Sustainable Bioresource Research Articles

Investigation the Thermal Behavior of Lemon and Orange Peels Composite Fuel Diesel

Background: The aim of this research is to investigate the thermal behavior of a composite fuel prepared by mixing diesel fuel with citrus peel powder in the presence of activators and combustion accelerators. The study focused on utilizing abundant citrus waste, such as lemon and orange peels, as sustainable bioresources to reduce environmental pollution and optimize fuel efficiency. The research explored the thermal properties of the composite fuel and compared it with pure diesel through combustion experiments conducted at atmospheric pressure and combustion pressure in the engine. Methods: The study set the limits of the investigation to various proportions of lemon and orange peel powder mixed with diesel, ranging from 5% to 15% by mass of the total fuel composite. Two catalysts, sodium hydroxide (NaOH) and sulfuric acid (H2SO4), along with calcium oxide (CaO) powder were incorporated into the mixtures as activators to enhance combustion efficiency. The composite fuel characterization included thermogravimetric analysis (TGA) and thermographmetric station experiments to observe the combustion processes and assess the thermal behavior of the composite fuel. Results: The results revealed four distinct phases of combustion during the burning time of 60 seconds: volatile combustion, liquid combustion, combustion of solid materials, and the interaction of active substances with combustion residues. Using activators and catalysts significantly enhanced combustion efficiency and minimized the amount of residue produced during the process, resulting in thermal behavior that is more similar to that of pure diesel. Lemon peel powder with activators demonstrates better thermal behavior compared to orange peel powder. Conclusions: Based on the findings, some recommendations are proposed for further development such as the optimization of activator ratios, exploration of different proportions of lemon and orange peel powder, and investigation of other catalysts. Real-world engine performance tests and emission profile analysis can validate the thermal behavior results obtained from combustion experiments.

The dissolution of galactomannans in type II/III deep eutectic solvents: Effect of polysaccharide structure and interaction mechanism

Deep eutectic solvents (DESs) have garnered increasing attention as sustainable solvents for natural polysaccharides. Galactomannans (especially guar and locust bean gums) are abundant natural compounds used in food, medicine, agriculture and daily chemical products, whereas their high molecular weight and randomly distributed non-linear structures remain a huge challenge in solubilization and high value-added utilization. In this study, the dissolution of galactomannans in type II/III DESs was comprehensively investigated using density functional theory (DFT) calculation, experimental results, and molecular dynamics simulation (MD). The results indicated that immense anionic and neutral H-bonds supported by type II DESs (consisting of a quaternary ammonium salt and a metal chloride hydrate) could break and rebuild galactomannan H-bond networks, thereby exhibiting remarkable physical solubilization. A large number of active acid sites in type III DESs (consisting of a quaternary ammonium salt and a hydrogen bond donor) greatly improved solubility and cleaved the glycosidic bond, enabling the recovery of polysaccharides with a target molecular weight. Furthermore, significant correlations between solubility and the structure of galactomannans had been established, which meant that high molecular weight and rich galactose side-chains produced repulsive interactions with DESs, directly hindering dissolution. Overall, this work not only offered a framework for enhancing the dissolution of polysaccharides, but also proposed a promising strategy for development of task specific DESs promoting green chemistry and the use of sustainable bioresources.

DELIGNIFICATION OF OIL PALM EMPTY FRUIT BUNCHES USING DEEP EUTECTIC SOLVENT IN PRESSURIZED REACTOR

Although lignin from oil palm empty fruit bunches (OPEFB) is a sustainable bioresource with several value-added uses, it is still difficult to extract lignin from lignocellulosic biomass economically. Lignin fractions are required for high-value applications and subsequently increase the feasibility of lignocellulosic biorefineries. Besides, the remaining cellulose could be further valorized into various chemical products. In this study, the delignification efficiency of OPEFB under inert and pressurized conditions has been studied as an effective pretreatment method for OPEFB. The optimal conditions of the high-pressure reactor to remove lignin from OPEFB were determined to be 80 °C at 30 bars with the presence of deep eutectic solvents (DES). It was identified that pressure affects the removal of lignin with the least amount of structural breakdown and the digestibility of cellulose. The effective removal of lignin from the OPEFB was established under mild conditions employing an inert nitrogen gas pressurized system. This work selectively removes lignin from the OPEFB of palm oil biomass plants using DES under mild extraction conditions. Solid residues were characterized by using FTIR, SEM, TGA, and XRD to investigate fractions under various reaction conditions, such as removal temperature, time, and pressure. The thermal stability of lignin was determined by TGA. In this study, 36.68% of lignin was removed under optimum pressure conditions at the lowest process temperature of 80 °C to determine how these factors influence the efficiency of lignin extraction in a high-pressure reactor.

