Production of pyrite nanoparticles using high energy planetary ball milling for sonocatalytic degradation of sulfasalazine

Enhanced tetracycline degradation with TiO2/natural pyrite S-scheme photocatalyst

In this study, TiO2 nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO2 nanoparticles were decorated on natural pyrite (TiO2/NP) and characterized using XRD, FTIR, and SEM-EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm2), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be ·OH radicals in the TiO2/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO2/NP system has high performance in photocatalytic TC removal under optimized experimental conditions.

Synergistic photocatalytic effect of α-Fe2O3-ZnO binary nanocatalyst toward methylene blue: An experimental design study

Due to the potential ecosystem protection and management applications, searching for highly optimized semiconductor-based solar energy photocatalysts is still a significant challenge. Coupled α-Fe2O3-ZnO nanoparticles were prepared in situ and characterized by various identification techniques such as XRD, SEM-EDX, TEM, DRS, and FT-IR. Its pHpzc was about 8.1. The band gap energies of ZnO, α-Fe2O3, and the coupled α-Fe2O3-ZnO system were 3.22, 2.08, and 2.09 eV, respectively. The boosted photocatalytic activity of the coupled catalysts was designed via the RSM approach, and the optimal RSM conditions were pH 5, 25 min irradiation time, and 0.3 g/L of the α-Fe2O3-ZnO containing 75 % ZnO. The center point conditions' run included 0.5 g/L of the coupled catalyst containing 50 % ZnO, pH 7, and 22.5 min illumination time. The study on scavenger agents showed the highest role of hydroxyl radicals in MB photodegradation by the proposed catalyst.

Insights into the effects of natural pyrite-activated sodium percarbonate on tetracycline removal from groundwater: Mechanism, pathways, and column studies

In-situ chemical oxidation based on sodium percarbonate (SPC) has received much attention for remediation of groundwater contaminated with organic pollutants due to the high efficiency, stable reaction, and sustainability of SPC. Currently, metal ions and their composite materials, are mainly employed for the activation of SPC. However, due to its narrow pH range, slow Fe3+/Fe2+ circulation, and generation of refractory sludge, its application in groundwater is limited. In this study, SPC was activated with natural pyrite (FeS2) to remove tetracycline, which was selected as the target pollutant. FeS2 exhibited excellent catalytic activity and stability towards the degradation of tetracycline. The tetracycline degradation efficiency of SPC/FeS2 system reached 70 % within 10 min, and nearly half of the tetracycline was degraded in the first 5 min of the reaction. The optimum SPC dosage for the tetracycline removal was 8 mM, with FeS2 dosage of 0.5 g/L. The tetracycline removal efficiency remained above 60 % after 4 cycles, indicating its good recycling efficiency of the system. SPC/FeS2 system was not significantly affected by the initial pH or the presence of Cl-, SO42-, NO3- while, HCO3-, Ca2+, Mg2+, and humid acid suppressed the reaction. The electron paramagnetic resonance spectroscopy and quenching experiments demonstrated that OH and O2- played a dominant role in tetracycline removal by the system. S22-, as an electron donor, was able to participate in the Fe3+/Fe2+ cycle. In addition, the 13 transformation products were determined by liquid chromatography-mass spectrometry predicted that the degradation pathway of tetracycline consisted of hydroxylation, demethylation, and decarbonylation reactions. Finally, the dynamic simulation experiments of SPC/FeS2 sand column showed that FeS2 effectively activated SPC and significantly reduced the toxicity in groundwater after the packed column treatment. This study reveals that FeS2 can efficiently activate SPC and has good prospects for tetracycline-contaminated groundwater remediation applications.

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.

