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1.
Chemosphere ; 338: 139623, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37487986

RESUMO

This work presents an integrated approach for the extraction of lipids from marine macroalgae using RSM optimization and thermo-kinetic analysis. The lipids were extracted from marine macroalgal biomass using a Soxhlet extractor. The Soxhlet extraction parameters, including temperature (60-80 °C), solvent-to-algae ratio (3:1-7:1), algal particle size (0.05-0.25 mm), and extraction time (60-180 min), were optimized using RSM to achieve the maximum possible lipid extraction yield from marine macroalgae. The highest lipid extraction yield of 12.76% was obtained using the optimized conditions, which included an extraction temperature of 72 °C, a solvent-to-algae ratio of 5:1, an algal particle size of 0.16 mm, and an extraction time of 134 min. The kinetic analysis revealed an activation energy of 52.79 kJ mol-1 for the Soxhlet extraction process. The thermodynamic analysis of the Soxhlet extraction process demonstrated the following results: ΔH = 49.98 kJ mol-1, ΔS = -128.24 J K-1 mol-1, and ΔG = 93.98 kJ mol-1. The GC-MS analysis confirmed that the extracted algal lipids exhibited a composition of 14.20% palmitic acid, 4.89% stearic acid, and 76.97% oleic acid. The physiochemical analysis ensured that the extracted algal lipids possess excellent qualities, making them desirable for sustainable biofuel production.


Assuntos
Alga Marinha , Cinética , Temperatura , Termodinâmica , Solventes , Lipídeos/análise
2.
RSC Adv ; 13(32): 22017-22028, 2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37483669

RESUMO

Metal sulfides and 2D materials are the propitious candidates for numerous electrochemical applications, due to their superior conductivity and ample active sites. Herein, CuS nanoparticles were fabricated on 2D greener HF-free Cl-terminated MXene (Ti3C2Cl2) sheets by the hydrothermal process as a proficient electrocatalyst for the hydrogen evolution reaction (HER) and overall water splitting. CuS/Ti3C2Cl2 showed an overpotential of 163 mV and a Tafel slope of 77 mV dec-1 at 10 mA cm-2 for the HER. In the case of the OER, CuS/Ti3C2Cl2 exhibited an overpotential of 334 mV at 50 mA cm-2 and a Tafel slope of 42 mV dec-1. Moreover, the assembled CuS/Ti3C2Cl2||CuS/Ti3C2Cl2 electrolyzer delivered current density of 20 mA cm-2 at 1.87 V for overall water splitting. The CuS/Ti3C2Cl2 electrocatalyst showed excellent stability to retain 96% of its initial value for about 48 hours at 100 mA cm-2 current density. The synthesis of CuS/Ti3C2Cl2 enriches the applications of MXene/metal sulfides in efficient bifunctional electrocatalysis for alkaline water splitting.

3.
Chemosphere ; 337: 139226, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37379972

RESUMO

In the leather industry, tannery sludge is produced in large volume. This study investigated the thermal degradation behavior of tannery sludge using thermogravimetric analysis (TGA). The experiments were carried out in an inert atmosphere using nitrogen gas at varied heating rates of 5, 10, 20, and 40 °C/min in the temperature range of 30-900 °C. For the kinetic parameters calculation, three different models, Friedman, Kissinger-Akahira-Sunose (KAS) and the Ozawa-Flynn-Wall (OFW), were employed. The average activation energy (Ea) obtained from Friedman, KAS, and the OFW methods were 130.9 kJ mol-1, 143.14 kJ mol-1, and 147.19 kJ mol-1 respectively. Along with that, experiment of pyrolysis was accomplished in fixed bed reactor (FBR) at temperature of 400 °C. Biochar produced from FBR had a yield of about 71%. The analysis of gas chromatography-mass spectroscopy shows the different chemical compounds present in the bio-oil containing hydrocarbons (alkanes and alkenes), oxygen containing compounds (alcohols, aldehyde, ketones, esters carboxylic acids and the esters) and the nitrogen containing compounds. The kinetic assessment was complemented by distributed activation energy model (DAEM). In the pyrolysis of tannery sludge six pseudo-components were found to be involved. Furthermore, artificial neural network (ANN) was used to predict the activation energy from conversion, temperature, and the heating rate data. MLP-3-11-1 (Multilayer Perceptrons) described well the conversion behavior of tannery sludge pyrolysis.


