Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (14)

Search Parameters:
Keywords = microwave-intensified extraction

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
15 pages, 3286 KB  
Article
Enhanced Sensitivity Microfluidic Microwave Sensor for Liquid Characterization
by Kim Ho Yeap, Kai Bor Tan, Foo Wei Lee, Han Kee Lee, Nuraidayani Effendy, Wei Chun Chin and Pek Lan Toh
Processes 2025, 13(7), 2183; https://doi.org/10.3390/pr13072183 - 8 Jul 2025
Viewed by 580
Abstract
This paper presents the development and analysis of a planar microfluidic microwave sensor featuring three circular complementary split-ring resonators (CSRRs) fabricated on an RO3035 substrate. The sensor demonstrates enhanced sensitivity in characterizing liquids contained in a fine glass capillary tube by leveraging a [...] Read more.
This paper presents the development and analysis of a planar microfluidic microwave sensor featuring three circular complementary split-ring resonators (CSRRs) fabricated on an RO3035 substrate. The sensor demonstrates enhanced sensitivity in characterizing liquids contained in a fine glass capillary tube by leveraging a novel configuration: a central 5-split-ring CSRR with a drilled hole to suspend the capillary, flanked by two 2-split-ring CSRRs to improve the band-stop filtering effect. The sensor’s performance is benchmarked against another CSRR-based microwave sensor with a similar configuration. High linearity is observed (R2 > 0.99), confirming its capability for precise ethanol concentration prediction. Compared to the replicated square CSRR design from the literature, the proposed sensor achieves a 35.22% improvement in sensitivity, with a frequency shift sensitivity of 567.41 kHz/% ethanol concentration versus 419.62 kHz/% for the reference sensor. The enhanced sensitivity is attributed to several key design strategies: increasing the intrinsic capacitance by enlarging the effective area and radial slot width to amplify edge capacitive effects, adding more split rings to intensify the resonance dip, placing additional CSRRs to improve energy extraction at resonance, and adopting circular CSRRs for superior electric field confinement. Additionally, the proposed design operates at a lower resonant frequency (2.234 GHz), which not only reduces dielectric and radiation losses but also enables the use of more cost-effective and power-efficient RF components. This advantage makes the sensor highly suitable for integration into portable and standalone sensing platforms. Full article
(This article belongs to the Special Issue Development of Smart Materials for Chemical Sensing)
Show Figures

Figure 1

15 pages, 5382 KB  
Article
Microwave Pre-Treatment for Efficient Zinc Recovery via Acid Leaching
by Bagdaulet Kenzhaliyev, Ainur Berkinbayeva, Kenzhegali Smailov, Zhazira Baltabekova, Shynar Saulebekkyzy, Nazerke Tolegenova, Azamat Yessengaziyev, Nauryzbek Bakhytuly and Symbat Tugambay
Materials 2025, 18(11), 2496; https://doi.org/10.3390/ma18112496 - 26 May 2025
Viewed by 581
Abstract
This study presents an innovative approach to processing refractory zinc-bearing clinker using microwave thermal treatment followed by acid leaching. Microwave irradiation induces phase transformations, converting sphalerite (ZnS) to zincite (ZnO), and generates microcracks that enhance clinker porosity and reactivity. These changes significantly improve [...] Read more.
This study presents an innovative approach to processing refractory zinc-bearing clinker using microwave thermal treatment followed by acid leaching. Microwave irradiation induces phase transformations, converting sphalerite (ZnS) to zincite (ZnO), and generates microcracks that enhance clinker porosity and reactivity. These changes significantly improve zinc dissolution during sulfuric acid leaching. Key parameters—acid concentration, temperature, solid-to-liquid ratio, and leaching time—were optimized, achieving a zinc extraction of 92.5% under optimal conditions (40 g/L H2SO4, solid-to-liquid ratio 1:4, 600 °C, 5–7 min) compared to 39.1% without pre-treatment. Thermodynamic analysis confirms the higher reactivity of ZnO, driven by favorable Gibbs free energy and exothermic reaction characteristics. These findings demonstrate the potential of microwave processing to intensify hydrometallurgical processes, offering energy efficiency and environmental benefits for industrial zinc recovery. Full article
(This article belongs to the Special Issue Advances in Process Metallurgy and Metal Recycling)
Show Figures

