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1.
J Fluoresc ; 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949753

RESUMO

Cellulose nanofiber (CNFs) obtained through TEMPO oxidation was structurally characterized using FT-IR (Fourier Transformed Infrared) and SEM (Scanning Electron Microscopy) spectroscopy. The molecular aggregation and spectroscopic properties of Rhodamine B (Rh-B) in CNFs suspension were investigated using molecular absorption and steady-state fluorescence spectroscopy techniques. The interaction between CNFs particles in the aqueous suspension and the cationic dye compound was examined in comparison to its behavior in deionized water. This interaction led to significant changes in the spectral features of Rh-B, resulting in an increase in the presence of H-dimer and H-aggregate in CNFs suspension. The H-type aggregates of Rh-B in CNFs suspensions were defined by the observation of a blue-shifted absorption band compared to that of the monomer. Even at diluted dye concentrations, the formation of Rh-B's H-aggregate was observed in CNFs suspension. The pronounced aggregation in suspensions originated from the strong interaction between negatively charged carboxylate ions and the dye. The aggregation behavior was discussed with deconvoluted absorption spectra. Fluorescence spectroscopy studies revealed a significant reduction in the fluorescence intensity of the dye in CNFs suspension due to H-aggregates. Furthermore, the presence of H-aggregates in the suspensions caused a decrease in the quantum yield of Rh-B compared to that in deionized water.

2.
J Fluoresc ; 34(1): 191-201, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37166612

RESUMO

In this present study, a straightforward and affordable method for the environmentally safe synthesis of carbon quantum dots (CQDs) by employing human hair as the carbon source without any need of chemicals was synthesized. CQDs obtained from human hair was further functionalized with Poly-L-Lysine to form PLLCQDs. The synthesized PLLCQDs was demonstrated numerous advantageous characteristics like strong fluorescence intensity, superior photostability, and outstanding water solubility. Various physicochemical characterization was employed to confirm successful formation of PLLCQDs including UV-vis Spectroscopy, Fluorescence Spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy, Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The size of synthesized PLLCQDs is 3 nm. The resultant PLLCQDs exhibited strong blue emission with a quantum yield of 28%. Under UV light, the synthesized PLLCQDs emit blue (at 365nm) fluorescence. The optimization of synthesis parameters including synthesis method, effect of reaction temperature, effect of reaction time and effect of reaction concentration have a significant impact on the quality and quantity of synthesized PLLCQDs, as well as their properties and applications. The effect of pH and UV radiation on synthesized PLLCQDs exhibited excellent photo and chemical stability. The cytotoxicity of bulk system (Hair precursor) and PLLCQDs was evaluated using fibroblast cell line (L929). The cell viabilities of 99.47% was obtained from L929 cells using MTT assay and it can applicably function as agents for cell labelling as a good bioimaging probe.


Assuntos
Pontos Quânticos , Humanos , Pontos Quânticos/química , Carbono/química , Linhagem Celular , Corantes Fluorescentes/química , Espectroscopia de Infravermelho com Transformada de Fourier
3.
Environ Res ; 250: 118503, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38367840

RESUMO

Existing fossil-based commercial products present a significant threat to the depletion of global natural resources and the conservation of the natural environment. Also, the ongoing generation of waste is giving rise to challenges in waste management. Conventional practices for the management of waste, for instance, incineration and landfilling, emit gases that contribute to global warming. Additionally, the need for energy is escalating rapidly due to the growing populace and industrialization. To address this escalating desire in a sustainable manner, access to clean and renewable sources of energy is imperative for long-term development of mankind. These interrelated challenges can be effectively tackled through the scientific application of biowaste-to-bioenergy technologies. The current article states an overview of the strategies and current status of these technologies, including anaerobic digestion, transesterification, photobiological hydrogen production, and alcoholic fermentation which are utilized to convert diverse biowastes such as agricultural and forest residues, animal waste, and municipal waste into bioenergy forms like bioelectricity, biodiesel, bio alcohol, and biogas. The successful implementation of these technologies requires the collaborative efforts of government, stakeholders, researchers, and scientists to enhance their practicability and widespread adoption.


