Hydrodynamic Cavitation Treatment Research Articles

Hydrodynamic Cavitation – A Promising Technology for Water Treatment

In today's context, water treatment assumes paramount importance due to the scarcity of potable water and the escalating needs of the global population. Hydrodynamic Cavitation (HC) emerges as a promising application in wastewater treatment, particularly when integrated with Advanced Oxidation Processes (AOPs). The study begins with a critical examination of the literature on combined approaches involving hydrodynamic cavitation, followed by experimental findings. The primary objective was to mitigate the chemical oxygen demand (COD) of the sample through HC in conjunction with hydrogen peroxide and Fenton reagent. Subsequently, each run was executed, and the output value obtained from HC was determined. Throughout the research, samples of river water were procured from the Mula-Mutha River in Pune. HC treatment reduced the COD of river water by approximately 60.83 % at 3 pH. Notably, the highest degradation was observed at 9 pH with the use of Sodium persulphate, with the optimal concentration estimated to be 600 ppm. Moreover, a COD reduction exceeding 89 % with a dosage of 15 mM H2O2. Treatment with Fenton reagent for 60 min demonstrated a remarkable COD decrease of up to 93 %, with an optimal H2O2 to FeSO4 molar ratio of 10:1 and at 3 pH. The Fenton procedure alone or in combination with H2O2 and HC proved to be the most efficient for river water characterized by extremely high COD levels, yielding the greatest reduction during experimental trials. The kinetics of HC degradation conformed to a first-order rate law, with the value of a rate constant (K = 7.21 × 10-4 s−1).

The changes induced by hydrodynamic cavitation treatment in wheat gliadin and celiac-toxic peptides

The changes induced by hydrodynamic cavitation treatment in wheat gliadin and celiac-toxic peptides

Insight into the Effects of Hydrodynamic Cavitation at Different Ionic Strengths on Physicochemical and Gel Properties of Myofibrillar Protein from Tilapia (Oreochromis niloticus).

Effects of different ionic strengths (0.2, 0.4, and 0.6 mol/L) and different hydrodynamic cavitation (HC) treatment times (0, 1, 2, 3, and 4 min) on the conformation and gel properties of tilapia myofibrillar proteins (TMP) were investigated. The results showed that the solubility of TMP was significantly enhanced (p < 0.05) with the increase in NaCl concentration, and the gel characteristics were significantly improved. After HC treatment of TMP, the average particle size was significantly reduced (p < 0.05) and solubility was significantly enhanced (p < 0.05) with the increase in treatment time, the internal hydrophobic groups and reactive sulfhydryl groups were exposed. The intrinsic fluorescence spectra showed the unfolding of the spatial tertiary structure of proteins, and the circular dichroism spectroscopy showed the significant reduction in the content of α-helix in the secondary structure of the proteins (p < 0.05). In addition, the WHC and gel strength of the TMP heat-induced gels were enhanced, which improved the microstructure of the gels, and scanning electron microscopy showed that the gel network of the TMP gels became denser and more homogeneous. Dynamic rheology results showed that HC treatment resulted in a significant increase in the final G' and G" values of TMP. In conclusion, HC treatment was able to improve the physicochemical structure and gel properties of TMP at different ionic strengths. This study presents a novel processing technique for the quality maintenance aspect of salt-reduced surimi gel products.

Integrated physicochemical processes to tackle high-COD wastewater from pharmaceutical industry