QTRAP LC/MS/MS of Garlic Nanoparticles and Improving Sunflower Oil Stabilization during Accelerated Shelf Life Storage

The purpose of this research was to assess and utilize the bioactive compounds of garlic nanoparticles (Ga-NPs) as a natural antioxidant in sunflower oil (SFO) stored at 65 ± 1 °C for 24 days. The garlic nanoparticles (Ga-NPs) from the Balady cultivar were prepared, characterized, and added to SFO at three concentrations: 200, 600, and 1000 ppm (w/v), and they were compared with 600 ppm garlic lyophilized powder extract (Ga-LPE), 200 ppm BHT, 200 ppm α-tocopherol, and SFO without Ga-NPs (control). The QTRAP LC/MS/MS profile of Ga-NPs revealed the presence of four organosulfur compounds. Ga-NPs exhibited the highest capacity for phenolic, flavonoid, and antioxidant compounds. In Ga-NP SFO samples, the values of peroxide, p-anisidine, totox, conjugated dienes, and conjugated trienes were significantly lower than the control. The antioxidant indices of SFO samples containing Ga-NPs were higher than the control. The Ga-NPs enhanced the sensory acceptability of SFO treatments up to day 24 of storage. The shelf life of SFO treated with Ga-NPs was substantially increased (presuming a Q₁₀ amount). The results show that Ga-NPs are a powerful antioxidant that improves SFO stability and extends the shelf life (~384 days at 25 °C).

Mechanochemical synthesis of catalysts and reagents for water decontamination: Recent advances and perspective

This paper aims to provide insights on mechanochemistry as a green and versatile tool to synthesize advanced materials for water remediation. In particular, mechanochemical methodologies for preparation of reagents and catalysts for the removal of organic pollutants are reviewed and discussed, focusing on those materials that, directly or indirectly, induce redox reactions in the contaminants (i.e., photo-, persulfate-, ozone-, and Fenton-catalysts, as well as redox reagents). Methods reported in the literature include surface reactivity enhancement for single-component materials, as well as multi-component material design to obtain synergistic effects in catalytic efficiency and/or reactivity. It was also amply demonstrated that mechanochemical surface activation or the incorporation of catalytic/reactive components boost the generation of reactive species in water by accelerating charge transfer, increasing superficial active sites, and developing pollutant absorption. Finally, indications for potential future developments in this field are debated.

Effects of Faba Bean Hull Nanoparticles on Physical Properties, Protein and Lipid Oxidation, Colour Degradation, and Microbiological Stability of Burgers under Refrigerated Storage

The processing of faba beans generates great quantities of hulls, which are high in bioactive compounds with demonstrated radical-inhibiting properties. There is no research on the impact of using faba bean hull nanoparticles (FBH-NPs) to improve the quality and extend the shelf-life of beef products. Hence, the target of this investigation was to assess the inhibiting influence of adding FBH-NPs at two different concentrations (1 and 1.5%) on the physical attributes, lipid and protein oxidation, colour degradation, and microbiological safety of burgers during refrigerated storage (4 ± 1 °C/12 days). The FBH-NPs presented great phenolic content (103.14 ± 0.98 mg GAE/g dw) and antioxidant potential. The water holding capacity and cooking properties in burgers including FBH-NPs were improved during storage. The FBH-NPs significantly (p < 0.05) decreased the reduction rate of redness and lightness during the burger refrigerated storage and the FBH-NPs were more beneficial in preventing cold burger discolouration. In the FBH-NPs-treated burgers, peroxide values, TBARS, and protein carbonyl content were lower than in the control (up to 12 days). The microbiological load of burgers including FBH-NPs was lower than the load of the control during refrigerated storage. The findings revealed that FBH-NPs were more efficient in enhancing the cooking characteristics, retarding lipid or protein oxidation, preventing colour detrition and improving the microbial safety of burgers.

Sonochemical processes for the degradation of antibiotics in aqueous solutions: A review

Antibiotic residues in water are general health and environmental risks due to the antibiotic-resistance phenomenon. Sonication has been included among the advanced oxidation processes (AOPs) used to remove recalcitrant contaminants in aquatic environments. Sonochemical processes have shown substantial advantages, including cleanliness, safety, energy savings and either negligible or no secondary pollution. This review provides a wide overview of the different protocols and degradation mechanisms for antibiotics that either use sonication alone or in hybrid processes, such as sonication with catalysts, Fenton and Fenton-like processes, photolysis, ozonation, etc.