Assuntos
Pirólise , Esgotos , Termogravimetria , Cinética , Redes Neurais de Computação , Nitrogênio , Biomassa
4.
Heliyon ; 9(3): e14237, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36950658

RESUMO

In this research, a dielectric barrier discharge (DBD) reactor is used to study the cracking of the toluene into C1-C6 hydrocarbons. The combined effect of parameters such as temperature (20-400 °C) and plasma power (10-40 W) was investigated to evaluate the DBD reactor performance. The main gaseous products from the decomposition of toluene include lower hydrocarbon (C1-C6). The cracking of toluene increases with power at all temperatures (20-400 °C). On the otherhand, it decreases from 92.8 to 73.1% at 10 W, 97.2 to 80.5% at 20, 97.5 to 86.5% at 30 W, and 98.4 to 93.7% at 40 W with raising the temperature from 20 to 400 °C. Nonetheless, as the temperature and plasma input power increase, the methane yield increases. At 40 W, the maximum methane yield was 5.1%. At 10 and 20 W, the selectivity to C2 increases as the temperature rises up to 400 °C. At 30 and 40 W, it began to drop after 300 °C due to the formation of methane and the yield of methane increases significantly beyond this temperature.

5.
Chemosphere ; 326: 138448, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36940825

RESUMO

The substantial quantity of Cr(VI) contaminants in the aqueous atmosphere is a major environmental fear that cannot be overlooked. For the first time, MXene and chitosan-coated polyurethane foam have been employed for wastewater treatment, including heavy metal ions (Cr (VI)) through a fixed-bed column study. It is also the most inexpensive, lightweight, and globally friendly material tested. The Mxene and chitosan-coated polyurethane foam hybrid materials were thoroughly investigated using FTIR (Fourier transform infrared), SEM (scanning electron microscope), XPS (X-ray photoelectron spectroscopy) and XRD (X-ray diffraction). The presence of the rough surface and the pore creation in the Mxene- MX3@CS3@PUF should rise its surface area, which is useful to interact the surface-active assembly of MX3@CS3@PUF and the Cr(VI) contaminations in the aqueous solution. With the help of the ion exchange mechanism and electrostatic contact, negatively charged MXene hexavalent ions were being adsorbed on the surface. MXene and chitosan have been coated on PUF foam in the form of three different layers, which shows the highest adsorption capacity, where up to ∼70% Cr (VI) was removed in the first 10 min and more than 60% elimination after 3 h when the metal ion concentration was 20 ppm. The electrostatic interaction between the negative charge MXene and the positive charge chitosan on the surface of PUF, which was absent in MX@PUF, is accountable for the high removal efficiency. This was done through a sequence of fixed-bed column studies, which took place in the continuous flowing of wastewater.


Assuntos
Quitosana , Poluentes Químicos da Água , Águas Residuárias , Quitosana/química , Poluentes Químicos da Água/análise , Cromo/química , Água/química , Íons , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
6.
RSC Adv ; 13(2): 1137-1161, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36686941

RESUMO

Worldwide demand for oil, coal, and natural gas has increased recently because of odd weather patterns and economies recovering from the pandemic. By using these fuels at an astonishing rate, their reserves are running low with each passing decade. Increased reliance on these sources is contributing significantly to both global warming and power shortage problems. It is vital to highlight and focus on using renewable energy sources for power production and storage. This review aims to discuss one of the cutting-edge technologies, metal-air batteries, which are currently being researched for energy storage applications. A battery that employs an external cathode of ambient air and an anode constructed of pure metal in which an electrolyte can be aqueous or aprotic electrolyte is termed as a metal-air battery (MAB). Due to their reportedly higher energy density, MABs are frequently hailed as the electrochemical energy storage of the future for applications like grid storage or electric car energy storage. The demand of the upcoming energy storage technologies can be satisfied by these MABs. The usage of metal-organic frameworks (MOFs) in metal-air batteries as a bi-functional electrocatalyst has been widely studied in the last decade. Metal ions or arrays bound to organic ligands to create one, two, or three-dimensional structures make up the family of molecules known as MOFs. They are a subclass of coordination polymers; metal nodes and organic linkers form different classes of these porous materials. Because of their modular design, they offer excellent synthetic tunability, enabling precise chemical and structural control that is highly desirable in electrode materials of MABs.

