Low-cost Renewable Resources Research Articles

Current status and future prospects of pretreatment for tobacco stalk lignocellulose.

With the growing demand for sustainable development, tobacco stalks, as a resource-rich and low-cost renewable resource, hold the potential for producing high-value chemicals and materials within a circular economy. Due to the complex and unique structure of tobacco stalk biomass, traditional methods are ineffective in its utilization, making the pretreatment of tobacco stalk lignocellulose a crucial step in obtaining high-value products. This paper reviews recent advancements in various pretreatment technologies for tobacco stalk lignocellulosic biomass, including hydrothermal, steam explosion, acid, alkaline, organic solvent, ionic liquid, and deep eutectic solvent pretreatment. It emphasizes the impact and efficiency of these pretreatment methods on the conversion of tobacco stalk biomass and discusses the advantages and disadvantages of each technique. Finally, the paper forecasts future research directions in the pretreatment of tobacco stalk lignocellulose, providing new insights and methods for enhancing its efficient utilization.

Synthesis, characterization, and antimicrobial activities of a starch-based polymer

Due to the rise of nosocomial infections and the increasing threat of antibiotic resistance, new techniques are required to combat bacteria and fungi. Functional antimicrobial biodegradable materials developed from low-cost renewable resources like polysaccharides would enable greater applications in this regard. Our group has developed and characterized a new antimicrobial polymer using commercially available N-ethyl piperazine and starch via simple one-pot method. The prepared antimicrobial polymer was characterized by FTIR and NMR. In addition, the thermal properties of the synthesized antimicrobial polymer were examined through TGA and DSC. The antimicrobial potential of the prepared material was investigated using the bacteria, Staphylococcus aureus, Escherichia coli, and Mycobacterium smegmatis and a fungi Candida albicans. The result indicates that, as the amount of polymer increases, the antimicrobial activity also increases. SA-E-NPz exhibited a zone of inhibition in the range of 8–13 mm, and the MIC was found to be < 0.625 mg against all four microbes. The antimicrobial activity of polymer coated on fabric was also studied. Furthermore, the cytotoxicity studied against human fibroblast cell lines showed that the prepared polymer is non-toxic to the cells. The study concluded that the synthesized polymer shows good antimicrobial activity, is non-toxic to human fibroblast cells, and thus can be used for wound dressing or textile applications.

Decision Support Tool for Electric Power Generation Development: A Feasibility Analysis for a Nigerian Case

Electricity is a crucial component of sustainable development in developing countries, providing opportunities to supply low-cost clean energy to their populations. This paper presents a decision support tool for the Nigerian case, allowing users to rank different enhancement options to meet future scenarios. The tool enables feasibility checks on infrastructure capacity and can handle various generation options, including low-cost renewable resources. It is easy to use for non-experts and decision-makers and incorporates an optimal power flow algorithm to minimize costs. Demonstrated on a modified IEEE 30-bus system informed by Nigerian scenarios, this tool can provide policymakers with valuable insights for long-term investment decisions and facilitate the delivery of low-cost clean energy to developing countries.

The Use of Black Pine Bark for Improving the Properties of Wood Pellets

The requirement for alternative raw materials for fuel pellets that would enable the use of readily available low-cost renewable resources and waste materials, such as bark, has always attracted interest. The aim of the current work was to assess the effect of black pine (Pinus nigra L.) bark content (0%–100%) as well as densification temperature on the properties of black pine wood pellets produced in a single pellet die. The quality assessment of the pellets was carried out by the determination of radial compression strength, density, moisture content, ash content, and surface roughness. The results showed that adding black pine bark to the pellet feedstock resulted in the production of substantially smoother and moderately denser pellets, which also exhibited higher mechanical strength than that of the respective pellets of pure wood. Finally, it was shown that black pine bark can be a valuable raw material, which can induce improved bonding of biomass particles and may provide the opportunity to create pellets of favorable characteristics at a lower temperature compared to those made of pure wood.

Degradation of switchgrass by Bacillus subtilis 1AJ3 and expression of a beta-glycoside hydrolase.

