic process for the degradation of Reactive Yellow 145 dye in aqueous solution

In-situ anion-exchange construction of Z-scheme Ag3PO4/AgI, derived AgCl/Ag3PO4/AgI and Ag2CO3/Ag3PO4/AgI composites with multiple redox energy bands and charge transfer pathways for efficient absorption and sonocatalytic properties

Z-scheme Ag3PO4/AgI composites were synthesized by facile in-situ anion-exchange method at room temperature (RT). All the catalysts have excellent affinity to dyes and adsorb larger than 70 % of Methyl blue. The fastest adsorption equilibrium of Ag3PO4 (qe: 25.9278 mg/g) with low specific surface area (SSA: 4.6624 m2/g) can be rapidly attained for 6 min. The best color removal efficiency (RE) for Methyl blue over all the composites can rapidly increase to 100 % within 45 min. Meanwhile, the highest RE for RhB over S3 is 98.9 % for 60 min, and corresponding rate constant (k) is 0.07018 min−1. After adding NaCl or Na2CO3 into sonocatalysis, because of the formation of novel ternary AgCl/Ag3PO4/AgI and Ag2CO3/Ag3PO4/AgI during sonocatalytic process, the best REs for RhB over S3 composite increase from 89.8 % (no scavenger) to 98.2 % (1.2 mM NaCl), or to 97.6 % (1.8 mM Na2CO3) for 30 min, respectively, and the REs for Methyl blue over S3 are about 100 % for 10 min. From single Ag3PO4 to binary Ag3PO4/AgI, and to ternary Ag2CO3/Ag3PO4/AgI or AgCl/Ag3PO4/AgI, REs are significantly enhanced. New redox energy bands and charge transfer channels lead to efficiently spatial charge separation and further activation of hole (h+), superoxide anions (·O2−), hydroxyl radicals (·OH). Additionally, the relation among oxygen vacancies (Ov), Zeta potential and RE was discussed in detail. Density functional theory (DFT) calculations were used to make clear charge transfer and sonocatalytic mechanism. The evaluation of used samples, adsorption kinetics and modes, diverse degradation pathways and sonocatalytic mechanisms were also discussed in detail. The work provides a novel in-situ strategy for real-time control of catalytic performance by rapidly forming new phase during catalysis at RT. Furthermore, the strategy obviously facilitates real-time development of rare more than ternary composites for enhanced catalytic performance.

Simultaneous anionic dyes degradation via H2O2 activation using Zeolite 4A/ZnO/Fe2(MoO4)3 nanoparticles in a sono-photocatalytic process

In this paper, a new sono-photocatalyst of Zeolite 4A/Zinc oxide/ Iron molybdate (Zeolite 4A/ZnO/Fe2(MoO4)3) nanoparticle was fabricated and used to decompose methyl orange (MO) and brilliant blue simultaneously (BB) dyes in the presence of ultrasonic waves and ultraviolet (UVC). The feature of the catalyst and its components was fully characterized. The results showed that the efficiency of the sono-photocatalytic process in the dye oxidation was higher than the photocatalytic and sonocatalytic processes. The synergistic effect of the sono-photocatic and photo-catalytic process for the MO and BB oxidation using Zeolite 4A/ZnO/Fe2(MoO4)3 was obtained 1.796 and 1.944, respectively. The active species of OH and h+ had a prominent role in the dye oxidation. Also, the Zeolite 4A/ZnO/Fe2(MoO4)3 catalyst was stable and reused seven times in the MO and BB decomposition. The ability of Zeolite 4A/ZnO/Fe2(MoO4)3 catalyst to treat actual wastewater samples was successfully explored. The by-products of purified wastewater were not toxic for the growth and germination of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Lens esculinaris. The studied photocatalyst removed dyes effectively in a reactor with ultrasonic waves and UVC.

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.

