Cavitation Technology Research Articles

Instability and collapse mechanisms of O2 and N2 nanobubble gas–liquid interfaces: A molecular dynamics simulation study

Nanobubbles, with their stability and oxidative properties, are widely applied in biomedicine, flotation, and environmental remediation. While experimental studies have explored their application effects, the dynamic behavioral characteristics of gas-containing nanobubbles during collapse remain insufficiently investigated. This study employs molecular dynamics simulation to examine nanobubble collapse under various conditions, including impact velocities, gas types, bubble sizes, and gas densities. Results show that increasing bubble size expands the microjet radiation area, while higher impact velocities increase microjet velocities. Gas types affect the jet radiation area due to differences in van der Waals forces and solubility. Vacuum nanobubbles exhibit higher maximum jet velocities than nitrogen and oxygen nanobubbles. Gas cushioning and compression rebound significantly influence maximum jet velocity. Microjets induce vortex structures, gas surface changes, and local pressure increases, leading to secondary water hammer impacts. Simulation results align well with theoretical calculations. This study provides the theoretical foundation for the industrial-scale implementation of nanobubble cavitation technology.

Modifications of biological membranes, fat globules and liposomes promoted by cavitation processes. Consequences and applications

Cavitation-based technologies, such as ultrasound (or acoustic cavitation, AC) and hydrodynamic cavitation (HC), are gaining interest among green processing technologies due to their cost effectiveness in operation, toxic solvent use reduction, and ability to obtain superior processed products, compared to conventional methods. Both AC and HC generate bubbles, but their effects may differ and it is difficult to make comparisons as both are based on different phenomena and are subject to different operational variables. AC is one of the most used techniques in extraction and homogenization processes at the laboratory level. However, upscaling to an industrial level is hard. On the other hand, HC is based on the passage of the liquid through a constriction (orifice plate, Venturi, throttling valve), which causes an increase in liquid velocity at the expense of local pressure, forcing the pressure around the contraction below the threshold pressure that induces the formation of cavities.Some applications of cavitation technologies, such as the production of liposomes or lipid nanoparticles (LNPs) allow the generation of delivery systems for biomedical applications.Many others (inactivation of pathogenic viruses, bacteria and algae for water purification, extraction procedures, third generation of biofuel production, green extractions) are based on the disruption of lipid membranes. There are also applications aimed at the modification of membranes (like the milk fat globule) for the development of innovative products. Process parameters, such as cavitation intensity, duration and temperature define the impact of the process on the physical, chemical, and biological characteristics of the membranes. Thus, the adequate implementation of cavitation processes requires understanding of interactions and synergistic mechanisms in complex systems and of their effects on membranes at the microscopic or molecular level. In the present work, the use of cavitation technologies for the generation of LNPs or nanostructured lipid carriers, and the effects of AC and HC treatments on several types of membrane systems (liposomes, solid lipid nanoparticles, milk fat globules, algae and bacterial membranes) are discussed, focusing on the structural and chemical modifications of lipidic structures under cavitation.

Preparation of water-soluble CdSeS alloy quantum dots with small particle size and high fluorescence lifetime by using hydrodynamic cavitation technology and their application in Ag+ detection

In this study, hydrodynamic cavitation (HC) is used as a novel and simple large-scale preparation technique. Water-soluble CdSeS alloy quantum dots (QDs) were successfully prepared by using Cd(NO3)2·4H2O, Na2S·9H2O and selenium powder as cadmium, sulfur and selenium sources. The effects of cycle time, reaction temperature, inlet pressure and Se/S molar ratio on the morphology, size and optical properties of CdSeS QDs were investigated. The prepared CdSeS QDs were characterized by X-ray diffractometer, X-ray photoelectron spectroscopy, transmission electron microscopy, UV–vis absorption spectra, fluorescence emission spectra and fluorescence attenuation curves. Finally, under the conditions of 12 h cycle time, 3.0 bar inlet pressure, 60 °C reaction temperature and 0.5/0.5 Se/S molar ratio, the ternary alloy CdSeS QDs with 2.62 nm average particle size and 482.62 ns fluorescence lifetime was obtained. Furthermore, a mechanism of preparing CdSeS QDs by using the HC method was proposed to explain the process of CdSeS precipitates conversion to CdSeS QDs. In addition, it is also found that Ag+ has a quenching effect on the prepared CdSeS QDs, which means that CdSeS QDs can be used as a fluorescence probe to specifically detect Ag+. This work not only provides a new possibility for large-scale preparation of high-performance QDs but also helps to understand the mechanism of CdSeS QDs as a metal ion selective fluorescence probe.