Increasing demand for carbon neutrality has led to the development of new techniques and modes of low carbon production. The utilization of microbiology to convert low-cost renewable resources into more valuable chemicals is particularly important. Here, we investigated the ability of a cellulolytic bacterium, Bacillus subtilis 1AJ3, in switchgrass lignocellulose degradation. After 5 days of culture with the strain under 37°C, cellulose, xylan, and acid-insoluble lignin degradation rates were 16.13, 14.24, and 13.91%, respectively. Gas chromatography–mass spectrometry (GC-MS) analysis and field emission scanning electron microscopy (FE-SEM) indicated that the lignin and surface of switchgrass were degraded after incubation with the bacterial strain. Strain 1AJ3 can grow well below 60°C, which satisfies the optimum temperature (50°C) condition of most cellulases; subsequent results emphasize that acid-heat incubation conditions increase the reducing sugar content in a wide range of cellulosic biomass degraded by B. subtilis 1AJ3. To obtain more reducing sugars, we focused on β-glycoside hydrolase, which plays an important role in last steps of cellulose degradation to oligosaccharides. A β-glycoside hydrolase (Bgl-16A) was characterized by cloning and expression in Escherichia coli BL21 and further determined to belong to glycoside hydrolase (GH) 16 family. The Bgl-16A had an enzymatic activity of 365.29 ± 10.43 U/mg, and the enzyme’s mode of action was explained by molecular docking. Moreover, the critical influence on temperature (50°C) of Bgl-16A also explained the high-efficiency degradation of biomass by strain under acid-heat conditions. In terms of potential applications, both the strain and the recombinant enzyme showed that coffee grounds would be a suitable and valuable substrate. This study provides a new understanding of cellulose degradation by B. subtilis 1AJ3 that both the enzyme action mode and optimum temperature limitation by cellulases could impact the degradation. It also gave new sight to unique advantage utilization in the industrial production of green manufacturing.

Gelatin-tannic acid coating for high flux oil-water separation

Special wettability material with super-hydrophilicity/underwater super-oleophobicity is one of the best materials for treating oily wastewater, developing an urgent demand for simple, green, low cost, and efficient in practical application. Both gelatin and tannic acid are natural and low-cost renewable resources. In this study, gelatin-tannic acid coating(FOGE-TA) that can be applied to different substrates was prepared by a simple and green dip-coating method using the film-forming properties of gelatin as well as the hydrophobic interactions and hydrogen-bonding interaction between gelatin and tannic acid. The coating can be applied to different substrates such as glass, PP melt-blown nonwoven fabric, copper mesh, and stainless steel mesh. After dipping FOGE-TA, the underwater oil contact angle of the mesh surface all reach over 150 °, and the water contact angle is 0 °. Among them, the prepared gelatin-tannic acid-coated stainless steel mesh(FOGE-TA-4 L-SSM) has a high water flux of over 1.74 × 105 L∙m-2∙h-1 and separation efficiency of over 99.0% for oil/water separation. Due to its excellent oil repellency only needs to be soaked and rinsed with deionized water when the flux decays to continue the oil-water separation. After 90 separations, the water flux and separation efficiency did not significantly decrease. In addition, the FOGE-TA-SSM has good stability in salt solutions and an acidic environment, making it an ideal material for solving oil-water separation problems.

Developing flame-retardant lignocellulosic nanofibrils through reactive deep eutectic solvent treatment for thermal insulation

