Value-added Materials Research Articles

Biyokütlelerden Karbon Bazlı Nanomalzemelerin Sentezi Üzerine Kısa Bir Bakış

Biomass from agricultural waste offers an abundant, natural and affordable carbon source for the synthesis of value-added carbonaceous materials. The conversion of these agricultural wastes into nanoscale products relies on the development of environmentally friendly, affordable, simple and scalable new synthesis methods for commercial production of graphene-type nanomaterials. However, all agricultural waste acts as a carbonaceous product required for GO production. Based on this, in this study, new biomass materials and economical approaches were proposed to prepare GO. In addition, the advantages and disadvantages of graphene synthesis methods were discussed and green nanotechnology was examined. Some studies on the synthesis of carbon-based nanomaterials from biomass were examined and the place of graphene in health applications was investigated. How lignocellulosic biomass was converted into carbon-based nanomaterials was investigated and its mechanism was discussed.

Reusing Waste Coffee Grounds as Electrode Materials: Recent Advances and Future Opportunities.

Coffee industry produces more than eight million tons of waste coffee grounds (WCG) annually. These WCG contain caffeine, tannins, and polyphenols and can be of great environmental concern if not properly disposed of. On the other hand, components of WCG are mainly macromolecular cellulose and lignocellulose, which can be utilized as cheap carbon precursors. Accordingly, various forms of carbon materials have been reportedly synthesized from WCG, including activated carbon, mesoporous carbon, carbon nanosheets, carbon nanotubes, graphene sheet fibers (i.e., graphenated carbon nanotubes), and particle-like graphene. Upcycling of various biomass and/or waste into value-added functional materials is of growing significance to offer more sustainable solutions and enable circular economy. In this context, this review offers timely insight on the recent advances of WCG derived carbon as value-added electrode materials. As electrodes, they have shown to possess excellent electrochemical properties and found applications in capacitor/supercapacitor, batteries, electrochemical sensors, owing to their low cost, high electrical conductivity, polarization, and chemical stability. Collectively, these efforts could represent an environmentally friendly and circular economy approach, which could not only help solve the food waste issue, but also generate high performance carbon-based materials for many electrochemical applications.

Lignins and their potential for use as biopolymers in pharmaceutical engineering - a review

Nature offers a diverse set of renewable biopolymers, among them the variety of natural polyphenols, whose structural diversity provides opportunities for further manipulation like the generation of chemicals and novel functional materials. These land‑based renewable biomaterials exhibit also a wide range of heterogeneous intrinsic reactivities and activities that render them ideal starting oligomeric and polymeric materials for the generation of multifunctional supramolecular structures as well as the development of high value-added materials.
 Lignins in particular display a variety of common physico‑chemical features that can be of enormous interest with respect to their eventual use in the pharmaceutical area. These natural polyphenols possess some interesting pharmaceutical properties such as antioxidant, anti‑inflammatory, antibacterial and eventually antiviral activities. In addition, based on their chemical features, i.e., oligomers and/or polymers of monolignol C9-building blocks. lignins can be exploited in the pharmaceutical sector mainly as material for generation of matrices and carriers for drug delivery. The present work attempts a review of the state of the art in lignin use in pharmaceutical applications.
 
 Keywords
 biopolymers, lignins, microcapsules, nanoparticles, renewable resources

Characterization, Properties and Mixing Mechanism of Rubber Asphalt Colloid for Sustainable Infrastructure.

Rubber asphalt has always been considered to have the most potential for the disposal of waste tires as sustainable infrastructure. However, the covalently cross-linked tire rubber presents an extreme challenge in reusing waste rubbers in roads. Rubberized asphalt with finely dispersed or colloidal structure has been regarded as a potential binder used as road material because of the improved properties in terms of storage stability, easy processing and high content of incorporation. However, the mixing mechanism between the finely dispersed rubber on micro-nano scale with asphalt is still not clear, which restricts its further development as value-added material. Devulcanized rubber (DR) was introduced to improve the compatibility between asphalt and rubber. The basic chemicals of DR and asphalt were introduced based on their structures. Furthermore, the interactions between DR and asphalt were discussed according to the functional elements at different levels, and the concept of DR as “the fifth component” of asphalt was put forward. Finally, high performance, environmental and economic effects and applications of devulcanized-rubber-modified asphalt (DRMA) were discussed. The review is expected to provide a guide for the wide application of DRMA, which is still restricted by poor compatibility and bad stability during processing, storage and recycling.