Figure 1

19 pages, 3496 KB  
Article
Microwave-Assisted Valorization of Tomato Pomace for Pectin Recovery: Improving Yields and Environmental Footprint
by Nikolina Golub, Emerik Galić, Kristina Radić, Nada Smigic, Ilija Djekić, Sandra Pedisić and Dubravka Vitali Čepo
Foods 2025, 14(9), 1516; https://doi.org/10.3390/foods14091516 - 26 Apr 2025
Cited by 2 | Viewed by 697
Abstract
Rising industrial demands emphasize the need for exploring other non-traditional sources for obtaining pectin. As efforts to enhance circular economy practices and reduce reliance on primary resources intensify; the focus has shifted towards utilizing various types of agricultural and food industry waste; including [...] Read more.
Rising industrial demands emphasize the need for exploring other non-traditional sources for obtaining pectin. As efforts to enhance circular economy practices and reduce reliance on primary resources intensify; the focus has shifted towards utilizing various types of agricultural and food industry waste; including tomato pomace waste (TPW). In this work; the microwave-assisted extraction (MAE) and TPW pretreatment methods were optimized to improve pectin yields and decrease the environmental impact of the extraction process; compared to conventional solvent extraction (CSE). The response surface methodology was used to model the optimization process. The physico-chemical properties of pectin were determined using titrimetric methods and FTIR spectroscopy. A life cycle assessment (LCA) was applied to assess the environmental impact of MAE and CSE. Optimal microwave conditions (11.66 min/600 W/pH 1) yielded two times more pectin than CSE (2 h/85 °C/pH 1.5). Pre-processing treatments (mechanical ball milling and defatting) showed marginal effects on pectin yields and properties; and; therefore; can be omitted in order to reduce the energy consumption of the process. The LCA showed that single conventional extraction treatment had two times higher values of the ecological footprint compared to MAE; for all indicators. The results suggest that MAE can be used as an efficient green method for pectin extraction from TPW Full article
(This article belongs to the Section Nutraceuticals, Functional Foods, and Novel Foods)
Show Figures

Figure 1

7 pages, 166 KB  
Perspective
Reshaping Chemical Manufacturing Towards Green Process Intensification: Recent Findings and Perspectives
by Giancarlo Cravotto
Processes 2025, 13(2), 459; https://doi.org/10.3390/pr13020459 - 8 Feb 2025
Cited by 4 | Viewed by 2603
Abstract
The chemical industry faces major challenges despite recent progress in the transition to more environmentally friendly processes. Sustainable industrial chemistry relies on the optimization of protocols and downstream processes such as extraction, purification, and drying. Process intensification, which includes non-conventional techniques and continuous [...] Read more.
The chemical industry faces major challenges despite recent progress in the transition to more environmentally friendly processes. Sustainable industrial chemistry relies on the optimization of protocols and downstream processes such as extraction, purification, and drying. Process intensification, which includes non-conventional techniques and continuous manufacturing, has emerged as a key strategy to improve efficiency and environmental impact. Technologies such as ultrasound, microwaves, mechanochemistry, and reactive extrusion offer improved performance but face scalability and proprietary barriers. Flow chemistry offers additional benefits, including smaller reactors, lower energy consumption (from 40 to 90%), and increased safety through continuous, automated reactions. However, implementing these methods requires overcoming engineering, economic, and regulatory hurdles. Biphasic catalysis and sonochemical activation in liquid–liquid systems are promising approaches for scalable reactions under mild conditions. The pharmaceutical industry, a major source of waste, has shown resistance due to high validation costs and complex regulations. Fortunately, international regulatory institutions have introduced programs to facilitate the introduction of advanced technologies. Future perspectives emphasize the integration of modular, intensified processes with digitalization and smart manufacturing. Collaborative, transdisciplinary research will be crucial for accelerating commercialization and addressing sustainability challenges in chemical production. Full article
Show Figures