Assuntos
Biocombustíveis , Gerenciamento de Resíduos/métodos , Conservação dos Recursos Naturais/métodos , Desenvolvimento Sustentável
4.
Environ Res ; 244: 117894, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38092236

RESUMO

Numerous efforts have been made to enhance the performance of anaerobic digestion (AD) for accelerating renewable energy generation, however, it remains unclear whether the intensified measures could enhance the proliferation and transmissions of antibiotic resistance genes (ARGs) in the system. This study assessed the impact of an innovative pig manure AD process, which includes hydrothermal pretreatment (HTP) and a two-stage configuration with separated acidogenic and methanogenic phases, on biomethane (CH4) production and ARGs dynamics. Results showed that HTP significantly increase CH4 production from 0.65 to 0.75 L/L/d in conventional single-stage AD to 0.82 and 0.91 L/L/d in two-stage AD. This improvement correlated with a rise in the relative abundance of Methanosarcina, a key methanogenesis microorganism. In the two-stage AD, the methanogenic stage offered an ideal environment for methanogens growth, resulting in substantially faster and higher CH4 production by about 10% compared to single-stage AD. Overall, the combined use of HTP and the two-stage AD configuration enhanced CH4 production by 40% compared to traditional single-stage AD. The abundance and diversity of ARGs were significantly reduced in the acidogenic reactors after HTP. However, the ARGs levels increased by about two times in the following methanogenesis stage and reached similar or higher levels than in single stage AD. The erm(F), erm(G), ant(6)-Ia, tet(W), mef(A) and erm(B) were the six main ARGs with significant differences in relative abundances in various treatments. The two-stage AD mode could better remove sul2, but it also had a rebound which elevated the risk of ARGs to the environment and human health. Network analysis identified pH and TVFAs as critical factors driving microbial communities and ARG proliferation in the new AD process. With the results, this study offers valuable insights into the trade-offs between AD performance enhancement and ARG-related risks, pinpointing essential areas for future research and practical improvements.


Assuntos
Antibacterianos , Microbiota , Humanos , Animais , Suínos , Antibacterianos/farmacologia , Esterco , Resistência Microbiana a Medicamentos/genética , Metano , Anaerobiose , Genes Bacterianos
5.
Chem Biodivers ; 21(2): e202301729, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38241063

RESUMO

Nature-derived products, like juices and peel extracts of fruits and vegetables, have emerged in recent years as interesting and sustainable alternatives to traditional solvents in several synthetic applications. Herein, we present a green and fast method for the N-acetylation of amino acids, using several bio-based solvents (vinegar, tomato/kiwi/apple peel extracts, lemon juice, etc.). The high reactivity of the amino group is often a limitation in synthetic processes, making its protection a necessary step to achieve pure products and limit side reactions. Therefore, versatile, time-efficient procedures, minimal purification efforts, and good yields are desirable features for these transformations. Our new method meets all these criteria, offering a valuable and eco-friendly alternative to traditional approaches. In detail, we managed to obtain comparable yields to established setups, while improving safety and reducing the environmental impact of the overall process. Most notably, the milder conditions made it possible to avoid the use of running water (saving about 250 L/reaction) and electric-powered cooling devices.


Assuntos
Aminoácidos , Frutas , Solventes , Acetilação , Aminas
6.
Int J Phytoremediation ; 26(9): 1500-1517, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38488041

RESUMO

Due to developing technology and increasing population, human needs have increased, and textile activities have gained momentum. Many synthetic dyestuffs are used to meet the needs in this field. In this study, a cheap, useful, innovative, environmentally friendly and sustainable adsorbent was developed for the removal of Methylene Blue(MB), which is one of the dyes that is harmful to the environment. In the cultivation of fruit trees, in addition to the product, very high amounts of by-products/waste (garbage, branches, bark, leaves, etc.) are produced. In this direction, fig tree wastes were immobilized with chitosan, made magnetic, and MB adsorption on the developed adsorbent was examined in a batch system. Glutaraldehyde was used as crosslinker. Characterization of synthesized glutaraldehyde cross-linked chitosan-coated magnetic vegetable waste composite beads (g-CMBW) was carried out by SEM, EDX, FTIR and XRD. In the study, the effects of temperature (25-55 °C), pH (3.0-8.0), initial MB concentration (10-250mg/L), contact time (5-360min) and the amount of adsorbent (2-10 g/L) on MB adsorption with g-CMBW were examined. The optimum conditions obtained were determined as pH 6.0, temperature 25 °C, adsorbent amount 6 g/L, and contact time 120 min. The maximum adsorption capacity in MB removal using g-CMBW composite beads was calculated as 103.1 mg/g according to the Langmuir isotherm model. The temperature studies showed that the adsorption capacity decreased with increasing temperature, showing that the system was exothermic. In light of these results, it was determined that there are new promising adsorbents of natural origin, with higher adsorption capacity, lower cost, and alternatives to commercially used adsorbents in the removal of MB from aqueous media.