Wastewater decontamination in pharmaceuticals is crucial to prevent environmental and health risks from API residues and other contaminants. Advanced oxidation processes (AOPs) combined with cavitational treatments offer effective solutions. Challenges include designing reactors on a large scale and monitoring the effectiveness and synergies of the hybrid technology. In the present work, pilot-scale treatment of a real high COD (485 g/L) pharmaceutical wastewater (PW) was investigated using hydrodynamic cavitation (HC) operated individually at 330 L/h or in combination with oxidants and electrical discharge (ED) with cold plasma (15 kV and 48 kHz). The first approach consisted of PW cavitational treatment alone of 7 L of 1:100 diluted PW at a HC-induced pressure of 60 bar and a flow rate of 330 L/h. However, this strategy did not provide satisfactory results for COD (∼15% less), and only when HC treatment was extended to more than 30 min in a recirculation mode, encouraging results were obtained (∼45% COD reduction). Consequently, a hybrid approach combining HC with ED-cold plasma was chosen to treat this high-COD PW. Aiming to establish an efficient flow-through hybrid process, after optimising all cavitation and electrical discharge parameters (45 bar HC pressure and 10 kHz ED frequency), the best COD abatement of ∼50 % was recorded with a 1:50 diluted PW. However, a subsequent adsorption step over activated carbon was required to achieve an almost quantitative COD reduction (95%+). Our integrated physicochemical process proved to be extremely efficient in treating high-COD industrial wastewater and resulted in a remarkable reduction of the COD value. In addition, the residual surfactants content in the PW were also drastically reduced (98%+) when a small amount of oxidants was added in the hybrid HC/ED treatment.

Comparison between hydrodynamic and ultrasound cavitation on the inactivation of lipoxygenase and physicochemical properties of soy milk

The effects of hydrodynamic cavitation (HC) and ultrasound cavitation (UC) on the lipoxygenase activity and physicochemical properties of soy milk were evaluated. The results revealed that both ultrasound cavitation and hydrodynamic cavitation significantly inactivated the lipoxygenase activity. After the exposure to ultrasound cavitation at 522.5 W/L and 70 °C for 12 min, the lipoxygenase activity was inactivated by 96.47 %. Meanwhile, HC treatment with the cavitation number of 0.0133 for 240 min led to the loss of 79.31 % of lipoxygenase activity. An artificial neural network was used to model and visualize the effects of different parameters after ultrasound cavitation treatment on the inactivation efficiency of soy milk. Turbiscan test results showed that hydrodynamic and ultrasound cavitation decreased the instability index and particle size of soy milk. Moreover, the total free amino acid content was significantly increased after hydrodynamic and ultrasound cavitation treatment. Gas chromatography-mass spectrometry showed that the total content of beany flavor compounds decreased after acoustic cavitation and HC treatment. Acoustic cavitation and HC affected the tertiary and secondary structure of soy milk, which was related to the inactivation of lipoxygenase. We aim to explore a potential and effective way of the application in soy milk processing by comparing the ultrasound equipped with heat treatment and hydrodymic cavitation.

Influence of low temperature hydrodynamic cavitation treatment on shelf life of ascorbic acid‐treated sugarcane juice

AbstractSugarcane juice has a lower shelf life owing to enzymatic browning as well as microbial activity. To overcome these issues, fresh sugarcane juice was treated with ascorbic acid, a strong antioxidant, and further subjected to low‐temperature hydrodynamic cavitation (LTHC) treatment at 4°C/.35 MPa for 30 min. The AALHC‐treated juice was filled into PET bottles and stored under atmospheric (25 ± 5°C) and refrigerated (4 ± 1°C) conditions. The changes in reducing sugar, total sugar, color (ΔE), microbial load, total phenolic content, total flavonoid content, and antioxidant activity of sugarcane juice during the storage period were evaluated. During the storage, better retention of the quality parameters was observed in the AALTHC processed sugarcane juice followed by AA‐treated sugarcane juice and fresh sugarcane juice. Under the atmospheric storage, fresh juice and AA‐treated juice were spoiled within a day, whereas the AALTHC‐treated sugarcane juice could last for 4 days. On the other hand, under the refrigerated storage conditions (4 ± 1°C), the quality of the fresh and AA‐treated sugarcane juice could last only for a week, while the quality of AALTHC could be maintained up to 42 days.Practical ApplicationsThe current study aims to improve the shelf life of sugarcane juice by low‐temperature orifice‐based hydrodynamic cavitation. Sugarcane juice has a short shelf life owing to high levels of microbiological contamination and enzymatic reactions that begin immediately following extraction. The use of hydrodynamic cavitation technique enables a significant reduction in microbial load as well as spoilage enzymes, with minimum effect on the nutrient profile and sensory qualities. The treatments presented in this study are successful, inexpensive, more practicable, and long‐term enough to be scaled up for larger‐scale production of sugar cane juice. The outcomes of this study may be useful for developing a fortified beverage industry employing low‐temperature hydrodynamic cavitation.