Controlled release formulations of organophosphorus pesticides based on ecofriendly novel and conventional matrices for agro-environmental sustainability

Controlled release formulations (CRFs) of the organophosphorus pesticides diazinon and dichlorvos were prepared from a novel cow dung ash (CDA) matrix and the more conventional starch (STA) matrix. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the CRFs. FTIR and XRD spectral data provide evidence for pesticide-matrix interactions fundamental to observed matrix surface binding and pesticide release behaviour in water and soil environments. Properties evaluation of the CRFs reveal similar magnitudes of loading capacity and encapsulation efficiency of CDA- and STA-based CRFs of both pesticides, while the order CDA > STA prevails in matrix porosity and swelling ability. Technical grade (TG) and the CRF-encapsulated pesticides exhibit “burst” release profiles in water; pesticide quantities released at similar lengths of time follow the order TG >> STA-CRF > CDA-CRF, thus revealing the capacity of the CRFs to constrain the active ingredients from free mobility, with CDA-CRF being the more slightly efficacious. The Korsmeyer-Peppas equation reasonably models pesticide release from both CRFs into water, giving n values consistent with both water diffusion into the matrix and matrix relaxation as kinetically important in both matrices. Soil column experiments demonstrate the potential of the CFRs to mitigate ground water pollution. Overall, the results show that CDA- and STA-based CRFs of both pesticides have roughly the same potency for pesticide controlled release and ground water pollution mitigation. Deployment of these CFRs can contribute to the drive for agro-environmental sustainability, while the use of CDA, a waste material, as a matrix in controlled pesticide delivery would resonate with sustainable bioresource utilization.

Unearthing the therapeutic benefits of culinary-medicinal mushrooms for humans: Emerging sustainable bioresources of 21st century.

Global interest in mushroom farming techniques has grown in the last few years. Despite not making up a large amount of the human diet at the moment, the nutritional worth of mushrooms has prompted their usage. The three main segments of the global mushroom industry are wild, culinary (edible), and medicinal mushrooms. The quality food that mushrooms provide can be utilized to build agricultural ecosystems that are more sustainable for increasing productivity and enhancing the effectiveness of resource usage. This is mostly because mushrooms can be utilized for the recycling of biomass and remains from crop production. Culinary-medicinal mushrooms are becoming more and more important because of their nutrient density, dietary value, and health advantages. Given its many bioactive components, which include polysaccharides, proteins, vitamins, minerals, dietary fiber, and secondary metabolites, mushrooms have been utilized extensively as health foods. These mushrooms exhibit pharmacological activities and possess prebiotic and antibacterial capabilities. This review provides information on the latest advancements in the sustainable cultivation of mushrooms, particularly with nontraditional substrates, and their potential therapeutic uses. Furthermore, some of the newest developments and difficulties in the production of mushrooms are explored.

Relationship between dietary fiber content and prebiotic potential of polysaccharides from the seaweeds of the North west coast of India

