Combined treatment approaches based on ultrasound for removal of triazophos from wastewater

High-performance activation of ozone by sonocavitation for BTEX degradation in water

This work presents a novel advanced oxidation process (AOP) for degradation of emerging organic pollutants - benzene, toluene, ethylbenzene and xylenes (BTEXs) in water. A comparative study was performed for sonocavitation assisted ozonation under 40-120 kHz and 80-200 kHz dual frequency ultrasounds (DFUS). Based on the obtained results, the combination of 40-120 kHz i.e., low-frequency US (LFDUS) with O3 exhibited excellent oxidation capacity degrading 99.37-99.69% of BTEXs in 40 min, while 86.09-91.76% of BTEX degradation was achieved after 60 min in 80-200 kHz i.e., high-frequency US (HFDUS) combined with O3. The synergistic indexes determined using degradation rate constants were found as 7.86 and 2.9 for LFDUS/O3 and HFDUS/O3 processes, respectively. The higher extend of BTEX degradation in both processes was observed at pH 6.5 and 10. Among the reactive oxygen species (ROSs), hydroxyl radicals (HO•) were found predominant according to scavenging tests, singlet oxygen also importantly contributed in degradation, while O2•- radicals had a minor contribution. Sulfate (SO42-) ions demonstrated higher inhibitory effect compared to chloride (Cl-) and carbonate (CO32-) ions in both processes. Degradation pathways of BTEX was proposed based on the intermediates identified using GC-MS technique.

Causal inference and mechanism for unraveling the removal of four pesticides from lettuce (Lactuca sativa L.) via ultrasonic processing and various immersion solutions

This study explores the reduction of carbamates (CAs) and pyrethroids (PYs) - commonly used pesticides - in lettuce using various immersion solutions and ultrasonic processing. It also examines the role of machine learning and molecular docking in understanding the mechanisms of pesticide reduction. The results revealed that the highest reduction of both CAs and PYs exceeded 80 % on lettuce leaves. In most samples, the reduction increased with the power of ultrasonic processing and processing time. The results of machine learning models (XGBoost and SHAP) showed that during the immersion cleaning of CAs and PYs, as well as during both immersion cleaning and ultrasonic processing of CAs + PYs, the reduction was most influenced by the initial pesticide levels and immersion time. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of lettuce's wax layer identified 24 compounds, including fatty alcohols, fatty acids, fatty acid esters, and triterpenoids. Despite the absence of active sites, the lipophilic nature of long-chain aliphatic compounds aids in pesticide binding, while triterpenoids form strong hydrogen bonds with pesticides, indicating a robust adsorption on the lettuce surface. This study aims to offer insights into the efficient removal of chemical pesticide residues from fruits and vegetables, addressing critical concerns for food safety and human health.

Oxidative treatment of micropollutants present in wastewater: A special emphasis on transformation products, their toxicity, detection, and field-scale investigations

Micropollutants have become ubiquitous in aqueous environments due to the increased use of pharmaceuticals, personal care products, pesticides, and other compounds. In this review, the removal of micropollutants from aqueous matrices using various advanced oxidation processes (AOPs), such as photocatalysis, electrocatalysis, sulfate radical-based AOPs, ozonation, and Fenton-based processes has been comprehensively discussed. Most of the compounds were successfully degraded with an efficiency of more than 90%, resulting in the formation of transformation products (TPs). In this respect, degradation pathways with multiple mechanisms, including decarboxylation, hydroxylation, and halogenation, have been illustrated. Various techniques for the analysis of micropollutants and their TPs have been discussed. Additionally, the ecotoxicity posed by these TPs was determined using the toxicity estimation software tool (T.E.S.T.). Finally, the performance and cost-effectiveness of the AOPs at the pilot scale have been reviewed. The current review will help in understanding the treatment efficacy of different AOPs, degradation pathways, and ecotoxicity of TPs so formed.