7.
Chemosphere ; 316: 137826, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36640973

RESUMO

Textile industries release effluent that contains the vast majority of heavy metals in which Cr (VI) is a toxic carcinogenic element that causes an environmental problem. The aim of the work is to synthesize algae-derived biochar derived from algae using slow pyrolysis at an operating temperature of 500 °C, a heating rate of 10 °C/min and a residence time of 60 min and to use it as an adsorbent to remove Cr (VI). The batch experiment was carried out using different concentrations of Cr (VI) (1, 10, 25, 50, 100, 125, 150 and 200 ppm) at different intervals of time (2.5, 5, 10, 15, 30, 60, 120 and 240 min). The maximum removal percentage of Cr (VI) is 97.88% for the metal concentration of 1 ppm exhibiting non-linear adsorption isotherm (Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin models) and kinetic models (pseudo-first order, pseudo-second order, nth order, and intra-particle diffusion) were analyzed using a solver add-in of Microsoft Excel. According to the results, the Langmuir isotherm model (R2 = 0.999) and pseudo-nth order models are suitable to describe monolayer adsorption and the process kinetics, respectively. The maximum adsorption capacity of algal biochar to adsorb is 186.94 mg/g. For the prediction of the optimal removal efficacy, an artificial neural network of the MLP-2-7-1 model was used. The results obtained are useful for future work using algal biochar as an adsorbent of Cr (VI) from textile wastewater to achieve sustainable development goals.


Assuntos
Cromo , Poluentes Químicos da Água , Cromo/análise , Águas Residuárias , Indústria Têxtil , Concentração de Íons de Hidrogênio , Carvão Vegetal , Cinética , Adsorção
8.
Environ Res ; 217: 114876, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36435501

RESUMO

Chemical looping combustion (CLC) is a promising technology that generates energy while inherently separating carbon dioxide from air using oxygen carriers. This allows for an efficient and cost-effective means of carbon capture and storage. Current CLC systems use coal with metal oxides for combustion in the fuel reactor, thus, resulting in some environmental impacts. Recent life cycle assessment (LCA) of CLC studies have indicated the environmental impacts of conventional coal-based CLC, especially on the global warming potential. To mitigate these environmental impacts, this study proposes the use of a biomass-based CLC and evaluates its impacts using LCA. A case study in the Philippines is adopted where rice husks are used as biomass feedstock. A kilowatt-hour of electricity generated from the CLC plant is utilized as the functional unit. A relative comparison of environmental impacts was considered between the coal-based power plant, the coal-based CLC plant, and the biomass-based CLC plant. The single score results have shown that the biomass-based CLC has the least environmental impacts relative to the coal-based power plant and the coal-based CLC plant. However, it is noted that water consumption is the main drawback of utilizing rice husks as CLC biomass feedstock. The majority of the environmental impacts of the coal-based CLC and the coal-based power plant were derived from upstream processes such as coal mining and processing. With the use of rice husks as CLC biomass feedstock, net negative emissions were achieved.


Assuntos
Carvão Mineral , Óxidos , Animais , Biomassa , Dióxido de Carbono , Estágios do Ciclo de Vida
9.
Chemosphere ; 309(Pt 1): 136622, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36181837

RESUMO

Lubricants operate as antifriction media, preserving machine reliability, facilitating smooth operation, and reducing the likelihood of frequent breakdowns. The petroleum-based reserves are decreasing globally, leading to price increases and raising concerns about environmental degradation. The researchers are concentrating their efforts on developing and commercializing an environmentally friendly lubricant produced from renewable resources. Biolubricants derived from nonedible vegetable oils are environmentally favorable because of their non-toxicity, biodegradability, and close to net zero greenhouse gas emissions. The demand for bio lubricants in industry and other sectors is increasing due to their non-toxic, renewable, and environmentally friendly nature. Good lubrication, anti-corrosion, and high flammability are characteristic properties of vegetable oils due to their unique structure. This study presents several key properties of nonedible oils that are used to produce lubricants via the transesterification process. Bibliometric analysis is also performed, which provides us with a better understanding of previous studies related to the production of bio lubricants from the transesterification process. Only 371 published documents in the Scopus database were found to relate to the production of bio lubricants using the transesterification process. The published work was mostly dominated by research articles (286; 77.088%). Significant development can be seen in recent years, with the highest occurrence in 2021, reaching 68 publications accounting for 18.38% of the total documents. In the second step, (i) the authors with the most number of publications; (ii) journals with the most productions; (iii) most productive countries; and (iv) the authors' most frequently used keywords were evaluated. These results will provide a pathway for researchers interested in this field. Lastly, recommendation is made on research gaps to device possible strategies for its commercialization.


