Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.7
3.5
Journals
Processes
Special Issues
Microwave Conversion Techniques Intensification
share announcement

Microwave Conversion Techniques Intensification

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Chemical Processes and Systems".

Deadline for manuscript submissions: closed (31 January 2021) | Viewed by 24128

Special Issue Editors

Dr. Mattia Bartoli

E-Mail Website
Guest Editor
Department of Applied Science and Technology (DISAT), Polytechnic of Turin, 10129 Turin, Italy
Interests: biochar; composites; polymers
Special Issues, Collections and Topics in MDPI journals
Dr. Mauro Giorcelli

E-Mail Website
Guest Editor
Department of Applied Science and Technology (DISAT), Polytechnic of Turin, 10129 Turin, Italy
Interests: biochar; carbon materials; composites; electrical characterization
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the last decades, the increased accountability of companies with regard to the environment has represented an astonishing driving force for the development of innovative industrial processes.

Since the assessment of green chemistry principles, the use of microwaves as valuable tool for sustainable and effective conversion technology has increased. Microwave-based processes have played a very relevant role in many technological fields, proving their feasibility. Furthermore, microwave heating has been proved as a breakthrough approach in the thermochemical conversion of polymeric materials. Additionally, the food and pharmaceutical sectors have adopted microwave processes as a common production stage in many industrial platforms. Last but not least, the manufacture of inorganics materials has also included microwave processing such as performing approach in several productions.

This Special Issue aims to provide an up-to-date picture of recent advances and outstanding innovations in the field of microwave technology. Studies of the intensification of industrial microwave procedures at lab-scale and with solid proof of concept about microwave conversions will reported.

Dr. Mattia Bartoli
Dr. Mauro Giorcelli
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Microwave pyrolysis
  • Microwave assisted organic synthesis
  • Food processing
  • Inorganics production
  • Process intensification
  • Microwave reactors

Published Papers (6 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

12 pages, 2206 KiB  
Article
Microwave-Assisted Pyrolysis of Pine Wood Sawdust Mixed with Activated Carbon for Bio-Oil and Bio-Char Production
by Anissa Khelfa, Filipe Augusto Rodrigues, Mohamed Koubaa and Eugène Vorobiev
Processes 2020, 8(11), 1437; https://doi.org/10.3390/pr8111437 - 10 Nov 2020
Cited by 18 | Viewed by 4504
Abstract
Pyrolysis of pine wood sawdust was carried out using microwave-heating technology in the presence of activated carbon (AC). Experimental conditions were of 20 min processing time, 10 wt.% of AC, and a microwave power varying from 100 to 800 W. The results obtained [...] Read more.
Pyrolysis of pine wood sawdust was carried out using microwave-heating technology in the presence of activated carbon (AC). Experimental conditions were of 20 min processing time, 10 wt.% of AC, and a microwave power varying from 100 to 800 W. The results obtained showed that the microwave absorber allowed increasing the bio-oil yield up to 2 folds by reducing the charcoal fraction. The maximum temperature reached was 505 °C at 800 W. The higher heating values (HHV) of the solid residues ranged from 17.6 to 30.3 MJ/kg. The highest HHV was obtained for the sample heated at 800 W with 10 wt.% of AC, which was 33% higher than the non-charged sample heated at the same power. Furthermore, the addition of AC allowed showing the probable catalytic effect of the AC in the charged sample pyrolysis bio-oils. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Figure 1

