Green Sustainable Chemical Processes

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 October 2020) | Viewed by 100382

Special Issue Editors

Chemical Engineering Department, Faculty of Chemistry, Campus de Espinardo sn, 30071 Murcia, Spain
Interests: green chemistry; ionic liquid; supercritical fluid; biocatalysis; separation processes
Special Issues, Collections and Topics in MDPI journals
Department of Chemical Engineering, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain
Interests: ionic liquid; green chemistry; membrane technology; fuel cell; biofuel
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The present Special Issue will include cutting-edge advances in green sustainable chemical processes. Research in this field is directed towards the development of methods and new chemical engineering routes that can be integrated into industrial processing for safer, more flexible, economic and ecological production processes in the context of green and sustainable chemical engineering.

We invite authors to submit original research and review articles that promote the design and efficient use of environmentally benign chemical processes. We are particularly interested in articles that explore the development of processes that use renewable resources and green solvents, alternative sources of energy, process intensification and innovative environmental technologies for water treatment and pollution control.

Potential topics include, but are not limited to:

  • Renewable resources (valorization of agricultural and industrial waste).
  • Alternative solvents (ionic liquid and supercritical fluids).
  • Biofuels and other alternative sources of energy.
  • Process intensification.
  • Catalysis and biocatalysis.
  • Nanotechnology.
  • Environmental technologies for water treatment and pollution control.
  • Process systems engineering

Prof. Dr. Francisco José Hernández Fernández
Prof. Dr. Antonia Pérez de los Ríos
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

  • Green Chemistry
  • Green Engineering
  • Alternative Solvent
  • Renewable Resource
  • Bioenergy
  • Wastewater Treatment
  • Process Intensification
  • Nanotechnology
  • Process Conceptualization

Published Papers (21 papers)

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Editorial

Jump to: Research, Review

5 pages, 200 KiB  
Editorial
Special Issue: Green Sustainable Chemical Processes
by Francisco J. Hernández Fernández and Antonia Pérez de los Ríos
Processes 2021, 9(7), 1097; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9071097 - 24 Jun 2021
Viewed by 1308
Abstract
Sustainable chemical process engineering results from applying the principles of green chemistry or sustainable chemistry to chemical process engineering [...] Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)