Processing Poly (ethylene terephthalate) Waste into Functional Carbon Materials by Mechanochemical Extrusion

With the plastic pollution becoming worse, the upcycling of plastic waste into functional materials is a great challenge. Herein, a mechanochemical extrusion approach was developed for processing poly(ethylene terephthalate) (PET) waste into porous carbon materials. The essence of the cyclic extrusion approach lies in the solvent-free mixing of thermoplastic PET with pore-directing additive (e. g., silica or zinc chloride) at the molecular level. PET waste could be upcycled into functional carbon with high surface area (up to 1001 m2 g-1 ), specific shapes, and preferred mechanical strength, after cyclic extrusion and carbonization. Moreover, metal species could be well dispersed onto porous carbons through solvent-free extrusion, different from traditional loading methods (impregnation method, deposition-precipitation method). In this manner, mechanochemical extrusion provides an alternative for upcycling plastic waste into value-added materials.

A System Thinking Normative Approach towards Integrating the Environment into Value-Added Accounting—Paving the Way from Carbon to Environmental Neutrality

Life Cycle Assessment (LCA) is increasingly being applied in corporate accounting. Recently, especially carbon footprinting (CF) has been adopted as ‘LCA light’ in accordance with the Greenhouse Gas Protocol. According to the strategy ‘balance, reduce, substitute, compensate’, the approach is intended to provide the basis for optimization towards climate neutrality. However, two major problems arise: (1) due to the predominant focus on climate neutrality, other decisive life-cycle impact categories are often ignored, resulting in a misrecognition of potential trade-offs, and (2) LCA is not perceived as an equal method alongside cost and value-added accounting in everyday business, as it relies on a fundamentally different system understanding. In this paper, we present basic considerations for merging the business and life-cycle perspectives and introduce a novel accounting system that combines elements of traditional operational value-added accounting, process and material flow analysis as well as LCA. The method is based on an extended system thinking, a set of principles, a calculation system, and external cost factors for the impact categories climate change, stratospheric ozone depletion, air pollution, eutrophication and acidification. As a scientifically robust assessment method, the presented approach is intended to be applied in everyday operations in manufacturing companies, providing a foundation for a fundamental change in industrial thought patterns on the way to the total avoidance of negative environmental impacts (i.e., environmental neutrality). Therefore, this is validated in two application examples in the German special tools industry, proving its practicability and reproducibility as well as the suitability of specifically derived indicators for the selective optimization of production systems.

Preparation of Iron Salt-Modified Sludge Biochar and Its Uptake Behavior for Phosphate

Residual sludge is a significant waste resource, and the preparation of biochar achieves sludge disposal. Biochar has a high uptake capacity for phosphate. To prepare a sludge biochar adsorbent for phosphate, sludge was chemically and anaerobically treated in the presence of iron salts and pyrolyzed. We investigated the effects of the pyrolysis temperature and iron salt on the phosphate uptake capacity, finding that the pretreatment of the sludge with iron salts removed intrinsic phosphate, thus improving the uptake ability. The optimal adsorbent, denoted SB-B-Fe, was prepared by pyrolysis at 700 °C and subsequently modified with a 20 g/L iron-containing solution, yielding a phosphate uptake capacity of 0.5 mg/g. Further, the performance of SB-B-Fe remains high at pH 5–9 and is less affected by interfering anions. The sorption kinetics are consistent with the pseudo-second-order kinetic model, suggesting uptake by chemisorption, and the Langmuir model has a saturation capacity of 0.85 mg/g for uptake and prefers monolayer molecular uptake. The characterization showed that the adsorbent surface provided many uptake sites for phosphate and a high specific surface area. We hope that these findings will encourage the development of other value-added waste-based materials for environmental remediation.

Highly Efficient and para-Selective C-H Functionalization of Polystyrene Providing a Versatile Platform for Diverse Applications.