Enhancement of physicochemical stability and reduction in enzyme and microbial activity of apple juice by hydrodynamic cavitation processing

Conventional thermally processed apple juices are nutritionally depleted because the heat sensitivity degrades the bioactive compounds that comprise them. This study proposed a non-thermal technique, hydrodynamic cavitation (HC), to preserve the nutritional content and prevent the loss of bioactive components in apple juice. In addition, the effect of hydrodynamic cavitation on the physicochemical, nutrition, and enzyme inactivation of freshly expressed apple juice has been studied. The design expert software has been used for process optimization, while fuzzy logic was applied for sensory. Hydrodynamic cavitation has been used on freshly extracted apple juice with inlet pressure in the range of (34.47–103.421 kPa) for a treatment time of (0–30 min). The apple juice was treated thermally at 90 °C for 2.5 min to compare the cavitation results. The settling of particles in the cavitation sample was 7%, which was lower than the heat-treated sample (10%) and untreated control sample (39%) and had a noticeable effect on the cloud value and stability of the apple juice. The HC treatment reduces the particle size of fresh apple juice from 8934.09 nm to 1112 nm, resulting in a homogenizing effect, a decrease in viscosity, and improved juice stability. Hydrodynamic cavitation reduced the antioxidant activity from 0.4987 mg GAE mL−1 (control) to 0.3951 mg GAE mL−1 yet retained better activity than the heat-treated apple juice (0.3489 ± 0.34 mg GAE mL−1) with microbial log reduction of 0.9 at 103.42 kPa treated for 30 min. After 15 days of storage at 4 °C, HC-treated juice had higher quality features and nutrient retention than heat-treated apple juice.

Enhancement of biomethane potential of brown sludge by pre-treatment using vortex based hydrodynamic cavitation

Novel, non-thermal and economically benign pre-treatment process was developed for enhancing valorisation potential of brown sludge generated by dairy industry wastewater treatment plant (WWTP). Vortex-based hydrodynamic cavitation (HC) device was used to quantify influence of pretreatment by measuring biomethane potential (BMP) of untreated and treated brown sludge. Pre-treatment parameters, primarily, pressure drop and number of passes through the cavitation device were varied to quantify influence on BMP. BMP tests were performed at 39 °C containing 5% of total solids in each reactors using an automatic BMP measurement system containing 15 reactors with each volume of 500 mL fitted with overhead stirrer. HC treatment increased the soluble chemical oxygen demand (sCOD) by more than 25% which increased the BMP. HC treatment was able to push the BMP of treated sludge to more than 80% of the theoretical BMP. Volatile solids (VS) removal was more than 65%. Highest methane yield was 376 mL/g-VS of sludge. The methodology and results presented here show significant potential to valorise brown dairy sludge via vortex based hydrodynamic cavitation.

Hydrodynamic cavitation-assisted preparation of porous carbon from garlic peels for supercapacitors

Hydrodynamic cavitation (HC), which can effectively induce sonochemical effects, is widely considered a promising process intensification technology. In the present study, HC was successfully utilized to intensify the alkali activation of GPs for SCs, for the first time. Five BDCMs were synthesized following the method reported in the literature. For comparison, four more BDCMs with HC-treated, among which a sample was further doped with nitrogen during the HC treatment, were prepared. Then all the samples were compared from microscopical characteristics to electrochemical performance as SCs materials. The morphology study demonstrated that the HC treatment had created many defects and amorphous carbon structures on the GP-based BDCMs, with the highest SSA reaching 3272 m2/g (1:6-HCGP), which 32 folded that of the Raw carbon sample’s. The HC treatment also intensified the N-doping process. XRD and XPS results manifested that the N content had been increased and consequently changed the electronic structure of the carbon atoms, leading to the increase of specific capacitance (1:6-HCGP+N-based SC, 227 F/g at 10 A/g). The cycle performance proved that the GP-based BDCMs have long-term stability, indicating that the HC-treated BDCMs were good choices for energy storage technologies. Compared with the ultrasound-assisted method, which may have a high energy density, the HC-assisted method enables high production and energy efficiency. This work is a first time attempt towards the industrial application of HC method in energy-related materials synthesis and encourages more in-depth studies in the future.

