Ultrasonic Process Research Articles

Highly water dispersible poly (caffeic acid - L-arginine)-MoS2 nanocomposite modified sensor for effective electrochemical detection of amlodipine drug

The present work applied a facile, green, and versatile approach to preparing self-organized redox polymers on 2D-MoS2 (Molybdenum Disulfide) nanosheets. It was utilized as the modified electrode material for electrochemical determination of 1, 4-dihydropyridine-based antihypertensive drugs viz amlodipine (AMD). Naturally available caffeic acid was used as a precursor, and it was polymerized through a 1, 4-Michael addition reaction with L-arginine. Oxidants and amine functional groups of L-arginine synergistically promote the polymerization of caffeic acid (P (CA-LA)). The P(CA-LA) in the 2D-MoS2 matrix was stabilized via self-assembly by intermolecular interaction between catechol groups and MoS2 sheets. The ultra-sonication process induced the subsequent polymerization and simultaneous exfoliation of MoS2 sheets. The self-assembled P(CA-LA)-MoS2 nanocomposite exhibits a good cyclic voltammetric response with excellent electrochemical oxidation of AMD. The electrochemical response of AMD was explored using a glassy carbon electrode (GCE) modified with P(CA-LA)-MoS2 nanocomposite employing differential pulse voltammetry (DPV). Under the optimized experimental conditions, electrochemical detection of AMD has been performed with a linear correlation between the anodic peak current of AMD observed at 0.8 V. Additionally, the designed self-assembled redox polymer-based nanocomposite sensor exhibited superior selectivity for the detection of AMD with two linear ranges from 0.010 to 16.82 µM and 16.82 to 433.3 µM with good detection limits of 3.6 nM. Moreover, the synergic interactions of polymers and MoS2 and their self-assembly nature can offer a good sensitivity of 0.42 μA μM−1 cm−2. Hence, the electrochemical behavior of self-assembled P(CA-LA)-MoS2/GCE may provide new insights into the recent era of electrodes and sensors.

Gradient nanostructure induces exceptional cryogenic mechanical properties in an additively manufactured medium entropy alloy

Developing additively manufactured alloys with high cryogenic performance can facilitate the development of geometrically complex components for cryogenic applications. In this study, we have implemented ultrasonic surface rolling process (USRP) on an additively manufactured CoCrNi-based medium entropy alloy to introduce a gradient nanostructure therein. The resulting alloy exhibits a substantial strength-ductility balance at 88 K, a relatively high ductility (24.6 %), 2.07 times higher than that at 293 K, as well as a yield strength as high as 1274 MPa. The exceptional yield strength is attributed to the high-density dislocations induced by additive manufacturing and ultrasonic surface rolling process, while the origin of impressive ductility promotion lies in two aspects, i.e., enhanced hetero-deformation induced hardening effect and activated twinning/microband behaviors at matrix region at 88 K. The former mainly comes from suppressed dynamic recovery in gradient layer. The latter is resulted from the lowered stacking faulting energy and high flow stress.

Effects of green and innovative pretreatment techniques on kinetic parameters of sunflower seed husk

The effects of green pretreatment processes, such as ultrasonic process (US) and deep eutectic solvent (DES), applied to the biomass on kinetic parameters are as important as their effects on characteristic properties. Process conditions and course of reaction progression depend on the knowledge about kinetic parameters, activation energy and reaction model of thermal degradation in scale-up studies. Therefore, in this study, the change in the kinetic parameters with US applied with both distilled water and DES (glycerol:sodium acetate) at 100 W power and 20 kHz frequency for 10 minutes to sunflower seed husk (SSH) was revelaed. Isoconversional methods Kissinger-Akahira-Sunose (KAS) and Flynn- Wall-Ozawa (FWO) were preferred for the evaluation of activation energy of SSH and pretreated SSH at 15°C/min, 20°C/min and 25°C/min heating rates. US pretreatment with DES instead of water resulted in increment of average activation energy values (Ea) from 113.13 to 143.65 kJ/mol in the KAS method. Ea values for all SSH samples changed in the range of 87.72-143.65 kJ/mol and higher Ea values was obtained with KAS method for pretreated SSH samples. Consequently, the use of DES in US pretreatment was more effective to change kinetic parameters of SSH compared to water.