The macroalgae are a sustainable bioresource that can be harnessed for their functional food and nutraceutical applications. This study characterized the biochemical composition and bioactive potential of natural biological macromolecules, such as macroalgal polysaccharides extracted using a green, aqueous extraction process. The in-vitro antioxidant and antiglycemic activity of these polysaccharides were evaluated using model, free radical and antiglycemic compounds. The prebiotic potential of macroalgal polysaccharides were analysed based on their ability to promote the growth of two potential probiotic bacteria Lactobacillus acidophilus and L. bulgaricus and suppress the growth of enteric bacteria, Escherichia coli. Among the polysaccharides studied, the brown algal polysaccharide MPS8 MPS9 and MPS10 exhibited good antioxidant, antiglycemic and prebiotic activity. Based on infrared spectroscopy, the functional groups sulfation and carboxylation were identified in potential polysaccharides. The monosaccharide composition in the bioactive polysaccharides was determined using High Performance Anion Exchange Chromatography Pulse Amperometric detector (HPAEC-PAD). These bioactive polysaccharides were fractionated using ion exchange chromatography to purify it and further characterized using gel permeation chromatography and NMR spectroscopy. The results these polysaccharides are mainly composed of fucose and glucose which is due to the fucoidan and laminarin, respectively. Such macromolecules with high dietary fiber content and bioactivity are in global demand as functional food, nutraceutical and pharmaceutical formulations.

Comparative antioxidant potential, proximal biochemical composition, and pigment content of 11 brown seaweeds from the West of Ireland

The biorefinery and valorisation of sustainable bioresources such as seaweeds have increased in response to global circular economy initiatives. Several seaweed species are exploited worldwide in the biofertilizer, nutrition, bioenergy, cosmetics, or pharmaceutical sectors. Brown seaweeds are widespread, easily accessible, and abundant in northwest Europe regions, with some species being commercially harvested and processed.Here, both commercially exploited, and less studied brown seaweeds (n = 11) were collected from Irelands Atlantic coast and analysed for soluble carbohydrates, lipids, proteins, fatty acid, and pigment profiles as well as antioxidant potential. Soluble carbohydrates (62.7 µg glucose eq mg−1 DW) were highest in Saccharina latissima while lipids (148.2 mg L g−1 DW), fucoxanthin (1.35 mg g−1) and β-carotene (4.10 mg g−1) were greater in Dictyota dichotoma. The highest antioxidant activity (456.3 µmol Trolox eq mg−1 DW with TEAC assay) and soluble protein content (562.5 µg BSA eq mg−1 DW) were in Halidrys siliquosa extracts.Data matrix multivariate ordination indicated that some less studied brown seaweeds have further valorisation potential owing to their biochemical composition and bioactivity. The development of species-specific tailored cultivation strategies as part of integrated multi-trophic aquaculture systems has potential to contribute to environmental sustainability while introducing new natural bioactive products to markets.

Evaluation of the potential of agricultural wastes-cattle manure and poultry manure for bioremediation of crude oil-contaminated soil

The Niger Delta region of Nigeria suffers from petroleum pollution, which affects ecosystem functioning and human health, which necessitates finding sustainable remediation options that utilize local resources. In this work, cattle manure (CM) and poultry manure (PM), which are primarily utilized as biofertilizer for agricultural purposes, were utilized to bioremediate crude oil-contaminated soil on a laboratory scale. In addition to being readily accessible, CM and PM are also sustainable bioresources that are host to a wide variety of microflora that can be used for bioaugmentation. At the end of the 1.5 month study, the impact of the amendments on speciated total petroleum hydrocarbons (STPH) in the range of nC10-nC40 was evaluated. A significantly higher STPH degradation of 36% in PM-amended soil was observed compared to CM-amended soil (23%); and only 1% degradation in enhanced by natural attenuation soil (RENA). The pre-dominant aliphatic fractions in the samples analyzed were nC16-nC35. In comparison to the CM amendment option, PM amendments achieved better bioremediation of these fractions. Moreover, the effect of biowaste ratio amendment to the contaminated soil showed that the ratio 1:1 (w/w) for both bioadmendments performed better than the ratio 1:2 (w/w), suggesting that the higher the amount of amendment to contaminated soil, the more effective the bioremediation. The results of this study demonstrate the potential of PM as a sustainable, affordable, and local bioremediation technique for recovering soil contaminated by crude oil in the Niger Delta.

Determining monolignol oxifunctionalization by direct infusion electrospray ionization tandem mass spectrometry.