The global consensus to pivot to a more sustainable lifestyle and achieve greater atom economy calls for not only sourcing advanced functional materials from biomass but also accomplishing high feedstock utilization with green and low-toxic reagents; yet, the multi-constituent nature of biomass with complex hierarchical structure makes this target difficult to meet. This study focused on the high-yield conversion of low-cost, coarsely pretreated biomass via reactive deep eutectic solvent (DES) pretreatment into lignocellulosic nanofibrils (LCNF) with high aspect ratio (up to ∼ 103) and high sulfate ammonium functionalization (up to 3.53 mmol/g). The aqueous suspension of LCNF exhibited high viscosity and superb colloidal stability. Such LCNF can be directly processed into highly porous aerogel with low apparent density, good mechanical properties, satisfactory thermal insulating performance (κ ranged 31.0–31.6 mW/m∙K) that is comparable to commercial petrochemical-based insulators. Moreover, the surface sulfate ammonium functionalized during DES pretreatment endowed LCNF with intrinsic flame retardancy and self-extinguishing property. Taken together, a facile valorization strategy is developed to convert low-cost renewable resources into functionalized nanofibrils at a high yield, which serve as an intrinsically flame-retardant platform material for thermal insulation applications.

Evaluation of the mechanical properties of biolaminates prepared by different manufacturing techniques

Laminates are composite materials of thermoset matrix reinforced with long fibers. Natural fibers are a low-cost renewable resource, have a low density (which gives them a high specific resistance), are not irritating or toxic, have no abrasive effects such as glass fibers, and are completely biodegradable. However, natural fibers have certain disadvantages with respect to synthetic fibers, such as their low decomposition temperature and their high hydrophilicity. There are numerous lamination manufacturing techniques: infusion, resin transfer and autoclave. The autoclave provides an improvement in the mechanical properties of the laminates due to the control of the manufacturing parameters. However, this technique is very expensive, so not all industrial sectors can access it. Knowing the mechanical performance of biolaminates prepared from different manufacturing techniques will open a window of alternate possibilities to the use of an autoclave, which includes the development of nanoreinforced biolaminates.

Analysis of the Manufacturing Variables of Binderless Panels Made of Leaves of Olive Tree (Olea europaea L.) Pruning Waste

While the construction industry consumes more raw materials than any other industrial sector, agriculture generates a large amount of waste that is not managed properly. The olive industry produces more than 7.5 million tons of waste that could be recovered. This paper presents a new method to valorize the leaves of olive tree pruning waste consisting of the manufacture of ecologic boards without adhesives by hot pressing. In order to analyze their influence, three manufacturing variables were varied to obtain the boards: leaf type (shredded and whole leaves), temperature (130, 140 and 150 °C) and time (4, and 12 min). Twenty-four boards were made and were then tested for their mechanical, physical and thermal properties according to the EN standards. The boards showed good results of thickness swelling (TS), water absorption (WA) and of thermal conductivity and can be used as an alternative for manufacturing thermal insulation boards. With a smaller particle size of shredded leaves, longer pressing times and higher pressing temperatures, the mechanical behavior of the boards could improve. The olive leaves are a low-cost renewable resource, and manufacturing products with a long, useful life can be beneficial to the environment.

Electrochemical Properties of Biobased Carbon Aerogels Decorated with Graphene Dots Synthesized from Biochar

Carbon aerogels prepared from low-cost renewable resources are promising electrode materials for future energy storage applications. However, their electrochemical properties must be significantly improved to match the commercially used high-carbon petroleum products. This paper presents a facile method for the green synthesis of carbon aerogels (CAs) from lignocellulosic materials and graphene dots (GDs) from commercially available biochar. The produced carbon aerogels exhibited a hierarchical porous structure, which facilitates energy storage by forming an electrical double-layer capacitance. Surprisingly, the electrochemical analyses of the GD-doped carbon aerogels revealed that in comparison to pristine carbon aerogels, the surface doping of GDs enhanced the electrochemical performance of carbon aerogels, which can be attributed to the combined effect from both double-layer capacitance and pseudocapacitance. Herein, we designed and demonstrated the efficacy of a supercapacitor device using our green carbon electrode as a sustainable option. These green carbon aerogels have opened a window for their practical use in designing sustainable energy storage devices.