Graphical abstract

15 pages, 6215 KB  
Article
Ultrasound-Assisted Determination of Selenium in Organic Rice Using Deep Eutectic Solvents Coupled with Inductively Coupled Plasma Mass Spectrometry
by Shanshan Zhang, Boyu Chen, Yu Liu, Haoyu Sun, Haixing Zhang, Na Li, Yang Qing, Jeevithan Elango, Dayun Zhao and Wenhui Wu
Foods 2025, 14(3), 384; https://doi.org/10.3390/foods14030384 - 24 Jan 2025
Viewed by 1117
Abstract
As the focus on green chemistry intensifies, researchers are progressively looking to incorporate biodegradable and environmentally friendly solvents. Given the prevalent use of inorganic solvents in conventional methods for detecting selenium content, this study utilized a mixture design approach to create four deep [...] Read more.
As the focus on green chemistry intensifies, researchers are progressively looking to incorporate biodegradable and environmentally friendly solvents. Given the prevalent use of inorganic solvents in conventional methods for detecting selenium content, this study utilized a mixture design approach to create four deep eutectic solvents (DESs). The elements of the DESs consisted of six different compounds: guanidine hydrochloride, fructose, glycerol, citric acid, proline, and choline chloride. The synthesized deep eutectic solvents (DESs) exhibited a uniform and transparent appearance. The ideal ratios for each DES were established based on their density and viscosity measurements, leading to the formulations of DES1 (34% guanidine hydrochloride, 21% fructose, 45% water), DES2 (23% guanidine hydrochloride, 32% glycerol, 45% water), DES3 (27.5% citric acid, 27.5% proline, 45% water), and DES4 (30% choline chloride, 25% citric acid, 45% water). The characterization of the deep eutectic solvents (DESs) was performed using nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy, which confirmed the molecular formation of each DES. Following this, the DESs were applied as extraction solvents in a process involving ultrasonic-assisted microextraction (UAE) combined with inductively coupled plasma mass spectrometry (ICP-MS) to assess the selenium levels in selenium-rich rice. The results were benchmarked against traditional microwave-assisted acid digestion (TM-AD), revealing selenium recovery rates ranging from 85.5% to 106.7%. These results indicate that UAE is an effective method for extracting selenium from selenium-rich rice, thereby establishing a solid data foundation for the environmentally friendly analysis of selenium content in rice. Full article
(This article belongs to the Section Food Analytical Methods)
Show Figures

Figure 1

13 pages, 3271 KB  
Article
Microwave Heating Characteristics on Lipid Quality in Sterilized Rainbow Trout (Oncorhynchus mykiss) Using Designed Heating Processing
by Ji Zhang and Donglei Luan
Foods 2024, 13(17), 2727; https://doi.org/10.3390/foods13172727 - 28 Aug 2024
Cited by 2 | Viewed by 1392
Abstract
The aim of this study was to simulate microwave heating characteristics to investigate the lipid quality in rainbow trout, including the impact of the heating rate, maximum temperature, and thermal processing level on the extent of lipid oxidation and on the fatty acid [...] Read more.
The aim of this study was to simulate microwave heating characteristics to investigate the lipid quality in rainbow trout, including the impact of the heating rate, maximum temperature, and thermal processing level on the extent of lipid oxidation and on the fatty acid extraction coefficient. Increasing F0 from 3 to 6 min improved fatty acid retention at high heating rates but led to a decrease in the measured results at low heating rates. Elevated thermal processing levels and maximum temperatures were observed to intensify the oxidation. At F0 = 3 min, an increase in maximum temperature led to an increase in the total lipid extraction coefficient but a decrease in the fatty acid extraction coefficient. However, an increase in maximum temperature resulted in a decrease in both extraction coefficients when F0 was 6 min. The coefficient spectra of fatty acid extraction obtained from the microwave and traditional heat treatments showed nonparallel trends, confirming the presence of non-thermal effects during microwave thermal processing. In conclusion, compared to conventional heat treatment methods, microwave processing has significant potential for enhancing the lipid quality of ready-to-eat rainbow trout products and effectively reducing production costs. Full article
Show Figures