We have successfully developed a validated high-throughput analysis method for the identification and quantification of native and oxifunctionalized monolignols using direct infusion electrospray ionization tandem mass spectrometry (DI-ESI-MS/MS). Oxifunctionalized monolignols generated through unspecific peroxygenase catalysis present a sustainable alternative to fossil aromatic hydrocarbons. This study emphasizes a sustainable analytical approach for these renewable biocatalytic precursors, addressing challenges such as matrix effects, accuracy, precision, and sensitivity of the method. Our findings demonstrate the potential of overcoming quantification difficulties using DI-ESI-MS. Notably, this analytical methodology represents a novel utilization of DI-ESI-MS/MS in examining monolignols and their functionalization, thereby advancing the exploration of lignin as a valuable and sustainable bioresource.

Comparative Study of Antibacterial Activity of Elephantopus scaber Linn. and Elephantopus mollis Kunth. Extract

Elephantopus scaber Linn. and E. mollis Kunth. are medicinal plant that are traditionally used in Indonesia. This research aimed to determine and compare the antibacterial activity of leaf, stem, and root extracts of the two Elephantopus species against various pathogen bacteria strains. The leaves, stem, and roots of E. scaber Linn. and E. mollis Kunth. were extracted using a Soxhlet apparatus. The disk diffusion method for screening antibacterial activity was conducted with a concentration of 50 mg/mL. The activities of the extracts were determined by Minimum Inhibitory Concentration (MIC) assay using broth microdilution method at a concentration range of 2500 to 1.2 µg/mL against nine human pathogenic bacteria. The results showed that all tested extracts demonstrated antibacterial activitied at varying degrees on all pathogen bacteria strains used in this study. The n-hexane and ethyl acetate extracts from both plants were potent antibacterials with MIC values of 19-156 µg/mL against Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC 25 175, Vibrio cholerae Inaba, and Pseudomonas aeruginosa ATCC 27853. The present study also revealed that among the bacteria tested, S. mutans ATCC 25175 was the most susceptible to antibacterial properties of E. scaber Linn. and E. mollis Kunth., especially in ethyl acetate fractions (MIC 19 and 39 µg/mL, respectively). The findings suggested that the leaves of both plants hold promise as sustainable bioresources for the development of antibacterial agents. Additionally, ethyl acetate and n-hexane extracts were found to be particularly effective for obtaining natural antibacterial agents from these plants. However, further optimization of the extraction process is needed.

Synergies of pH-induced calcium phosphate precipitation and magnetic separation for energy-efficient harvesting of freshwater microalgae

Energy- and time-consuming concentration steps currently limit the industrial application of microalgae. Compared to state-of-the-art technologies, magnetic separation shows a high potential for efficient harvesting of microalgae. This study presents a novel approach to combine pH-induced calcium phosphate precipitation with cheap natural magnetite microparticles for magnetic separation of the freshwater microalgae Chlorella vulgaris. Harvesting efficiencies up to 98% were achieved at moderate pH and low particle and calcium phosphate concentrations in a model medium. However, cultivation-dependent high loads of algogenic organic matter can severely inhibit flocculation and particle/algae interactions, requiring higher salt concentrations or pH. Harvesting efficiencies above 90% were still attainable at moderate pH with increased calcium phosphate concentrations of 10mM. Acidification of the suspension to pH 5 allows for simple and reversible particle recycling. The presented process provides a promising path to universal and cost-effective harvesting, advancing the utilization of microalgae as a sustainable bioresource.

High-efficiency harvesting of microalgae enabled by chitosan-coated magnetic biochar

Magnetic flocculation which uses magnetic particles is an emerging technology for harvesting microalgae. However, the potential modification and use of cost-effective and sustainable biochar-based composites is still in its infancy. As such, this study aimed to compare the harvesting efficiency of peanut shell biochar (BC), biochar modified with FeCl3 (FeBC), and biochar dual-modified with chitosan and FeCl3 (CTS@FeBC) on microalgae. The results showed CTS@FeBC exhibited significantly higher microalgae harvesting efficiency compared to BC and FeBC. Both acidic and alkaline conditions were favorable for harvesting microalgae by CTS@FeBC. At pH 2 and pH 12, the harvesting efficiency reached 96.9% and 98.8% within 2 min, respectively. The primary adsorption mechanism of CTS@FeBC on microalgae mainly involved electrostatic attraction and sweeping flocculation. Furthermore, CTS@FeBC also showed good biocompatibility and reusability. This study clearly demonstrated a promising technique for microalgae harvesting using biochar-based materials, offering valuable insights and potential applications in sustainable bioresource management.