Experimental Study on Preparation of Nano ZnO by Hydrodynamic Cavitation-Enhanced Carbonization Method and Response Surface Optimization

The carbonization method for preparing Nano ZnO is characterized by its simplicity, ease of reaction control, high product purity, environmental friendliness, and potential for CO2 recycling. However, traditional carbonization processes suffer from poor heat and mass transfer, leading to in situ growth and agglomeration, resulting in low carbonization efficiency, small specific surface area, and inferior product performance. To enhance micro-mixing and mass transfer efficiency, ZnO derived from zinc ash calcination was used as the raw material, and hydrodynamic cavitation technology was employed to intensify the carbonization reaction process. The reaction mechanism of hydrodynamic cavitation was analyzed, and a single-factor experimental study investigated the effects of reaction time, reaction temperature, solid–liquid ratio, calcination temperature, incident angle, cavitation number, and position height on the specific surface area and carbonization rate of Nano ZnO. The response surface method was utilized to explore the significance of the three most influential factors—solid–liquid ratio, cavitation number, and position height—on the carbonization rate and specific surface area. The products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analysis, and specific surface area analysis. The results showed that the optimal process parameters were a reaction temperature of 80 °C, a reaction time of 120 min, a solid–liquid ratio of 5.011:100, a calcination temperature of 500 °C for 1 h, an incident angle of 60°, a cavitation number of 0.366, and a position height of 301.128 mm. The interaction between solid–liquid ratio and position height significantly influenced the process parameter variations. Under these conditions, the specific surface area and carbonization rate were 63.190 m2/g and 94.623%, respectively. The carbonized product was flaky Nano ZnO with good dispersion and small particle size. Compared to traditional mechanical stirring and bubbling methods, the specific surface area increased by 1.5 times, the carbonization rate improved by 10%, and the particle size decreased by half, significantly enhancing the product performance.

The Effect of Hydrodynamic Cavitation on the Structural and Functional Properties of Soy Protein Isolate-Lignan/Stilbene Polyphenol Conjugates.

In this study, hydrodynamic cavitation technology was utilized to prepare conjugates of soy protein isolate (SPI) with polyphenols, including resveratrol (RA) and polydatin (PD) from the stilbene category, as well as arctiin (AC) and magnolol (MN) from the lignan category. To investigate the effects of hydrodynamic cavitation treatment on the interactions between SPI and these polyphenols, the polyphenol binding capacity with SPI was measured and the changes in the exposed sulfhydryl and free amino contents were analyzed. Various methods, including ultraviolet-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy, were also used to characterize the structural properties of the SPI-polyphenol conjugates. The results showed that compared to untreated SPI, SPI treated with hydrodynamic cavitation exposed more active groups, facilitating a greater binding capacity with the polyphenols. After the hydrodynamic cavitation treatment, the ultraviolet-visible absorption of the SPI-polyphenol conjugates increased while the fluorescence intensity decreased. Additionally, the content of exposed sulfhydryl and free amino groups declined, and changes in the secondary structure were observed, characterized by an increase in the α-helix and random coil content accompanied by a decrease in the β-sheet and β-turn content. Furthermore, the SPI-polyphenol conjugates treated with hydrodynamic cavitation demonstrated improved emulsifying characteristics and antioxidant activity. As a result, hydrodynamic cavitation could be identified as an innovative technique for the preparation of protein-phenolic conjugates.