Photosono catalytic behaviour of phthalocyanine when supported on electrospun nanofibers: The effect of radical initiators

In this study, two Zn phthalocyanine (ZnPc) complexes containing substituents with varying number of the methoxy groups were investigated when supported on TiO2 fibers in sono-, photo-, and photosono-catalytic degradation of Rhodamine 6 G. The ZnPc on fibers displayed higher activity than when alone. The photosonocatalytic process displayed higher degradation aptitude than sonocatalytic and photocatalytic processes. The electron paramagnetic resonance studies revealed that the photocatalytic process is instigated by singlet oxygen only. However, sonocatalytic and photosonocatalytic processes are instigated by both singlet oxygen and •OH radicals. The utilization of azo-bis-isobutyronitrile and tert-butyl hydrogen peroxide as radical initiators improved the degradation efficiency of photo-, sono- and photosono- catalytic processes. The re-used fibers from sonocatalytic process resulted in significant decrease in catalytic activity, whereas the fibers from photocatalytic process were highly reusable.

Topological Regulating Bismuth Nano-Semiconductor for Immunogenic Cell Death-Mediated Sonocatalytic Hyperthermia Therapy.

Immunogenic cell death (ICD) can activate the body's immune system via dead cell antigens to achieve immunotherapy. Currently, small molecule drugs have been used for ICD treatment in clinical, however, how to precisely control the induced ICD while treating tumors is of great significance for improving therapeutic efficacy. Based on this, a sono/light dual response strategy to tumor therapy and activation of ICD is proposed. A topological synthesis method is used to obtain sulfur-doped bismuth oxide Bi2 O3-x Sx (BS) using BiF3 (BF) as a template through reduction and a morphology-controllable bismuth-based nano-semiconductor with a narrow bandgap is constructed. Under the stimulation of ultrasound, BS can produce reactive oxygen species (ROS) through the sonocatalytic process, which cooperates with BS to consume glutathione and enhance cellular oxidative damage, further inducing ICD. Due to the introduction of sulfur in the reduction reaction, BS can achieve photothermal conversion under light, and combine with ROS to treat tumors. Further, with the assistance of ivermectin (IVM) to form composite (BSM), combined with sono/light dual strategy, ICD is promoted and DCs maturation is accelerated. The proposed ICD-mediated hyperthermia/sonocatalytic therapy strategy will pay the way for synergetic enhancement of tumor treatment efficacy and provide a feasible idea for controllable induction of ICD.

Recyclable MXene-bridged Z-scheme NiFe2O4/MXene/Bi2WO6 heterojunction with enhanced charge separation for efficient sonocatalytic removal of ciprofloxacin

Sonocatalysis has emerged as a promising technology for addressing environmental pollution issues. However, the efficacy of sonocatalytic processes is primarily hindered by challenges related to the sluggish flow rate of photogenerated electrons. This study presents a novel approach to address this issue by developing an improved Z-scheme NiFe2O4/MXene/Bi2WO6 (NMB) composite that exhibits exceptional sonocatalytic activity for ciprofloxacin (CIP) degradation. In particular, the NiFe2O4/MXene (5 wt%)/Bi2WO6 composite could achieve high CIP (at 10 mg/L) degradation efficiency (97.39 %) after 60 min of ultrasonic irradiation. The exceptional sonocatalytic activity of the composite was attributed to the synergistic interaction of the Z-scheme heterojunction charge transfer route and the electron mediator of Ti3C2-MXene, which enhances light collection capacity, separates photogenerated carriers efficiently, and improves redox activity of the composite. The scavenging experiments reveal that the sonocatalytic degradation of CIP was driven by holes (h+), hydroxyl radicals (•OH), and superoxide anion radicals (•O2−), with the former playing a dominant role. The results of reuse experiments demonstrate the outstanding sonocatalytic stability of the catalyst, as well as its uncomplicated recovery. The developed NMB Z-scheme composite shows promise for sonocatalytic treatment of antibiotics in industrial wastewaters, particularly those with high turbidity and/or low transparency. The findings also open up avenues for developing efficient and cost-effective sonocatalysts with good recyclability and remarkable performance.