Valorisation of organic carbons and organo-solvents by mixotrophic cultivation of methylotrophic Tetraselmis indica for enhanced biomolecules production

Microalgal biomass is a sustainable bioresource for producing a wide range of biomolecules such as lipids and chlorophylls, astaxanthin, and β-carotene. The mixotrophic cultivation using organic carbon (OCs) and traditional organo-solvents (OSs), especially methanol (MeOH), has been shown to improve biomass productivity and biomolecule yield. However, limited studies have explored the utilization of OSs as an external carbon source to produce microalgal biomass and for subsequent biorefinery. Thus, the present study evaluates the effects on the cultivation of industrial important microalgal Tetraselmis indica BDUG001 (T. indica BDUG001) through supplementation of various OCs and OSs at different day-night cycles under sterile mixotrophic conditions. Among all the OCs and OSs, MeOH showed the best growth, biomass, and biomolecule production. Interestingly, MeOH at a varying concentration (0–10 g/L) was an ideal carbon source for enhancing T. indica BDUG001 growth, biomass, and biomolecules productivity. At the 7.5 g/L concentration of MeOH, T. indica BDUG001 showed maximized biomass production (2.45 ± 0.07 g/L), lipid content (42.85 ± 1.20%), total lipid yield (1.05 ± 0.03 g/L), photosynthetic pigments [chl-a (3.27 mg/L), chl-b (2.25 mg/L) and TCs (1.27 mg/L]. While the maximum astaxanthin (0.77 μg/gm) and β-carotene (5.21 μg/mg) were observed at 10 and 5.0 g/L, respectively. The present investigation will aid in the microalgal research pipeline for the selection of novel OSs tolerant microalgae strains and utilization of waste OSs for mass-scale sterile mixotrophic cultivation. Moreover, the proposed cultivation system will help to develop low-cost algal biorefinery systems to attain high-quality industrial important biomolecules.

Advances in green materials derived from wood for detecting and removing mercury ions in water

The issue of mercury pollution in environmental remediation has garnered significant attention due to its severe health hazards to humans. Various strategies have been devised to mitigate the impact of toxic mercury ions, including coagulation, ion exchange, adsorption, membrane technology, and electrochemical treatment. Among these approaches, adsorption has emerged as an efficient and widely employed method for the uptake of low concentrations of mercury ions. It offers convenient operation, high removal efficiency, and facile regeneration of the adsorbent. Wood, being the most abundant renewable and sustainable bioresource, has garnered attention as a promising material for treating heavy metal wastewater. This is attributed to its unique physical and chemical characteristics, encompassing hierarchical pores, aligned channels, active functional groups, biodegradability, and cost-effectiveness. However, a comprehensive examination of the cutting-edge applications of wood and wood-derived biopolymers in the detection and removal of mercury ions from wastewater has yet to be undertaken. Consequently, this article presents a chronological overview of recent advancements in materials and structures derived from bulk wood and its constituents, including cellulose, lignin, hemicellulose, and tannin, with a specific focus on their utility in detecting and eliminating mercury from water sources. Subsequently, the most promising techniques and strategies involving wood and wood-derived biopolymers in addressing the predicament of mercury pollution are explored. Furthermore, this piece offers insights into the existing challenges and future prospects concerning environmentally friendly materials derived from wood, aiming to foster the development of cost-effective mercury adsorbents and detection devices.

