In this work we developed an eco-friendly valorisation of Citrus wastes (CWs), through a solvent-assisted ultrasonication extraction technique, thus having access to a wide range of bio-active compounds and polysaccharides, extremely useful in different industrial sectors (food, cosmetics, nutraceutical). Water-based low-amplitude ultrasonication was examined as a potential method for pectin extraction as well as polar and non-polar citrus extractives (CEs), among which hesperidin and triglycerides of 18 carbon fatty acids were found to be the most representative ones. In addition, citric acid:glycerol (1:4)-based deep eutectic solvent (DES) in combination with ultrasonic extraction was utilized to extract microcellulose (CMC), from which stable cellulose nanocrystals (CNCs) with glycerol-assisted high amplitude ultrasonication were obtained. The physical and chemical properties of the extracted polysaccharides (pectin, micro and nanocellulose) were analysed through DLS, ζ-potential, XRD, HP-SEC, SEM, AFM, TGA-DSC, FTIR, NMR, and PMP-HPLC analyses. The putative structure of the extracted citrus pectin (CP) was analysed and elucidated through enzyme-assisted hydrolysis in correlation with ESI-MS and monosaccharide composition. The developed extraction methods are expected to influence the industrial process for the valorisation of CWs and implement the circular bio-economy.

This paper investigates the effects of ultrasonication on cellulose microparticles in different conditions. FTIR (Fourier transformed infrared spectrometry) and XRD (X-ray diffraction) analyses were used to compare the changes in the cellulose microstructure caused by the following various ultrasonic treatment conditions: time, amplitude of generated ultrasound waves, output power converted into ultrasound, the liquid medium (water and isopropyl alcohol) used for ultrasonication, and the shape of the vessel used for sonication. The cumulative results lead to an increase in the crystalline region directly proportional to the condition of sonication. Also, the total crystallinity index varied from 1.39 (pristine cellulose) to 1.94 for sonication in alcohol to 0.56 for sonication in water. The crystallinity index varied from 67% (cellulose) to 77% for the sample with 15 min of sonication in isopropyl alcohol and 50.4% for the sample with 15 min of sonication in water.

Carbon fiber reinforced polymer (CFRP) composites have very high specific properties, which is why they are used in the aerospace, wind power, and sports sectors. However, the high consumption of CFRP compounds leads to a high volume of waste, and it is necessary to formulate mechanical recycling strategies for these materials at the end of their useful life. The recycling differences between cutting-end mills and high-energy ball milling (HEBM) were evaluated. HEBM recycling allowed us to obtain small recycled particles, but separating their components, carbon fiber, epoxy resin, and CFRP particles, was impossible. In the case of mill recycling, these were obtained directly from cutting a CFRP composite laminate. The recycled materials resulted in a combination of long fibers and micrometric particles-a sieving step allowed for more homogeneous residues. Although long, individual carbon fibers can pass through the sieve. Ultrasonication did not significantly affect HEBM recyclates because of the high energy they are subjected to during the grinding process, but it was influential on end mill recyclates. The ultrasonication amplitude notably impacted the separation of the epoxy resin from the carbon fiber. The end mill and HEBM waste production process promote the presence of trapped air and electrostatics, which allows recyclates to float in water and be hydrophobic.

Bromine (Br2) and related species removal from water systems are rather complicated due to the complicated chemistry instability, and materials with high Br2 removal rate and efficiency, along with stimuli/apparatus suitable for highly corrosive environments, are necessary. Ultrasonication as a non-destructive process is especially suitable in scenarios where conventional stir apparatus is not applicable, such as highly corrosive environments. Considering the validity nature of Br2 and combining the advantages of ultrasonic with a highly stable Br2 fixation method through aromatic polymer nanoparticles, we demonstrate highly efficient acoustic-aided Br2 removal in aqueous solutions with two times capacity compared to the non-treated sample. Related aquatic applications are also proposed for the materials to be cost-effective, including silver (Ag) recovery, recyclable MnO2-mediated Br2 deep removal, and aqueous zinc anode modification. The coupled novel-material-based processes motivate the strategic design of water purification with high-safety and sustainable industrial procedures and post-value-added utilizations.