Graphical abstract

24 pages, 6228 KB  
Article
Optimizing Microwave-Assisted Extraction from Levisticum officinale WDJ Koch Roots Using Pareto Optimal Solutions
by Michał Plawgo, Sławomir Kocira and Andrea Bohata
Processes 2024, 12(5), 1026; https://doi.org/10.3390/pr12051026 - 18 May 2024
Cited by 1 | Viewed by 1195
Abstract
The current research trend is not only focused on advanced techniques to intensify the extraction of bioactive compounds from plants, but also on the optimization process. The objective of this work was the implementation of the multiple criteria analysis using navigation on Pareto [...] Read more.
The current research trend is not only focused on advanced techniques to intensify the extraction of bioactive compounds from plants, but also on the optimization process. The objective of this work was the implementation of the multiple criteria analysis using navigation on Pareto sets to determine the optimal parameters for the microwave-assisted extraction of Levisticum officinale WDJ Koch roots in order to obtain the maximum efficiency of the antioxidant potential of the extracts. The optimized parameters were extraction time, microwave power, and plant biomass/solvent ratio, while the evaluation criteria were based on the total phenols, flavonoids, reducing sugars, and antioxidant capacity. It was shown that the process parameters analyzed, i.e., biomass/solvent ratio, process time, and microwave power, determined the extraction efficiency of total phenolic content (TPC). A different observation was made for the analysis of total flavonoid content (TFC) and total antioxidant potential (TAA). Compared to the assessment of TFC and TAA, a completely different trend was observed for the analysis of total reducing sugars (RSC). Sets of Pareto optimal, compromise, and preferred solutions were identified that will maximize the efficiency of the extraction of bioactive compounds from biomass. Due to the determined number of Pareto optimal solutions, an approach related to the introduction of preferences in the optimization procedure was applied. It was shown that for a satisfactory level of bioactive compounds, extraction should be carried out at a maximum microwave power of 750 W. Preferred solutions were obtained for root biomass to water ratios ranging from 0.0536 g/mL to 0.0679 g/mL. The preferred optimal time for microwave-assisted water extraction ranged from 64.2857 to 85.7143 s. Full article
Show Figures

Graphical abstract

15 pages, 4491 KB  
Article
Parameter Optimization of Ultrasonic–Microwave Synergistic Extraction of Taxanes from Taxus cuspidata Needles
by Zirui Zhao, Yajing Zhang, Wenlong Li, Yuanhu Tang and Shujie Wang
Molecules 2023, 28(23), 7746; https://doi.org/10.3390/molecules28237746 - 24 Nov 2023
Cited by 5 | Viewed by 1706
Abstract
Taxanes are the best-known compounds in Taxus cuspidata owing to their strong anticancer effects. However, the traditional taxanes extraction method is the solid–liquid extraction method, which is limited by a large energy consumption and low yield. Therefore, it is urgent to find an [...] Read more.
Taxanes are the best-known compounds in Taxus cuspidata owing to their strong anticancer effects. However, the traditional taxanes extraction method is the solid–liquid extraction method, which is limited by a large energy consumption and low yield. Therefore, it is urgent to find an efficient method for taxanes extraction. The ultrasonic microwave synergistic extraction (UME) method integrates the cavitation effect of ultrasound and the intensifying heat transfer (ionic conduction and dipole rotation of molecules) effect of microwave to accelerate the release of intracellular compounds and is used in active ingredient extractions. This study aimed to evaluate the performance of UME in extracting taxanes from T. cuspidata needles (dichloromethane-ethanol as extractant). A single-factor experiment, Plackett–Burman design, and the response surface method showed that the optimal UME parameters for taxanes extraction were an ultrasonic power of 300 W, a microwave power of 215 W, and 130 sieve meshes. Under these conditions, the taxanes yield was 570.32 μg/g, which increased by 13.41% and 41.63% compared with the ultrasound (US) and microwave (MW) treatments, respectively. The reasons for the differences in the taxanes yield were revealed by comparing the physicochemical properties of T. cuspidata residues after the UME, US, and MW treatments. The cell structures were significantly damaged after the UME treatment, and numerous tiny holes were observed on the surface. The absorption peaks of cellulose, hemicellulose, and lignin increased significantly in intensity, and the lowest peak temperature (307.40 °C), with a melting enthalpy of −5.19 J/g, was found after the UME treatment compared with the US and MW treatments. These results demonstrate that UME is an effective method (570.32 μg/g) to extract taxanes from T. cuspidata needles by destroying cellular structures. Full article
Show Figures