Research

Jump to: Editorial, Review

14 pages, 4362 KiB  
Article
Improving the Imazapyr Degradation by Photocatalytic Ozonation: A Comparative Study with Different Oxidative Chemical Processes
by Salma Bougarrani, Zakarya Baicha, Lahbib Latrach, Mohammed El Mahi and Francisco José Hernandez Fernandez
Processes 2020, 8(11), 1446; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111446 - 11 Nov 2020
Cited by 4 | Viewed by 1699
Abstract
The degradation of imazapyr (C13H15N3O3), an active element in the aqueous solution of commercial herbicide, was investigated. This study was the first to evaluate in a comprehensive manner the efficiency of advanced oxidation processes for [...] Read more.
The degradation of imazapyr (C13H15N3O3), an active element in the aqueous solution of commercial herbicide, was investigated. This study was the first to evaluate in a comprehensive manner the efficiency of advanced oxidation processes for imazapyr degradation. Results showed that Imazapyr degradation is significantly affected by operational conditions such as TiO2 concentration, ozone concentration, initial concentration of imazapyr and pH. The kinetics of Imazapyr consumption was the first order with respect to Imazapyr concentration and zero order with respect to ozone concentration with a constant rate of 0.247 min−1 and 0.128 min−1 for photocatalytic ozonation and heterogeneous photocatalysis, while it was the first order with respect to Imazapyr and the first order with respect to ozone concentrations when only ozone was used with a constant rate of 0.053 mol L−1 min−1 at pH 7. The results revealed that more than 90 percent of the removal efficiency representing the elimination of imazapyr was held up to 7 μM. Further increase in the concentration of imazapyr leads to a drop in the removal efficiency, however the total imazapyr degradation was reached in 20 min utilizing photocatalytic ozonation for 5 μM of Imazapyr in the presence of 100 mg L−1 of TiO2, 10 mg L−1 of ozone at pH 7. Photocatalytic ozonation and heterogeneous photocatalysis utilizing TiO2 as a semiconductor process appeared possible and well suited for the treatment of organic contaminants such as imazapyr herbicides, although at certain dosages of pH and common time for wastewater treatment, imazapyr was not degraded with ozonation on its own. The association of two oxidation processes, ozonation and photocatalysis, has improved oxidation efficiencies for water treatment under optimal conditions, leading to the development of non-selective hydroxyl and more reactive radicals in the oxidation medium, as well as the resulting synergistic effects between photocatalysis and ozonation that react more rapidly with imazapyr herbicide. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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15 pages, 1212 KiB  
Article
Prediction of the Solubility of CO2 in Imidazolium Ionic Liquids Based on Selective Ensemble Modeling Method
by Luyue Xia, Shanshan Liu and Haitian Pan
Processes 2020, 8(11), 1369; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111369 - 28 Oct 2020
Cited by 5 | Viewed by 2111
Abstract
Solubility data is one of the essential basic data for CO2 capture by ionic liquids. A selective ensemble modeling method, proposed to overcome the shortcomings of current methods, was developed and applied to the prediction of the solubility of CO2 in [...] Read more.
Solubility data is one of the essential basic data for CO2 capture by ionic liquids. A selective ensemble modeling method, proposed to overcome the shortcomings of current methods, was developed and applied to the prediction of the solubility of CO2 in imidazolium ionic liquids. Firstly, multiple different sub–models were established based on the diversities of data, structural, and parameter design philosophy. Secondly, the fuzzy C–means algorithm was used to cluster the sub–models, and the collinearity detection method was adopted to eliminate the sub–models with high collinearity. Finally, the information entropy method integrated the sub–models into the selective ensemble model. The validation of the CO2 solubility predictions against experimental data showed that the proposed ensemble model had better performance than its previous alternative, because more effective information was extracted from different angles, and the diversity and accuracy among the sub–models were fully integrated. This work not only provided an effective modeling method for the prediction of the solubility of CO2 in ionic liquids, but also provided an effective method for the discrimination of ionic liquids for CO2 capture. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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16 pages, 3304 KiB  
Article
Characterisation of Bioactive Ingredients in Extracts of Fresh and Dried Coniferous Trees for the Development of Sustainable Packaging Materials
by Thomas Havelt, Jan Niklas Frase, Ralf Pude and Michaela Schmitz
Processes 2020, 8(11), 1366; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111366 - 28 Oct 2020
Cited by 5 | Viewed by 2518
Abstract
Background: Coniferous woods (Abies nordmanniana (Stev.) Spach, Abies procera Rehd, Picea abies (L.) H.Karst, and Picea pungens Engelm.) could contain useful secondary metabolites to produce sustainable packaging materials, e.g., by substitution of [...] Read more.
