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15 pages, 1568 KiB

Open AccessArticle

Greenness Assessment and Synthesis for the Bio-Based Production of the Solvent 2,2,5,5-Tetramethyloxolane (TMO)

by Fergal P. Byrne, James H. Clark, Carlo Angelici, Ed de Jong and Thomas J. Farmer

Sustain. Chem. 2021, 2(3), 392-406; https://doi.org/10.3390/suschem2030023 - 28 Jul 2021

Cited by 8 | Viewed by 4889

Abstract

2,2,5,5-tetramethyloxolane (TMO) has recently been identified and demonstrated as a safer solvent to replace toluene, THF, and hydrocarbons in a handful of applications. Herein, several bio-based routes to TMO are presented and assessed for greenness, assisted by the CHEM21 Metrics Toolkit and BioLogicTool [...] Read more.

2,2,5,5-tetramethyloxolane (TMO) has recently been identified and demonstrated as a safer solvent to replace toluene, THF, and hydrocarbons in a handful of applications. Herein, several bio-based routes to TMO are presented and assessed for greenness, assisted by the CHEM21 Metrics Toolkit and BioLogicTool plots. Using glucose as a common starting point, two chemocatalytic routes and two biochemical routes to TMO were identified and the pathways compared using the aforementioned tools. In addition, bio-based TMO was synthesised via one of these routes; from methyl levulinate supplied by Avantium, a by-product of the sugar dehydration step during the production of 2,5-furandicarboxylic acid. First, methyl levulinate underwent triple methylation using methyl magnesium chloride (MeMgCl) to yield 2,5-dimethylhexane-2,5-diol (DHL) in high yields of 89.7%. Then DHL was converted to high purity TMO (>98.5%) by cyclodehydration using H-BEA zeolites based on the previously reported approach. Bio-based content of this TMO was confirmed by ASTM D6866-20 Method B and found to have 64% bio-based carbon, well above the threshold of 25% set by CEN/TC 411 standards and matching the anticipated content. This study represents the first demonstration of a bio-based synthesis of TMO and confirmation of bio-content by accepted standards. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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16 pages, 3235 KiB

Open AccessArticle

Markedly Different Decomposition Temperature and Products of Biomass Pyrolysis at Low Temperature—Differentiation of Acids in Their Effects on Pretreatment

by Peifang Yan, Xiumei Liu, Zhanwei Xu and Zongchao Conrad Zhang

Sustain. Chem. 2021, 2(1), 8-23; https://doi.org/10.3390/suschem2010002 - 12 Jan 2021

Cited by 3 | Viewed by 2863

Abstract

Pine as a softwood and poplar as a hardwood pretreated with hydrochloric acid (HCl), phosphoric acid (H₃PO₄), and hypophosphorous acid (H₃PO₂) are studied for the pyrolytic properties and products in thermogravimetry (TG) and fixed bed [...] Read more.

Pine as a softwood and poplar as a hardwood pretreated with hydrochloric acid (HCl), phosphoric acid (H₃PO₄), and hypophosphorous acid (H₃PO₂) are studied for the pyrolytic properties and products in thermogravimetry (TG) and fixed bed reactor. The pyrolysis performances are pronouncedly distinguished due to the compositional and structural changes induced by the acid pretreatments. Reduction in the mineral content in the biomass feedstocks by pretreatment with the acids results in significant changes in the pyrolytic products. The residual P in the H₃PO₂-pretreated biomass apparently catalyzed the biomass deeper dehydration in pyrolysis compared to the other two mineral acids. TG analysis shows a shift of the temperature of maximum mass loss (T_max) by more than 40 °C to lower temperature in the decomposition of the H₃PO₂-pretreated biomass from that of the untreated and the HCl- and H₃PO₄-pretreated biomass. Inspired by the striking differences in TG profiles of biomass pretreated by the three acids, thermal pyrolysis of pretreated biomass was carried out in a fixed bed reactor aimed at producing biochemicals at low temperatures (330 °C and 400 °C). The liquid products obtained from the fixed bed reactor show remarkably different major anhydrosugars as a result of pretreatment by the three acids. While phenolics dominate in the collected pyrolysis liquid from untreated biomass samples, biomass pretreated with all three acids results in substantially reduced phenolics in the bio-oils. The reduction in phenolic compounds in the bio-oil may be attributed to the reduction in mineral content in the feedstock. Consequently, the yields of anhydrosugars, mainly levoglucosan (LG) and levoglucosenone (LGO) are increased. LG yields of 20.9–28.5% from the cellulose content are obtained from HCl- and H₃PO₄-pretreated pine/poplar, with very low LGO yield (less than 1.7%). However, H₃PO₂-pretreated biomass is selective to produce LGO, especially at 330 °C. LGO yields of 7.4% and 6.7% are obtained from H₃PO₂-pretreated pine and poplar, respectively. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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11 pages, 5146 KiB