Postpolymerization modification of polystyrene (PS) can afford numerous value-added materials with different functions and applications, but it has been hampered by the lack of efficient methods. We report herein a highly efficient and para-selective conversion of the C-H bonds of the aromatic ring of PS into diverse functional groups using a combination of thianthrenation and thio-Suzuki-Miyaura coupling reaction. Notably, the thianthrenation efficiency of PS is as high as 99% and the degree of thianthrenation can be conveniently controlled using stoichiometric tuning of the amount of thianthrene-S-oxide added, resulting in 24-99 mol % thianthrenation. In the subsequent thio-Suzuki-Miyaura coupling reaction, 18 functionalized PS containing various functional groups (-CH2OH, -OMe, -SMe, -OTBS, -CH3, -NHBoc, -OCOMe, -CHO, -COMe, -Si(Me)3, etc.) were successfully prepared with a high degree of functionalization (64-99 mol %). The obtained functionalized PS can be readily converted into diverse functional materials, including solid-phase synthesis resins, aggregation-induced emission fluorophores, as well as ionomer binders and ion-exchange membranes for energy conversion devices. This method imparts diverse functionality onto PS with extremely high efficiency and selectivity, providing a versatile platform to transform existing commodity PS plastics into high-performance materials.

Recycled Multi-Material Packaging Reinforced with Flax Fibres: Thermal and Mechanical Behaviour.

In this work, the use of a recycled mix stemming from the treatment of multilayer aseptic packaging used in the food and beverage industry is proposed as the matrix for short fibre composites reinforced with flax fibres, to generate value-added materials in contrast to the more common end-of-life scenario including energy recovery. This is expected to be a preferred choice in the waste hierarchy at the European level. A commercially available material (EcoAllene) obtained from multilayer packaging recycling was compounded with short flax fibres up to 30 wt.% by twin screw extrusion, with a view to enhancing its poor mechanical profile and broadening its applications. Composites were in depth analyzed by thermogravimetric analysis and differential scanning calorimetry, which highlighted the complex nature of this recycled product, a limited nucleation ability of flax fibres and a lower thermal stability due to the premature degradation of natural hemicellulose and cellulose, though featuring in any case onset degradation temperatures higher than 300 °C. Composites’ mechanical properties were assessed in tension, bending and impact conditions, with remarkable improvements over the neat matrix in terms of stiffness and strength. In particular, at 30 wt.% fibre content and with 5 wt.% of maleated coupling agent, an increase in tensile and flexural strength values by 92% and 138% was achieved, respectively, without compromising the impact strength. The effectiveness of flax fibres confirmed by dynamo-mechanical analysis is beneficial to the exploitation of these composites in automotive interiors and outdoor decking applications.

Comprehensive Characterization of Mutant Pichia stipitis Co-Fermenting Cellobiose and Xylose through Genomic and Transcriptomic Analyses.

The development of a yeast strain capable of fermenting mixed sugars efficiently is crucial for producing biofuels and value-added materials from cellulosic biomass. Previously, a mutant Pichia stipitis YN14 strain capable of co-fermenting xylose and cellobiose was developed through evolutionary engineering of the wild-type P. stipitis CBS6054 strain, which was incapable of cofermenting xylose and cellobiose. In this study, through genomic and transcriptomic analyses, we sought to investigate the reasons for the improved sugar metabolic performance of the mutant YN14 strain in comparison with the parental CBS6054 strain. Unfortunately, comparative wholegenome sequencing (WGS) showed no mutation in any of the genes involved in the cellobiose metabolism between the two strains. However, comparative RNA sequencing (RNA-seq) revealed that the YN14 strain had 101.2 times and 5.9 times higher expression levels of HXT2.3 and BGL2 genes involved in cellobiose metabolism, and 6.9 times and 75.9 times lower expression levels of COX17 and SOD2.2 genes involved in respiration, respectively, compared with the CBS6054 strain. This may explain how the YN14 strain enhanced cellobiose metabolic performance and shifted the direction of cellobiose metabolic flux from respiration to fermentation in the presence of cellobiose compared with the CBS6054 strain.