Background: Coniferous woods (Abies nordmanniana (Stev.) Spach, Abies procera Rehd, Picea abies (L.) H.Karst, and Picea pungens Engelm.) could contain useful secondary metabolites to produce sustainable packaging materials, e.g., by substitution of harmful petrol-based additives in plastic packaging. This study aims to characterise the antioxidant and light-absorbing properties and ingredients of different coniferous wood extracts with regard to different plant fragments and drying conditions. Furthermore, the valorisation of used Christmas trees is evaluated. Methods: Different drying and extraction techniques were applied with the extracts being characterised by determining the total phenolic content (TPC), total antioxidant capacity (TAC), and absorbance in the ultraviolet range (UV). Gas chromatography coupled with mass spectrometry (GC-MS) and an acid–butanol assay (ABA) were used to characterise the extract constituents. Results: All the extracts show a considerably high UV absorbance while interspecies differences did occur. All the fresh and some of the dried biomass extracts reached utilisable TAC and TPC values. A simplified extraction setup for industrial application is evaluated; comparable TAC results could be reached with modifications. Conclusion: Coniferous woods are a promising renewable resource for preparation of sustainable antioxidants and photostabilisers. This particularly applies to Christmas trees used for up to 12 days. After extraction, the biomass can be fully valorised by incorporation in paper packaging. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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18 pages, 19197 KiB  
Article
Discovering Low Toxicity Ionic Liquids for Saccharomyces cerevisiae by Using the Agar Well Diffusion Test
by Fatiha Missoun, Antonia Pérez de los Ríos, Víctor Ortiz-Martínez, María José Salar-García, Jesús Hernández-Fernández and Francisco José Hernández-Fernández
Processes 2020, 8(9), 1163; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8091163 - 16 Sep 2020
Cited by 18 | Viewed by 3190
Abstract
Ionic liquids (ILs) are new solvents widely used in many technologies due to their unique and advantageous physicochemical properties. In biotechnological applications, ILs can be used along with microorganisms such as Saccharomyces cerevisiae. Due to the enormous number of ILs that can [...] Read more.
Ionic liquids (ILs) are new solvents widely used in many technologies due to their unique and advantageous physicochemical properties. In biotechnological applications, ILs can be used along with microorganisms such as Saccharomyces cerevisiae. Due to the enormous number of ILs that can be synthesized through the combination of different anions and cations, it is necessary to have an easy and quick tool for the preliminary screening of their biocompatibility for being used in biotechnological applications. In this work, the agar well diffusion test was successfully applied as a rapid method to identify toxic/nontoxic ILs toward S. cerevisiae. Sixty-three ILs containing a diverse set of cations and anions were used. Through this methodology, nine fully biocompatible ILs toward S. cerevisiae were identified, including: [Bmim+] [NO3], [HOPmim+] [NO3], [Bmim+] [NTf2], [N8,8,8,1+] [NTf2], [S2,2,2+] [NTf2], [EMPyr+] [NTf2], [BMPi+] [NTf2], [Moxa+] [MeSO4] and [Chol+] [H2PO4]. The analysis of the results also provides preliminary rules to enable the design of biocompatible ILs with S. cerevisiae. In this context, the toxicity was mainly determined by the cation nature although some anions can also display a strong influence on the IL biocompatibility as the bistriflimide anion. Besides, it was observed that an increase in the alkyl chain length of cations, such as imidazolium or pyridinium, involves an increase in the IL toxicity. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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13 pages, 1944 KiB  
Article
Green Corrosion Inhibitors from Agri-Food Wastes: The Case of Punica granatum Extract and Its Constituent Ellagic Acid. A Validation Study
by Mirko Magni, Ester Postiglione, Stefania Marzorati, Luisella Verotta and Stefano P. Trasatti
Processes 2020, 8(3), 272; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8030272 - 27 Feb 2020
Cited by 13 | Viewed by 3172
Abstract
Giving a “new life” to wastes should be the golden rule for all production processes in the forthcoming future, aiming at making them more sustainable and environmentally friendly. In the corrosion science field, the ambitious circular economy paradigm has recently led to the [...] Read more.
Giving a “new life” to wastes should be the golden rule for all production processes in the forthcoming future, aiming at making them more sustainable and environmentally friendly. In the corrosion science field, the ambitious circular economy paradigm has recently led to the employment of extracts from plants (and, in less extent, from agri-food wastes) as green inhibitors against corrosion of metals. However, in spite of the number of scientific papers published in the field, a deep revision of the scientific approach is needed both in the execution of experiments and in the critical analysis of the results. Starting from some discrepancies in published data, the corrosion inhibition effect induced by a well-characterized methanolic extract from wastes of fermented Punica granatum and by its main component (ellagic acid, EA) was validated. The corrosion behaviour of Armco® pure iron in the presence of small concentrations of ellagic acid and extract (containing ca. 10 µM and 100 µM EA) was studied by combining results from mass loss tests, at free corrosion potential, and from polarization tests, by linearly sweeping the potential applied to the metal substrate. Experiments were carried out both in acidic medium (typical for a general corrosion phenomenon) and in near-neutral chloride bearing solution (characteristic of a localized pitting corrosion phenomenon). Neat conflicts with already published data have been identified first in the solubility of the inhibitor and then in the inhibition efficiency (around 40% in a 0.05 M HCl). The very limited solubility in aqueous environment was identified as the main drawback, hindering any possible exploitation of ellagic acid and pomegranate extract as promising green corrosion inhibitors. Results point to the necessity to establish clear and rigorous good laboratory practices to follow while reporting results on such complex matrices like vegetable extracts. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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15 pages, 2239 KiB  