Treatment methods for plant fibers for use as reinforcement in cement-based materials

The use of natural fibers in cement-based building materials has become an emerging field in the building and construction industry. Natural plant fibers are green, sustainable, and low-cost renewable resources that can be found in all parts of the world. Besides their biodegradability, studies have also established that the natural fibers also positively impacted the mechanical properties of the resulting composites. However, their utilization has also presented some challenges due to their high-water absorption, limited tensile strength, and open surface morphology that is exposed to cement hydration products and microbial degradation. Also, the fiber-cement matrix bonding and adhesion is another challenge limiting natural fiber utilization. Successful research on these challenges has been conducted and improvements were observed for the fiber-matrix adhesion and durability. Thus, herein we critically review the articles, discuss the science behind the treatment methods and suggest some intriguing issues for further investigation.

Fast-Curing Mussel-Inspired Adhesive Derived from Vegetable Oil.

The development of functional materials based on renewable resources is of great significance in today's resource shortage. Here, we present an effective way to synthesize a mussel-inspired adhesive from acrylated epoxidized soybean oil (AESO), a renewable and commercially available small molecular material with a molecular weight around 1200 Da, by a one-step esterification reaction with the affordable 3,4-dihydroxybenzoic acid (DHA). By taking advantages of both the double bond and the catechol moiety presented in this small molecular adhesive, a short curing time was achieved with UV irradiation. An average bonding strength around 1.4 MPa at a curing time of only around 10 min on a glass substrate was observed, which reached 3.1 MPa (average 2.8 MPa) at a curing time of 2 h under ambient conditions. The curing time is much shorter, and the bonding strength is obviously stronger than the conditions where conventional oxidation agents such as IO4- or oxidation/coordination agents such as Fe3+ are used as the curing agent. Furthermore, the AESO-g-DHA can be used as an underwater adhesive, and an appreciable bonding strength up to 0.64 MPa was observed, which is superior than most of currently known commercialized glues. Given that the adhesive could be synthesized from low-cost renewable resources in one step, it might be a potential candidate for large-scale practical application.

Planning for low-cost renewable energy

Renewable energy is increasingly cost-competitive with conventional generation technologies. Traditional approaches to utility resource planning and resource investment and procurement (“acquisition”) will, however, prevent utilities from taking fuller advantage of low-cost renewable resources. This paper describes three areas where enhancements in utility resource planning can more accurately reflect the benefits and costs of renewable generation: (1) how operational uncertainties associated with wind and solar generation are characterized in planning models; (2) how reliability services provided by wind and solar generation are valued in planning models; and (3) alignment between cost assumptions used in planning and market conditions. The paper also describes three areas where enhancements in utility resource acquisition can better align decision-making with market outcomes: (1) reducing the time between planning-procurement cycles; (2) shifting from a needs-based to an opportunity-based approach to planning and acquisition; and (3) ensuring comparability among different technology and ownership options. Nascent efforts to resolve challenges in these six areas illustrate the need for utilities and state regulators to expand and upgrade their analytical capabilities.

Facile green synthesis of bioresorbable polyester from soybean oil and recycled plastic waste for osteochondral tissue regeneration

Despite the recent progress in the field of tissue engineering still there are great challenges to regenerate osteochondral tissue interface due to its complex material composition and mechanical properties. A series of biomaterials have been developed in the last few decades, still suitable biomaterial remained undiscover to regenerate osteochondral tissue interface. Here we have reported a new family of low cost biopolymer derived from edible soybean oil (SO) and recycled polyethylene terephthalate (PET) waste along with other renewable resources such as citric acid, sebacic acid and mannitol by facile catalyst and solvent free melt polycondensation process. The physicochemical properties of the synthesized polyester can be tailored by simply varying the monomer feed ratio. The polyesters were found to be elastomeric and biodegradable in nature. 3D porous scaffold shows in vitro mineralization which attributes that the polymer may be applicable for bone formation. 2D polyester film exhibited excellent cytocompatibility to the stem cell and interestingly the polyester guided the stem cell towards both osteogenic and chondrogenic differentiation without using any external differentiating chemicals. Thus this novel class of polyester derived from SO, recycled PET waste and other low cost renewable resources may be a potential candidate in field of interfacial tissue engineering for the treatment of arthritic patients in future.