Efficient activation of oxone by pyrite for the degradation of propanil: Kinetics and degradation pathway

Pyrite (FeS₂) is an abundant sulfide-associated iron mineral that exists in the earth. In this study, the pyrite/oxone process was demonstrated to be an effective approach for the catalytic degradation of propanil, where more than 90% decay ([propanil]₀ = 0.01 mM) was achieved within 15 min. Typically, the effects of various experimental parameters, including catalyst loading, oxone dosage, propanil concentration, and initial solution pH, were examined. Two optimal reaction pH values were observed at pH 9.1 and pH 2.9. The generated SO₄－ and OH were verified to be the dominant reactive radicals and primarily responsible for the propanil degradation. Both Fe(II) regeneration and sulfur conversion play an important role in oxone activation mechanism and effectively aid the catalytic activity of pyrite. Different co-existing natural water constituents exert dissimilar effects on the pyrite/oxone process. Additionally, the reusability test of pyrite exhibited a reasonable catalytic activity. The pyrite/oxone process was proven efficient in terms of propanil mineralization. A series of reaction intermediates was detected via four major degradation pathways. Overall, the pyrite/oxone process could be a promising approach for the removal of organic compounds in water.

BiVO4/WO3 nano-composite: characterization and designing the experiments in photodegradation of sulfasalazine

A BiVO₄-WO₃ nano-composite (NC) was hydrothermally prepared and characterized by different techniques including X-ray diffraction (XRD), scanning electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer, X-ray mapping, UV-Vis reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The average crystallite size of 8.5 nm was estimated for the composite by the Williamson-Hall equation. The band gap energies of 2.46, 3.02, and 2.95 eV were obtained for the direct electronic transitions of BiVO₄, WO₃, and the composite, respectively. The point of zero charges (pHpzc) of the composite was also estimated at 5. The composite was then used in the photodegradation of sulfasalazine (SSZ). When the moles of WO₃ was four times greater than BiVO₄, the best photocatalytic activity and the lowest PL intensity were obtained. The simultaneous effects of the experimental variables on the boosted photocatalytic activity of the composite (to the single semiconductors) were studied by the response surface methodology (RSM). A significant quadratic model was confirmed for processing the data based on the F value of a model F value of 63.55 > F_{0.05, 14, 13} = 2.55. This was also confirmed by LOF F value of 2.56 < F_{0.05, 10, 3} = 8.79. Besides, the multiple correlation coefficients R² (R² = 0.9856), adjusted R² (adj-R² = 0.9701), and predicted R² (pred-R² = 0.9098) confirm the goodness of the model. The optimal run included C_SSZ 9 mg/L, pH 4, 40 min irradiation time, and 0.8 g/L of the composite under the visible light irradiation.

Sonochemical synthesis of high-performance Pd@CuNWs/MWCNTs-CH electrocatalyst by galvanic replacement toward ethanol oxidation in alkaline media

In this paper, a fast and effective method for the palladium (Pd) wire nanostructures synthesis with the great surface area through galvanic replacement reaction utilizing copper nanowires (CuNWS) as a template by the assistance of ultrasound under room temperature condition is proposed. A multifunctional catalyst with the mentioned nanostructure, Pd@CuNWs, and multi walled carbon nanotubes (MWCNTs) and chitosan (CH) as a binder was fabricated. To investigate the morphology and bulk composition of the prepared catalyst, Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), and Inductively Coupled Plasma atomic Emission Spectroscopy (ICP-AES) were utilized. Various electrochemical techniques including chronoamperometry and cyclic voltammetry were employed for the electrocatalytic activity of ethanol electrooxidation and durability in basic solution. Electrochemical catalytic activity and durability evaluation results proved that the as-synthesized Pd@CuNWs/MWCNTs-CH has a super electrocatalytic activity compared to Pd/MWCNTs and Pd/C electrocatalysts for ethanol electrooxidation. Pd@CuNWs/MWCNTs-CH catalyst demonstrated substantially enhanced performance and long-term stability for ethanol electrooxidation in the basic solution in comparison to Pd/MWCNTs and commercial Pd/C demonstrated the potential in utilizing Pd@CuNWs/MWCNTs-CH as an efficient catalyst for ethanol oxidation. Additionally, thermodynamic and kinetic evaluations revealed that the Pd@CuNWs/MWCNTs-CH catalyst has lower activation energy compared to Pd/MWCNTs and Pd/C which leads to a lower energy barrier and an excellent charge transfer rate towards ethanol oxidation. Noticeably, the Pd@CuNWs/MWCNTs-CH presented excellent catalytic activities with high peak current density which was 9.5 times more than Pd/C, and more negative onset potential in comparison to Pd/C is acquired for ethanol electrooxidation denoting synergistic effect between CuNWs/MWCNs-CH and Pd. The Pd@CuNWs/MWCNTs-CH can be considered as a valid candidate among available electrocatalysts in direct ethanol fuel cells (DEFCs).