Evaluation of the influence of hydrodynamic cavitation treatment of dark petroleum products on the yield of fractions with boiling points up to 400°C

Objectives. The reduction of the anthropogenic burden on the environment is generally associated with the transition to alternative energy sources. However, some of these have only regional significance, while the effectiveness of others remains doubtful. On this point, innovative processes aimed at increasing the depth of oil refining may be equally important for reducing the carbon footprint. Wave-based technologies such as cavitation may also be included in these processes. Among the various methods for inducing such cavitation phenomena in oil refining, hydrodynamic approaches are especially promising. It has been shown that the treatment effectiveness increases with greater pressure or when augmenting the number of cavitation processing cycles. The aim of this work is to identify the factor (i.e., pressure gradient or number of treatment cycles) having the greatest influence on the change of the characteristics of the oil product.Methods. Cavitation phenomena were created by pumping dark oil products through a diffuser. The pressure gradient ranged from 20 to 50 MPa, while the number of cavitation processing cycles varied from 1 to 10. The influence of cavitation conditions on the change of fractional composition of petroleum products was analyzed. Target fractions are those having a boiling point up to 400°C.Results. It is shown that increased pressure generated in the diffuser leads to a linear increase in the yield of desired cuts. The dependence of the yield of these fractions on the number of processing cycles is described by the growth model with saturation. A proposed equation describes the influence of pressure and number of cycles on the yield of the fractions from initial boiling point temperature (TIBP) to 400°C following cavitation processing of dark oil products. Some of the coefficients of this equation have been associated with the physicochemical characteristics of the feedstock.Conclusions. An equation for predicting the maximum possible yield of the TJBP-400°C fraction as a result of cavitation processing under different conditions of the process is proposed according to the physicochemical characteristics of the feedstock. The prediction error did not exceed 12%. The equation analysis and comparison of energy consumption between different process regimes shows that a higher yield of the target product is achieved by increasing pressure gradient rather than the number of processing cycles.

Hydrodynamic cavitation processing of ascorbic acid treated precooled sugarcane juice for physiochemical, bioactive, enzyme stability, and microbial safety

AbstractA hydrodynamic cavitation (HC) system (0.35 MPa) with a cooling arrangement was developed for the treatment of ascorbic acid (AA)‐treated sugarcane juice (AASCJ). The AASCJ was precooled to different temperatures (4, 17, and 30°C) and underwent HC processing for different durations (10, 20, 30, and 40 min). The quality parameters such as pH, total soluble solids, titratable acidity, polyphenol oxidase (PPO), peroxidase (POD) activity, viscosity, total color difference, microbial load, total phenolic, flavonoids, AA, and antioxidant activity were investigated. The processed AASCJ precooled to 4°C resulted in more than 90% retention in color, total phenolic content, flavonoid content, and antioxidant activity. The PPO and POD activities significantly reduced after HC treatment. A 3 log reduction in the microbial population was achieved during HC processing. The optimized condition for HC treatment of AASCJ was a precooling temperature of 4°C and a treatment time of 30 min.Practical applicationsSugarcane juice has a short shelf life due to the high rate of microbiological contamination and enzymatic reactions that occur shortly after extraction. Low‐temperature HC is a nonthermal approach for processing low viscous liquid foods. The HC processed AASCJ is microbiologically safe, with reduced PPO and POD activity, and better retention of bioactive compounds. The low‐temperature HC processing can be used instead of thermal processing to reduce both enzymatic and nonenzymatic browning reactions and eradicate pathogenic microorganisms while maintaining the sugarcane juice quality. This approach is simple to handle, requires little investment, and does not use environmentally hazardous chemicals.