Microstructure, mechanical and corrosion properties of FeCrNiCoMnSi0.1 high-entropy alloy coating via TIG arc melting technology and high-frequency ultrasonic impact with welding

With the increase in studies on high-entropy alloys and their impressive structural properties, the preparation processes and applications of high-entropy alloys have become a popular research topic in metallic materials. In this paper, the preparation of FeCrNiCoMnSi0.1 high-entropy alloy coatings was carried out by the follow-welding high-frequency power ultrasonic impact composite TIG arc melting process, the effects of different power ultrasonic impacts on the microstructure and properties of the coatings are investigated. The results showed that the average grain size is reduced by 74 % (from 278 μm to 72 μm), the average microhardness is increased by 41 % from 568 HV1 to 807 HV1, the abrasion resistance is improved by 68 % under the effect of ultrasonic impact. The ultrasonic impact treatment process can effectively refine the microstructure of the coatings and improve the strength of grain boundaries. The corrosion resistance of the coating in 3.5 wt% NaCl solution is enhanced by 65 %, the corrosion type was changed from intergranular corrosion to uniform corrosion. This is mainly caused by the ultrasonic impact treatment which suppresses the elemental segregation of Cr and Mn and improves the grain boundary strength.

Establishment and Optimization of Flavonoid Extraction and Detection System for Hemerocallis

Hemerocallis is a characteristic vegetable with outstanding edible and medicinal value. Flavonoids are important bioactive components of Hemerocallis. To improve the extraction efficiency and detection accuracy of flavonoids from Hemerocallis, we established a high-performance liquid chromatography (HPLC) detection system, which can simultaneously detect multiple flavonoids. In addition to the previously developed organic solvent extraction method, an ultrasonic-assisted extraction technique that uses fewer samples was established to extract flavonoids from Hemerocallis. The extraction conditions of the ultrasonic-assisted extraction were optimized via a single-factor experiment and a response surface experiment. The HPLC system detected and determined the contents of rutin, isoquercetin, myricetin, quercetin, apigenin, and diosmetin from 70 Hemerocallis germplasm resources. In addition, we evaluated the antioxidant activity of flavonoids in Hemerocallis using DPPH free radical scavenging capacity with ascorbic acid (Vc) as a positive control. The results showed that the optimum conditions for the ultrasonic extraction process were as follows: sample weight of 0.25 g, ethanol volume fraction of 72%, ethanol volume of 2.5 mL, and ultrasonic extraction time of 17 min. Under these conditions, flavonoid extraction had a strong scavenging effect on DPPH. With the increase in the sample solutions’ concentrations, its antioxidant capacity was gradually enhanced, and the DPPH scavenging rate reached 70.2%. The optimized ultrasonic-assisted extraction technology can increase the total content of six flavonoids in day lily bud by 59.01%, especially the content of rutin (increased by 64.41%) in Hemerocallis flower buds. Among 70 Hemerocallis plant resources, we selected materials H0087 and H0059 with high and stable flavonoid content, with the total content of six substances being 4390.54 ug/g and 3777.13 ug/g. Thus, this study provides a reference for extracting and determining flavonoid contents in Hemerocallis materials. It also provides a theoretical basis for high-quality individual plant breeding.