Figure 1

16 pages, 2380 KB  
Article
High Solubility and Bioavailability of Lobster Shell-Derived Calcium for Significantly Proliferating Bone and Skin Cells In Vitro
by Trung T. Nguyen, Thanh Hoang, Tuyet Pham, Vi Khanh Truong, Xuan Luo, Jian Qin and Wei Zhang
Mar. Drugs 2023, 21(6), 358; https://doi.org/10.3390/md21060358 - 11 Jun 2023
Cited by 2 | Viewed by 3564
Abstract
Shell wastes pose environmental and financial burdens to the shellfish industry. Utilizing these undervalued shells for commercial chitin production could minimize their adverse impacts while maximizing economic value. Shell chitin conventionally produced through harsh chemical processes is environmentally unfriendly and infeasible for recovering [...] Read more.
Shell wastes pose environmental and financial burdens to the shellfish industry. Utilizing these undervalued shells for commercial chitin production could minimize their adverse impacts while maximizing economic value. Shell chitin conventionally produced through harsh chemical processes is environmentally unfriendly and infeasible for recovering compatible proteins and minerals for value-added products. However, we recently developed a microwave-intensified biorefinery that efficiently produced chitin, proteins/peptides, and minerals from lobster shells. Lobster minerals have a calcium-rich composition and biologically originated calcium is more biofunctional for use as a functional, dietary, or nutraceutical ingredient in many commercial products. This has suggested a further investigation of lobster minerals for commercial applications. In this study, the nutritional attributes, functional properties, nutraceutical effects, and cytotoxicity of lobster minerals were analyzed using in vitro simulated gastrointestinal digestion combined with growing bone (MG-63), skin (HaCaT), and macrophage (THP-1) cells. The calcium from the lobster minerals was found to be comparable to that of a commercial calcium supplement (CCS, 139 vs. 148 mg/g). In addition, beef incorporated with lobster minerals (2%, w/w) retained water better than that of casein and commercial calcium lactate (CCL, 21.1 vs. 15.1 and 13.3%), and the lobster mineral had a considerably higher oil binding capacity than its rivals (casein and CCL, 2.5 vs. 1.5 and 1.0 mL/g). Notably, the lobster mineral and its calcium were far more soluble than the CCS (98.4 vs. 18.6% for the products and 64.0 vs. 8.5% for their calcium) while the in vitro bioavailability of lobster calcium was 5.9-fold higher compared to that of the commercial product (11.95 vs. 1.99%). Furthermore, supplementing lobster minerals in media at ratios of 15%, 25%, and 35% (v/v) when growing cells did not induce any detectable changes in cell morphology and apoptosis. However, it had significant effects on cell growth and proliferation. The responses of cells after three days of culture supplemented with the lobster minerals, compared to the CCS supplementation, were significantly better with the bone cells (MG-63) and competitively quick with the skin cells (HaCaT). The cell growth reached 49.9–61.6% for the MG-63 and 42.9–53.4% for the HaCaT. Furthermore, the MG-63 and HaCaT cells proliferated considerably after seven days of incubation, reaching 100.3% for MG-63 and 115.9% for HaCaT with a lobster mineral supplementation of 15%. Macrophages (THP-1 cells) treated for 24 h with lobster minerals at concentrations of 1.24–2.89 mg/mL had no detectable changes in cell morphology while their viability was over 82.2%, far above the cytotoxicity threshold (<70%). All these results indicate that lobster minerals could be used as a source of functional or nutraceutical calcium for commercial products. Full article
(This article belongs to the Special Issue High-Value Compounds from Marine Unutilized Resources)
Show Figures

Figure 1

17 pages, 3584 KB  
Article
Enhanced Recovery of Natural Antioxidants from Grape Waste Using Natural Eutectic Solvents-Based Microwave-Assisted Extraction
by Raquel Cañadas, Blanca Sáenz de Miera, Paloma Méndez, Emilio J. González and María González-Miquel
Molecules 2023, 28(3), 1153; https://doi.org/10.3390/molecules28031153 - 24 Jan 2023
Cited by 13 | Viewed by 2966
Abstract
The evaluation of sustainable solvents as alternatives to more harmful conventional solvents combined with intensification techniques to recover phenolic compounds from agri-food waste is in the spotlight. The wine industry generates large amounts of waste as a consequence of grape processing operations, which [...] Read more.
The evaluation of sustainable solvents as alternatives to more harmful conventional solvents combined with intensification techniques to recover phenolic compounds from agri-food waste is in the spotlight. The wine industry generates large amounts of waste as a consequence of grape processing operations, which can be revalued by solvent extraction of valuable antioxidants for food and fine chemical applications. Therefore, the present study focuses on the use of natural eutectic solvents (NAESs) with benign environmental, health, and safety profiles, for valorization of grape waste in the context of a circular economy. Herein, up to 15 NAESs consisting of combinations of three hydrogen bond acceptors (choline chloride, L-proline, and betaine) and four hydrogen bond donors (1,2-propanediol, glycerol, and 1,2- and 1,3-butanediol) were evaluated for antioxidant recovery. After an initial screening of the performance of NAESs by conventional extraction, the process was intensified by microwave-assisted extraction (MAE). The extracts were analyzed by UV/VIS spectrophotometric and HPLC methods. Promising results were obtained with the solvent betaine, 1,2-butanediol [1:4], using MAE at 100 °C for 3 min. Overall, the proposed NAESs-based MAE method was successfully applied to recover target compounds from grape waste, with great prospects for the antioxidants market and sustainable development for the winery sector. Full article
Show Figures