Mesoporous cobalt oxide nanoparticles synthesized by a sonochemical method in the presence of a deep eutectic solvent for oxidative sonophotocatalytic decomposition of caffeine

Herein, for the first time, we have prepared mesoporous Co3O4 nanoparticles (NPs) by the ultrasound-assisted method in the presence of deep eutectic solvent (DES) for sonophotocatalytic degradation of caffeine (CAF). The porosity, crystallinity, and morphology of the as-synthesized NPs were investigated by using Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The as-prepared NPs were applied in sonophotocatalytic, photocatalytic, and sonocatalytic degradation of CAF in low energy and low-frequency ultrasound at neutral pH. The sonophotocatalytic process was the most effective in degrading CAF, reaching about 99.5 % in less than an hour with a pseudo-first-order rate constant of 0.0902 min−1. The photocatalytic and sonocatalytic processes degraded 83.4 % and 22.7 % of CAF, respectively, with lower rate constants of 0.0288 and 0.0049 min−1. Notably, the simultaneous application of UV light and ultrasound irradiation in a sonophotocatalytic decomposition process had a positive synergy effect of about 62.64 %. The commercial tablet was degraded by the optimum sonophotocatalytic process to prove the applicability of the catalyst. The reusability test of the NPs was examined, and after four consecutive uses, the NPs had negligible fading of their sonophotocatalytic performance. Due to the excellent sonophotocatalytic performance of the NPs, it is a suitable candidate for a broad range of environmental and remediation applications.

Carbonaceous CoCr LDH nanocomposite as a light-responsive sonocatalyst for treatment of a plasticizer-containing water

The carbonous-based nanocomposites of CoCr layered double hydroxide (LDH) with graphene oxide (GO) and reduced graphene oxide (rGO) were prepared. The successful synthesis of the CoCr LDH in hydrotalcite crystalline structure was deduced from the pattern obtained from X-ray diffraction, and the chemical composition of its surface was checked by X-ray photoelectron spectroscopy. The prosperous decorating of LDH on the sheets of rGO and GO was authenticated by the energy dispersive X-ray spectroscopy analysis and micrographs of scanning electron and transmission electron microscopy. The photo-assisted sonocatalytic activity of the prepared nanocomposites was appraised for the decomposition of dimethyl phthalate (DMP) as a plasticizer. The highest decomposition efficiency of 100% was obtained in the existence of CoCr LDH/rGO nanocomposite (0.5 g/L) during 20 min of reaction time via photo-assisted sonocatalysis. The rGO improved the catalytic activity of the CoCr LDH by increasing the specific surface area from 1.2 m2/g to 4.5 m2/g and reducing the band gap from 1.7 eV to 1.3 eV. Moreover, the results of the colony-forming unit method endorsed antibacterial property improvement of the CoCr LDH via hybridizing with rGO. The results of this research provide an optimistic perspective for applying carbonous-based nanocomposites of CoCr LDH as a novel catalyst with antibacterial properties in photo-assisted sonocatalytic processes.

Sonocatalytic process of penicillin removal using - Fe2O3 / effect of different parameters / degradation mechanism/ kinetic study/optimisation with response surface model

ABSTRACT More than 200 types of antibiotics are used worldwide to fight and treat infections. Penicillin is one of the most commonly used. The disadvantages of this antibiotic include the contamination of water and soil and the emergence of drug-resistant bacteria. In this work, we removed penicillin from the aqueous environment using a sonocatalytic process and meg-haematite nanoparticles. The research was conducted on a laboratory scale by measuring the effects of various variables on the operation, such as the nanoparticle dose, pH, initial antibiotic concentration, as well as the frequency of the sound waves and ultrasound power. The response surface method was used to optimise the design method. The research results show that this method is effective in removing penicillin and under optimal conditions more than 90% of this antibiotic is removed. The degradation mechanism of this antibiotic follows first order kinetics