Rice husk waste into various template-engineered mesoporous silica materials for different applications: A comprehensive review on recent developments

Following the discovery of Stöber silica, the realm of morphology-controlled mesoporous silica nanomaterials like MCM-41, SBA-15, and KCC-1 has been expanded. Due to their high BET surface area, tunable pores, easiness of functionalization, and excellent thermal and chemical stability, these materials take part a vital role in the advancement of techniques and technologies for tackling the world's largest challenges in the area of water and the environment, energy storage, and biotechnology. Synthesizing these materials with excellent physicochemical properties from cost-efficient biomass wastes is a foremost model of sustainability. Particularly, SiO2 with a purity >98% can be obtained from rice husk (RH), one of the most abundant biomass wastes, and can be template engineered into various forms of mesoporous silica materials in an economic and eco-friendly way. Hence, this review initially gives insight into why to valorize RH into value-added silica materials. Then the thermal, chemical, hydrothermal, and biological methods of high-quality silica extraction from RH and the principles of synthesis of mesoporous and fibrous mesoporous silica materials like SBA-15, MCM-41, MSNs, and KCC-1 are comprehensively discussed. The potential applications of rice husk-derived mesoporous silica materials in catalysis, drug delivery, energy, adsorption, and environmental remediation are explored. Finally, the conclusion and the future outlook are briefly highlighted.

Conversion of Sugarcane Trash to Nanocrystalline Cellulose and its Life Cycle Assessment

Sugarcane trash (SCT) is a promising, underutilized raw material for producing value-added bio-based materials. Nanocrystalline cellulose (NCC) production conditions were obtained from the experiment. On the other hand, bioethanol production conditions were retrieved from the secondary data. This study compared the environmental impact of SCT in NCC production to that of bioethanol. For NCC production, SCT was subjected to organosolv pretreatment (140, 160, or 180 °C) in a mixed solvent system (methyl isobutyl ketone (MIBK), ethanol, and water), bleached, and then hydrolyzed with different concentrations of sulfuric acid (50 and 58%) for varying times. Organosolv pretreatment at 180 °C removed 98.24 and 81.15% of the hemicellulose and lignin, respectively, resulting in 73.51 and 79.72% cellulose purity and recovery. In addition, bleaching increased the cellulose purity to 95.42%. Field Emission Transmission Electron Microscopy (FE-TEM) analysis showed that NCC’s small 2:1 elliptical particles were found at the hydrolysis of 50% H2SO4 for 45 min. The X-ray diffraction (XRD) pattern revealed 70% crystalline index values for NCC obtained from 50% H2SO4 with 45 min retention times. Then, the optimum conditions of NCC production were used for LCA analysis (Sigmapro software). The analysis included global warming, marine ecotoxicity, fresh water, and human carcinogenic toxicity. NCC production’s electricity consumption (freeze-dried step) was the highest environmental impact on LCA analysis.

Development of a Prediction Method of Cell Density in Autotrophic/Heterotrophic Microorganism Mixtures by Machine Learning Using Absorbance Spectrum Data.

Microflora is actively used to produce value-added materials in industry, and each cell density should be controlled for stable microflora use. In this study, a simple system evaluating the cell density was constructed with artificial intelligence (AI) using the absorbance spectra data of microflora. To set up the system, the prediction system for cell density based on machine learning was constructed using the spectra data as the feature from the mixture of Saccharomyces cerevisiae and Chlamydomonas reinhardtii. As the results of predicting cell density by extremely randomized trees, when the cell densities of S. cerevisiae and C. reinhardtii were shifted and fixed, the coefficient of determination (R2) was 0.8495; on the other hand, when the cell densities of S. cerevisiae and C. reinhardtii were fixed and shifted, the R2 was 0.9232. To explain the prediction system, the randomized trees regressor of the decision tree-based ensemble learning method as the machine learning algorithm and Shapley additive explanations (SHAPs) as the explainable AI (XAI) to interpret the features contributing to the prediction results were used. As a result of the SHAP analyses, not only the optical density, but also the absorbance of the Soret and Q bands derived from the chloroplasts of C. reinhardtii could contribute to the prediction as the features. The simple cell density evaluating system could have an industrial impact.