In this study, we developed a renewable magnetic composite bead as a low-cost pioneer based on a new sustainable biopolymer using chitosan and plant waste. The novelty of this work is based on the development of a new composite adsorbent that can be synthesized in a fast, simple, and environmentally friendly method, not requiring expensive reagents or complex equipment. Another innovation is that methylene blue, a common micropollutant, can be easily removed from polluted water using simple biowaste-based adsorbents by adopting appropriate procedures. It exhibited higher micropollutant adsorption performance compared to most other adsorbents. These results showed that it could be a very effective adsorbent for methylene blue removal from aqueous media.


Assuntos
Biodegradação Ambiental , Quitosana , Hidrogéis , Azul de Metileno , Poluentes Químicos da Água , Azul de Metileno/química , Quitosana/química , Adsorção , Hidrogéis/química , Biomassa , Corantes/química , Ficus
7.
J Environ Manage ; 351: 119712, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38070427

RESUMO

This study presents a novel treatment system using a submerged anaerobic membrane bioreactor (SAnMBR) followed by adsorption onto thermally treated biowaste, and ending with a final treatment using powdered activated carbon (PAC). Despite limited phosphate and ammonium ion removal during SAnMBR operation, thermally treated eggshell (EGSL) and seagrass (SG) received SAnMBR effluent and enhanced phosphate recovery, achieving removal rates of 71.8-99.9% and 60.5-78.0%, respectively. The SAnMBR achieved an 85% COD removal, which was slightly reduced further by biowaste treatment. However, significant further reductions in COD to 20.2 ± 5.2 mg/L for EGSL effluent and 57.0 ± 13.3 mg/L for SG effluent were achieved with PAC. Phytotoxicity tests showed the SAnMBR effluent after PAC treatment notably improved seed growth compared to untreated wastewater. In addition, volatile organic compounds (VOCs) were significantly reduced in the system, including common wastewater contaminants such as dimethyl disulfide, dimethyl trisulfide, phenol, p-cresol, nonanal, and decanal. Fractionation analysis of the solid fraction, post-adsorption from both synthetic and domestic wastewater, indicated that for SG, 77.3%-94% of the total phosphorus (TP) was inorganically bound, while for EGSL, it ranged from 94% to 95.3%. This study represents the first attempt at a proof-of-concept for simultaneous treatment of domestic wastewater and phosphorus recovery using this integrated system.


Assuntos
Águas Residuárias , Purificação da Água , Carvão Vegetal , Fosfatos , Eliminação de Resíduos Líquidos , Pós , Anaerobiose , Reatores Biológicos , Fósforo , Membranas Artificiais
8.
J Environ Manage ; 358: 120895, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38626487

RESUMO

Microbial inoculation plays a significant role in promoting the efficiency of biowaste conversion. This study investigates the function of Streptomyces-Bacillus Inoculants (SBI) on carbon (C) and nitrogen (N) conversion, and microbial dynamics, during cow manure (10% and 20% addition) and corn straw co-composting. Compared to inoculant-free controls, inoculant application accelerated the compost's thermophilic stage (8 vs 15 days), and significantly increased compost total N contents (+47%) and N-reductase activities (nitrate reductase: +60%; nitrite reductase: +219%). Both bacterial and fungal community succession were significantly affected by DOC, urease, and NH4+-N, while the fungal community was also significantly affected by cellulase. The contribution rate of Cupriavidus to the physicochemical factors of compost was as high as 83.40%, but by contrast there were no significantly different contributions (∼60%) among the top 20 fungal genera. Application of SBI induced significant correlations between bacteria, compost C/N ratio, and catalase enzymes, indicative of compost maturation. We recommend SBI as a promising bio-composting additive to accelerate C and N turnover and high-quality biowaste maturation. SBI boosts organic cycling by transforming biowastes into bio-fertilizers efficiently. This highlights the potential for SBI application to improve plant growth and soil quality in multiple contexts.