Jet cavitation-enhanced hydration method for the preparation of magnesium hydroxide

During the preparation of magnesium hydroxide via the hydration method, in-situ growth and agglomeration often inhibit the reaction. This study used active magnesium oxide as the raw material and employed jet cavitation technology to enhance the hydration process. Based on the growth process of magnesium hydroxide, the mechanism of jet-enhanced hydration was analyzed. The effects of reaction temperature (T), reaction time (t), solid-liquid ratio (s), and cavitation number (σ) on the hydration rate were investigated. An L25(54) orthogonal experiment explored the significance of each factor's impact on the hydration rate. The hydration products were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and a specific surface area analyzer. Results indicate that the factors affecting the hydration rate, in order of significance, are cavitation number > reaction temperature > solid-liquid ratio > reaction time. The optimal process parameters were determined to be a reaction temperature of 70 °C, reaction time of 80 min, solid-liquid ratio of 1:12, and cavitation number of 0.42. Under these conditions, the hydration rate reached 94.87 %, producing well-dispersed lamellar magnesium hydroxide with a narrow particle size distribution (median particle size D50 = 4.511 μm) and a BET specific surface area of 11.345 m²/g.

Cavitation intensity prediction and optimization for a Venturi cavitation reactor using deep learning

The Venturi reactor, widely used in process intensification through hydrodynamic cavitation technology, has proven highly effective in various chemical and environmental applications. The cavitation intensity of a Venturi is primarily influenced by shape parameters such as the convergent angle (β1), throat diameter (dth), throat length (lth), and divergent angle (β2). However, the impact of these parameters on cavitation intensity has not been sufficiently clarified. In this study, the structural optimization of a Venturi reactor was accomplished by integrating deep neural networks with particle swarm optimization. The Cavitation Intensity Prediction Network model, which combines artificial neural networks and numerical simulation, was used to establish the nonlinear relationship between shape parameters and cavitation intensity. Partial dependence plots and individual conditional expectation plots were utilized to clarify the influence of each parameter. The findings reveal that the cavitation intensity of the optimal Venturi is 2.76 times greater than that of the original design. Reducing β1 resulted in a swift conversion of static pressure into dynamic pressure, but it also caused an uneven distribution of fluid velocity. To reduce this unevenness and allow the dynamic pressure in the throat to reach its peak, which is advantageous for cavitation generation, lth should be extended. dth directly influenced the efficiency of converting static pressure into dynamic pressure and was a key factor in determining cavitation intensity. β2 indirectly impacted cavitation intensity by modulating the space available for cavitation development. The insights gained from this study may provide valuable guidance for designing Venturis in process intensification applications.

Synthesis of uniform sized ZnS quantum dots using hydrodynamic cavitation and their characterization

As representative non-toxic cadmium-free quantum dots (QDs), ZnS QDs with high quantum efficiency, super stability and excellent biocompatibility had attracted wide attention in the fields of photocatalysis, solar cells and biomedicine. In this study, hydrodynamic cavitation (HC) technology was applied to the preparation of ZnS QDs. By adjusting HC device parameters, water soluble ZnS QDs with small particle size, narrow particle size distribution range, high absorbance, high luminous efficiency and high quantum yield were prepared. The morphology, size distribution, element composition and optical properties of ZnS QDs were studied by various characterization methods. ZnS QDs with average particle size of 1.48 nm, fluorescence quantum yield of 34.07% and Stokes shift of 112 nm were obtained. In addition, the mechanism of preparation of ZnS QDs by using HC method was also studied. It is hoped that this HC technology can provide a new idea for large-scale preparation of ZnS QDs with excellent properties.