Effects of piezoelectric coefficients on the sonocatalytic performance of Na0.5Bi0.5TiO3-xSrTiO3 solid solution

Sonocatalysis has received much attention due to its ability to completely degrade organic matter without secondary contamination. However, there are still different opinions about the factors affecting sonocatalysis, such as the role of the piezoelectric coefficient in the sonocatalytic process needs to be clarified. To understand the influence of piezoelectric coefficient, Na0.5Bi0.5TiO3-xSrTiO3 (NBT-xST, 0.20 ≤x ≤ 0.30) with different piezoelectric coefficients and different phase states (ferroelectric phase/relaxor) were obtained. The sonocatalytic experiments revealed a significant correlation between the piezoelectric coefficient and the catalytic performance in the ferroelectric phase. Still, more influencing factors need to be considered in the relaxor region.

Sonocatalyst degradation of catechol from aqueous solution using magnesium oxide nanoparticles

<p>Catechol is a highly toxic phenolic organic compound used in various industries such as refineries, toxics, dyes and plastics. When this compound enters the environment, it can have negative effects on human health and the ecosystem. In this study-removed pyrocatechol from aqueous solutions using a sonocatalytic process using magnesium oxide nanoparticles. The study was conducted on a laboratory scale and the effects of pH, catalyst dose, initial concentration and reaction time under 130-kHz ultrasonic waves on the sonocatalytic degradation of pyrocatechol were investigated. The maximum process efficiency under optimal conditions (i.e. pyrocatechol concentration of 25 mg / l, pH = 3, nanoparticle dose of 500 mg / l after a contact time of 60 min) was 92%. The results showed that this process follows first order pseudokinetics. The results show that the sonocatalytic process in the presence of magnesium oxide nanoparticles has a high efficiency in removing catechol from aqueous solutions</p>

Enhanced Sonophotocatalytic Degradation of Acid Red 14 Using Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) Based on Metal-Organic Framework

Here, the magnetic Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) with a new core-shell structure was synthesized, and its sonophotocatalytic properties were evaluated for acid red 14 (AR14) degradation. Particle characterizations were determined by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and vibrating-sample magnetometer (VSM), and the analysis results offered an excellent synthesis of mesoporous particles. Fe3O4@SiO2/PAEDTC@MIL-101 (Fe)/UV/US showed high degradation kinetics rate (0.0327 min−1) compared to sonocatalytic processes (0.0181 min−1), photocatalytic (0218 min−1), sonolysis (0.008 min−1), and photolysis (0.005 min−1). Maximum removal efficiencies of AR14 (100%) and total organic carbon (69.96%) were obtained at pH of 5, catalyst mass of 0.5 g/L, initial AR14 concentration of 50 mg/L, and ultrasound power of 36 W. Evaluation of BOD5/COD ratio during dye treatment confirmed that the sonophotocatalysis process can be useful for converting major contaminant molecules into biodegradable compounds. After recycling eight times, the prepared composite still has sonophotocatalytic degradation stability above 90% for AR14. Scavenging tests confirmed that holes (h+) and hydroxyl (•OH) were the pivotal agents in the decomposition system. Based on the results, the synthesized sample can be suggested as an excellent and promising sonophotocatalyst for the degradation of AR14 dye and its conversion into biodegradable compounds.