Article
Kinetic Modelling of the Coproduction Process of Fumaric and Malic Acids by Rhizopus arrhizus NRRL 1526
by Victor Martin-Dominguez, Laura Bouzas-Santiso, Nieves Martinez-Peinado, Victoria E. Santos and Miguel Ladero
Processes 2020, 8(2), 188; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8020188 - 05 Feb 2020
Cited by 4 | Viewed by 2679
Abstract
The production of organic acids by biotechnological processes has experienced a notable impulse with the advent of first and second generation biorefineries and the need of searching for renewable and sustainable feedstock, such as biomass. Fumaric acid is a promising biomonomer for polyamide [...] Read more.
The production of organic acids by biotechnological processes has experienced a notable impulse with the advent of first and second generation biorefineries and the need of searching for renewable and sustainable feedstock, such as biomass. Fumaric acid is a promising biomonomer for polyamide production and a well-known acidulant and preservative in food and feed industries. Malic acid is a well-known food acidulant with a high market share. The biotechnological Fumaric and Malic acid production via fungi of the Rhizopus genus is being explored nowadays as a process for the valorization of food and food-related waste to obtain food ingredients and key platform chemicals of the so-called biochemical biorefinery. In this work, a preliminary study is performed to find reproducible conditions for the production of the acids by Rhizopus arrhizus NRRL 1526 by controlling fungi morphology and inoculum conditions. Afterwards, several production runs are performed to obtain biomass, glucose, and acid concentration data at different processing time values. Finally, an unstructured, unsegregated model including a logistic-type equation for biomass and potential-type equations for the substrate and the products is fitted to experimental data. We find that the production of the organic acids is mainly non-associated with fungal growth. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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13 pages, 2634 KiB  
Article
Environment-Friendly and Efficient Gaseous Insulator as a Potential Alternative to SF6
by Hafiz Shafqat Kharal, Muhammad Kamran, Rahmat Ullah, Muhammad Zaheer Saleem and Muhammad Junaid Alvi
Processes 2019, 7(10), 740; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7100740 - 14 Oct 2019
Cited by 9 | Viewed by 3259
Abstract
Sulfur hexafluoride (SF6) is commonly used in electrical insulation networks due to its superior dielectric properties. However, it possesses a high Global Warming Potential (GWP) of 22,800 times compared to CO2 (at equal mass over a time span of 100 [...] Read more.
Sulfur hexafluoride (SF6) is commonly used in electrical insulation networks due to its superior dielectric properties. However, it possesses a high Global Warming Potential (GWP) of 22,800 times compared to CO2 (at equal mass over a time span of 100 years) and a high atmospheric lifetime. This alarming metric prompted investigation for substitute gases with minor environmental influences. The overall objective of this research is to evaluate refrigerant R152a as a potential alternative for SF6 in electrical insulation systems. R152a gas has a significantly reduced value of GWP (140) and is a cheap insulation medium as compared to SF6. In this paper, dielectric breakdown testing of R152a and a mixture of CO2 with different concentrations have been tested. The dielectric strength of R152a/CO2 gas shows a saturated growth trend with increasing the gap difference, gas pressure and mixing ratio of R152a. Based on our experimental conditions, R152a/CO2 gas reveals good dielectric properties, and insulation performance can reach up to 96% of SF6. Finally, this work will bring a cost-effective and environment-friendly gaseous insulator for utility companies and power equipment manufacturers. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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16 pages, 2142 KiB  
Article
Valorization of Swine Manure into Hydrochars
by Zac Lentz, Praveen Kolar and John J. Classen
Processes 2019, 7(9), 560; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7090560 - 23 Aug 2019
Cited by 14 | Viewed by 3461
Abstract
There is a significant interest in valorizing swine manure that is produced in enormous quantities. Therefore, considering the high moisture content in swine manure, the objective of this research was to convert manure slurry into hydrochars via hydrothermal carbonization and analyze the yields, [...] Read more.
There is a significant interest in valorizing swine manure that is produced in enormous quantities. Therefore, considering the high moisture content in swine manure, the objective of this research was to convert manure slurry into hydrochars via hydrothermal carbonization and analyze the yields, pH, energy contents, and thermal and oxidation kinetic parameters. Experiments were performed in triplicate in 250 mL kettle reactors lined with polypropylene at 180 °C, 200 °C, 240 °C, 220 °C, and 260 °C for 24 h. Analyses of the results indicated that the process temperature affected the hydrochar yields, with yield generally decreasing with increasing temperature, but it had little effect on the composition of the hydrochar. The hydrochars were found to have higher volatile contents and H/C and O/C ratios and about 85% of the energy compared to coal. However, the presence of high fraction (35–38%) of ash in hydrochars is a serious concern and needs to be addressed before the complete utilization of hydrochars as fuels. The surface characterization of hydrochars coupled with wet chemistry experiments indicated that hydrochars were equipped with nitrogen functional groups with points of zero charges between 6.76 and 7.85, making them suitable as adsorbents and soil remediation agents and energy storage devices. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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11 pages, 5587 KiB  