Development of Simple Fluorescence Analytical Strategy for the Detection of Triazophos Using Greenish-Yellow Emissive Carbon Dots Derived from Curcuma longa

This study describes a new method for synthesizing water-soluble carbon dots (CDs) using "Curcuma longa" (green source) named CL-CDs via a single-step hydrothermal process. The as-synthesized CL-CDs exhibited greenish-yellow fluorescence at 548 nm upon excitation at 440 nm. It shows good water stability and exhibits a quantum yield of 19.4%. The developed probe is utilized for sensing triazophos (TZP) pesticide via a dynamic quenching mechanism, exhibiting favorable linearity ranging from 0.5-500 μM with a limit of detection of 0.0042 μM. The as-prepared CL-CDs probe was sensitive and selective towards TZP. Lastly, the successful application of the CL-CDs-based fluorescent probe in water and rice samples highlights its potential as a reliable and efficient method for the detection of TZP in various real sample matrices. Eventually, bioimaging and biocompatibility aspects of CL-CDs have been assessed on Saccharomyces cerevisiae (yeast) cell and lung cancer (A549) cell lines, respectively.

Process intensification approaches in wastewater and sludge treatment for the removal of pollutants

Process Intensification (PI) is the modification or integration of conventional or novel processes within a single unit operation in order to improve product quality and reduce waste. PI offers numerous advantages, including a reduction in the initial and operational costs, an improvement in product quality/quantity, the generation of less waste, and an increase in process safety. The synergistic effect of PI in comparison to the conventional procedure ensures maximizing resource efficiency. PI can be accomplished in two ways: either by integrating various processes or by modifying the design of equipment to improve operational efficiency. In this regard, the present review provides a comprehensive insight into the application of PI in wastewater and sludge treatment methods and discusses the operational advantages. This review provides a comprehensive list of different PI approaches applied in wastewater and sludge treatment to remove pollutants and the various equipment, techniques and reactors used in PI. The second section addresses the challenges of PI in wastewater treatment that removes dyes, pesticides, organic and inorganic pollutants, micro- and nano-plastics, persistent organic pollutants, pharmaceutical and personal care pollutants.

Removal of triazole and pyrethroid pesticides from wheat grain by water treatment and ultrasound-supported processes

A simple way to reduce pesticides in cereal grains is to use washing methods. The challenge of this study was to evaluate the effectiveness of reduction of 3 triazole fungicides (difenoconazole, tebuconazole, tetraconazole) and 3 pyrethroid insecticides (beta-cyfluthrin, cypermethrin, deltamethrin) commonly used in wheat protection. Four different pre-washing methods (hot and cold water washing, twice water, and ultrasound-supported washing) were evaluated. The processing factor (PF) was calculated based on the concentration of pesticides determined by LC-MS/MS in the samples of cereal grains before and after the washing process. PFs were within the range 0.01-0.97. Time, teperature and ultrasound were factors influencing the efficiency of water treatment. The study showed that ultrasound-supported washing eliminated pesticide residues to a greater extent than ordinary washing. This process significantly affected or completely reduced concentrations of triazoles in wheat grains. The highest reduction of residues (99%) was received for tebuconazole and ultrasound washing with heating temperature of 60 °C for a total of 10 min. In all washing processes, pyrethroids were removed with lower efficiency than triazoles. The lowest residue reduction was obtained for cypermethrin and washing under cold water for 5 min (3%; PF = 0.97). Beta-Cyfluthrin showed only a 6-27% reduction regardless of the process (PF: 0.73-0.95). Using static analysis, the relationship between the properties of pesticides and the reduction of their concentration in cereals was clarified and showed a strong correlation.

Optimize lettuce washing methods to reduce the risk of microplastics ingestion: The evidence from microplastics residues on the surface of lettuce leaves and in the lettuce washing wastewater