Research on ultrasonic assisted press-fit assembly of small interference fits

Interference fits are widely used in aerospace, precision instruments and other fields. Press-fit assembly is one of the traditional assembly methods for interference fitting parts. Wear during assembly will affect the performance of interference components and the service life of marine equipment. Ultrasonic assisted press-fit can significantly reduce the press-mounting force of an interference fit. However, its effect on connection quality is rarely studied. The mechanism of ultrasonic assisted press-fit is unclear. In this paper, ultrasonic assisted press-fit was simulated and experimentally studied. The effects of ultrasonic vibration on heat generation, press-mounting force, connection strength, and interface wear were analyzed and discussed. Through analogy analysis with similar ultrasonic assisted machining processes, the mechanism of ultrasonic assisted press-fit was revealed. The results show that the superimposed ultrasonic vibration can effectively reduce the joining force (up to 33.5%), and increase the connection coefficient from 10% to 40%. This is due to stress superposition, friction reduction and acoustic softening that reduces interface wear. The increase of the interface roughness Rz from 3.681 to 4.586 μm confirms this analysis. Furthermore, the ultrasonic vibration can effectively reduce the material plastic flow of contact interface. This study reveals the significant advantages of ultrasonic assisted press-fit assembly (UAPA) method and provided a basis to understand the underlying mechanisms of UAPA.

Enhancing Disinfection Efficiency of Wastewater Treatment Plant Effluent: The Role of ZnO Nanoparticles in Ultrasonic and UV-C Processes

Ultrasonic (US) and UV-C disinfection technologies have been successfully used in wastewater treatment plants (WWTPs) for disinfection purposes. The US technology is typically used as a pre-treatment step to break down larger particles and make them more susceptible to disinfection. The UV-C technology is commonly used as a final disinfection step in many WWTPs. The study aimed to assess the potential of using Zinc Oxide (ZnO) Nanoparticles (NPs) to improve the effectiveness of UV-C and US disinfection methods in treating wastewater effluent, offering a more comprehensive solution to wastewater treatment. In this experimental study, a Laboratory US Bath (40[Formula: see text]kHz) and a UV-C lamp (16[Formula: see text]W) were used. In order to investigate the effectiveness of ZnO NPs in the reduction of microbial load, 5[Formula: see text]mg/L of ZnO NPs was added to the effluent samples. Then, samples were examined for Total Coliform (TC) and Fecal Coliform (FC) reduction by the standard MPN/100[Formula: see text]mL test. The Chick‘s law was used to calculate the efficiency of microbial load. The relationship between variables was determined by regression analysis using Excel and SPSS-ver 21 software. In this study, the samples were examined in three groups: Samples that were only exposed to sonication or received UV-C radiation with Turbidity of 18 NTU (Group A) and Turbidity of 5 NTU (Group B), and Samples that received 5 mg/L of ZnO NPs (Group C). By increasing the time from 0.5 min to 10 min in the presence of UV-C, the amount of microbial population decreased, and 2 min was considered the optimal time. The maximum removal efficiencies by US for TC were 74.07,77.7, 85.1% (40∘C) and 92.5,100, and 100% (60∘C) in group A (in 30 min sonication), 85.7, 85.7, 100% (40∘C), respectively, and were 100% in other groups (B and C), respectively. The maximum removal efficiencies by US for FC were 76.4%, 88.2%, and 100% (40∘C) and 88.2%, 100%, and 100% (60∘C) in group A (in 30 min sonication), respectively, and were 100% in other groups (B and C). In this study, an important increase in the disinfection ability of ZnO NPs has been observed in the presence of US and UV-C. So, the ZnO NPs/UV-C and ZnO NPs/US processes are valuable alternatives to conventional disinfection processes by over 90% improvement of disinfection efficiency.

Optimizing conditions for the recovery of lignans from sesame cake using three green extraction methods: Microwave-, ultrasound- and accelerated-assisted solvent extraction