Hybrid persulfate/sonocatalysis for degradation of acid orange 7 in the presence of Ag2O/CuWO4 composite: Operating parameters and sonocatalytic mechanism

A series of Ag2O/CuWO4 composite catalysts were constructed and the effects, parameters and mechanisms of their sonocatalytic degradation of acid orange 7 (AO7) and hybrid persulfate/sonocatalysis for degradation of AO7 were studied. Ag2O/CuWO4 composite catalysts were constructed by coprecipitation method. The crystal characteristics, surface element composition, valence state and electrochemical characteristics, etc. of the composite were characterized by relevant instruments. The sonocatalytic process of Ag2O/CuWO4 composite catalyst was studied and optimized. Under the condition of ultrasonic power of 500 W, AO7 solution with initial concentration of 15 mg/L was sonocatalytic degraded for 1 h by Ag2O/CuWO4 (1:10) composite catalyst (adding amount of 1 g/L), and the degradation effect was the best, with the maximum degradation rate of 84.97 ± 2.23%. When persulfate was combined with sonocatalysis, the degradation rate of AO7 continued to increase to 99.01 ± 0.04% after 15 min of reaction. Compared with the single action, it not only improved the efficiency but also improved the effect. The trapping experiment showed that the active substances generated during the sonocatalytic degradation of AO7 by Ag2O/CuWO4 included hydroxyl radical, holes and superoxide anion radical. Based on this, the mechanism of sonocatalytic degradation was proposed. At the same time, Ag2O/CuWO4 composite catalyst showed good stability and reusability for recycling, which has the potential for further industrial development and application.

Green synthesis of CuO nanoparticles using Peganum harmala extract for photocatalytic and sonocatalytic degradation of reactive dye and organic compounds

The present study was performed to evaluate the effectiveness of photocatalytic and sonocatalytic processes for the removal of reactive blue 5 dye and organic compounds of textile effluent in the presence of copper oxide nanoparticles (CuO NPs). CuO NPs were synthesized using Peganum harmala seed extract. The structure of NPs was confirmed using SEM, TEM, XRD, EDX, and FTIR techniques. The tests were carried out in a batch system to assess factors affecting the dye removal efficiency, including contact time, pH, NPs dosage, and initial dye concentration. The experimental results showed that the photocatalytic process (98.42%) produced a higher degradation percentage than the sonocatalytic process (76.16%). While, the dye removal efficiency was not significant in the dark conditions (without UV or US waves). The maximum removal of reactive blue 5 dye under photocatalytic and sonocatalytic conditions occurred at the presence of 0.15 g of CuO NPs and dye concentration of 40 and 60 mg/L, respectively. The kinetic data followed a pseudo-second-order model in both photocatalytic and sonocatalytic processes with a correlation coefficient higher than 0.99. Isotherm studies showed that the Langmuir model was the best isothermal model to describe the adsorptive behavior of CuO NPs in a dark condition. The results obtained from GC-MS showed that the photocatalytic process had a degradation efficiency of over 87% in the removal of organic compounds.

Peroxydisulfate-assisted sonocatalytic degradation of metribuzin by La-doped ZnFe layered double hydroxide.

Metribuzin is an herbicide that easily contaminates ground and surface water. Herein, La-doped ZnFe layered double hydroxide (LDH) was synthesized for the first time and used for the degradation of metribuzin via ultrasonic (US) assisted peroxydisulfate (PDS) activation. The synthesized LDH had a lamellar structure, an average thickness of 26nm, and showed mesoporous characteristics, including specific surface area 110.93m2 g-1, pore volume 0.27cm3 g-1, and pore diameter 9.67nm. The degradation efficiency of the US/La-doped ZnFe LDH/PDS process (79.1%) was much greater than those of the sole processes, and the synergy factor was calculated as 3.73. The impact of the reactive species on the sonocatalytic process was evaluated using different scavengers. After four consecutive cycles, 10.8% loss occurred in the sonocatalytic activity of the La-doped LDH. Moreover, the efficiency of the US/La-doped LDH/PDS process was studied with respect to the degradation of metribuzin in a wastewater matrix. According to GC-MS analysis, six by-products were detected during the degradation of metribuzin. Our results indicate that the US/La-doped ZnFe LDH/PDS process has great potential for efficient degradation of metribuzin-contaminated water and wastewater.