Native lotus (Nelumbo nucifera G.) seed starch (LSS) was single- and dual-modified by heat-moisture treatment (HMT), ultrasonication (US), HMT followed by the US (HMT-US), and the US followed by HMT (US-HMT). The modified lotus seed starch (LSS) was evaluated for its physicochemical, pasting, thermal, and rheological properties and in vitro digestibility. All treatments decreased the swelling power (10.52-14.0 g/g), solubility (12.20-15.95 %), and amylose content (23.71-25.67 %) except for ultrasonication (17.67 g/g, 17.90 %, 29.09 %, respectively) when compared with native LSS (15.05 g/g, 16.12 %, 27.12 %, respectively). According to the rheological study, G\' (1665-4004 Pa) was greater than G″ (119-308 Pa) for all LSS gel samples demonstrating their elastic character. Moreover, gelatinization enthalpy (17.56-16.05 J/g) increased in all treatments compared to native LSS (15.38 J/g). Ultrasonication treatment improved the thermal stability of LSS. The digestibility results showed that dual modification using HMT and US significantly enhanced resistant starch (RS) and reduced slowly digestible starch (SDS) in LSS. Cracks were observed on the surface of the modified LSS granules. Peak viscosity decreased in all modified starches except for ultrasonication, suggesting their resistance to shear-thinning during cooking, making them ideal weaning food components. The results obtained after different modifications in this study could be a useful ready reference to select appropriate modification treatments to produce modified LSS with desired properties depending on their end-use.

Poor dispersibility of carbon nanotubes greatly hinders their practical applications. Herein, a long-term stable dispersion of multiwalled carbon nanotubes (MWCNTs) in peroxydisulfate (PDS) is achieved. MWCNTs at 40 mg L-1 are completely dispersed by PDS upon ultrasonication (US/PDS) within 64 min and a stable dispersion is maintained at least 20 days. Mechanistically, US created defects on the nanomaterial and PDS-origin free radicals attacked these defects to introduce O-containing moieties (─OH and ─COOH). Interestingly, dispersion efficiency of MWCNTs by US/PDS initially at pH 7 and 3.8 is comparable, but lower than that initially at pH 12. Both •OH and SO4 •- are produced under alkaline condition, while SO4 •- is the dominant free radicals initially at pH 7 and 3.8 during the whole dispersion period. Stronger dispersion of MWCNTs initially at pH 12 resulted from greater amounts of O-containing moieties mainly in ─OH (46.32%) rather than ─COOH (24.19%) form. This differential more strongly promotes MWCNTs-water interaction via hydrogen bonding, thereby enhancing the dispersion. Notably, no significant mass loss of MWCNTs occurred during dispersion. Overall, the developed method achieves long-term stable dispersion of MWCNTs in a manner that can significantly extend their applications.

Hyssopus officinalis L. (HO) is, as one of the most prevalently utilized plants, used in traditional medicine to cure various diseases as well as the in food and cosmetic industries. Moreover, HO is a rich source of polyphenols with potent antioxidant properties. However, the studies on the extraction of such compounds from HO are scanty and sparse. This study aims to optimize the extraction of polyphenols and maximize the antioxidant activity in HO extracts. A comprehensive experimental design was employed, encompassing varied extraction parameters to determine the most effective ones. Alongside conventional stirring (ST), two green approaches, the ultrasonic treatment (US) and the pulsed electric field (PEF), were explored, either alone or in combination. The extracted polyphenolic compounds were identified with a high-performance liquid chromatography-diode array detector (HPLC-DAD). According to the results, the employment of ST along with an ethanolic solvent at 80 °C for 150 min seems beneficial in maximizing the extraction of polyphenols from HO, resulting in extracts with enhanced antioxidant activity. The total polyphenol was noted at 70.65 ± 2.76 mg gallic acid equivalents (GAE)/g dry weight (dw) using the aforementioned techniques, and the antioxidant activity was noted as 582.23 ± 16.88 μmol ascorbic acid equivalents (AAE)/g dw (with FRAP method) and 343.75 ± 15.61 μmol AAE/g dw (with the DPPH method). The as-prepared extracts can be utilized in the food and cosmetics industries to bestow or enhance the antioxidant properties of commercial products.