A Review - Studies on Jute Properties, Characteristics and Application in Textile Industry

Jute plant fibres made up of cellulose and lignin. Jute is an appealing and versatile fibre with a pleasing appearance. Because of its biodegradability, the Golden Fiber has grown in popularity all over the world. It is a natural vegetable fibre that blends with soil and does not produce toxic fumes or residue when burned. Jute fibre is now widely used in both industry and the production of various value-added materials for domestic use. The main issue in the jute industry today is producing high-quality fibre. This fibre is increasingly being used in the production of diverse and value-added products such as upholstery, furnishing, decorative, and secondary apparel. In this paper deals with jute fibre and fabric properties , characteristics and different applications .

(Invited, Digital Presentation) From Textile Waste to Cellulose Aerogel Beads Using Ionic Liquid

A huge amount of waste textile is produced every year, and the majority is either burned, or buried in landfills, or downcycled. We propose making high added-value materials, aerogels, from textile waste, using ionic liquids. Aerogels are light-weight and nanostructured porous materials with high specific surface area. Depending on the type of textile, we use ionic liquid either to completely dissolve it (case of rayon or viscose), or to selectively dissolve cellulose (case of polycotton). Cellulose aerogels were made in the form of beads by prilling via dissolution in ionic liquid, coagulation and drying with supercritical CO2. Reference cellulose aerogel beads were made from microcrystalline cellulose to compare with textile-based aerogels.The rheological properties of cellulose-ionic liquid solutions were studied to select the processing conditions. Aerogel beads of the size from 0.5 to 1.5 mm with excellent circularity were obtained. Cellulose-based aerogel beads from textile and from microcrystalline cellulose have density around 0.1 g/cm3, porosity around 90% and high specific surface area, around 300 m²/g. Cytotoxicity tests showed that these aerogels may potentially be used for life science applications.AcknowledgementsWe are grateful to Institut Carnot MINES for the financial support of this work, Julien Jaxel (PERSEE) for the drying with supercritical CO2, Antoine Perron (GALA – RAPSODEE) for the prilling and Suzanne Jacomet (CEMEF) for the help in SEM pictures.

Opportunities in valorisation of industrial food waste into extruded snack products – A review

Fruit and vegetable by-product production produces a large amount of waste material, which poses a significantdisposal issue for the food industry and can have harmful effect on the environment, if left unused. This waste includes nutrients like dietary fibre, vitamins and minerals, as well as bioactive like flavonoids and lycopene. The functional and nutritional characteristics of by-products of fruit and vegetable processing, as well as their possible utilization in food extrusion technology as noble ingredients for enhancing the nutritional value in snack foods are the subject of this study. This review also proposes a method for producing a less expensive value-added ingredient, which reduces the current methods of disposing of these waste (that can have a negative impact on the environment) but still saving money for the manufacturer. The potential and opportunity for fruit and vegetable by-products incorporation in extruded snack products, thereby enriching the fibre and other nutritional components of the snack, is reflected in this paper. Ingredient industries are constantly searching for cheaper but value-added raw materials. So, this review will also enhance the horizon for not only the food industries but also encourage micro food entrepreneurs, the Self Help Groups and certain other domestic food enterprises in terms of the utility of the food waste, the methods of development and value added aspects as a whole.

Insights into synergistic utilization of residual of ternary layered double hydroxide after oxytetracycline as a potential catalyst for methanol electrooxidation

Oxytetracycline (OTC) is one of the most important antibiotic drugs and it is most commonly used to treat bacterial infections in livestock. In this study, the principal purpose is to define the adsorption mechanisms of removing pharmaceutical pollutant (OTC) on a fabricated catalyst Zn/Co/Fe LDH. For adsorption process, the influence of the adsorbent dose, initial concentration, initial pH and contact time was studied and investigated. Several models of kinetic and isotherm are carried out at pH= 5. The removal percentage of OTC was 100% by Zn/Co/Fe LDH. The maximum adsorption capacity for OTC is 240.29 mg/g. Possible adsorption mechanisms for OTC on the Zn/Co/Fe LDH (001, 010, and 100) surfaces were explored by Monte Carlo simulation. The influence of the waste material was used as active catalyst for supporting the methanol oxidation in fuel cell with high stability in basic medium (KOH). The proposed approach opens up the new avenue for recycling the wastes after adsorption into value-added materials for utilizing in energy production with excellent electrocatalytic performance.