Lignans, a group of polyphenolic low molecular weight bioactive compounds with health benefits, are major constituents of sesame cake (SC), a by-product derived from sesame oil processing. The utilization of this by-product in the food or nutraceutical industries could explore its valorization route in compliance with sustainability and circular economy principles. This study aimed to investigate the impact of different environmental-friendly processing approaches such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) for lignans extraction from SC using central composite design (CCD) with response surface methodology (RSM). Sesaminol triglucoside (SETRI) and sesaminol diglucoside (SEDI) were identified and quantified as the major lignan glucosides in SC. Ethanol/water mixture was selected as ‘green’ solvent for all extraction methods. The influence of ethanol concentration (X1), extraction time (X2), temperature (X3) and solid-to-solvent (SS) ratio or solid weight (X4) on extraction yield (EY), SETRI and SEDI contents for each technique was examined. The developed models exhibited a high degree of desirability (> 0.72) with determined optimal levels of extraction parameters as follows: X1 = 71%, X2 = 10 min, X3 = 50 °C, X4 = 1.50 g/20 mL for UAE; X1 = 80%, X2 = 5 min, X3 = 50 °C, X4 = 0.85 g/20 mL for MAE; X1 = 80%, X2 = 20 min, X3 = 65 °C, X4 = 2 g for ASE. Under these optimal conditions, the experimental values for EY, SETRI and SEDI contents in SC extracts were: 8.28%, 105.98 mg/g and 16.93 mg/g, respectively for UAE; 8.75%, 105.41 mg/g and 18.76 mg/g, respectively for MAE; 9.34%, 108.00 mg/g and 18.34 mg/g, respectively for ASE. The ANOVA analysis from the RSM were fitted with quadratic models yielding acceptable R2 (> 0.87), adjusted R2 (> 0.77), predicted R2 (> 0.74), and nonsignificant lack-of-fit (p > 0.05) values. Ethanol concentration and solid-to-solvent ratio were the most influencing factors affecting lignans extraction. Although ASE was found as the most suitable method for extracting lignans from SC, from an industrial viewpoint, UAE could be a more affordable technique due to advances in ultrasonic processing devices for large scale applications.

A study on reducing hydrogen content in steel using ultrasonic cavitation process

In this study, a novel process utilizing ultrasonic cavitation(UC) was proposed to decrease hydrogen content in steel. Electrochemical hydrogen-charging and UC were performed on steels with different elemental species and ratios, and hydrogen embrittlement(HE) susceptibility was evaluated by slow strain rate tensile(SSRT). UC effectively reduced hydrogen-induced plasticity loss by removing hydrogen trapped by traps, particularly in SA508Gr.3. Dehydrogenation effects and recovery mechanisms were explored. Hydrogen trapped by low-energy traps played a critical role in hydrogen-induced hardening. The cleavage platforms of the specimen after UC was reduced, but a large number of microcracks appeared in the fracture due to residual hydrogen.

Ultrasonic processing of WO3 nanosheets integrated Ti3C2 MXene 2D-2D based heterojunctions with synergistic effects for enhanced water splitting and environmental remediation

This article describes a straightforward chemical procedure that involves hydrothermal and ultrasonic treatments to create a new 2D/2D ultrathin WO3/Ti3C2 heterojunctions. The features of the fabricated heterojunctions were characterized and examined by field emission electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), optical absorption spectroscopy (UV–Vis). By photodegrading an organic dye under the influence of visible light, the photocatalytic degradation capabilities of the heterojunctions were also investigated. The performance of WO3/Ti3C2 was superior to that of bare WO3, with a removal rate of 94% and a kinetic rate constant (k) that was approximately 3 times that of WO3. The creation of 2D/2D heterojunction was observed to encourage the spatial charge separation and increase the surface reactive sites, to result with the increased photocatalytic activity in WO3/Ti3C2 heterojunction. The photocurrent values discovered through photoelectrochemical studies further indicated Ti3C2′s active function in enhancing water-splitting performance. The impedance analysis examined by an electrochemical method revealed that heterojunctions might be helpful in accelerating the migration of charges quickly to get the outcomes seen.