Fundamental alteration of cellular biochemicals from attached microalgae onto palm kernel expeller waste upon optimizing the growth environment in forming adhesion complex

Changing the growth environment for microalgae can overall lead to the fundamental alteration in cellular biochemicals whilst attaching onto palm kernel expeller (PKE) waste to form adhesion complex in easing harvesting at stationary growth phase. This study had initially optimized the PKE dosage, light intensity and photoperiod in maximizing the attached microalgal productivity being attained at 0.72 g/g day. Lipid content increased progressively from pH 3 to pH 11, with the highest value observed at pH 11. Meanwhile, in terms of protein and carbohydrate contents, the highest values were obtained by cultivation medium of pH 5 with 9.92 g and 17.72 g, respectively followed by pH 7 with 9.16 g and 16.36 g, respectively. Moreover, the findings also suggested that the low pH mediums utilized polar interactions in the formation of complexes between PKE and microalgae, whereas at higher pH levels, the non-polar interactions became more significant. The work of attachment was thermodynamically favourable towards the attachment formation with values greater than zero which was also aligned with the microscopic surface topography, i.e., revealing a clustering pattern of microalgae colonizing the PKE surface. These findings contribute to comprehensive understanding of optimizing growth condition and harvesting strategy of attached microalgae in attaining the cellular biochemical components, facilitating the development of efficient and sustainable bioresource utilization.

Recent advances in biological hydrogen production from algal biomass: A comprehensive review

Clean fuels play a crucial role in the industrialized world's efforts to combat greenhouse gas emissions. Among the cleanest fuels available, hydrogen stands out as it produces water as a byproduct during combustion. To ensure the sustainable generation of clean fuels, it is imperative to produce hydrogen from environmentally friendly and renewable sources. Biological processes present a promising avenue for the production of hydrogen from affordable and sustainable bio-resources, including biomass and solar energy, using diverse techniques such as direct/indirect photolysis, photo-fermentation, dark-fermentation, and Microbial electrolysis cell. This comprehensive study delves into various aspects of biological hydrogen production, encompassing discussions on microorganisms, different types of substrates and their concentrations, the role of chemical additives, and key operational parameters like temperature, pH, agitation, and insights into hydrogenase and nitrogenase properties. For light-dependent processes, the study also explores the influence of illumination systems. Furthermore, the research examines different configurations of biological processes, integrating light, dark, and photo-fermentation in two- and three-component systems. By investigating these critical factors, the study aims to shed light on optimizing biological hydrogen production. The findings offer valuable insights for advancing the sustainable and efficient utilization of clean fuels in the global effort to mitigate greenhouse gas emissions.

Morphological, Spectroscopic and Thermal Analysis of Cellulose Nanocrystals Extracted from Waste Jute Fiber by Acid Hydrolysis

Natural cellulose, a sustainable bioresource, is highly abundant in nature. Cellulosic materials, particularly those that explore and employ such materials for industrial use, have recently attracted significant global attention in the field of material science because of the unique properties of cellulose. The hydroxyl groups enable the formation of intra- and inter-molecular hydrogen bonding and the arrangement of cellulose chains in a highly ordered crystalline zone, with the remaining disordered structure referred to as an amorphous region. The crystalline areas of cellulose are well-known as cellulose nanocrystals (CNCs). In the present study, we extracted CNCs from pure cellulose isolated from waste jute fibers by sulfuric acid hydrolysis, followed by characterization. Pure cellulose was isolated from jute fibers by treating with sodium hydroxide (20% w/w) and anthraquinone (0.5%) solution at 170 °C for 2 h, followed by bleaching with chlorine dioxide and hydrogen peroxide solution. CNCs were isolated from pure cellulose by treating with different concentrations (58% to 62%) of sulfuric acid at different time intervals (20 min to 45 min). The FTIR study of the CNCs reveals no peak at 1738 cm-1, which confirms the absence of hemicellulose in the samples. The CNCs obtained after 45 min of acid hydrolysis are rod-shaped, having an average length of 800 ± 100 nm and width of 55 ± 10 nm, with a high crystallinity index (90%). Zeta potential significantly increased due to the attachment of SO42- ions on the surface of CNC from -1.0 mV to about -30 mV, with the increment of the reaction time from 20 min to 45 min, which proved the higher stability of CNC suspension. Crystallinity increased from 80% to 90% when the reaction time was increased from 20 to 45 min, respectively, while a crystallite size from 2.705 to 4.56 nm was obtained with an increment of the acid concentration. Acid hydrolysis enhanced crystallinity but attenuated the temperature corresponding to major decomposition (Tmax) at 260 °C and the beginning of degradation (Ti) at 200 °C due to the attachment of SO42- ions on the surface, which decreased the thermal stability of CNC. The second degradation at 360 °C indicated the stable crystal structure of CNC. The endothermic peak at 255 °C in the DTA study provided evidence of sulfated nanocrystal decomposition and the recrystallization of cellulose I to cellulose II, the most stable structure among the other four celluloses. The proposed easy-to-reproduce method can successfully and efficiently produce CNCs from waste jute fibers in a straightforward way.