Synthesis of ZrO2 nanoparticles on pumice and tuff for sonocatalytic degradation of rifampin

ZrO₂-pumice and ZrO₂-tuff nanocomposites were synthesized via a modified sol-gel method and used as efficient catalysts for sonocatalytic degradation of rifampin (RIF). The physico-chemical properties of the prepared catalysts were examined using XRF, SEM, EDX, FT-IR and BET analyses and compared to pure pumice and tuff samples. Subsequently, the efficacy of catalysts in degradation of RIF was assessed under various experimental conditions. Both ZrO₂-pumice and ZrO₂-tuff (1.5 g L^-1) exhibited promising catalytic activity for sonocatalytic degradation of RIF at its initial concentration of 20 mg L^-1, natural pH and under ultrasonic irradiation power of 300 W. In this condition, about 95% and 83% of RIF was removed through US/ZrO₂-pumice and US/ZrO₂-tuff processes, respectively. Furthermore, the influence of the addition of a number of scavengers, enhancers and gases on the degradation of RIF was studied. The pronounced degradation effectiveness of the catalysts under ultrasound irradiation could be assigned to their synergetic ability to produce reactive species and subsequent radical reactions. The intermediate products formed in the solution from degradation of RIF were also identified and a decomposition pathway was proposed using GC-MS, COD, TOC and IC analyses.

Preparation of magnetite nanoparticles by high-energy planetary ball mill and its application for ciprofloxacin degradation through heterogeneous Fenton process

In this study, the heterogeneous Fenton oxidation of ciprofloxacin (CIP) in an aqueous solution was examined over the nano-sized magnetite (Fe₃O₄) as a catalyst supplied through high-energy planetary ball milling process. To characterize the magnetite samples after and before ball milling operation, the X-ray diffraction (XRD), High-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FTIR) analysis were applied. The catalytic properties of the magnetite were considerably improved because of the enhancement in its physical properties, resulted from milling process. The findings also indicated that 6 h ball-milled magnetite demonstrated better properties for elimination of CIP of about 89% following 120 min reaction at optimal conditions of H₂O₂ 12 mM, Fe₃O₄ 1.75 g L^-1, CIP 10 mg L^-1 and pH 3.0. The effects of various operational parameters, including the initial pH of the solution, H₂O₂ initial concentration, catalyst dosage, milling time and CIP initial concentration was investigated. Application of organic and inorganic scavengers considerably decreased the CIP removal efficiency. Correspondingly, with respect to the leached iron values at pH 3, it was concluded that CIP elimination was mainly occurred through heterogeneous Fenton procedure. This process included the adsorption and oxidation phases in which the hydroxyl radicals (OH) played a significant role. GC-MS analysis was used for recording of the generated intermediates of the CIP removal in the course of heterogeneous Fenton process.