Valorization of Spent Brewer’s Yeast Bioactive Components via an Optimized Ultrasonication Process

The increasing need for sustainable waste management and food fortification requires continuous agri-food biotechnological innovation. Spent brewer’s yeast (SBY) is a mass-produced underutilized by-product of the brewery industry and has elevated bioactive potential. The current study presents a streamlined ultrasonic SBY cell lysis method, with the main goal of bioactive compound valorization. The influence of selected ultrasonication parameters on protein release and, implicitly, on the cell disruption efficiency, was assessed. The SBY derivatives resulting from the ultrasonic cell lysis were SBY extracts (SBYEs) and cell walls (SBYCWs), which were evaluated in terms of protein content, antioxidant activity (AOA) and total polyphenol content. Scanning electron microscopy (SEM) and FT-IR spectroscopy were used to characterize SBYCWs in relation to the morphological and chemical transformations that follow ultrasonic yeast cell disruption. The optimal ultrasonication conditions of 6.25% SBY concentration, 40 °C and 33.33% duty cycle (DC) ensured the most efficient lysis. The SBY derivatives with the most elevated antioxidant activity were obtained at temperatures below 60 °C. SBYCWs had the highest polyphenol content and a relatively high content of β-glucan under these parameters. Optical microscopy and SEM confirmed the release of intracellular content and separation of SBYCWs.

Enhanced scale inhibition and anti-wax capacities of passive materials via ultrasonic rolling processing

Scale damage and wax formation on pipelines surface have become prevalent issues in the development and production of the oil and gas industry throughout the world. The utilization of the ultrasonic surface rolling process (USRP) on pipeline surfaces is a promising protective approach and its universal verification for the enhancement of the scale inhibition and anti-wax capacities of passive materials is presented in this work. The effect of USRP on surface integrity (including roughness, cross-sectional microstructure, residual stress and water contact angle), scaling and wax deposition behavior, passive film structure and characteristics are experimentally analyzed by comparing three passive materials (13Cr stainless steel, 825 nickel-base alloy and Ti6Al4V alloy) with 3Cr carbon steel. The results indicate that USRP can effectively reduce the surface roughness and contribute to the growth of passive film due to the enriched passive elements on the metal surface, which consequently endow the passive materials with reduced surface free energy and enhanced anti-scaling/anti-wax capacities. Furthermore, benefitting from the surface passivation, the enhancement in the corrosion resistance of the film helps to provide good chemical stability. The main reason for why USRP has a protective effect on the scale inhibition and anti-wax capacities of the passive materials is also elucidated. The input energy of USRP not only achieves chip-free polishing and triggers structural response changes in the surface and subsurface plastic deformation but also produces a unique passivation response that can alter the chemical composition, thickness, compactness and defect density of the passive film. This in turn leads to significant changes in its corrosion resistance, which is related to the semiconductor characteristics of the materials, surface energy, and hydrophilic–hydrophobic physical and chemical properties. This results in a significant inhibitory effect on the deposition of scaling ions or wax crystals at the passive film/solution interface.

Enhanced strength-ductility synergy of an AlCoCrFeNi2.1 eutectic high entropy alloy by ultrasonic vibration

The mechanical properties of eutectic high entropy alloys (EHEAs) can be significantly improved by adjusting its microstructure; however, the conventional adjustment approaches are inefficient and trapped in a strength-ductility tradeoff. In this study, we applied a compressive stress of 350 MPa (about 60 % yield strength) with ultrasonic vibration of 20 kHz frequency and 20 μm amplitude on an AlCoCrFeNi2.1 EHEA for different processing time. The ultimate tensile strength and total elongation of the EHEA were prominently enhanced to 1050 MPa and 27.4 % after 20 min ultrasonic processing, representing an increment of 17 % and 54 % from the initial state (900 MPa and 17.8 %), realizing the synergistic enhancement of both strength and ductility. The structural analysis of the ultrasonically processed AlCoCrFeNi2.1 EHEA shows that the strengthening effect induced by BCC(B2) precipitates with a typical size of 1 μm provoked by ultrasonic vibration was the primary reason for the enhanced strength. The synchronous deformation of alternating soft FCC(L12) phase and hard BCC(B2) phase as well as the motivated multiple slip systems intensified the strain hardening effect, resulting in the improvement of strength-ductility synergy. This study provided a new and efficient way to overcome the strength-ductility tradeoff and prepare a EHEAs with high mechanical properties.