Article
On the Selective Transport of Nutrients through Polymer Inclusion Membranes Based on Ionic Liquids
by Z. Baicha, M.J. Salar-García, V.M. Ortiz-Martínez, F.J. Hernández-Fernández, A.P. de los Ríos, D.P. Maqueda Marín, J.A. Collado, F. Tomás-Alonso and M. El Mahi
Processes 2019, 7(8), 544; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7080544 - 16 Aug 2019
Cited by 11 | Viewed by 3358
Abstract
In the last few years, the use of ionic liquid-based membranes has gained importance in a wide variety of separation processes due to the unique properties of ionic liquids. The aim of this work is to analyze the transport of nutrients through polymer [...] Read more.
In the last few years, the use of ionic liquid-based membranes has gained importance in a wide variety of separation processes due to the unique properties of ionic liquids. The aim of this work is to analyze the transport of nutrients through polymer inclusion membranes based on different concentrations of methyltrioctylammonium chloride, in order to broaden the application range of these kinds of membranes. Calcium chloride (CaCl2) and sodium hydrogen phosphate (Na2HPO4) nutrients were used at the concentration of 1 g·L−1 in the feeding phase. The evolution of the concentration in the receiving phase over time (168 h) was monitored and the experimental data fitted to a diffusion-solution transport model. The results show very low permeation values for CaCl2. By contrast, in the case of Na2HPO4 the permeation values were higher and increase as the amount of ionic liquid in the membrane also increases. The surface of the membranes was characterized before and after being used in the separation process by scanning electron microscopy coupled to energy dispersive X-Ray spectroscopy (SEM–EDX) and elemental mapping analysis. The SEM–EDX images show that the polymer inclusion membranes studied are stable to aqueous solution contacting phases and therefore, they might be used for the selective transport of nutrients in separation processes. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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14 pages, 1507 KiB  
Article
Determination of the Potential Impact of Domestic Anaerobic Digester Systems: A Community Based Research Initiative in Rural Bangladesh
by Khondokar M. Rahman, Lynsey Melville, David J. Edwards, David Fulford and Wellington Didibhuku Thwala
Processes 2019, 7(8), 512; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7080512 - 05 Aug 2019
Cited by 14 | Viewed by 3524
Abstract
This research examines the potential impact of domestic anaerobic digester (AD) systems adopted in Bangladesh and similar developing countries. Cattle dung and poultry litter feed stocks were specifically investigated, because these were freely available and plentiful to people living within agricultural areas of [...] Read more.
This research examines the potential impact of domestic anaerobic digester (AD) systems adopted in Bangladesh and similar developing countries. Cattle dung and poultry litter feed stocks were specifically investigated, because these were freely available and plentiful to people living within agricultural areas of rural Bangladesh. Data was collected to ascertain whether these two representative AD facility types provide tangible social, economic and environmental impact that benefits homeowners. Primary quantitative and qualitative data was obtained by field data collection, and meeting with expert groups and stakeholders. Empirical analysis conducted revealed that variations were found in the biomass feedstocks available on different sites but also differences were apparent in terms of the operations and maintenance (O and M) systems of the biogas plants operated. The biogas and methane yield variation was also measured, and variations were found in the cattle dung and poultry litter AD yield capacity. Overall, 64% of feedstock was utilised, 91% of biogas plants remain underfed and energy yield efficiency was 57% from cattle smallholdings’ AD and 28% from poultry farms’ AD. These results showed that small scale AD can offer a significant impact upon rural lifestyles through augmented economics, improved social activities, relationship building with neighbours and improved lifestyle achieved via time savings accrued. These results could help rural entrepreneurs, AD equipment providers and government institutions to develop a road map to implement future AD installation on a much wider geographical scale. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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19 pages, 5910 KiB  
Article
Natural Deep Eutectic Solvent-Assisted Pectin Extraction from Pomelo Peel Using Sonoreactor: Experimental Optimization Approach
by Amal A. M. Elgharbawy, Adeeb Hayyan, Maan Hayyan, Mohamed E. S. Mirghani, Hamzah Mohd. Salleh, Shahidah Nusailah Rashid, Gek Cheng Ngoh, Shan Qin Liew, Mohd Roslan Mohd Nor, Mohd Yakub Zulkifli bin Mohd Yusoff and Yatimah Alias
Processes 2019, 7(7), 416; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7070416 - 02 Jul 2019
Cited by 26 | Viewed by 9814
Abstract
Background: Natural deep eutectic solvents (NADESs) can be used for extracting a wide range of biomaterials, such as pectin. This study introduces a new generation of natural solvents for pectin extraction which could replace the conventional solvents in the food industry. Methods: In [...] Read more.