Open AccessArticle

Enhancing the Oxygen Barrier Properties of Nanocellulose at High Humidity: Numerical and Experimental Assessment

by Ali H. Tayeb, Mehdi Tajvidi and Douglas Bousfield

Sustain. Chem. 2020, 1(3), 198-208; https://doi.org/10.3390/suschem1030014 - 24 Sep 2020

Cited by 19 | Viewed by 4501

Abstract

Films formed from cellulose nanofibrils (CNFs) are known to be good barrier materials against oxygen, but they lose this feature once placed in humid conditions. To tackle this issue, we applied an optimized pressing condition under elevated temperature to increase the films’ density [...] Read more.

Films formed from cellulose nanofibrils (CNFs) are known to be good barrier materials against oxygen, but they lose this feature once placed in humid conditions. To tackle this issue, we applied an optimized pressing condition under elevated temperature to increase the films’ density and improve their barrier performance. Furthermore, a water barrier coating was employed on the surfaces to control the moisture uptake at high relative humidity (RH). Neat self-standing films of CNF with the basis weight of 70 g/m² were made through a filtration technique and pressed for 1 hour at 130 °C. The resulting nanostructures were covered on both sides using a water-borne barrier layer. Hot-pressing resulted in a significant reduction in oxygen transmission rate (OTR) values, from 516.7 to 3.6 (cm³/(m²·day)) and to some degree, helped preserve the reduced oxygen transmission at high relative humidity. Introducing 35 g/m² of latex coating layer on both sides limited the films’ swelling at 90% RH for about 4 h and maintained the OTR at the same level. A finite element model was used to predict the dynamic uptake of water into the systems. The model was found to over-predict the rate of water uptake for uncoated samples but gave the correct order of magnitude results for samples that were coated. The obtained data confirmed the positive effect of hot-pressing combined with coating to produce a film with low oxygen transmission rate and potential to maintain its oxygen barrier feature at high relative humidity. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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20 pages, 3995 KiB

Open AccessArticle

Pt-Promoted Tungsten Carbide Nanostructures on Mesoporous Pinewood-Derived Activated Carbon for Catalytic Oxidation of Formaldehyde at Low Temperatures

by Qiangu Yan and Zhiyong Cai

Sustain. Chem. 2020, 1(2), 86-105; https://doi.org/10.3390/suschem1020008 - 7 Aug 2020

Cited by 2 | Viewed by 3244

Abstract

Tungsten carbide (WC) nanostructures were prepared by carbothermal reduction (CR) of tungsten-impregnated pinewood-derived activated carbon (AC) at 1000 °C under an inert atmosphere. Brunauer-Emmet-Teller (BET) surface area, pore structures of the AC, and catalyst samples were evaluated by N₂ adsorption-desorption experiments. The [...] Read more.