19 pages, 4295 KiB  
Article
Short-Chain Polyglycerol Production via Microwave-Assisted Solventless Glycerol Polymerization Process Over Lioh-Modified Aluminium Pillared Clay Catalyst: Parametric Study
by Muhammad Sajid, Muhammad Ayoub, Suzana Yusup, Bawadi Abdullah, Rashid Shamsuddin, Roil Bilad, Chi Cheng Chong and Aqsha Aqsha
Processes 2020, 8(9), 1093; https://doi.org/10.3390/pr8091093 - 03 Sep 2020
Cited by 2 | Viewed by 2239
Abstract
In the current study, microwave-assisted glycerol polymerization for short-chain polyglycerol production was conducted unprecedentedly over low-cost catalyst, lithium-modified aluminium pillared clay (Li/AlPC) catalysts without the solvent. The influences of disparate reaction parameters such as the effects of Li loadings (10, 20, 30 wt.%), [...] Read more.
In the current study, microwave-assisted glycerol polymerization for short-chain polyglycerol production was conducted unprecedentedly over low-cost catalyst, lithium-modified aluminium pillared clay (Li/AlPC) catalysts without the solvent. The influences of disparate reaction parameters such as the effects of Li loadings (10, 20, 30 wt.%), catalyst loadings (2, 3, 4 wt.%), operating temperatures (200, 220, 240 °C) and operating times (1–4 h) on the glycerol conversions, and polyglycerol yield (particularly for diglycerol and triglycerol), were elucidated. The fresh catalysts were subjected to physicochemical properties evaluation via characterization techniques, viz. N2 physisorption, XRD, SEM, NH3-TPD and CO2-TPD. In comparison, 20 wt.% Li/AlPC demonstrated the best performance under non-conventional heating, credited to its outstanding textural properties (an increase of basal spacing to 21 Ȧ, high surface area of 95.48 m2/g, total basicity of 34.48 mmol/g and average pore diameter of 19.21 nm). Within the studied ranges, the highest glycerol conversion (98.85%) and polyglycerol yield (90.46%) were achieved when catalyst loading of 3 wt.%, reaction temperature of 220 °C and reaction time of 3 h were adopted. The results obtained also anticipated the higher energy efficiency of microwave-assisted polymerization than conventional technique (>8 h), as the reaction time for the former technology was shorter to attain the highest product yield. The study performed could potentially conduce the wise utilization of surplus glycerol generated from the biodiesel industry. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Figure 1

18 pages, 924 KiB  
Article
Hybrid Drying of Murraya koenigii Leaves: Energy Consumption, Antioxidant Capacity, Profiling of Volatile Compounds and Quality Studies
by Choong Oon Choo, Bee Lin Chua, Adam Figiel, Klaudiusz Jałoszyński, Aneta Wojdyło, Antoni Szumny, Jacek Łyczko and Chien Hwa Chong
Processes 2020, 8(2), 240; https://doi.org/10.3390/pr8020240 - 20 Feb 2020
Cited by 21 | Viewed by 4204
Abstract
This study aims to reduce the amount of specific energy consumed during the drying of fresh Murraya koenigii leaves by comparing four drying methods: (1) convective hot-air drying (CD; 40, 50 and 60 °C); (2) single-stage microwave-vacuum drying (MVD; 6, 9 and 12 [...] Read more.
This study aims to reduce the amount of specific energy consumed during the drying of fresh Murraya koenigii leaves by comparing four drying methods: (1) convective hot-air drying (CD; 40, 50 and 60 °C); (2) single-stage microwave-vacuum drying (MVD; 6, 9 and 12 W/g); (3) two-stage convective hot-air pre-drying followed by microwave-vacuum finishing–drying (CPD-MVFD; 50 °C, 9 W/g); and (4) freeze-drying as a control in the analysis sections. The drying kinetics were also modelled using thin-layer models. The quality parameters of dried M. koenigii leaves were measured including total polyphenolic content (TPC), antioxidant capacity (ABTS and FRAP), profiling of volatile compounds, colour analysis and water activity analysis. Results showed that CPD-MVFD effectively reduced the specific energy consumption of CD at 50 °C by 67.3% in terms of kilojoules per gram of fresh weight and 48.9% in terms of kilojoules per gram of water. The modified Page model demonstrated excellent fitting to the empirical data obtained. FD showed promising antioxidant activity. The major contributor of antioxidant capacity was TPC. The volatile compounds profiled by gas chromatography-mass spectrometry, namely, β-phellandrene (31%), α-pinene (19.9%), and sabinene (16%) were identified as the major compounds of dried M. koenigii leaves. Colour analysis showed MVD’s high performance in preserving the colour parameters of M. koenigii leaves under all conditions. The colour parameters were correlated to the antioxidant capacity and TPC. Water activity analysis showed that the water activity of M. koenigii leaves for all drying methods indicating that the conditions were microbiologically and shelf-stable. Pearson correlation showed the colour parameters of the leaves had a strong correlation to TPC. Overall, MVD showed promising energy consumption reduction and recovery in TPC and volatile compounds. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Figure 1