Airborne microplastics have been identified as an emerging contaminant that can adhere to the surface of leafy vegetables, and if not completely removed by washing, there is a high risk that human consumption of these plastics may cause harm to humans. In this study, we simulated atmospheric pollution by spraying microplastic particles (MPs) with particle sizes of 100 nm and 500 nm to determine whether MPs particles would adhere to the lettuce surface and whether different common cleaning methods (water rinsing, ultrasonic vibration cleaning, and edible detergent cleaning) would be effective in removing MPs from the leaf surfaces. We scanned the leaf surface with a laser confocal microscope and examined the wash water with a flow cytometer and found that simple rinsing was not effective in removing plastic particles from lettuce leaves. In comparison, ultrasonic vibratory cleaning showed a better efficiency, 4 times higher than more MPs being washed from the leaves. The most effective method was detergent washing, with the washing efficiency increased by 6.9 times. Ultrasonic vibrations can partially break the chemical bonds between MPs and plant surfaces, and detergents' surfactants can enhance MPs' hydrophilicity. MPs with a particle size of 100 nm were more difficult to clean than those with a particle size of 500 nm. This finding has important implications for the interaction of MPs contamination with vegetables and the cleaning of vegetables.

Sustainable emerging sonication processing: Impact on fungicide reduction and the overall quality characteristics of tomato juice

Sonication is an emerging sustainable and eco-friendly technology that has been broadly explored in food processing and preservation. Sonication has the edges of low energy consumption and high efficiency than conventional decontamination methods and would not pass on secondary pollutants. In the current research, we analyzed the impact of sonication on anilazine fungicide reduction, bioactive compound, antioxidant activity, colloidal stability, and enzymatic and microbial load of tomato juice. Sonicated treatments were carried out at 40 kHz, 480 W, 30 ± 2 °C for 0, 8, 16, 24, 32, and 40 min in an ultrasonic bath cleaner. The GC-MS outcomes revealed that the anilazine maximum reduction in tomato juice attained 80.52 % at 40 min of sonication. The anilazine concentration reduced significantly (p ≤ 0.05) with increased sonication time. In contrast, sonication treatments have acquired the highest TFC, TPC, ascorbic acid, carotenoids, lycopene, ABTS, and ORAC assay than the untreated sample. The Sonication process significantly improved (p ≤ 0.05) colloidal stability by reducing particle size distribution, apparent viscosity, and sedimentation index. Sonication prolonged tomato juice's shelf life by reducing the total viable count from 6.31 to 1.91 log CFU/mL. Polygalacturonase and pectin methyl esterase of the sonication sample at 40 min were inactivated by 44.32 % and 64.2 %, respectively. Considering this issue from a future perspective, sonication processing can be used industrially to enhance fruit juice's nutritional properties and shelf life and reduce pesticides and other organic residues.

Preparation of BiFeO3 and photodegradation of tetracycline pollutant in the UV-heterogeneous Fenton-like system

Surplus tetracycline in the water body causes damage to the ecology balance and human health. Therefore, this work established an efficient strategy, namely, the BFO-based UV-heterogeneous Fenton-like system, to eliminate TC pollution. The photocatalytic oxidation system has been integrated with the heterogeneous Fenton-like system, cooperated with the photolysis of H₂O₂. These synergistic effects could boost the generation of reactive species for the TC degradation and mineralization, due to the reduction of Fe(III) to Fe(II) by photogenerated electrons and the separation of photogenerated electron-hole pairs. The prepared BFO was stable with no secondary pollution, and could be recovered by an extra magnet to reuse. Compared with other single oxidation systems, this coupled system showed an outstanding performance in TC disposal, and TC and TOC removal efficiencies could reach 100% and 74.92%, respectively. Moreover, the mechanisms for TC degradation involved that TC was degraded by oxidation species, such as superoxide radicals, hydroxyl radicals, and positive holes, and intermediate products in the TC degradation process mainly were products at m/z = 459, m/z = 445, and m/z = 134. The promising TC disposal efficiency achieved by the integration between BFO-based photocatalytic and heterogeneous Fenton-like system sheds light on applying BFO to control water pollution.