Comparison of the effect of hydrodynamic and acoustic cavitations on functional, rheological and structural properties of egg white proteins

The impacts of hydrodynamic cavitation (HC) (orifice plate-2 mm) and acoustic cavitation/ultrasound (US) (probe sonicator- 50% amplitude; 20 kHz frequency) on the functional (foaming, gelling, emulsifying), physicochemical (solubility), rheological and structural properties of egg white proteins (EWP) were evaluated. The egg white solutions were treated for 5, 10 and 15 min for both HC and US. The results suggested that HC-treated samples had higher impact on physiochemical and functional properties when compared to US-treated samples. The best foaming, emulsifying and gelling property was obtained for HC-treated samples (15 min treatment time). Both cavitation treatments exhibited shear thinning behavior, among which US-treated samples had the lowest viscosity. HC-treatment applied for 15 min provided the highest in vitro digestibility (75.51 ± 0.126%) among all the samples. The FTIR spectra of EWP exhibited similar backbone structure for all the samples, while the secondary structure obtained from deconvolution of Amide-I peak differed significantly. Moreover, for product development with EWP, HC -treated samples were more appropriate in gelling and emulsifying applications, which can ensure quality products with higher in vitro digestibility. Overall, this study indicated that HC treatment (for 15 min) improved the functional, rheological, and structural properties of EWP.

A comparative study on the decolorization of Tartrazine, Ponceau 4R, and Coomassie Brilliant Blue using persulfate and hydrogen peroxide based Advanced Oxidation Processes combined with Hydrodynamic Cavitation

Decolorization of Ponceau 4R, Tartrazine, and Coomassie Brilliant Blue (CBB) was studied using hybrid processes of hydrodynamic cavitation (HC) with potassium persulfate (KPS) and hydrogen peroxide (H2O2). The different properties of these dyes such as hydrophobicity, molecular structures, and molecular weights provided this opportunity to investigate the effects of these factors by comparing the decolorization values of the dyes. Treatment process was optimized in respect to cavitation number, HC inlet pressure, and the concentration of external oxidants. The application of dual oxidation system under cavitation conditions revealed a synergetic effect. Maximum decolorization values of 92.27%, 50.1%, and 42.3% were obtained applying this combined process for CBB, Tartrazine, and Ponceau 4R, respectively. The different values of decolorization of the dyes were explained based on their different properties. The kinetic study led to first order rate constants of 10−3 min−1, 6.4*10−3 min−1, 9.2*10−3 min−1, and 4.16*10−2 min−1 using KPS, H2O2, HC, and HC-KPS-H2O2, respectively. A synergetic coefficient of 2.51 obtained by HC-KPS-H2O2 proved the effectiveness of this combined process. Analysis of cavitation yield efficiency showed an improvement of 98% for the HC-KPS-H2O2 combined process as compared to sole HC treatment process.

Insight into the sludge reduction performances by hydrodynamic cavitation

Insight into the sludge reduction performances by hydrodynamic cavitation (HC) were investigated. Mixed liquor suspended sludge (MLSS) and mixed liquor volatile suspended solids (MLVSS) decreased first and then increased as the increase of HC time from 0 to 240 min, and the lowest MLSS was 756.86 mg/L at 120 min. HC treatment promoted the increase in the solute chemical oxygen demand (sCOD) concentration and disintegration degree (DDsCOD) of sludge, and the values of sCOD and DDsCOD at 240 min were 319.66 mg/L and 22.98 %, respectively. The particle sizes at the 10th percentile (d(0.1)), the 50th percentile (d(0.5)) and the 90th percentile (d(0.9)) in particle size distributions decreased from 8.97, 21.10 and 49.10 μm to 0.04, 4.45 and 26.90 μm, respectively. The protein concentration in tightly bound extracellular polymers (TB-EPS) reduced with the increasing HC time from 0 to 240 min, while that in loosely bound EPS (LB-EPS) decreased firstly (during 0–120 min) and then gradually increased (during 120–240 min). As the increase of HC time, tryptophan protein in LB-EPS at 120 min and tyrosine protein in TB-EPS at 240 min disappeared in 3D excitation–emission matrix spectra.