Degradation of sodium isopropyl xanthate from aqueous solution using sonocatalytic process in the presence of chalcocite nanoparticles: Insights into the degradation mechanism and phyto-toxicity impacts

In the present work, the sonocatalytic degradation of sodium isopropyl xanthate (SIPX) was investigated in the presence of Cu₂S nanoparticles. Cu₂S nanoparticles were produced by means of a high-energy planetary mechanical ball milling method within the processing times of 0.5, 1.5, 3 and 4.5 h. The physical and chemical characteristics of Cu₂S particles were studied before and after ball milling process using various analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) coupled Energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectroscopy (AAS) and nanoparticles size distribution (NSD). The XRD pattern of the samples confirmed the presence of tetragonal and cubic crystalline phases of Cu₂S. In addition, the results of SEM and NSD analysis showed that the increase in the ball milling time from 0.5 to 4.5 h notably decreased the size of nanoparticles to the range of 20-40 nm. Furthermore, AAS result showed that the concentration of Cu⁺ ions was much lower than that of the accepted value in the aqueous media (0.009 mg/L) after 60 min of the sonocatalysis. The study on the effects of the main key parameters showed that 93.99% of SIPX (10 mg/L) was removed during 60 min of the sonocatalytic process under the optimum conditions: pH of 7.3, Cu₂S concentration of 1.5 g/L, and ultrasonic power of 150 W. The sonocatalytic degradation mechanism was thoroughly examined in the presence of different organic and inorganic scavenger compounds, including ethanol, EDTA, NaCl and Na₂SO₄. The obtained results confirmed OH and holes (h⁺) as the dominant oxidizing species in Cu₂S catalyzed sonolysis. In order to get the benefits of the integrated sonocatalytic process, different rate enhancing compounds were introduced into the system. For the first time, the S₂O₈^2- and Cu₂S catalyzed sonolysis (US/Cu₂S/S₂O₈^2-) system was introduced as an efficient and novel sonocatalytic system for fast degradation of SIPX. Moreover, the phyto-toxicological assessments proved the reduction in the toxicity of the sonocatalytic-treated SIPX solution by increase in the reaction time, from 20 to 60 min.

ZnFe-Cl nanolayered double hydroxide as a novel catalyst for sonocatalytic degradation of an organic dye

ZnFe nanolayered double hydroxide (NLDH) with anions of Cl^- in its interlayer space was synthesized using a facile co-precipitation method. The synthesized ZnFe-Cl NLDH was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), N₂ adsorption/desorption, diffuse reflectance spectroscopy (DRS) and point of zero charge pH (pHpzc) analyses. In this research, the sonocatalytic activity of the as-prepared NLDH was investigated for removal of acid red 17 as model pollutant. The effects of the operating parameters including sonocatalyst concentration, pH, initial dye concentration, intensity of ultrasonic irradiation and the presence of radical scavengers and process enhancers were studied on the sonocatalytic degradation of acid red 17. The decreased decolorization efficiency in the presence of the radical scavengers confirmed that the free radicals play the basic roll in the degradation of acid red 17 molecules. In addition a probable mechanism for degradation of acid red 17 through the sonocatalytic process was proposed according to the identified intermediates detected using gas chromatography-mass (GC-MS) spectroscopy.

Aqueous norfloxacin sonocatalytic degradation with multilayer flower-like ZnO in the presence of peroxydisulfate

Multilayer ZnO nanoflowers were synthesized through a simple precipitation method and characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and nitrogen absorption-desorption techniques. The FE-SEM images show the integrated morphology of an individual flower-like ZnO nanostructure, which is made of nano-platelets with uniform thickness (20-30nm). The average pore size and Brunauer-Emmet-Teller (BET) surface area of the as-synthesized ZnO were 27.25nm and 13.53m²/g. The sonocatalytic ability of the prepared samples was evaluated through norfloxacin (NF) degradation in an aqueous system using ultrasound (US) irradiation. To improve degradation efficiency, peroxydisulfate (Na₂S₂O₈) was introduced to develop a US/ZnO/peroxydisulfate system, which exhibited an excellent synergistic effect. The effects of ZnO dosage, Na₂S₂O₈ concentration, pH, and initial NF concentration were studied to determine the performances of the US/ZnO/peroxydisulfate process. Corresponding results showed that NF degradation rate increased with the increase of ZnO dosage but decreased with the increase of initial NF concentration. Under the optimal Na₂S₂O₈ concentration of 0.1gL^-1 at pH 9, the best degradation efficiency can be achieved. Moreover, based on the scavenging experiment results and literatures, NF degradation through US/ZnO/peroxydisulfate system is majorly induced by OH and SO₄^- radicals.