Ultrasonic-assisted ozone degradation of organic pollutants in industrial sulfuric acid

In this work, a combination of ozone (O₃) and ultrasound (US) has been firstly used to decolorize black concentrated sulfuric acid with high organic content. The effect of different reaction factors on the transparency, extent of decolorization, H₂SO₄ mass fraction, and organic pollutants removal is studied. In addition, the systematic interaction between ultrasound and ozone on the decolorization process is reviewed through comparative experiments of O₃, US and US/O₃. A sulfuric acid product that meets the requirements for first-class products in national standards, with an extent of decolorization of 74.07%, transparency of 70 mm, and a mass fraction of 98.04%, is obtained under the optimized conditions. Under the same conditions, it has been established that the treatment time can be saved by 25% using the US/O₃ process compared to using O₃. Further, the production of oxidative free radicals (•OH) in a concentrated sulfuric acid system is enhanced using the US/O₃ process compared with O₃. In addition, the degree of effectiveness of different oxidizing components on the decolorization process is revealed by adding different free radical shielding agents when the US/O₃ process is used.

A novel technique for the reduction of pesticide residues by a combination of low-intensity electrical current and ultrasound applications: A study on lettuce samples

In this study, effects of low-intensity electrical currents (200, 800 and 1400 mA), ultrasound frequencies (24 and 40 kHz) and their combinations were applied at the duration period of 2, 4, 6, 8, and 10 min for the degradation of captan, thiamethoxam and metalaxyl residues in lettuce samples. Residues of the pesticides were determined by gas chromatography with tandem mass spectrometry and electron capture detector. The results indicated that the combination of low-intensity electrical current and ultrasound was found to be effective for the reduction of the pesticides. The most effective combination was obtained to be current of 1400 mA and ultrasound frequency of 24 kHz at 10 min. Under this circumstance, 92.57, 81.99 and 93.09% of captan, thiamethoxam and metalaxyl residues were decreased, respectively. The findings suggest that the combination of low-intensity electrical current and ultrasound applications has an important potential for the degradation of pesticide residues.

A critical analysis of sono-hybrid advanced oxidation process of ferrioxalate system for degradation of recalcitrant pollutants

The emerging contaminants in wastewater discharged from numerous chemical process industries, pharmaceutical industries, textile, and wineries have attracted the attention of the scientific community due to their toxicity and persistence in the environment. The conventional techniques are incompetent to treat many of such recalcitrant toxic pollutants. To achieve high mineralization, advanced oxidation processes (AOPs) are found to be more efficient for the degradation of these organic pollutants without producing secondary pollutants with no/less amount of sludge. The primary oxidation agents for AOPs are in-situ generated free radicals, which are highly reactive and effective oxidants for degrading any type of organic molecules present in the wastewater. In the past decades, the combination of AOPs or simultaneous application of more than one AOP has been investigated extensively for wastewater treatment and these hybrid-AOPs have been reported to be beneficial for high-level mineralization of organic pollutants. This paper presented the characteristics, properties and influence of parameters in sono-photo-ferrioxalate system. The primary operating parameters in sono-photo-ferrioxalate system that affect the kinetics are defined as the solution pH, temperature, molar ratio of Fe³⁺/C₂O₄^2-, H₂O₂ concentration, source of light, ultrasound intensity, dissolved gases, and size of cavitation bubble. In this process, several oxidizing radicals are generated such as HO^•, HO₂^•, C₂O₄^•-, CO₂^•- and O₂^•- which are also responsible for degradation. In this review, we have mainly addressed the degradation of recalcitrant pollutants using the sono-photo-ferrioxalate system and a critical analysis of process parameters that influence mineralization efficiency.

Application of ultrasonic technology in postharvested fruits and vegetables storage: A review

It has been an important research topic and a serious applicable issue to extend storage time of fruits and vegetables using advanced scientific and effective technology. Among various approaches, ultrasound has been regarded as one of the most pollution-free and effective technical means to significantly improve the preservation of fruits and vegetables. This paper summarizes the application of ultrasonic technology in fruits and vegetables storage in recent years, including removal of pesticide residues and cleaning, sterilization, enzyme inactivation, effect on physico-chemical indexes. Additionally, we also discussed limitations and negative effects of ultrasonic treatment on fruits and vegetables such as damages to tissues and cells. Furthermore, a proper application of ultrasonic technology has been proven to effectively extend the storage period of postharvest fruits and vegetables and maintain the quality. Moreover, the combination of ultrasound and other conventional preservation technologies can further improve the preservation in a coordinate manner and even have a broader application prospect.