Graphical abstract

14 pages, 3422 KB  
Review
Plant Extraction in Water: Towards Highly Efficient Industrial Applications
by Lorenzo Gallina, Christian Cravotto, Giorgio Capaldi, Giorgio Grillo and Giancarlo Cravotto
Processes 2022, 10(11), 2233; https://doi.org/10.3390/pr10112233 - 31 Oct 2022
Cited by 22 | Viewed by 6861
Abstract
Since the beginning of this century, the world has experienced a growing need for enabling techniques and more environmentally friendly protocols that can facilitate more rational industrial production. Scientists are faced with the major challenges of global warming and safeguarding water and food [...] Read more.
Since the beginning of this century, the world has experienced a growing need for enabling techniques and more environmentally friendly protocols that can facilitate more rational industrial production. Scientists are faced with the major challenges of global warming and safeguarding water and food quality. Organic solvents are still widely used and seem to be hard to replace, despite their enormous environmental and toxicological impact. The development of water-based strategies for the extraction of primary and secondary metabolites from plants on a laboratory scale is well documented, with several intensified processes being able to maximize the extraction power of water. Technologies, such as ultrasound, hydrodynamic cavitation, microwaves and pressurized reactors that achieve subcritical water conditions can dramatically increase extraction rates and yields. In addition, significant synergistic effects have been observed when using combined techniques. Due to the limited penetration depth of microwaves and ultrasonic waves, scaling up entails changes to reactor design. Nevertheless, the rich academic literature from laboratory-scale investigations may contribute to the engineering work involved in maximizing mass/energy transfer. In this article, we provide an overview of current and innovative techniques for solid-liquid extraction in water for industrial applications, where continuous and semi-continuous processes can meet the high demands for productivity, profitability and quality. Full article
Show Figures

Figure 1

12 pages, 1002 KB  
Article
Microwave-Assisted Extraction of Multiple Trace Levels of Intermediate Metabolites for Camptothecin Biosynthesis in Camptotheca acuminata and Their Simultaneous Determination by HPLC-LTQ-Orbitrap-MS/MS and HPLC-TSQ-MS
by Zhaoxia Jin, Ruyi Wan, Ruxue Yan, Yingying Su, Honglan Huang, Lihan Zi and Fang Yu
Molecules 2019, 24(4), 815; https://doi.org/10.3390/molecules24040815 - 25 Feb 2019
Cited by 13 | Viewed by 3979
Abstract
Camptothecin (CPT) has strong antitumor activity and is used as an anticancer therapeutic agent. To better understand and decipher the pathway of CPT biosynthesis in Camptotheca acuminata, the main purpose here was focused on creating an effective extraction strategy for a rich [...] Read more.
Camptothecin (CPT) has strong antitumor activity and is used as an anticancer therapeutic agent. To better understand and decipher the pathway of CPT biosynthesis in Camptotheca acuminata, the main purpose here was focused on creating an effective extraction strategy for a rich intermediate metabolite profile. In the present study, a 70% aqueous acetonitrile was verified as an optimal extraction solvent for microwave-assisted extraction (MAE) of metabolites by spiking experiments. Based on multi-objective optimization, the best extraction conditions of a solid-liquid ratio of 1:20, microwave power of 230 W, and a time of 4 min were achieved using a full factorial 34 experimental design. Crude extracts obtained from the shoot apex of C. acuminata using MAE have been qualitatively profiled by high-performance liquid chromatography coupled with linear ion trap quadrupole-orbitrap mass spectrometry (HPLC-LTQ-Orbitrap-MS/MS) and a HPLC triple quadrupole-MS (HPLC-TSQ-MS) analysis was conducted for their metabolite content in different tissues. CPT, and ten related metabolites and their isomers, including tryptamine, loganic acid, secologanic acid, strictosidinic acid, strictosamide, strictosamide epoxide, strictosamide diol, strictosamide ketolactam, pumiloside, and deoxypumiloside, were detected and tentatively identified. Scanning electron microscopy (SEM) imaging of the shoot apex demonstrated that severe cell disruption was evident after intensified extraction processes. The study showed the difference of metabolite profiles and the enhancement of metabolite content after microwave-pretreated techniques, and the established MAE procedure is an effective methodology to preserve valuable metabolite compounds for analysis. Full article
Show Figures