Improvement of technologies for recycling waste petroleum

Relevance. Currently, the rational and economical use of petroleum products is of particular importance. This applies, among other things, to all known types of oils. Waste oils entering the natural environment are only partially neutralized as a result of natural processes. Most of them are a source of pollution of soils, water bodies and atmospheric air, leading to disruption of the reproduction of birds, fish, mammals, and having a harmful effect on humans. Thus, the widespread problem of collecting and recycling waste petroleum products is a relevant, cost-effective and knowledge-intensive area; since with the correct organization of regeneration, the cost of recovered oils is 40–70% lower than the cost of fresh oils with almost the same quality. Aim. To improve the technology of recycling spent petroleum products in the conditions of the northern territories in order to achieve eco- and energy efficiency. After the regeneration stage, used oils can be used for their intended purpose – returned to equipment lubrication systems, this is up to 75–80% of the original amount of waste oil generated. The remaining, “unrecovered” amount of 20–25% is burned in the form of a water-fuel mixture at enterprises equipped with liquid fuel boilers. The information available in the literature is insufficient to create an effective system for the disposal of used oils and other petroleum products, especially in the circumpolar territories. A differentiated approach to the problem is required, taking into account the peculiarities of the climate, the remoteness of the Arctic territories from the transport infrastructure, with mandatory compliance with environmental standards. Methods. cavitation technology (i. e. cavitation effects) and the LSTM (Long Short-Term Memory) deep learning method for processing hydrocarbon waste using the example of industrial oil W30 and, accordingly, modeling the migration of pollutants from industrial objects in open natural water sources. Results and conclusions. The results obtained indicate that the integrated use of raw materials is the result of the most complete, economically and environmentally justified application of all advantageous components contained in raw materials, as well as in production waste. Any hydrocarbon waste can be considered as secondary material resources that can be used for economic purposes, partially or completely replacing traditional types of material, raw materials and fuel and energy resources, the main value of which is their constant reproducibility in the production sector.

Degradation of tetracycline by combining hydrodynamic cavitation (HC) and persulfates (PS)

Abstract The ecological and human health risks caused by the overuse of antibiotics have aroused widespread concern. Due to the characteristics of antibiotics themselves, they cannot be effectively removed by traditional treatment methods. HC is considered as a new and innovative chemical process enhancement technique. which exhibits remarkable efficiency in degrading stubborn organic pollutants, and can effectively cooperate with various physical and chemical methods. In this study, the hydrodynamic cavitation (HC) technology was used to activate peroxymonosulfate (PMS) and peroxodisulfate (PDS) to produce strong oxidizing active substances (SO4 -•) to degrade tetracycline (TC) wastewater with an initial concentration of 30 mg/L. The results show that a positive relationship between the degradation efficiency of TC and both the inlet pressure as well as the dose of PS applied. HC can enable full activation of PMS and PS, the max synergistic index of HC-PMS and HC-PDS was 1.72 and 24.81, respectively. Therefore, the HC-PS system can provide a novel technical route for the treatment of antibiotic wastewater.

Comparative studies on enhancing pea protein extraction recovery rates and structural integrity using ultrasonic and hydrodynamic cavitation technologies

This study explored the efficacy of various cavitation technologies, including ultrasonic bath (USB), ultrasonic plate (US-plate), ultrasonic probe (US-probe), and hydrodynamic cavitation (HDC), in extracting proteins from peas. US-probe showed the highest protein recovery rate (52.53 g/hg protein in pea powder) among all lab-scale cavitation equipment while HDC demonstrated significant potential for scaling up, notably improving both the purity (80.35 g/hg dried precipitate) and recovery rate (56.85 g/hg) of pea protein isolate (PPI) compared to conventional extraction (CE). SDS-PAGE, LC-MS/MS, FTIR and Fluorescence analysis were used to analyse the impact of these cavitation technologies on the structures of pea protein. The results confirmed that cavitation preserved PPI's primary structure while altering its secondary and tertiary structures, particularly under US-probe treatment, which significantly unfolded proteins. The SEM results revealed a marked reduction in protein bodies adhering to starch granules in residues from US-probe and HDC treatments compared to CE, correlating with their higher protein recovery rates.