Tungsten carbide (WC) nanostructures were prepared by carbothermal reduction (CR) of tungsten-impregnated pinewood-derived activated carbon (AC) at 1000 °C under an inert atmosphere. Brunauer-Emmet-Teller (BET) surface area, pore structures of the AC, and catalyst samples were evaluated by N₂ adsorption-desorption experiments. The structures of the catalysts were characterized using X-ray powder diffraction (XRD). The morphologies and particle structures of the synthesized WC nanoparticles were investigated by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The WC/AC material was used as support of the platinum catalysts for catalytic oxidation of formaldehyde (HCHO) from interior sources. Pt-WC/AC catalysts with different platinum loadings were assessed for the catalytic oxidation of HCHO at low temperature. The catalytic performance was found to be significantly influenced by reaction temperature, initial formaldehyde concentration, relative humidity, and space velocity. The testing results demonstrated that HCHO can be totally oxidized by the 1 wt% Pt-WC/AC catalyst in the gas hourly space velocity (GHSV) = 50,000 h⁻¹ at 30 °C with a relative humidity (RH) of 40%. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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Review

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15 pages, 706 KiB

Open AccessReview

Lignocellulosic-Based Sorbents: A Review

by Kaana Asemave, Ligom Thaddeus and Philip T. Tarhemba

Sustain. Chem. 2021, 2(2), 271-285; https://doi.org/10.3390/suschem2020016 - 10 Apr 2021

Cited by 21 | Viewed by 5657

Abstract

The combustion of fossil fuels is intensifying global warming and destructing the ecosystem with negative human health impacts as well. Even so, other anthropogenic activities have unfortunately constituted pollution also to our environment, say, in the form of waste waters. Beside these, the [...] Read more.

The combustion of fossil fuels is intensifying global warming and destructing the ecosystem with negative human health impacts as well. Even so, other anthropogenic activities have unfortunately constituted pollution also to our environment, say, in the form of waste waters. Beside these, the existing technologies for waste water treatment have problems such as high costs, sludge disposal challenges, etc. Thus, it is now important to find economically viable and safe alternatives to decontaminate waste waters. Hence, low cost, renewable, easily accessible, and readily prepared biosorbents have become favourable alternatives to traditional counterpart for the elimination of pollutants from aqueous systems. Fortunately, these biosorbents also have requisite and comparable properties necessary for adsorption of pollutants. Many studies have been reported on the application of biosorbents for pollutants removal. However, this paper provides an overview of biosorbents preparation, properties, their applications in pollutants removal and related use. Biosorbents are usually used in raw or processed forms such as activated carbon (AC), biobar (BC), and charcoal (CC) for removal of pharmaceuticals, pesticides, organics, inorganics, mycotoxins, etc. from aqueous systems. Besides classical sorption of the pollutants, biosorbents have prospect of applications as electrodes in the microbial fuel cells, green packaging materials, energy storage devices, catalysts, soil remediation agent, carbon sequestration, etc. Hence, further concerted investigations should be exercised to develop feasibly best conditions for the preparations and modifications of biosorbents. In addition, mean pore size, pore size distribution, porosity, surface functionality, and zeta potential studies are necessary to be had about biosorbents, especially novel types. There is need for development of biosorbents for specific tasks. Another essential thing is to determine desorption studies of these novel biosorbents. Focus should also be directed on more economically viable and sustainable biosorbents to enhance their use. Again, it is suggested that more suitable biomasses be identified to enable successful preparation of efficient biosorbents. More so, biosorbents can be recycled after use to avoid littering and possible pollution. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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16 pages, 6924 KiB

Open AccessReview

Electrochemical Degradation of Lignin by ROS

by Haomin Jiang, Aiguo Xue, Zhaohui Wang, Ruyue Xia, Lei Wang, Yang Tang, Pingyu Wan and Yongmei Chen

Sustain. Chem. 2020, 1(3), 345-360; https://doi.org/10.3390/suschem1030023 - 12 Dec 2020

Cited by 15 | Viewed by 4898

Abstract

Lignin is a unique renewable aromatic resource in nature. In the past decades, researchers have attempted to breakdown the linkage bonds in lignin to provide aromatic platform chemicals that used to come from the petrochemical industry. In recent years, electrochemical lignin degradation under [...] Read more.