Graphical abstract

11 pages, 3548 KB  
Article
Gold Extraction from Cyanidation Tailing Using Microwave Chlorination Roasting Method
by Fei Zhu, Libo Zhang, Haoyu Li, Shaohua Yin, Sivasankar Koppala, Kun Yang and Shiwei Li
Metals 2018, 8(12), 1025; https://doi.org/10.3390/met8121025 - 5 Dec 2018
Cited by 18 | Viewed by 5113
Abstract
At present, gold mines are increasingly scarce in the world. The yield of cyanidation tailing (CT) of refractory gold ores with a grade of 10 g/T is huge; however, the effective capitalization of the cyanidation tailing is a significant problem in the gold [...] Read more.
At present, gold mines are increasingly scarce in the world. The yield of cyanidation tailing (CT) of refractory gold ores with a grade of 10 g/T is huge; however, the effective capitalization of the cyanidation tailing is a significant problem in the gold industry. In this work, a new treatment method, a microwave-roasting process developed. The effect of roasting temperature, calcium chloride concentration, holding time and mineral size on the recovery of Au researched under conventional and microwave conditions. It found that, under the same processing conditions, the Au recovery in the microwave field is much higher than that of conventional conditions. The preliminary reinforcing role of the microwave discussed in the recovery of gold. This might be because of the microwave absorption ability of CaCl2 is much better, heated quickly and the reactions intensified among CaCl2, O2, and H2O. As a result, the extraction of gold in CT drastically increased in the microwave field, and the microwave roasting technology shows the characteristics of environmental protection in terms of low energy consumption and high efficiency. Full article
Show Figures

Figure 1

11 pages, 6870 KB  
Article
Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process
by Jingpeng Wang, Yimin Zhang, Tao Liu and Jing Huang
Minerals 2018, 8(3), 113; https://doi.org/10.3390/min8030113 - 9 Mar 2018
Cited by 9 | Viewed by 4204
Abstract
The microwave assisted leaching of the vanadium bearing-high carbonaceous shale process was investigated using surface response methodology (RSM) based on Box–Behnken design (BBD). The effect of important factors such as CaF2 usage, H2SO4 concentration, leaching time and microwave power, [...] Read more.
The microwave assisted leaching of the vanadium bearing-high carbonaceous shale process was investigated using surface response methodology (RSM) based on Box–Behnken design (BBD). The effect of important factors such as CaF2 usage, H2SO4 concentration, leaching time and microwave power, as well as the interactive coefficients, the signification of the model and factors were analyzed. With the condition of 9.8 wt % CaF2, 23.0 vol % H2SO4, 170.6 min and 350 W, the actual values of vanadium (V) leaching efficiency in microwave heating (MH) and conventional heating (CH) were 85.43% and 79.64%, which agreed well with the predicted values. Meanwhile, the influence order of the factors in MH and CH was CaF2 dosage > H2SO4 concentration > leaching time. Microwave was an efficacious impetus for V extraction, but the microwave power itself was not a significant factor when the temperature of leaching system was high enough. The further characterization of mineral components before and after leaching confirmed that the prior dissolving of muscovite and pyrite in MH was intensified, while both minerals were in fine grains and filled with black carbon. The selective heating of carbon and pyrite sequenced the large temperature gradient between solids and liquids, which accelerated the dissolving reaction of muscovite with CaF2 present in MH condition. Full article
(This article belongs to the Special Issue Towards Sustainability in Extractive Metallurgy)
Show Figures

Figure 1

Back to TopTop