Investigation of singlet oxygen and superoxide radical produced from vortex-based hydrodynamic cavitation: Mechanism and its relation to cavitation intensity

Presently, the hydroxyl radical oxidation mechanism is widely acknowledged for the degradation of organic pollutants based on hydrodynamic cavitation technology. The presence and production mechanism of other potential reactive oxygen species (ROS) in the cavitation systems are still unclear. In this paper, singlet oxygen (1O2) and superoxide radical (·O2−) were selected as the target ROS, and their generation rules and mechanism in vortex-based hydrodynamic cavitation (VBHC) were analyzed. Computational fluid dynamics (CFD) were used to simulate and analyze the intensity characteristics of VBHC, and the relationship between the generation of ROS and cavitation intensity was thoroughly revealed. The results show that the operating conditions of the device have a significant and complicated influence on the generation of 1O2 and ·O2−. When the inlet pressure reaches to 4.5 bar, it is more favorable for the generation of 1O2 and ·O2− comparing with those lower pressure. However, higher temperature (45 °C) and aeration rate (15 (L/min)/L) do not always have positive effect on the 1O2 and ·O2− productions, and their optimal parameters need to be analyzed in combination with the inlet pressure. Through quenching experiments, it is found that 1O2 is completely transformed from ·O2−, and ·O2− comes from the transformation of hydroxyl radicals and dissolved oxygen. Higher cavitation intensity is captured and shown more disperse in the vortex cavitation region, which is consistent with the larger production and stronger diffusion of 1O2 and ·O2−. This paper shed light to the generation mechanism of 1O2 and ·O2− in VBHC reactors and the relationship with cavitation intensity. The conclusion provides new ideas for the research of effective ROS in hydrodynamic cavitation process.

Preparation of water-soluble cadmium sulfide quantum dots with narrow small-size distribution by controlling hydrodynamic cavitation device parameters

With the increasingly broad application of quantum dots in many fields, how to further improve the performance of quantum dots in various aspects has become an urgent problem to be solved. In this study, hydrodynamic cavitation (HC) technology was applied for the first time in the preparation of quantum dots. Specifically, cadmium sulfide quantum dots (CdS QDs) with small particle size, narrow distribution, high concentration and large Stokes shift are prepared. Firstly, CdS precipitation was obtained in an aqueous solvent, using cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) and sodium sulfide nonahydrate (Na2S·9H2O) as Cd and S sources, respectively. Subsequently, CdS QDs were formed from top to bottom through hydrodynamic cavitation reactor, which generates high temperature, high pressure, high-speed jets, shear forces, and shock waves. In summary, the intrinsic advantages of HC technology offer a new opportunity for manufacturing large-scale quantum dots with superb performance.

Analysis of the influence of ions on degradation of benzamide with hydrodynamic cavitation technology

In recent years, hydrodynamic cavitation technology has become a research hotspot in various fields. This study establishes a benzamide model with different ion types, ion concentrations, and bubble radii. The model is used to study the diffusivity of water molecules on the benzamide wall and structural changes in benzamide. The influence of ion type, ion concentration, and bubble radius on the degradation of pollutants is examined. The results are as follows: the larger the bubble radius and ion concentration, the larger the rate of change of maximum radial distribution function of carbon atoms (w). The effect of ion type on the diffusion coefficient of water molecules on the benzamide wall is as follows: H2O2 > HCO3−1 > NO3−1. In terms of structural changes in the benzamide, in the model containing H2O2, ion concentration has a greater effect than bubble radius. In the model containing HCO3−1, bubble radius has a greater effect than ion concentration. In the model containing NO3−1, bubble radius and ion concentration have an equal effect. w decreases most in the model containing H2O2 and least in the model containing NO3−1. The model containing H2O2 produces the most powerful effect in benzamide pollutant degradation. This study provides technical guidance and a theoretical basis for the green treatment of pollutants using cavitation theory.

Yellow Field Pea Protein (Pisum sativum L.): Extraction Technologies, Functionalities, and Applications.