Assuntos
Carbono , Compostagem , Nitrogênio , Streptomyces , Streptomyces/metabolismo , Nitrogênio/metabolismo , Carbono/metabolismo , Esterco , Bacillus/metabolismo , Bactérias/metabolismo
9.
Molecules ; 29(14)2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39064865

RESUMO

Hydrothermal carbonization (HTC) serves as a sustainable method to transform pine needle waste into nitrogen-doped (N-doped) hydrochars. The primary focus is on evaluating these hydrochars as catalytic electrodes for the oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR), which are pivotal processes with significant environmental implications. Hydrochars were synthesized by varying the parameters such as nitrogen loading, temperature, and residence time. These materials were then thoroughly characterized using diverse analytical techniques, including elemental analysis, density measurements, BET surface area analysis, and spectroscopies like Raman, FTIR, and XPS, along with optical and scanning electron microscopies. The subsequent electrochemical assessment involved preparing electrocatalytic inks by combining hydrochars with an anion exchange ionomer (AEI) to leverage their synergistic effects. To the best of our knowledge, there are no previous reports on catalytic electrodes that simultaneously incorporate both a hydrochar and AEI. Evaluation metrics such as current densities, onset and half-wave potentials, and Koutecky-Levich and Tafel plots provided insights into their electrocatalytic performances. Notably, hydrochars synthesized at 230 °C exhibited an onset potential of 0.92 V vs. RHE, marking the highest reported value for a hydrochar. They also facilitated the exchange of four electrons at 0.26 V vs. RHE in the ORR. Additionally, the CO2RR yielded valuable C2 products like acetaldehyde and acetate. These findings highlight the remarkable electrocatalytic activity of the optimized hydrochars, which could be attributed, at least in part, to their optimal porosity.

10.
Molecules ; 29(2)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38257398

RESUMO

The paper discusses the perspectives of further implementation of the autocatalytic properties of a soluble biopolymer (SBP) derived from municipal biowastes for the realisation of a biorefinery producing value-added bio-products for consumer use. The reaction of an SBP and water is reported to cause the depolymerisation and oxidation of the pristine SBP organic matter with the formation of carboxyl-functionalised polymers having lower molecular weight and CO2. These findings demonstrate the oxidation of the SBP via water, which could only occur through the production of O and OH radicals catalysed by the SBP. According to the adopted experimental plan, the anaerobic digestate supplied by an Italian municipal biowaste treatment plant was hydrolysed in pH 13 water at 60 °C. The dry product was re-dissolved in plain water at pH 10 and used as a control against the same solution with hydrogen peroxide at 0.1-3 H2O2 moles per SBP carbon mole added. The control and test solutions were kept at room temperature, in the dark or in a climatic chamber under irradiation with simulated solar light, until the pH of the solutions remained constant. Afterwards, the solutions were processed to recover and analyse the crude soluble products. The present work reports the results obtained for the control solution and for the test solutions treated in the presence and absence of H2O2, with and without pH control, in the dark and under irradiation with simulated solar light.


Assuntos
Peróxido de Hidrogênio , Polímeros , Humanos , Biopolímeros , Carbono , Água
11.
J Sci Food Agric ; 104(1): 21-31, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37555350

RESUMO

Agriculture products form the foundation building blocks of our daily lives. Although they have been claimed to be renewable resources with a low carbon footprint, the agricultural community is constantly challenged to overcome two post-harvest bottlenecks: first, farm bio-waste, a substantial economic and environmental burden to the farming sector, and second, an inefficient agricultural processing sector, plagued by the need for significant energy input to generate the products. Both these sectors require extensive processing technologies that are demanding in their energy requirements and expensive. To address these issues, an enzyme(s)-based green chemistry is available to break down complex structures into bio-degradable compounds that source alternate energy with valuable by-products and co-products. α-Galactosidase is a widespread class of glycoside hydroxylases that hydrolyzes α-galactosyl moieties in simple and complex oligo and polysaccharides, glycolipids, and glycoproteins. As a result of its growing importance, in this review we discuss the source of the enzyme, production and purification systems, and enzyme properties. We also elaborate on the enzyme's potential in agricultural bio-waste management, secondary agricultural industries like sugar refining, soymilk derivatives, food and confectionery, and animal feed processing. Insight into this vital enzyme will provide new avenues for less expensive green chemistry-based secondary agricultural processing and agricultural sustainability. © 2023 Society of Chemical Industry.