Background: Natural deep eutectic solvents (NADESs) can be used for extracting a wide range of biomaterials, such as pectin. This study introduces a new generation of natural solvents for pectin extraction which could replace the conventional solvents in the food industry. Methods: In this study, NADESs were used for pectin extraction from pomelo (Citrus grandis (L.) Osbeck) peels using a sonoreactor. Definitive screening design (DSD) was used to screen the influence of time, temperature, solid/liquid ratio, and NADES/water ratio on the pectin yield and degree of esterification (DE). Results: The primary screening revealed that the best choices for the extraction were choline chloride–malonic acid (ChCl-Mal) and choline chloride–glucose–water (ChCl:Glc:W). Both co-solvents yielded 94% pectin and 52% DE after optimization at 80 °C, with 60 min of sonication, pH < 3.0, and a NADES-to-water ratio of 1:4.5 (v/v). Morphological screening showed a smooth and compact surface of the pectin from ChCl-Mal where glucose-based pectin had a rough surface and lower DE. Conclusions: NADESs proved to be promising co-solvents for pectin extraction with a high degree of esterification (>55%). Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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12 pages, 2667 KiB  
Article
Kinetics of Arsenic Removal in Waste Acid by the Combination of CuSO4 and Zero-Valent Iron
by Yunhao Xi, Yongguang Luo, Jingtian Zou, Jing Li, Tianqi Liao, Libo Zhang, Chen Wang, Xiteng Li and Guo Lin
Processes 2019, 7(7), 401; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7070401 - 28 Jun 2019
Cited by 7 | Viewed by 2983
Abstract
In this study, we investigated the kinetics of arsenic removal from waste acid by the combination of zero-valent iron (ZVI) and CuSO4. ZVI samples were characterized by X-ray diffraction and scanning electron microscopy before and after arsenic removal; the results showed [...] Read more.
In this study, we investigated the kinetics of arsenic removal from waste acid by the combination of zero-valent iron (ZVI) and CuSO4. ZVI samples were characterized by X-ray diffraction and scanning electron microscopy before and after arsenic removal; the results showed that after the arsenic removal reaction, As2O3 and magnetite phases were detected on the surface of these samples. Kinetic studies were carried out under different reaction temperatures, with different CuSO4 concentrations, and with different iron to arsenic molar ratios (Fe/As). The kinetic data of the arsenic removal were fitted to different kinetic models. The fitting results showed that the arsenic removal process could be described by the shrinking core model, controlled by residual layer diffusion. The apparent activation energy of the reaction was 9.0628 kJ/mol, the reaction order with the CuSO4 concentrations was −0.12681, and the reaction order with the molar ratio of iron to arsenic (Fe/As) was 3.152. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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15 pages, 5996 KiB  
Article
Evaluation of the Methane Production Potential of Catfish Processing Wastewater Using Various Anaerobic Digestion Strategies
by Mark E. Zappi, Dhan Lord Fortela, Wayne Sharp, Rakesh Bajpai, Daniel Gang, William Holmes, Rafael Hernandez and Emmanuel D. Revellame
Processes 2019, 7(6), 368; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7060368 - 12 Jun 2019
Cited by 4 | Viewed by 4068
Abstract
The U.S. catfish industry is a major industry that has been declining over the years due to imports competition and growing operational costs. Catfish processing wastewater management and high energy requirement put a large financial burden on catfish processing facilities. Recovered protein-based solids [...] Read more.
The U.S. catfish industry is a major industry that has been declining over the years due to imports competition and growing operational costs. Catfish processing wastewater management and high energy requirement put a large financial burden on catfish processing facilities. Recovered protein-based solids have provided some value-added co-products, however, more co-products are needed to offset processing costs. Anaerobic digestion is a proven waste treatment method that produces methane, which is an energetic co-product that can be used within the processing facilities. This study was conducted to evaluate the potential of anaerobic digestion as an alternative to the currently used aerobic biotreatment of catfish processing wastewater. Initial assessments indicated the recalcitrance of the full-strength wastewater to anaerobic digestion, yielding only ~4 m3 per ton (U.S.) of input chemical oxygen demand (CODinput). Thus, several strategies were evaluated to improve the methane yield from the wastewater. These strategies include nutrient (nitrogen and sulfur) amendment, along with ozone, HCl, and NaOH pretreatment. The results showed that nutrient amendment was the most suitable strategy for improving the digestibility of the catfish processing wastewater. A methane yield of 121–236 m3/ton (U.S.) CODinput was obtained, with a purity of 67–80 vol.%. These results are similar to yields and purities of biogas from other feedstock, such as food waste, wastewater solids, and fish canning wastewater. This indicates that anaerobic digestion could be a viable alternative for simultaneous treatment and energetic co-product generation from catfish processing wastewater. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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16 pages, 1408 KiB  
Article
Prediction of CO2 Solubility in Ionic Liquids Based on Multi-Model Fusion Method
by Luyue Xia, Jiachen Wang, Shanshan Liu, Zhuo Li and Haitian Pan
Processes 2019, 7(5), 258; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7050258 - 03 May 2019
Cited by 11 | Viewed by 2847