Yellow field peas (Pisum sativum L.) hold significant value for producers, researchers, and ingredient manufacturers due to their wealthy composition of protein, starch, and micronutrients. The protein quality in peas is influenced by both intrinsic factors like amino acid composition and spatial conformations and extrinsic factors including growth and processing conditions. The existing literature substantiates that the structural modulation and optimization of functional, organoleptic, and nutritional attributes of pea proteins can be obtained through a combination of chemical, physical, and enzymatic approaches, resulting in superior protein ingredients. This review underscores recent methodologies in pea protein extraction aimed at enhancing yield and functionality for diverse food systems and also delineates existing research gaps related to mitigating off-flavor issues in pea proteins. A comprehensive examination of conventional dry and wet methods is provided, in conjunction with environmentally friendly approaches like ultrafiltration and enzyme-assisted techniques. Additionally, the innovative application of hydrodynamic cavitation technology in protein extraction is explored, focusing on its prospective role in flavor amelioration. This overview offers a nuanced understanding of the advancements in pea protein extraction methods, catering to the interests of varied stakeholders in the field.

Exploring Osborne fractionation and laboratory/pilot scale technologies (conventional extraction, ultrasound-assisted extraction, high-pressure processing and hydrodynamic cavitation) for protein extraction from faba bean (Vicia faba L.)

This study explores Osborne fractionation of proteins of Vicia faba L. variety ′Lynx', the extraction of protein by laboratory scale technologies (conventional extraction (CE), ultrasound-assisted extraction (UAE) and high-pressure processing (HPP)) and the scale-up of the most efficient extraction and post-extraction processing method at pilot scale through hydrodynamic cavitation (HDC). Osborne fractionation revealed that the highest amount of protein was extracted with distilled water, namely albumins; followed by glutelin, globulin and prolamin. UAE using distilled water generated the highest protein content in the isolate (≈84%) compared to HPP (≈63%). HDC with distilled water, 20 passes and post-extraction by isoelectric precipitation achieved protein contents and recovery rates of approximately 89% and 72%, respectively. Scanning electron microscopic images revealed that cavitation technologies were capable of facilitating an efficient separation of starch and protein bodies leading to higher protein extraction compared to the other methods explored.

Evaluation of the controlled hydrodynamic cavitation as gas mass transfer system for ex-situ biological hydrogen methanation

The present work represents the first study focused on controlled hydrodynamic cavitation applied as gas transfer system to supply the methanogenic archaea with exogenous H2 and CO2. Starting from a generic mixed inoculum sampled from a thermophilic full-scale anaerobic digester, a bubble column bioreactor was coupled with a rotating hydrodynamic cavitator and fed with different H2/CO2 loading rates. Process efficiency and long-term effects on process stability and microbial population were evaluated. Gas sparging through the controlled hydrodynamic cavitation device is feasible under the operating conditions tested, resulting in almost 100% efficiency in H2 utilization and recording a CH4 volumetric content more than 99% in the gas leaving the reactor, without any gas recirculation from the headspace. The experimental trials lasted about 160 days and the behavior of the bioreactor showed a substantial stability over the time. Metagenomic and FISH analyses were carried out at the end of the experimental trials, revealing a remarkable increase of hydrogenotrophic methanogens species, related to the selection-effect of H2 on community composition. The findings provide previously unidentified insights into long-term effect on process stability and microbial community diversity in the biological hydrogenotrophic methanation process coupled with a gas–liquid mass transfer system based on controlled hydrodynamic cavitation technology.