Insight into nitriding behavior and corrosion mechanism in 17-4PH steel: The influence of nanocrystalline structure

In this study, the influence of nanocrystalline structure on the plasma nitriding (PN) behavior of 17-4PH steel and corresponding corrosion mechanisms under different treatments were systematically investigated. The results showed that nanocrystalline structures introduced by ultrasonic surface rolling process (USRP) would affect the nitrides morphology, composition and distribution via accelerating element diffusion. The fabricated nanocrystalline structures could enhance the corrosion resistance of original and plasma-nitrided 17-4PH steel, which was attributed to its various microstructures. Homogeneous microstructures suppressed or alleviated the formation of micro-galvanic couple in USRP-treated 17-4PH steel and USRP-15 + PN specimen.

Improving fatigue performance of Cr-coated zirconium alloy cladding by ultrasonic shot-peening proces

In this paper, Cr-coated zirconium fuel claddings were treated with ultrasonic shot-peening process (USPP). The mechanism of improving fatigue performance of Cr-coated zirconium fuel cladding was investigated by low cycle fatigue experiment. It was shown that USPP effectively improved fatigue life of Cr-coated zirconium fuel cladding under different temperatures. The enhancement mechanism is that USPP treatment changes the surface topography, increases in residual compressive stress and decreases surface roughness of the Cr coating. The fracture cross-section of tested specimens show that the Cr coating has little plastic deformation, showing brittle fracture characteristics. In addition, compared to the large amount of cracking inside the original Cr coating, the integrity of the USPP-Cr coating is better. The USPP-Cr coating has fewer cracks penetrating into the substrate, indicating that the Cr coating with USPP treatment has excellent fatigue crack resistance.

Novel g-C3N4/PrFeO3 nanocomposites with Z-scheme structure and superior photocatalytic activity toward visible-light-driven removal of tetracycline antibiotics

In the presented work, heterostructured nanocomposites based on g-C3N4 and PrFeO3 with different mass content of PrFeO3 (0–10 wt%) were prepared by ultrasonic processing to study their photocatalytic activity in the process of antibiotic degradation under visible light. The study of phase composition, structural, morphological and textural characteristics carried out by powder X-ray diffraction, scanning electron microscopy and adsorption-structural analysis confirmed the presence of two phases - graphite-like C3N4 and orthorhombic PrFeO3 with average crystallite sizes of 5 and 21 nm and mesoporous structure with specific surface area of 57.2–68.6 m2/g and average pore size of 20 nm. The measured values of the forbidden bandwidth for the obtained nanocomposites were ∼3 eV, indicating potential activity under visible light irradiation. The efficiency of antibiotic removal under visible light was evaluated in the degradation of TCHCl. It was found that 5 % PrFeO3 content was optimal and increased the TOF by 5 times compared to pure g-C3N4. The results of photocatalytic test with absorbers showed that photocatalysis occurs by Z-scheme mechanism. The results obtained allow us to consider this nanocomposite as an effective and stable photocatalyst for pharmaceutical wastewater treatment.

Surface integrity study of ZrO2 ceramic for ultrasonic vibration-assisted polishing processing

Due to the unique physical property, the surface integrity is a critical indicator to characterize the processing quality for hard and brittle materials. In this study, the ZrO2 ceramic is taken as a representative to investigate the surface integrity during ultrasonic vibration-assisted polishing (UVAP) processing. The effects of processing parameters on surface micro-morphology, surface hardness, scratch property and residual stress are analyzed by UVAP orthogonal experiments. The experiment results indicate that the UVAP processing can effectively improve the surface integrity of the ZrO2 ceramic. The research results are of great significance in guiding the UVAP controlled processing of hard and brittle materials.