Lignin is a unique renewable aromatic resource in nature. In the past decades, researchers have attempted to breakdown the linkage bonds in lignin to provide aromatic platform chemicals that used to come from the petrochemical industry. In recent years, electrochemical lignin degradation under mild conditions has drawn much attention from the scientific community owing to its potential to scale up and its environmental friendliness. Sustainable electrochemical degradation of lignin consumes less energy and usually requires mild conditions, but low degradation efficiency and insufficient product selectivity are still significant challenges. The method for lignin degradation by reactive oxygen species (ROS) generated through the water oxidation reaction (WOR) at the anode and oxygen reduction reaction (ORR) at the cathode are more attractive for sustainable electrochemical degradation. The present contribution aims to review advancements in electrochemical degradation of lignin in aqueous or non-aqueous supporting electrolytes, focusing on the regulation of ROS in situ generated on the electrode. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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19 pages, 1648 KiB

Open AccessReview

A Review of Cottonseed Protein Chemistry and Non-Food Applications

by H. N. Cheng, Zhongqi He, Catrina Ford, Wade Wyckoff and Qinglin Wu

Sustain. Chem. 2020, 1(3), 256-274; https://doi.org/10.3390/suschem1030017 - 5 Oct 2020

Cited by 31 | Viewed by 6399

Abstract

There has been increasing interest in recent years in the use of agro-based raw materials for the production of bio-friendly and sustainable products. Plant-based proteins are among the popular materials being studied. In particular, cottonseed protein (a byproduct of cotton fiber production) is [...] Read more.

There has been increasing interest in recent years in the use of agro-based raw materials for the production of bio-friendly and sustainable products. Plant-based proteins are among the popular materials being studied. In particular, cottonseed protein (a byproduct of cotton fiber production) is widely available and has useful properties. Although not as well-known as soy protein, cottonseed protein has been shown to be a potentially valuable raw material for numerous applications. In this review, the latest developments in isolation, composition and molecular weight, chemical and enzymatic modifications, and non-food applications are delineated. Among these applications, films and coatings, interfacial and emulsifying applications, adhesives, and bioplastics seem to attract the most attention. A particular effort has been made to cover the literature on these topics in the past 10 years. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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Other

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10 pages, 4120 KiB

Open AccessTechnical Note

Three-Dimensional Imaging of Plant Cell Wall Deconstruction Using Fluorescence Confocal Microscopy

by Aya Zoghlami, Yassin Refahi, Christine Terryn and Gabriel Paës

Sustain. Chem. 2020, 1(2), 75-85; https://doi.org/10.3390/suschem1020007 - 30 Jul 2020

Cited by 1 | Viewed by 3323

Abstract

Lignocellulosic biomass (LB) is recalcitrant to enzymatic hydrolysis due to its compact and complex cell wall structure. To identify the parameters behind LB recalcitrance, experimental data over hydrolysis time must be collected. Here, we describe a novel method to collect time-lapse images during [...] Read more.

Lignocellulosic biomass (LB) is recalcitrant to enzymatic hydrolysis due to its compact and complex cell wall structure. To identify the parameters behind LB recalcitrance, experimental data over hydrolysis time must be collected. Here, we describe a novel method to collect time-lapse images during cell wall deconstruction by enzymatic hydrolysis. The protocol includes instructions for sample preparation, layout of a custom designed incubation chamber and instructions for confocal time lapse acquisition. The protocol sets out a detailed plan where cross-sections of untreated and pretreated poplar samples are mounted in a sealed frame containing a buffer and an enzymatic cocktail. The sealed frame is then placed into an incubator to maintain the sample at a constant temperature of 50 °C, which is optimal for enzymatic reaction while avoiding enzymatic cocktail evaporation. Using lignin natural autofluorescence, confocal z-stacks of untreated and pretreated samples were acquired at regular time intervals during enzymatic hydrolysis for 24 h. Acquisition parameters were optimized to compromise between image resolution and reduced photo-bleaching. The acquired image might then be processed by further development of algorithms to extract precise quantitative information on cell wall deconstruction. This protocol is an important first step towards elucidating the underlying parameters of LB recalcitrance by allowing the acquisition of high-quality images of LB hydrolysis for extracting quantitative data on LB deconstruction. Full article

(This article belongs to the Special Issue Chemicals and Materials from Lignocellulose: From Biomass to End Products)

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