Key Issues in Microalgae Biofuels: A Short Review

The fossil fuels accomplish almost 80% of the world energy needs. The ever increasing exploitation of fossil fuels has led to environmental pollution, global climate change and health problems to living beings. Hence to meet the needs of the future energy and to mitigate the environmental pollution, it is critical to look for the alternate fuels. Global energy infrastructure in the future is believed to be accomplished by the energy generated from the low-cost renewable resources. Algae biomass has emerged as a promising biofuel source, as microalgae-based biofuels are biodegradable, renewable, and eco-friendly in comparison to fossil driven fuels. This study aims to examine the importance of microalgae as an alternative renewable energy source and evaluate the key challenges in the production of microalgae biofuel.

Rice Husk Ash-Derived Silica Nanofluids: Synthesis and Stability Study.

Nanofluids, colloidal suspensions consisting of base fluids and nanoparticles, are a new generation of engineering working fluids. Nanofluids have shown great potential in heat/mass transfer applications. However, their practical applications are limited by the high production cost and low stability. In this study, a low-cost agricultural waste, rice husk ash (RHA), was used as a silicon source to the synthesis of silica nanofluids. First, silica nanoparticles with an average size of 47 nm were synthesized. Next, by dispersing the silica nanoparticles in water with ultrasonic vibration, silica nanofluids were formed. The results indicated that the dispersibility and stability of nanofluids were highly dependent on sonication time and power, dispersant types and concentrations, as well as pH; an optimal experiment condition could result in the highest stability of silica nanofluid. After 7 days storage, the nanofluid showed no sedimentation, unchanged particle size, and zeta potential. The results of this study demonstrated that there is a great potential for the use of RHA as a low-cost renewable resource for the production of stable silica nanofluids. Graphical Rice husk ash was used as a low-cost renewable resource for production of silica nanofluids with high stability.

Percolated conductive polyaniline-clay nanocomposite in polyvinyl chloride through the combined approach porous template and self-assembly

In this paper, we are reporting a novel strategy for the preparation of conductive polyaniline-clay nanocomposite in Polyvinylchloride (PVC) matrix by admicellar emulsion polymerization using a low cost renewable resource based sur- factant cum dopant. The highly oriented percolated network of polyaniline-clay nanocomposite in PVC matrix was revealed from the studies made by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) results suggested that porous template was formed by the noncovalent interactions among the hydroxyl groups present in the nanoclay edges and the chloride ions present in PVC matrix. Here, the bio-based surfactant, 4-hydroxy-2-pentadecyl benzene-1-sulphonic acid (PDPSA) performed multiple roles of dopant, emulsifier and soft template during the polymerization of anilinium + PDPSA - (An + PDPSA - ) in PVC-clay matrix. The prepared composite exhibited electrical conductivity (!dc) of 4.8·10 -2 S/cm and electromagnetic interference shielding efficiency (EMI SE) of 55.2 dB suggesting it as a prospectable candidate for the encapsulation of electronic devices in high technological applications.