Abstract
Reducing the emissions of greenhouse gas is a worldwide problem that needs to be solved urgently for sustainable development in the future. The solubility of CO2 in ionic liquids is one of the important basic data for capturing CO2. Considering [...] Read more.
Reducing the emissions of greenhouse gas is a worldwide problem that needs to be solved urgently for sustainable development in the future. The solubility of CO2 in ionic liquids is one of the important basic data for capturing CO2. Considering the disadvantages of experimental measurements, e.g., time-consuming and expensive, the complex parameters of mechanism modeling and the poor stability of single data-driven modeling, a multi-model fusion modeling method is proposed in order to predict the solubility of CO2 in ionic liquids. The multiple sub-models are built by the training set. The sub-models with better performance are selected through the validation set. Then, linear fusion models are established by minimizing the sum of squares of the error and information entropy method respectively. Finally, the performance of the fusion model is verified by the test set. The results showed that the prediction effect of the linear fusion models is better than that of the other three optimal sub-models. The prediction effect of the linear fusion model based on information entropy method is better than that of the least square error method. Through the research work, an effective and feasible modeling method is provided for accurately predicting the solubility of CO2 in ionic liquids. It can provide important basic conditions for evaluating and screening higher selective ionic liquids. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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10 pages, 1433 KiB  
Article
Characterization of the Primary Sludge from Pharmaceutical Industry Effluents and Final Disposition
by Renata Xavier Alberico Freitas, Lara Aguiar Borges, Handray Fernandes de Souza, Fernando Colen, Alex Sander Rodrigues Cangussu, Eliane Macedo Sobrinho, Francine Souza Alves Fonseca, Sérgio Henrique Sousa Santos, Bruna Mara Aparecida de Carvalho and Igor Viana Brandi
Processes 2019, 7(4), 231; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7040231 - 24 Apr 2019
Cited by 5 | Viewed by 4066
Abstract
The generation of large volumes of waste by industrial processes has become an object of study because of the necessity to characterize the composition of residues in order to suggest appropriate treatments and to minimize adverse environmental impacts. We performed analyses of total [...] Read more.
The generation of large volumes of waste by industrial processes has become an object of study because of the necessity to characterize the composition of residues in order to suggest appropriate treatments and to minimize adverse environmental impacts. We performed analyses of total fixed and volatile solids, moisture, and chemical oxygen demand (COD). We found high organic matter content. We also measured physicochemical characteristics, including corrosivity, reactivity, and toxicity. Sewage sludge showed levels of chloride and sodium above the maximum allowed limits. These data suggest the potential for anaerobic digestion as a treatment option for sewage sludge and for its use as a biofertilizer. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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14 pages, 2912 KiB  
Article
Life Cycle Assessment and Economic Analysis of an Innovative Biogas Membrane Reformer for Hydrogen Production
by Gioele Di Marcoberardino, Xun Liao, Arnaud Dauriat, Marco Binotti and Giampaolo Manzolini
Processes 2019, 7(2), 86; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7020086 - 08 Feb 2019
Cited by 25 | Viewed by 6262
Abstract
This work investigates the environmental and economic performances of a membrane reactor for hydrogen production from raw biogas. Potential benefits of the innovative technology are compared against reference hydrogen production processes based on steam (or autothermal) reforming, water gas shift reactors and a [...] Read more.
This work investigates the environmental and economic performances of a membrane reactor for hydrogen production from raw biogas. Potential benefits of the innovative technology are compared against reference hydrogen production processes based on steam (or autothermal) reforming, water gas shift reactors and a pressure swing adsorption unit. Both biogas produced by landfill and anaerobic digestion are considered to evaluate the impact of biogas composition. Starting from the thermodynamic results, the environmental analysis is carried out using environmental Life cycle assessment (LCA). Results show that the adoption of the membrane reactor increases the system efficiency by more than 20 percentage points with respect to the reference cases. LCA analysis shows that the innovative BIONICO system performs better than reference systems when biogas becomes a limiting factor for hydrogen production to satisfy market demand, as a higher biogas conversion efficiency can potentially substitute more hydrogen produced by fossil fuels (natural gas). However, when biogas is not a limiting factor for hydrogen production, the innovative system can perform either similar or worse than reference systems, as in this case impacts are largely dominated by grid electric energy demand and component use rather than conversion efficiency. Focusing on the economic results, hydrogen production cost shows lower value with respect to the reference cases (4 €/kgH2 vs 4.2 €/kgH2) at the same hydrogen delivery pressure of 20 bar. Between landfill and anaerobic digestion cases, the latter has the lower costs as a consequence of the higher methane content. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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Review