Novel metabolites of triazophos formed during degradation by bacterial strains Pseudomonas kilonensis MB490, Pseudomonas kilonensis MB498 and pseudomonas sp. MB504 isolated from cotton fields

In the current scenario of overuse of pesticides (resulting in soil and water pollution and ultimately leading to biomagnification), a research project was carried out to study biodegradation of Triazophos. For this purpose, three bacterial strains (Pseudomonas kilonensis MB490, Pseudomonas kilonensis MB498 and Pseudomonas sp. MB504), isolated from cotton fields of Mianwali, Pakistan were investigated for Triazophos degradation and metabolite formation in M-9 broth, soil slurry and soil microcosm after incubation for 9 days. There was 88.4-95.8% Triazophos degradation in M-9 broth, 99.90% degradation in soil slurry and 92.74 to 96% Triazophos degradation in soil microcosm by these bacteria after 9 days. While there was negligible Triazophos degradation (upto 7%) in the controls without bacteria. According to GCMS analysis, 7 unique and novel metabolites (1, 2, 4-Triazole-4-amine, N-(2-Thienylmethyl), Benzene sulfonic acid hydrazide, Benzene sulfonic acid methyl ester, 4H-1,2,4-Triazole-4-benzenesulfonamide, 4, 5 dihydro-N-(O-toyl)-3-furamide, Ethyl 4-phenyldiazenylbenzoate and Dibutyl methanephosphonate) of Triazophos were revealed. Current results strongly suggest the potential of these bacterial strains for the remediation of Triazophos contaminated agricultural soils.

Ultrasound and heterogeneous photocatalysis for the treatment of vinasse from pisco production

Production of the distilled alcohol pisco results in vinasse, dark brown wastewater with high polyphenols contents and chemical oxygen demand (COD). No prior research exists on the efficiency of advanced oxidations processes (AOPs) in treating pisco vinasse. Therefore, the purpose of this study was to assess the efficiency of ultraviolet (UV), ultrasound (US), US + UV, heterogeneous photocatalysis (HP), and HP + US treatments. Polyphenols, COD, and color removal, as well as oxidation-reduction potential, were monitored over a 60-minute treatment period. Energy consumption levels and synergies were also calculated. The HP + US treatment achieved the best removal ratios for polyphenols (68%), COD (70%), and color (48%). While the HP treatment was the second most efficient in terms of polyphenols (62%), COD (58%), and color (40%) removal, this AOP comparatively required the least amount of energy. Considering the energy efficiency and relatively high pollutant-removal rates of the HP treatment, this AOP is recommended as a practical alternative for treating pisco vinasse.

Sonochemical degradation of pesticides in aqueous solution: investigation on the influence of operating parameters and degradation pathway – a systematic review

Along with the wide production, consumption and disposal of pesticides in the world, the concerns over their human and environmental health impacts are rapidly growing.

Fate of environmental pollutants

This annual review covers the literature published in 2018 on topics related to the occurrence and fate of environmental pollutants in wastewater. Due to the vast amount of literature published on this topic, we have discussed only a portion of the quality research publications, due to the limitation of space. The abstract search was carried out using Web of Science, and the abstracts were selected based on their relevance. In a few cases, full-text articles were referred to understand new findings better. This review is divided into the following sections: antibiotic-resistant bacteria (ARBs) and antibiotic-resistant genes (ARGs), disinfection by-products (DBPs), drugs of abuse (DoAs), estrogens, heavy metals, microplastics, per- and polyfluoroalkyl compounds (PFAS), pesticides, and pharmaceuticals and personal care products (PPCPs), with the addition of two new classes of pollutants to previous years (DoAs and PFAS).