Assuntos
Gerenciamento de Resíduos , alfa-Galactosidase , Animais , Agricultura , Fazendas , Pegada de Carbono
12.
Microb Cell Fact ; 22(1): 246, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38053171

RESUMO

Biodiesel, unlike to its fossil-based homologue (diesel), is renewable. Its use contributes to greater sustainability in the energy sector, mainly by reducing greenhouse gas emissions. Current biodiesel production relies on plant- and animal-related feedstocks, resulting in high final costs to the prices of those raw materials. In addition, the production of those materials competes for arable land and has provoked a heated debate involving their use food vs. fuel. As an alternative, single-cell oils (SCOs) obtained from oleaginous microorganisms are attractive sources as a biofuel precursor due to their high lipid content, and composition similar to vegetable oils and animal fats. To make SCOs competitive from an economic point of view, the use of readily available low-cost substrates becomes essential. This work reviews the most recent advances in microbial oil production from non-synthetic sugar-rich media, particularly sugars from lignocellulosic wastes, highlighting the main challenges and prospects for deploying this technology fully in the framework of a Biorefinery concept.


Assuntos
Biocombustíveis , Saccharomyces cerevisiae , Óleos de Plantas
13.
Environ Res ; 227: 115780, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36990197

RESUMO

Hydrogen is a clean and green biofuel choice for the future because it is carbon-free, non-toxic, and has high energy conversion efficiency. In exploiting hydrogen as the main energy, guidelines for implementing the hydrogen economy and roadmaps for the developments of hydrogen technology have been released by several countries. Besides, this review also unveils various hydrogen storage methods and applications of hydrogen in transportation industry. Biohydrogen productions from microbes, namely, fermentative bacteria, photosynthetic bacteria, cyanobacteria, and green microalgae, via biological metabolisms have received significant interests off late due to its sustainability and environmentally friendly potentials. Accordingly, the review is as well outlining the biohydrogen production processes by various microbes. Furthermore, several factors such as light intensity, pH, temperature and addition of supplementary nutrients to enhance the microbial biohydrogen production are highlighted at their respective optimum conditions. Despite the advantages, the amounts of biohydrogen being produced by microbes are still insufficient to be a competitive energy source in the market. In addition, several major obstacles have also directly hampered the commercialization effors of biohydrogen. Thus, this review uncovers the constraints of biohydrogen production from microbes such as microalgae and offers solutions associated with recent strategies to overcome the setbacks via genetic engineering, pretreatments of biomass, and introduction of nanoparticles as well as oxygen scavengers. The opportunities of exploiting microalgae as a suastainable source of biohydrogen production and the plausibility to produce biohydrogen from biowastes are accentuated. Lastly, this review addresses the future perspectives of biological methods to ensure the sustainability and economy viability of biohydrogen production.


Assuntos
Cianobactérias , Microalgas , Fermentação , Cianobactérias/metabolismo , Hidrogênio/análise , Hidrogênio/metabolismo , Biocombustíveis , Biomassa
14.
Environ Res ; 220: 115075, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36566967

RESUMO

Biowaste generation is considerably increasing multiple times recently due to various social and environmental changes like population growth, economic prosperity, globalisation etc. they contain different composition and generated at different stages of their life cycle. Though studies reported for recycle, reproduce and reuse of them, this investigation is unique by focussing to investigate the ideal circumstances for the production of biogas and methane from anaerobic digestion of vegetable waste using response surface methods and artificial neural networks with thermophilic temperature range. Thermophilic temperature of 20.78, organic loading rate of 0.2, pH of 8.81, agitation time of 5.8 and hydro retention time of 3 are the ideal input parameter values for the generation of biogas 3.03 m3 and methane% 186.08 with a desirability of 1. The Response surface model was surpassed by the Artificial Neural Network model.