From pollution to wealth: Soot-graphene hybrid structure as supercapacitor electrode for high-performance alternating current filtering

Efficiently employing air pollution substances as functional materials cannot only realize recycling environmental wastes into wealth, but also alleviate the air pollution and respiratory disease problems. Herein, we report a soot-graphene hybrid structure as supercapacitor electrode materials for achieving good alternating current (AC) filtering performances. Soot particles, which cause environmental pollution, can be readily renewable from daily combustion wastes with abundant natural resources, enabling fast electrolyte-ion migration on their surface. Graphene can be grown from either methane or renewable peanut oil to reduce interfacial resistance between soot and current collector, assisting in making the most of structural advantages of soot. The synergistic effect offers supercapacitor with good frequency-response ability and AC filtering performances in both aqueous and organic electrolytes: high impedance phase angle of −80.7° and high energy density of 509 μF V2 cm−2 at 120 Hz, short RC time constant of 0.213 ms, excellent electrochemical stability, as well as a good ability for filtering AC signals with different waveforms into direct current signals. This study offers a sustainable strategy to recycle environmental pollution into value-added electrode materials for high-performance AC filtering supercapacitors, which displays promising potential in eco-friendly and cost-effective development of small-volume AC filters for miniaturized electronics.

Development of sustainable biocomposite panels assisted with deep eutectic solvent pretreatment of agro-industrial residue

The pretreatment of lignocellulosic biomass in biorefineries is a very promising path for their conversion into value-added products. However, development of sustainable pretreatment for efficient conversion of lignocellulosic biomass into value-added materials is still an emergent and challenging field. Herein, a new direction for the utilization of deep eutectic solvent (DES) pretreatment of lignocellulosic biomass in the fabrication of compression-molded biocomposite panels was studied. The impact of untreated and DES-treated fibers of three types of lignocellulosic waste—corn stover (CS), peanut shell powder (PSP), and sugarcane bagasse (SCB)—on the properties of biocomposite panels using urea–formaldehyde binder was investigated. Cellulose-rich fiber (CRF) was extracted by pretreating lignocellulosic materials with choline chloride and glycerol-based synthesized DES under mild operating conditions, and high solids loading and mechanical and water absorption properties of the biocomposite board prepared from untreated and DES-treated fibers were measured. The effect of DES pretreatment on the properties of lignocellulosic fibers was evaluated using Fourier transform infrared spectroscopy (FTIR), lignocellulosic compositional analysis (LCA), thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). These analyses revealed that cellulosic content and thermal stability of all DES-treated fibers improved compared to untreated samples. The biocomposite board made from DES-treated fibers had higher strength and modulus than the untreated composite board, as determined by the three-point bending test. Specifically, the modulus of rupture (MOR) and modulus of elasticity (MOE) of SCB biocomposite panels increased from 26.15 MPa and 1564.65 MPa to 31.28 MPa and 1871.74 MPa in DES-treated panels, respectively. These findings suggest that the novel DES-based pretreatment could be a promising sustainable processing strategy for converting agro-industrial waste into CRF to fabricate wood-composite panels with a wide range of furniture and construction applications.

Direct conversion of methane to zeolite-templated carbons, light hydrocarbons, and hydrogen

Efficient direct valorization of methane to value-added chemicals and materials remains an unsolved challenge for modern chemistry and materials science. In this work, we explored direct non-oxidative conversion of methane to hydrogen, hydrocarbons, and valuable zeolite-templated carbon materials. First, using a set of spectroscopy and microscopy characterization tools, we investigated how the reaction conditions influence the process of carbon formation inside the typical zeolite-based catalyst Mo/ZSM-5. Then, we explored the effect of the zeolite topology on the growth of carbon materials from methane decomposition over Mo/MFI, Mo/MOR, Mo/BEA, and Mo/FAU templates. Finally, we applied the obtained insights to prepare high-quality zeolite-templated carbons directly from methane using Fe/BEA and Fe/FAU templates. Altogether, our results represent a carbon-economic method of methane conversion to COx-free hydrogen gas, a mixture of light aliphatic and aromatic hydrocarbons, and valuable carbon materials.