Intensification of biodiesel production by hydrodynamic cavitation: A critical review

Biodiesel, with its nature of clean, biodegradability, and renewability, is an ideal substitute for fossil diesel. This critical review focuses on the advances in process intensification of biodiesel production by the emerging hydrodynamic cavitation (HC) technology. The recent progress in HC reactors and HC-assisted biodiesel production are summarized and discussed. Several key operating factors (i.e., reactor structure, cavitation intensity, temperature, molar ratio of alcohol to oil, catalyst, and duration) and the economic feasibility are analyzed. It is found that HC can effectively enhance acid- and alkali-catalyzed production processes by using various edible and non-edible oils (e.g., waste cooking oil) as feedstocks, and have economic practicability for industrialization. HC can achieve as high as over 99% yields in a short time, and the quality of the high-purity products meets EN 14214 and ASTM D6751 standards. Although the process simulation and life cycle cost analysis (LCCA) validated that the economics of HC process is far superior to that of conventional mechanical stirring at large scales, the experimental research at pilot or industrial scales is absent, and the amplification effect of both the reactor and process is unclear. Moreover, the investigations on the cavitation flow mechanism, structural optimization and design of HCRs, and feasibility (e.g., life cycle analysis (LCA), LCCA, and LCA-LCCA), have to be focused on in the future. At last, the strengths, weaknesses, opportunities, and threats (SWOT) of the HC process are evaluated by a SWOT matrix, which may hopefully provide some inspiration for the future development of this novel technology.

Research on the kinetics and degradation pathways of gaseous acetic acid ester organics

ABSTRACT Designed to meet the specific needs of the printing industry exhaust gas emissions, this paper proposes a method for the degradation of gaseous acetic acid ester organics that is environmentally friendly, safe, and simple to use: micro-nano cavitation technology. In the process of using micro-nano cavitation technology to degrade acetic acid ester organics, the products in the degradation process were analyzed by gas chromatography-mass (GC-MS) spectrometry, and the degradation pathways of acetic acid ester organics were identified. Under high temperatures and high pressure caused by cavitation collapse, the C–C bond and C–O bond on the main chain of organic matter are cleaved to form low molecular products. Low-molecular intermediate products are continuously produced as the reaction advances, and these intermediate products are further oxidized and decomposed into carbon dioxide and water. Besides, the factors that influence the degradation rate of acetic acid ester organics were investigated. Based on the experimental data, acetic acid esters can degrade with the greatest efficiency when their initial concentration is 200 ± 50 mg/m3 and their treatment time is 20∼30 min. Moreover, the experiment was optimized using the response surface method. The results suggested that for an initial concentration of 155.544 mg/m3 and a reaction time of 21.961 min, the best degradation rate was 0.251 min−1. Micro-nano cavitation technology is a novel and promising technology for the degradation of volatile organic compounds, with a wide range of practical applications.

The application of a novel hydrodynamic cavitation device to debride intra-articular monosodium urate crystals

IntroductionEfficient and complete debridement of intra-articular deposits of monosodium urate crystals is rarely achieved by existing arthroscopic tools such as shavers or radiofrequency ablation, while cavitation technology represents a prospective solution for the non-invasive clearance of adhesions at intra-articular interfaces.MethodsSimulation modeling was conducted to identify the optimal parameters for the device, including nozzle diameters and jet pressures. Gouty arthritis model was established in twelve rats that were equally and randomly allocated into a cavitation debridement group or a curette debridement group. A direct injection nozzle was designed and then applied on animal model to verify the effect of the cavitation jet device on the removal of crystal deposits. Image analysis was performed to evaluate the clearance efficiency of the cavitation device and the pathological features of surrounding tissue were collected in all groups.ResultsTo maximize cavitation with the practical requirements of the operation, an experimental rig was applied, including a 1 mm direct injection nozzle with a jet pressure of 2.0 MPa at a distance of 20 mm and a nitrogen bottle as high-pressure gas source. With regards to feasibility of the device, the clearance rates in the cavitation group were over 97% and were significantly different from the control group. Pathological examination showed that the deposition of monosodium urate crystals was removed completely while preserving the normal structure of the collagen fibers.ConclusionsWe developed a promising surgical device to efficiently remove intra-articular deposits of monosodium urate crystals. The feasibility and safety profile of the device were also verified in a rat model. Our findings provide a non-invasive method for the intraoperative treatment of refractory gouty arthritis.