Highly stable lead-free perovskite Cs2AgBiBr6/UiO-66 Z-scheme heterostructures with enhanced photocatalytic activity for CO2 photoreduction and organic dyes degradation

Excessive combustion of traditional fossil fuels causes seriously global warming (Carbon dioxide, CO2) and energy crisis. Photocatalytic CO2 conversion to fuels has emerged as one of the most effective strategies. Herein, an environmentally friendly nanocomposite based on lead-free Cs2AgBiBr6 (CABB) perovskite nanocrystals and the UiO-66 metal–organic framework was fabricated by a facile ultrasonic process for efficient CO2 photoreduction. The obtained CABB/UiO-66 consisted of uniform CABB nanocrystals (10–12 nm) attached to the UiO-66 surface and exhibited a high surface area (1031 m2/g). The composite displayed enhanced light-harvesting capacity than the individual components and provided sufficient active sites for promoting photocatalytic activity. A typical Z-scheme heterostructure between the CABB and UiO-66 was realized by forming an inner electric field, leading to the occurrence of efficient excited state charge transfer. The efficient charge transfer of CABB/UiO-66 inspired its use as an active photocatalyst for the reduction of CO2 with significantly improved photocatalytic activity against its individual components. Specifically, CABB/UiO-66 exhibited 38 and 40-fold improvement in catalytic activity compared to respective CABB and UiO-66 in terms of the total yield of CO, CH4, and C2H6. Moreover, the nanocomposite displayed excellent activity towards the oxidative photocatalytic degradation of aqueous environmental contaminant rhodamine B. We believe that this work provides a guide for designing lead-free perovskite-based renewable catalysts and offers new opportunities for the photocatalytic conversion of CO2 photoreduction.

Ultrasound-assisted fortification of yellow sweet potato (Ipomoea batatas) with iron and ascorbic acid

The objective of this study was to evaluate the effect of ultrasound on the incorporation of iron and ascorbic acid (AA) in sweet potato (Ipomoea batatas) and to optimize the process parameters to obtain a fortified food. The incorporation was carried out using cubes of sweet potato submerged in 0.1% m/v ferrous sulfate and 1% m/v AA solutions, treated at different times and sonication frequencies (37 and 80 kHz), at 100 watts of power and 30 ± 5°C. ANOVA and Tukey’s test at 5% significance were applied to establish significant differences and the process was evaluated using a factorial design. The results revealed that the application of ultrasound influences the content of iron and AA, incorporating greater amount of iron and AA compared to samples not treated with ultrasound. Similarly, longer times led to higher incorporation of iron and AA content in sweet potatoes; the frequency was not statistically significant. The highest iron content was 105.91 ± 0.03 mg/100 g and for AA, it was 392.65 ± 4.84 mg AAE/100 g. The defined ultrasonic process conditions produced an increase of 4928.99 and 610.65%, respectively, in iron and AA content in sweet potato.

Fabrication of a 3D structure MnO2 electrode with high MnO2 mass loading as the cathode for high-performance aqueous zinc-ion batteries

Benefiting from the remarkable advantages (eco-friendly, cost-effective, and high safety) of rechargeable aqueous zinc-ion batteries (AZIBs), AZIBs are regarded as viable alternatives to traditional Lithium-ion batteries (LIBs). However, in prevailing research, the excellent electrochemical performance usually achieved by ultra-low active material loadings (e.g., <1 mg/cm²), which is far from the active material mass loading of commercial electrodes in practical (≥10 mg/cm²). Balancing superior properties with high mass loading has posed a challenge. To surmount this, an innovative method combined ultrasonic processing, freeze-drying, and 3D printing technologies is used to engineer a high MnO2 mass loading cathode for AZIBs (3D cathode). Notably, the grid structure of 3D cathode substantially augmenting the surface area for redox reactions during charge/discharge processes, which greatly enhanced the pseudo-capacitance process of cathode. Additionally, the uniform and stable microstructure exhibited the dual capability of expediting ion/electron transfer and sustaining the structural integrity throughout charge/discharge cycles. Consequently, the 3D cathode demonstrated superior comprehensive electrochemical properties at the MnO2 high mass loading of 10 mg/cm2 (138.7 mAh/g at 1 A/g, 87.4 mAh/g after 500 cycles, 82 % energy efficiency) and 15 mg/cm2 (113.3 mAh/g at 1 A/g, 56.3 mAh/g after 400 cycles, 81 % energy efficiency).