Jump to: Editorial, Research

23 pages, 3028 KiB  
Review
Theoretical and Experimental Approaches Aimed at Drug Design Targeting Neurodegenerative Diseases
by Samuel Morales-Navarro, Luis Prent-Peñaloza, Yeray A. Rodríguez Núñez, Laura Sánchez-Aros, Oscar Forero-Doria, Wendy González, Nuria E. Campilllo, Miguel Reyes-Parada, Ana Martínez and David Ramírez
Processes 2019, 7(12), 940; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7120940 - 10 Dec 2019
Cited by 7 | Viewed by 4541
Abstract
In recent years, green chemistry has been strengthening, showing how basic and applied sciences advance globally, protecting the environment and human health. A clear example of this evolution is the synergy that now exists between theoretical and computational methods to design new drugs [...] Read more.
In recent years, green chemistry has been strengthening, showing how basic and applied sciences advance globally, protecting the environment and human health. A clear example of this evolution is the synergy that now exists between theoretical and computational methods to design new drugs in the most efficient possible way, using the minimum of reagents and obtaining the maximum yield. The development of compounds with potential therapeutic activity against multiple targets associated with neurodegenerative diseases/disorders (NDD) such as Alzheimer’s disease is a hot topic in medical chemistry, where different scientists from various disciplines collaborate to find safe, active, and effective drugs. NDD are a public health problem, affecting mainly the population over 60 years old. To generate significant progress in the pharmacological treatment of NDD, it is necessary to employ different experimental strategies of green chemistry, medical chemistry, and molecular biology, coupled with computational and theoretical approaches such as molecular simulations and chemoinformatics, all framed in the rational drug design targeting NDD. Here, we review how green chemistry and computational approaches have been used to develop new compounds with the potential application against NDD, as well as the challenges and new directions of the drug development multidisciplinary process. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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26 pages, 4546 KiB  
Review
Flexible Energy Storage System—An Introductory Review of Textile-Based Flexible Supercapacitors
by Chi-yuen Hui, Chi-wai Kan, Chee-leung Mak and Kam-hong Chau
Processes 2019, 7(12), 922; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7120922 - 04 Dec 2019
Cited by 25 | Viewed by 5066
Abstract
Recently, researchers have become interested in exploring applications of rechargeable battery storage technology in different disciplines, which can help our daily life, such as textile-based supercapacitors. This paper briefly describes this development and classification of supercapacitors. Besides, various types of materials which are [...] Read more.
Recently, researchers have become interested in exploring applications of rechargeable battery storage technology in different disciplines, which can help our daily life, such as textile-based supercapacitors. This paper briefly describes this development and classification of supercapacitors. Besides, various types of materials which are commonly used to prepare supercapacitors, such as carbons, metal oxides, alkaline earth metal salts and polymers, are introduced. Moreover, applications and methodology to prepare textile materials with supercapacitors are described. Finally, the commonly used non-destructive measuring methods for textile-based supercapacitors are also introduced. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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34 pages, 1973 KiB  
Review
Nanoemulsions: Factory for Food, Pharmaceutical and Cosmetics
by Nor Azrini Nadiha Azmi, Amal A. M. Elgharbawy, Shiva Rezaei Motlagh, Nurhusna Samsudin and Hamzah Mohd. Salleh
Processes 2019, 7(9), 617; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7090617 - 11 Sep 2019
Cited by 123 | Viewed by 12516
Abstract
Nanotechnology, particularly nanoemulsions (NEs), have gained increasing interest from researchers throughout the years. The small-sized droplet with a high surface area makes NEs important in many industries. In this review article, the components, properties, formation, and applications are summarized. The advantages and disadvantages [...] Read more.
Nanotechnology, particularly nanoemulsions (NEs), have gained increasing interest from researchers throughout the years. The small-sized droplet with a high surface area makes NEs important in many industries. In this review article, the components, properties, formation, and applications are summarized. The advantages and disadvantages are also described in this article. The formation of the nanosized emulsion can be divided into two types: high and low energy methods. In high energy methods, high-pressure homogenization, microfluidization, and ultrasonic emulsification are described thoroughly. Spontaneous emulsification, phase inversion temperature (PIT), phase inversion composition (PIC), and the less known D-phase emulsification (DPE) methods are emphasized in low energy methods. The applications of NEs are described in three main areas which are food, cosmetics, and drug delivery. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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17 pages, 1716 KiB  
Review
Metabolic Engineering and Fermentation Process Strategies for L-Tryptophan Production by Escherichia coli
by Lina Liu, Muhammad Bilal, Hongzhen Luo, Yuping Zhao and Hafiz M. N. Iqbal
Processes 2019, 7(4), 213; https://0-doi-org.brum.beds.ac.uk/10.3390/pr7040213 - 12 Apr 2019
Cited by 17 | Viewed by 15653
Abstract
L-tryptophan is an essential aromatic amino acid that has been widely used in medicine, food, and animal feed. Microbial biosynthesis of L-tryptophan through metabolic engineering approaches represents a sustainable, cost-effective, and environmentally friendly route compared to chemical synthesis. In particular, metabolic pathway engineering [...] Read more.
L-tryptophan is an essential aromatic amino acid that has been widely used in medicine, food, and animal feed. Microbial biosynthesis of L-tryptophan through metabolic engineering approaches represents a sustainable, cost-effective, and environmentally friendly route compared to chemical synthesis. In particular, metabolic pathway engineering allows enhanced product titers by inactivating/blocking the competing pathways, increasing the intracellular level of essential precursors, and overexpressing rate-limiting enzymatic steps. Based on the route of the L-tryptophan biosynthesis pathway, this review presents a systematic and detailed summary of the contemporary metabolic engineering approaches employed for L-tryptophan production. In addition to the engineering of the L-tryptophan biosynthesis pathway, the metabolic engineering modification of carbon source uptake, by-product formation, key regulatory factors, and the polyhydroxybutyrate biosynthesis pathway in L-tryptophan biosynthesis are discussed. Moreover, fermentation bioprocess optimization strategies used for L-tryptophan overproduction are also delineated. Towards the end, the review is wrapped up with the concluding remarks, and future strategies are outlined for the development of a high L-tryptophan production strain. Full article
(This article belongs to the Special Issue Green Sustainable Chemical Processes)
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