15 pages, 1418 KiB  
Article
Optimization of Microwave-Assisted Extraction Process of Callicarpa candicans (Burm. f.) Hochr Essential Oil and Its Inhibitory Properties against Some Bacteria and Cancer Cell Lines
by Quoc Toan Tran, Thu Le Vu Thi, Tien Lam Do, Hong Minh Pham Thi, Bich Hoang Thi, Quang Truyen Chu, Phuong Thao Lai Phuong, Huu Nghi Do, Hoai Thu Hoang Than, Thu Thuy Ta Thi, Van Huyen Luu, Phuong Thi Mai Duong and Huong Thi Thu Phung
Processes 2020, 8(2), 173; https://doi.org/10.3390/pr8020173 - 04 Feb 2020
Cited by 13 | Viewed by 3449
Abstract
Callicarpa candicans (Burm. f.) Hochr. (Callicarpa cana L.) is a medicinal plant that is distributed mainly in the tropics and subtropics of Asia and finds a wide range of uses in traditional medicine. In this study, we attempted and optimized the microwave-assisted [...] Read more.
Callicarpa candicans (Burm. f.) Hochr. (Callicarpa cana L.) is a medicinal plant that is distributed mainly in the tropics and subtropics of Asia and finds a wide range of uses in traditional medicine. In this study, we attempted and optimized the microwave-assisted hydro-distillation (MAHD) process to obtain essential oil from the leaves of C. candicans. In addition, the obtained oil was analyzed for volatile composition by gas chromatography–mass spectrometry (GC-MS) and assayed for bioactivity against several bacteria and cancer cell lines. To optimize the extraction process, response surface methodology (RSM) in combination with central composite design (CCD) was adopted. Experimental design and optimization were carried out with respect to three experimental factors including the ratio of water to raw material, extraction time, and microwave power. The optimal extraction conditions were obtained as follows: water to raw material ratio of 6/1 (v/w), extraction time 42 min, and microwave power 440 W. Composition determination of the obtained C. candicans essential oil indicated the presence of predominant components including caryophyllene <b-> (10.45%), cadinene <d-> (10.28%), gurjunene <a-> (8.95%), muurolene <g-> (8.92%), selinene <a-> (7.06%), selinene <b-> (5.59%), and copaene <a-> (5.40%). In comparison with the essential oils obtained via traditional hydro-distillation method, the essential oil extracted by MAHD exhibited superior anti-proliferative activity on all tested cancer cell lines. Current results imply that the MAHD is capable of recovering biologically-active natural products of greater quantity than that recovered by the conventional distillation. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Figure 1

Review

Jump to: Research

17 pages, 2181 KiB  
Review
A Review of Bio-Oil Production through Microwave-Assisted Pyrolysis
by Mauro Giorcelli, Oisik Das, Gabriel Sas, Michael Försth and Mattia Bartoli
Processes 2021, 9(3), 561; https://doi.org/10.3390/pr9030561 - 23 Mar 2021
Cited by 17 | Viewed by 3868
Abstract
The issue of sustainability is a growing concern and has led to many environmentally friendly chemical productions through a great intensification of the use of biomass conversion processes. Thermal conversion of biomass is one of the most attractive tools currently used, and pyrolytic [...] Read more.
The issue of sustainability is a growing concern and has led to many environmentally friendly chemical productions through a great intensification of the use of biomass conversion processes. Thermal conversion of biomass is one of the most attractive tools currently used, and pyrolytic treatments represent the most flexible approach to biomass conversion. In this scenario, microwave-assisted pyrolysis could be a solid choice for the production of multi-chemical mixtures known as bio-oils. Bio-oils could represent a promising new source of high-value species ranging from bioactive chemicals to green solvents. In this review, we have summarized the most recent developments regarding bio-oil production through microwave-induced pyrolytic degradation of biomasses. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Figure 1

14 pages, 1639 KiB  
Review
An Overview of Temperature Issues in Microwave-Assisted Pyrolysis
by Mattia Bartoli, Marco Frediani, Cedric Briens, Franco Berruti and Luca Rosi
Processes 2019, 7(10), 658; https://doi.org/10.3390/pr7100658 - 26 Sep 2019
Cited by 33 | Viewed by 4862
Abstract
Microwave-assisted pyrolysis is a promising thermochemical technique to convert waste polymers and biomass into raw chemicals and fuels. However, this process involves several issues related to the interactions between materials and microwaves. Consequently, the control of temperature during microwave-assisted pyrolysis is a hard [...] Read more.
Microwave-assisted pyrolysis is a promising thermochemical technique to convert waste polymers and biomass into raw chemicals and fuels. However, this process involves several issues related to the interactions between materials and microwaves. Consequently, the control of temperature during microwave-assisted pyrolysis is a hard task both for measurement and uniformity during the overall pyrolytic run. In this review, we introduce some of the main theoretical aspects of the microwaves–materials interactions alongside the issues related to microwave pyrolytic processability of materials. Full article
(This article belongs to the Special Issue Microwave Conversion Techniques Intensification)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-6
Back to TopTop