A Review on Ultrasonic Catalytic Microbubbles Ozonation Processes: Properties, Hydroxyl Radicals Generation Pathway and Potential in Application

Ozone-based advanced oxidant processes (AOPs) have attracted remarkable attention as an alternative and effective approach for mineralization of refractory organics to innocuous substances. Key issues for ozone-based AOPs mainly focused on how to enhance ozone mass transfer and improve the production of hydroxyl radicals. Unfortunately, great efforts have been made, though, the application of ozone-based AOPs still remained in the laboratory scale due to lack of understanding of mechanisms of these hybrid processes. Besides, obtaining the balance of economical-technical feasibility is a great challenge. Ultrasonic catalytic microbubbles ozonation could be considered as a promising method, despite that there are a few studies that addressed this potential technology. Therefore, in this review, summaries about ozone-based microbubbles process, ultrasonic catalytic ozonation process, and ultrasonic catalytic microbubbles ozonation process have been provided in order to give a novel prospective about these hybrid technologies. The main influential parameters, such as initial pH, ozone dosage, intake flow rate, operating temperature, bubble size distributions, ultrasonic frequency, ultrasonic power density, and natural water constituents have also been well discussed. We truly hope that this paper will bring convenience to researchers that are devoted in the field of application of ozone-based AOPs for mineralizing refractory organics in wastewater.

Ultrasound-Assisted Removal of Tetracycline by a Fe/N-C Hybrids/H2O2 Fenton-like System

In this work, the degradation of tetracycline (TC) in water by the integrated ultrasound (US)-Fenton process was investigated. For this, a new composite Fe/N-C-x (x is the molar ratio of iron salt Fe(NO₃)₃·9H₂O) catalyst was synthesized through simple carbonization of the mixture of glucose and iron salt Fe(NO₃)₃·9H₂O in the presence of ammonium chloride as the nitrogen source. The resultant catalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and N₂ adsorption-desorption, showing a typical graphite porous structure and good magnetic properties. The results indicated that the optimized Fe/N-C-2 catalyst prepared with a mole ratio of glucose/Fe(NO₃)₃·9H₂O/NH₄Cl of 5:2:16.8 exhibited the highest TC removal in the Fe/N-C-2/H₂O₂/US system at a wide pH range from 3.0 to 11.0. At an initial pH of 7.0, TC removal in the Fe/N-C-2/H₂O₂/TC/US system was 1.83, 18.69, and 28.75 times of that in Fe/N-C-2/TC/H₂O₂, H₂O₂/TC/US, and TC/H₂O₂ systems, showing a positive synergistic action between US and Fe/N-C-2. The effects of catalyst dosage, H₂O₂ concentration, ultrasonic power, humic acid, and coexisting anions on TC removal were investigated. The preliminary analysis suggested that the Fe-N species and the graphite N dispersed in the carbon matrix are responsible for the efficient catalytic activity. By a simple magnetic separation, the Fe/N-C-2 catalyst was easily recovered and used for the next degradation experiment. Above 88% catalytic ability of Fe/N-C-2 was retained even after six successive runs, suggesting its good reusability. The simple preparation strategy, good magnetic property, and good catalytic ability of the Fe/N-C-2 materials make them promising alternative Fenton-like catalysts for the antibiotics abatement in water.

Sonochemical synthesis of WS2 nanosheets and its application in sonocatalytic removal of organic dyes from water solution

In this research, tungsten disulfide (WS₂) nanosheets as sonocatalyst were synthesized through a sonochemical route. Characterization of as-synthesized sonocatalyst was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX), Dot-mapping, high resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) analysis. WS₂ nanosheets were evaluated for their sonocatalytic performance in order to remove basic violet 10 (BV10) under ultrasonic irradiation. The removal efficiency was maximized (94.01%) via the use of 1 g L^-1 catalyst and 10 mg L^-1 BV10 at pH = 4.5 and an ultrasonic power of 400 W within a reaction time of 150 min. In addition to BV10, the sonocatalytic elimination for a number of organic dyes viz. direct blue 71, acid blue 92, methylene blue, basic orange 2 and basic red 46 was examined to demonstrate the performance of WS₂ nanosheets under the ultrasonic irradiation. The experimentation of trapping was conducted using edetate disodium (EDTA-2Na), tert-butyl alcohol (t-BuOH), and benzoquinone (BQ). According to the results, all radicals participated in the sonocatalytic activity. OH played a more prominent role than h⁺ and O₂^-∙ in the process of BV10 separation. Following five repetitive runs, the nanocomposites revealed a reusability of circa 18% drop in the elimination efficiency. The main removal intermediates were recognized by GC-MS technique.