Assuntos
Biocombustíveis , Metano , Anaerobiose , Temperatura , Redes Neurais de Computação , Reatores Biológicos
15.
Environ Res ; 236(Pt 1): 116655, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37500043

RESUMO

The impact of biosynthesized zirconium nanoparticles originated from biological waste, blended in diesel fuel processed through bio-refining strategy and its combustion, emissions, and overall diesel engine performance towards safety has been examined. Different weight fractions of zirconia nanoparticles were combined with crude diesel at 10, 20, and 30 mg/L values. According to the engine tests, Zirconia (20 nm) added to pure diesel at a concentration of 30 parts per million incremented thermal efficiencies by 4.9% compared to regular diesel fuel. The average reduction in specific fuel consumption for clean diesel fuel when the engine was operating at full power was 2.9%, 3.9%, and 4.9%. Diesel smoke, hydrocarbon, CO, and NOx emissions were reduced by 13%, 20%, 25%, and 29%, respectively, when nano additives were used at a concentration of 30 ppm.Nanoparticles enhance fuel stability, overcome detonation difficulties, and avoid fouling spark plugs. The pressure within cylinder, the temperature, and the rate at which heat is released was improved when alumina nanoparticles were appended to diesel fuel. However, both the length of the combustion and further delay in ignition were cut down. The ideal concentration of zirconia nanoparticles for improving combustion, efficiency, and emissions along with safety attainment in an internal combustion engine is recorded at 30 ppm.

16.
Environ Res ; 218: 115013, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36495970

RESUMO

Food loss or waste is a far-reaching problem and has indeed become a worrying issue that is growing at an alarming rate. Fruits and vegetables are lost or wasted at the highest rate among the composition of food waste. Furthermore, the world is progressing toward sustainable development; hence, an efficient approach to valorise fruit and vegetable waste (FVW) is necessary. A simple phenotypic characterisation of microbiota isolated from the fermented FVW was conducted, and its effectiveness toward wastewater treatment was investigated. Presumptive identification suggested that yeast is dominant in this study, accounting for 85% of total isolates. At the genus level, the enriched medium's microbial community consists of Saccharomyces, Bacillus and Candida. Ammonium in the wastewater can enhance certain bacteria to grow, such as lactic acid bacteria, resulting in decreased NH4+ concentration at the end of the treatment to 0.5 mg/L. In addition, the fermented biowaste could reduce PO43- by 90% after the duration of treatment. Overall, FVW is a valuable microbial resource, and the microbial population enables a reduction in organic matter such as NH4+ and PO43-. This study helps explore the function and improve the effectiveness of utilising biowaste by understanding the microorganisms responsible for producing eco-enzyme.


Assuntos
Eliminação de Resíduos , Purificação da Água , Verduras , Frutas , Águas Residuárias , Fermentação
17.
Environ Res ; 226: 115715, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36934862

RESUMO

Corncob (CC) is an industrial biological waste that is generated in significant quantities, and converting such biological wastes into value-added hydrochars through a viable process such as hydrothermal carbonization can provide significant benefits. It is of great importance to ensure eco-friendly and appropriate methods that are suitable for the area where the hydrochar will be used. This study aimed to synthesize hydrochars from a solid food waste, CC, using two different hydrothermal carbonization methods based on microwave-assisted (MHC) and subcritical water (SHC) using them as a biosorbent for NH4+ adsorption from water and characterizing their specific features. Hydrochars were synthesized in 1 h at 180 °C and 240 °C by MHC and SHC methods, respectively. Hydrochars synthesized by MHC and SHC methods were characterized by SEM-EDX, N2 adsorption-desorption isotherms, and FT-IR analyses. According to the EDX results, the C/O ratio (atomic %) in MHC and SHC was determined to be 0.55 and 0.35, respectively. Nitrogen adsorption-desorption isotherms revealed that hydrochars obtained by both methods have three distinct pore types, namely, micro, meso, and macro. In the energy consumption per unit adsorbent, a lower value was obtained for MHC than SHC. NH4+ adsorption using MHC and SHC was found to be compatible with the Langmuir isotherm model and the NH4+ adsorption capacities were 13.09 and 10.54 mg/g, respectively. pH was the most effective variable on hydrochars in the NH4+ adsorption based on the response surface method (RSM), and the highest adsorption occurred at pH 6.5 and 40 mg/L of initial NH4+ concentration, using 1.5 g/L of adsorbent at 35 °C. The results revealed that MHC is a unique method that can be used for hydrochars derived from CC in NH4+ adsorption, and MHC is more cost-effective than SHC in hydrochar production.