Camellia oleifera Shell Biochar as a Robust Adsorbent for Aqueous Mercury Removal

Camellia oleifera fruit shell (COS) is an agricultural waste product generated in large quantities by the seed oil extraction industry. Due to its hierarchical thickness structure, COS shows huge potential in constructing porous carbon materials after thermal chemical modification. Herein, a series of COS biochars were synthesized by a carbonization-activation process and achieved excellent mercury removal performance in an aqueous environment. High-temperature carbonization was found to facilitate lignin removal and porosity generation, while retaining hydroxyl and carbonyl groups available for mercury adsorption. A volume of micropores of 594 × 10−3 cm−3/g with average pore diameter of 1.7 nm was achieved in activated COS biochar. At 550 °C, an adsorption capacity of 57.6 mg/g was realized in 1 mg/L Hg2+ solution under different pH environments. This work provides an alternative adsorbent for removing hazardous materials using sustainable bioresources.

Enhancing Polyphenols and Tannins Concentration on Cotton Dyed with Red Tea

Natural dyes, obtained from plants, insects/animals, and minerals, are renewable and sustainable bioresource products with minimum environmental impact. However, there are still many issues to solve related to natural dyes; consequently, synthetic dyes are still wildly used. Natural dyes have a low affinity towards the substrate cotton, so a solution had to be found: mordants. Mordants can also be harmful to the environment, which is why bio-mordants are used. The mordant used in this paper is chitosan. Cotton is pre-mordanted using the pad dyeing method. By using the exhaustion method, the fabric was coloured with red Camellia sinensis (tea) extracts. The colour, absorption of polyphenols and tannins, and ultraviolet protection (UPF) were tested. A comparison study was carried out between the cotton fabric and the cotton padded with chitosan at two different concentrations. The results are impressive. Cotton pre-mordanted with chitosan can absorb more polyphenols and tannins than cotton itself, and the colour fastness and UPF, once the fabric is laundered, demonstrate there is some kind of bonding between the fibre, quitosan, and active compounds from tea. The UPF was also doubled by using chitosan and the reddish colour obtained by Camellia sinensis extracts were darker on the cotton fabric. The increase in UPF protection on mordanted fabrics is higher than the gap obtained by colour difference, which means there are active compounds that do not confer colour, but enhance UPF protection.

Sustainable bio & waste resources for thermal insulation of buildings

A growing awareness of the environmental impact of construction materials is leading to development of more sustainable building products, with particular attention focussed on bio-based resources and circularity. In recent years the market share of bio-based building products has grown significantly, supported by research on materials such as wood fibre, hemp, and straw bale. At the same time there has been growing awareness of the potential for greater circularity in construction, prolonging the life of existing products and materials, thus minimising embodied carbon emissions of future projects, as well as reducing reliance on primary resources and impact on landfill. This paper presents results of an investigation into the thermal and hygric characteristics of three novel insulation prototypes developed from bio-based or waste-stream materials. The experimental development and characterisation of insulation using maize pith, recycled bedding (polyester duvet) materials, and wheat straw insulating prototypes are presented. Hygric and thermal performance are compared to a mineral wool insulation product. As part of this work a series of large-scale thermal conductivity and hygric investigations were also conducted in which the performance of each insulation product with a timber framed wall was studied under steady state and variable environmental conditions. This work was part of a larger international research project aimed at developing insulating materials from bio-based and waste streams and will support market development of novel materials and products into mainstream construction.