Investigation of the effect of hydrodynamic cavitation treatment on the aging of tender coconut–palmyra wine

The effect of hydrodynamic cavitation (HC) on accelerated aging of tender coconut and palmyra blend wine was investigated at 3.45 bar pressure and 15–60 min of treatment (72 to 287 passes). The concentrations of phenolic (3.09 mgGAE/ml) and vitamin C (61.11 mg/100 ml) were maximum after 60 min treatment. However, as treatment time increased, the combined effect of temperature and pressure decreased antioxidant content while increasing the b* value. The overall acidity and pH did not vary significantly. As a result, a 15-min treatment at 3.45 bar pressure was the most effective. Particle size analysis demonstrated a drop in particle size (D50 549.7 to 246.5) following HC treatment, indicating that HC-treated wine had a greater influence on aging than standard wine. This research highlights the application of HC as a green technique for wine aging, which might be a game changer in beverage sector. Novelty impact statement Effect of hydrodynamic cavitation at 3.45 bar for 15–60 min for the aging of wine was studied Treatment had a synergistic effect on phenols and Vit C and an antagonistic effect on color and antioxidants FTIR showed that alterations in functional compounds with time during aging of sample wines were comparable to commercial wine.

A dye-methylene blue (MB)-degraded by hydrodynamic cavitation (HC) and combined with other oxidants

As a kind of AOPs, hydrodynamic cavitation (HC) has the characteristics of energy savings and easy amplification. It is of great significance to study the degradation of dye molecules with HC, due to the toxicity, chroma and difficult biodegradation of dyes. In the present work, the HC treatment of methylene blue (MB) was investigated, and the effects of inlet pressure, solution pH, and initial concentration on the degradation of MB dye were explored. The maximum degradation rate of MB was obtained at 0.3 MPa, pH = 2, and an initial concentration of 10 mg/L. The combination of Na2S2O8 or O3 with HC were also conducted to explore their synergistic effect. The results indicated that the degradation performance of introducing ozone is better that of adding Na2S2O8. When the amount of O3 gas was 0.12 g/h, the MB degradation rate was over 99%, and the synergy index was 3.58. The intermediate products in the MB disintegration process were detected based on LC-MS, and the reaction mechanism and path of MB were proposed.

Continuous Cultivation of Microalgae in Cattle Slaughterhouse Wastewater Treated with Hydrodynamic Cavitation

Cattle slaughtering produce large amounts of wastewater containing high concentrations of organic matter and nutrients and requires significant treatment before disposal or reutilization. However, the nutrients contained can be valued as a medium for microalgal biomass generation. In this work, hydrodynamic cavitation (HC) followed by membrane filtration or biological (microalgae cultivation) treatment in continuous mode were performed. From cattle slaughterhouse wastewater (CSW), by the effect of HC treatment with air injection in batch mode, more than 20% of the chemical oxygen demand (COD) was removed. In a continuous HC process, the COD content in output was 324 mg O2/L, which is 68% lower than the supplied CSW. After that, 76% of residual COD was removed by filtration through a tubular alumina membrane (600 nm). Finally, 85% of residual COD after HC treatment in 24 h in a batch mode was removed by microalgae. On the other hand, the COD concentration in the output was around 59 mg O2/L in continuous mode, which represents 85–93% COD removal. The process involving HC and microalgae growing looks promising since in addition to water treatment, the microalgae produced could be valued in a biorefinery concept.

Hydrodynamic cavitation-enhanced heterogeneous activation of persulfate for tetracycline degradation: Synergistic effects, degradation mechanism and pathways