Assuntos
Alimentos , Eliminação de Resíduos , Zea mays , Micro-Ondas , Água , Espectroscopia de Infravermelho com Transformada de Fourier , Adsorção , Carbono
18.
Environ Res ; 216(Pt 2): 114543, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36252841

RESUMO

Globally, to ensure food security bio-based fertilizers must replace a percentage of chemical fertilizers. Such replacement must be deemed sustainable from agronomic and greenhouse gas (GHG) emission perspectives. For agronomic performance several controlled protocols are in place but not for testing GHG emissions. Herein, a pre-screening tool is presented to examine GHG emissions from bio-waste as fertilizers. The various treatments examined are as follows: soil with added mineral nitrogen (N, 140 kg N ha-1) fertilizer (MF), the same amount of MF combined with dairy processing sludge (DS), sludge-derived biochar produced at 450 °C (BC450) and 700 °C (BC700) and untreated control (CK). These treatments were combined with Danish (sandy loam) or Irish (clay loam) soils, with carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions and soil inorganic-N contents measured on selected days. During the incubation, biochar mitigated N2O emissions by regulating denitrification. BC450 reduced N2O emissions from Danish soil by 95.5% and BC700 by 97.7% compared to emissions with the sludge application, and for Irish soil, the N2O reductions were 93.6% and 32.3%, respectively. For both soils, biochar reduced CO2 emissions by 50% as compared to the sludge. The lower N2O reduction potential of BC700 for Irish soil could be due to the high soil organic carbon and clay content and pyrolysis temperature. For the same reasons emissions of N2O and CO2 from Irish soil were significantly higher than from Danish soil. The temporal variation in N2O emissions was correlated with soil inorganic-N contents. The CH4 emissions across treatments were not significantly different. This study developed a simple and cost-effective pre-screening method to evaluate the GHG emission potential of new bio-waste before its field application and guide the development of national emission inventories, towards achieving the goals of circular economy and the European Green Deal.


Assuntos
Gases de Efeito Estufa , Solo , Solo/química , Fertilizantes/análise , Esgotos , Dióxido de Carbono/análise , Argila , Carbono , Óxido Nitroso , Metano/análise , Dinamarca , Agricultura
19.
Environ Res ; 231(Pt 2): 116210, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37217132

RESUMO

Soil erosion is a serious and complex environmental problem worldwide, especially in the centre west of Tunisia. Whereas the construction of hill reservoirs is part of the soil and water conservation strategy, many of these have a siltation problem. Dhkekira is one of the smallest watersheds in central Tunisia whose most lithological formation consists of materials that are quite susceptible to water erosion. Due to the lack of low-scale lithological data, digital IR aerial photos with 2 m spatial resolution were considered. A semi-automatic classification of aerial photos, based on the image's textural indices is developed. The lithologic map extracted from aerial photos was used as input for ANSWERS-2000 water erosion model. Results obtained indicate first, with the semi-automatic classification of the mean and standard deviation of the thumbnail histograms that image output could help to give an idea about the existence of some surface lithological formation. The model applied to Dhkekira watershed showed that the spatial difference in water erosion was not caused only by land cover and slope, but also by lithological formation. The percentage of each lithological formation in sediment yield at the Dhkekira hill reservoir was estimated to be 69% sediment yield from Pleistocene and 19.7% from Lutetian-Priabonian.


Assuntos
Recuperação e Remediação Ambiental , Erosão do Solo , Conservação dos Recursos Naturais/métodos , Água , Monitoramento Ambiental/métodos , Solo
20.
Biotechnol Appl Biochem ; 70(5): 1629-1640, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36964948

RESUMO

Bacteria are considered mini chemical factories that help us in providing a wide range of products for various purposes. These days, bacterial cellulose (BC) is getting attention by researchers due to its quality, eco-friendly nature, and excellent physical-mechanical qualities. It is being used in the fabrication of nanocomposites. Its nanocomposites can be used in various industries, including medicine, food, leather, textiles, environment, electronics, and cosmetics. This area of research is emerging and still in its infancy stage, as new applications are still coming up. Most of the work on BC has been done during the last two decades and serious inputs are required in this direction in order to make the production process commercially viable and ultimately the application part. Biowastes, such as fruits and vegetables wastes, can be used as a cost-effective medium to minimize the cost for large-scale production of BC-based nanocomposites thus will valorize the biowaste material into a valuable product. Using biowaste as media will also aid in better waste management along with reduction in detrimental environmental effects. This review will help the readers to understand the potential applications of BC and its nanocomposites as well as their vital role in our daily lives.


Assuntos
Celulose , Nanocompostos , Bactérias , Indústrias
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