Impact of biofuel utilization in engine fuel: an ecofriendly product

Biofuel initiative has been backed by government policies in the quest for energy security through partially replacing the limited fossil fuels and reducing threat to the environment from exhaust emissions and global warming. The main fuel found to be an increasingly important alternative to petroleum is bio-fuel. It is biodegradable, and produces significantly less air pollution than fossil fuel. In a large excess Biofuels (Bioethanol, Biodisel) are produced by agroresidues and from algal biomass. Agro residues are the main source of lignocellulosic biomass. Lignocellulosic materials composed of cellulose, hemicelluloses and lignin, are the world's most widely available low-cost renewable resources to be considered for ethanol production. Sugarcane bagasse, rice hulls, wheat straw, rape straw, wheat bran, barley straw and cassava stalks are agricultural and agro-industrial residues that could be considered for bioconversion. Bioethanol is an attractive, sustainable energy source to fuel transportation, which is prepared by these agro residues in different steps. Pretreatment is the first step to degrade the biomass component. There are different types of methods of pretreatment one of which dilute acid pretreatment. After pretreatment enzymatic hydrolysis is used to ferment pre-treated biomass either by using simultaneous saccharification or by further acid treatment. Simultaneous saccharification and fermentation (SSF) process is favoured for producing ethanol from the major fraction of lignocellulosic biomass, cellulose, because of its low cost potential. An attempt has been made in this paper to use alternative fuel in four stroke Gasoline engine. As a gaseous fuel, gains from LPG have already been established in terms of low emissions of carbon monoxide, hydrocarbon. Ethanol is one of the fuel additive has some advantages such as better antiknock characteristics and the reduction of CO and HC emissions. It can be considered as renewable energy under the environmental consideration. The purpose of this study is to investigate experimentally and compare the engine performance and pollutant emission of a SI engine using ethanol-gasoline blended fuel and pure gasoline. The results showed that when ethanol is added, the heating value of the blended fuel decreases, while the octane number of the blended fuel increases. The results of the engine test indicated that when ethanol-gasoline blended fuel is used, the engine power and specific fuel consumption of the engine slightly increase; CO emission decreases dramatically as a result of the leaning effect caused by the ethanol addition; HC emission decreases in some engine working conditions; and CO 2 emission increases because of the improved combustion.

Process simulation of a SOFC and double bubbling fluidized bed gasifier power plant

The development of reliable fuel cells power plant based on renewable fuels stands out as one of the promising energy systems solutions for the future. Indeed fuel cells can increase the efficiency and the cleaning of the electrical energy production from renewable fuels. Process simulations of advanced power plants fed by low cost renewable fuels like biomass waste are a key step to develop renewable resources based on high temperature fuel cells applications. The aim of this work is to predict the component behaviour of a specific power plant mainly composed of a small indirectly heated gasifier and a Solid Oxide Fuel Cell (SOFC) and fed by chestnut coppice, waste available in great quantity in Central Italy, as well as in several other European regions. The plant's thermodynamic behaviour is analysed by means of the process simulator CHEMCAD© in which particular models for the SOFC and the gasifier have been developed in FORTRAN by the authors and then interfaced to commercial software. The results of the predictive model are presented and discussed, showing the possibility of an extremely interesting “carbon neutral” small plant configuration with high electrical and global efficiency exclusively based on the use of low cost renewable resources.

Bioconversion of Saccharum spontaneum (wild sugarcane) hemicellulosic hydrolysate into ethanol by mono and co-cultures of Pichia stipitis NCIM3498 and thermotolerant Saccharomyces cerevisiae-VS 3

The lignocellulosic biomass is a low-cost renewable resource for eco-benign liquid fuel 'ethanol'. To resolve the hydrolysis of mixed sugars in lignocellulosic substrate Saccharum spontaneum, the microbial co-cultures of Pichia stipitis NCIM 3498 and thermotolerant Saccharomyces cerevisiae-VS(3) were analyzed for efficient bioconversion of mixed sugars into ethanol. Among the hydrolysis conditions, the acid hydrolysis released maximum sugars along with furans, phenolics and acetic acid. The acidic hydrolysate was detoxified and fermented by monocultures of P. stipitis NCIM3498 (P.S.) and thermotolerant S. cerevisiae VS(3) (S.C.), and co-culture of P.S. (7.5 mL) and S.C. (2.5 mL). Before the fermentation of hemicellulose acid hydrolysate, both the monocultures (P.S. and S.C.), and varying ratios of P.S. and S.C. microorganisms in co-cultures #1, #2 and #3 were grown on simulated synthetic medium. The ethanol yield from monocultures of P.S. (0.44 ± 0.021 g/g), S.C. (0.22 ± 0.01 g/g) and co-culture #3 (0.49 ± 0.02 g/g) revealed unique characteristics of each mono and co-culture technology. The fermentation of hemicellulose acid hydrolysate with monocultures of P.S., S.C. and co-culture #3 produced 12.08 ± 0.72 g/L, 1.40 ± 0.07 g/L, and 15.0 ± -0.92 g/L ethanol, respectively.