• Mass transfer and oxidant utilization are two key issues in SO 4 •− oxidation. • Hydrodynamic cavitation (HC) is a green, effective solution to solve these issues. • Mass transfer was enhanced by HC-induced turbulence via Fe 0 → Fe 2+ →Fe 3+ →Fe 2+ . • HC promotes persulfate (PS) utilization in HC-Fe 0 /PS system. • Mass spectra and theoretical calculations reveal tetracycline degradation pathways. Mass transfer and oxidant utilization are perhaps two of the most critical issues in sulfate radical (SO 4 •− ) based advanced oxidation technologies (AOTs) and their scaled-up implementation. In this study, we propose using hydrodynamic cavitation (HC), considered a green, effective method, to promote both mass transfer and oxidant utilization in zero-valent iron (Fe 0 ) activated persulfate (PS) system. Whilst the BET surface area of Fe 0 was increased by 8 times after HC treatment, concentration of Fe 2+ derived from Fe 0 oxidation is greatly increased for effective PS activation. The reappearance of Fe 0 and Fe 2+ after cavitation ensured a good reusability of the catalyst. Likewise, the impact of pH revealed that TC adsorption on catalyst at acidic pH favored its degradation compared with that at higher pH. With respect to oxidant utilization, it is observed that PS even at a high dosage (2.8 mM) was completed converted within 30 min in the HC-Fe 0 /PS system. According to SEM, TEM, and BET analysis, we conclude that the microjets induced by cavitation bubbles or direct abrasion by HC agitation have contributed to the removal of hydroxide/oxide layers on the Fe 0 surface, thus reactivating its catalytic activity. Given these reasons, we observed up to 97.80% removal of Tetracycline (TC), the model pollutant, with a synergistic coefficient as high as 2.62. After confirming SO 4 •− as the most dominant reactive species, five degradation pathways of TC were proposed given the intermediate evidence from LC-MS/MS analysis and density functional theory (DFT) calculations. Results from this study could provide new insights into the role of HC on PS activation and shed light on the potential implementation of the SO 4 •− -based AOTs for scaled-up wastewater treatments.

Efficiency Evaluation of Cavitation Heat Generator Used for Desalination of Saline Solutions

Nowadays, the issue of efficient desalination and treatment of seawater for its further use in various domains of human activity is of much interest worldwide. There are plenty of known treatment techniques. This research paper discusses the method of hydrodynamic cavitation treatment in a heat generator in various modes and proves the performance efficiency of this method. The process of treating saline solutions of different concentrations and registration of electric conductivity of solutions are studied. The possibility of changing the concentration of salt in the solution by treating it in a vortex cavitation heat generator is undertaken. The efficiency of the cavitation process depends on the temperature of the working environment: with the temperature increase, the desalination intensity decreases. Two possible scenarios of the process are revealed, i.e., the decrease in the concentration of salt in the solution or its increase in the presence of a salt source. When working on depleted solutions with a salinity of 1÷5 ‰ at high temperatures, the reverse diffusion of previously adsorbed salts from the internal surfaces into the solution takes place. When working on solutions of elevated concentrations in the same high-temperature range, the reverse diffusion decreases and at a salinity of 67 ‰, its effect ceases, since the concentration of salts on the inner surfaces becomes comparable to the concentration of the solution. The hypothesis of centrifugal separation of salts from water is experimentally proved.

Non-thermal hydrodynamic cavitation processing of tomato juice for physicochemical, bioactive, and enzyme stability: Effect of process conditions, kinetics, and shelf-life extension

Fresh tomato juice was processed by hydrodynamic cavitation (HC) at 5 to 15 psi pressures for 5–30 min. A full factorial design was applied to optimize the HC treatment of tomato juice quality. Optimal conditions were recorded at 10 psi for 10 min, which showed no significant (p < 0.05) change in lycopene content to that of freshly obtained unprocessed tomato juice (control). After processing, the retention of 93% ascorbic acid and 96.6% of total phenolic compounds (TPC) was observed. Similarly, sedimentation and viscosity were mildly affected by HC processing (89.2 and 94.4% of values in the treated sample, respectively). While pH, total soluble solids (TSS), titratable acidity (TA) of HC treated sample remained unchanged (p < 0.05). The results were also compared with the conventional thermally processed tomato juice (90 °C for 90 s). Although thermal treatment resulted in the inactivation of 92.2% of pectin methylesterase and a 5 log reduction in total plate counts, it also showed significant reductions in ascorbic acid (61.4%), TPC (72.3%), and physical properties (37.7% of SI and 83.2% viscosity). However, HC processing could achieve a maximum of 4.9% inactivation of PME and 1 log reduction at high treatment conditions, respectively (15 psi for 30 min). The shelf-life study showed more retention of bioactives and better physicochemical properties in tomato juice samples stored at 4 °C for 15 days than the control. Sensory evaluation revealed that the overall acceptability of the optimized HC treated (0.714) sample was better than the thermally treated sample (0.591). The observed results concluded that HC-treated tomato juice was comparatively better than thermally-treated tomato juice in retaining bioactive compounds. Consequently, HC constitutes a promising approach in food processing to improve and retain the beneficial properties of tomato juice.