Ultrasound-assisted extraction using response surface methodology was employed to extract marigold flower, resulting in a marigold flower extract (MFE) with elevated levels of total phenolic compounds (TPCs), total flavonoid content (TFC), total carotenoid content (TCC), and antioxidant activity, as assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, under conditions of 40 °C temperature, 15 min extraction time, and 68% ethanol concentration. The MFE was subsequently encapsulated using spray drying with 45% maltodextrin (MD) (MFE-MD; 1:1, 1:2) and 20% gum arabic (GA) (MFE-GA; 1:2, 1:3). The MD (1:2 ratio) sample showed the highest encapsulation yield, while the 45% MD (1:1 ratio) sample exhibited the highest encapsulation efficiency (p ≤ 0.05). Samples containing 45% MD (1:1 ratio) and 20% GA (1:2 ratio) had the highest moisture content, with the 45% MD (1:1 ratio) sample showing the lowest water activity (p > 0.05). These samples also displayed higher L* and a* values compared to the 20% GA samples, which had increased b* values (p ≤ 0.05). Micrographs of the 20% GA (1:3 ratio) and 45% MD (1:2 ratio) samples revealed spherical shapes with smooth surfaces. The 20% GA (1:2 ratio) microcapsules exhibited the highest total phenolic content (TPC) among the samples (p ≤ 0.05). Thus, ultrasound-enhanced extraction combined with response surface methodology proved effective in producing functional food ingredients from plants.

Moringa oleifera (M. oleifera) is globally recognized for its medicinal properties and offers high-quality, protein-rich seeds. This study aimed to explore the potential of M. oleifera seeds as a significant source of protein-based nanoparticles (PBNPs) using the ultrasonication technique after desolvation and to evaluate their cytotoxicity in the human leukemia cell line (THP-1) for the first time. The properties of the PBNPs were confirmed by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The extracted protein from moringa seed cake flour had a significant protein content of 54.20%, and the resulting PBNPs had an average size of 134.3 ± 0.47 nm with a robust zeta potential of -43.15 mV. Notably, our study revealed that PBNPs exhibited cytotoxic potential at high concentrations, especially against the THP-1 human leukemia cell line, which is widely used to study immunomodulatory properties. The inhibitory effect of PBNPs was quantitatively evidenced by a cytotoxicity assay, which showed that a concentration of 206.5 μg mL-1 (log conc. 2.315) was required to inhibit 50% of biological activity. In conclusion, our findings highlight the potential of M. oleifera seeds as a valuable resource in the innovative field of eco-friendly PBNPs by combining traditional medicinal applications with contemporary advancements in protein nanotechnology. However, further studies are required to ensure their biocompatibility.

Waste printed circuit boards (WPCBs) encompass abundant metals (gold, silver, and copper), along with other harmful materials including brominated epoxy resins, plastics, and heavy metals (lead, mercury, and cadmium). Direct burning and landfilling of WPCBs may cause severe health issues and impair the environment. Therefore, sustainable treatment of WPCBs is necessary to recover valuable metals and remove hazardous materials before disposal. The present work investigates the separation of copper-rich metallic fractions from the WPCBs by the combination of hammer milling and ultrasonic irradiation. Initially, discarded mobile phone PCBs are pre-processed and shortened into 1 × 1 cm2. Downscaled WPCBs are fed into the hammer mill to obtain the fine ground powder. The Powdered WPCBs are further processed through ultrasonic treatment to acquire metal-rich fraction. XRD, SEM-EDS, and ICP/AAS analysis revealed that the current technique can efficiently separate the metal-rich fraction without using toxic solvents. Results show the enhancement of copper fraction from 42.73 to 87 wt. % after ultrasonic treatment of WPCBs ground powder. Further, nitric acid leaching has been implemented to metal-rich fractions, and the parameters have been optimized for copper leaching with the assistance of response surface methodology (RSM) of the design of experiments (DOE). Quantitative dissolution (98.96%) of copper occurred using 3.5 M nitric acid within 3 h at 30 °C with 50 GPL pulp density and 500 rpm agitation speed. Finally, the kinetics of the leaching process were studied to conform the kinetics model. Moreover, the activation energy for diffusion (19.075 kJ/mole) and reaction kinetics model (13.29 kJ/mole) has also been calculated. The low energy consumption due to room temperature pre-treatment and effective leaching ensures the industrial feasibility of the proposed process.