Assuntos
Gases de Efeito Estufa , Petróleo , Reprodutibilidade dos Testes , Lubrificantes/química , Óleos de Plantas
10.
Chemosphere ; 307(Pt 4): 136001, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35987263

RESUMO

Purification of Natural gas is vital for utilizing it as a source of energy harvesting for the world. Amine-based chemical absorption technique is the most utilized in the gas field for the purification of gas that ensures the purity of the sweet gas stream with the elimination of carbon dioxide. However, it is considered an energy-intensive process to deal with considerable energy loss and environmental damage to the ecosystem. Five cases have been developed in this study based on various blends comprising mono and tertiary amines in combination with piperazine with a focus on the use of Aqueous Monodiethanolamine (Aq. MDEA), Aqueous Monoethanolamine (Aq. MEA) and piperazine (Pz) for the CO2 sequestration from the sour natural gas extracted from the remote location located in the province of Baluchistan in Pakistan. The use of exergy, advanced exergy, and exergo environment for optimizing and selecting a suitable solvent combination that may result in an effective separation process has been proposed. Five cases have been developed based on various blends such as mono and tertiary amines combined with piperazine. From the results of all the studied scenarios, Case IV, based on the combination of Aqueous monoethanolamine and piperazine, provides reduced exergy destruction of 2551.7 KW. It was observed that the maximum removal of CO2 around 99.87 wt% is achieved in case IV. In addition, advance exergy analysis also highlights that case-IV has a venue of 25% exergy destruction avoidable, which would further enhance its performance. Nevertheless, still, case-IV has 75% exergy destruction unavoidable. The environmental factors show that Case-IV has a reduced exergy destruction factor of 0.96, a highly environmentally benign choice as a solvent with a high value of 1.03, and case-IV has the higher operational stability and higher exergy efficiency with an exergy stability value of 0.40. Therefore, monoethanolamine combined with piperazine to be an effective and efficient solvent blend that could be an energy-effective approach for sweetening the natural gas.


Assuntos
Aminas , Etanolamina , Dióxido de Carbono , Ecossistema , Gás Natural , Piperazina , Solventes , Água
11.
Chemosphere ; 306: 135565, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35793745

RESUMO

Textile industry utilize a massive amount of dyes for coloring. The dye-containing effluent is released into wastewater along with heavy metals that are part of dye structure. The treatment of textile industry wastewater using conventional techniques (coagulation, membrane technique, electrolysis ion exchange, etc.) is uneconomical and less efficient (for a low concentration of pollutants). Moreover, most of these techniques produce toxic sludge, making them less environmentally friendly. Algae base industry is growing for food, cosmetics and energy needs. Algae biomass in unique compared to lignocellulosic biomass due to presence of various functional group on its surface and presence of various cations. These two characteristics are unique for biochar as a tool for environmental decontamination. Algae biomass contain functional groups and cations that can be effective for removal of organic contaminants (dyes) and heavy metals. Algae can be micro and macro and both have entirely different biomass composition which will lead to a synthesis of different biochar even under same synthesis process. This study reviews the recent progress in the development of an economically viable and eco-friendly approach for textile industry wastewater using algae biomass-derived absorbents. The strategy employed microalgal biochar to remove organic pollutants (dyes) and heavy metals from textile effluents by biosorption. This article discusses different methods for preparing algal biochar (pyrolysis, hydrothermal carbonization and torrefaction), and the adsorption capacity of biochar for dyes and heavy metals. Work on hydrothermal carbonization and torrefaction of microalgal biomass for biochar is limited. Variation in structural and functional groups changes on biochar compared to original microalgal biomass are profound in contract with lignocellulosic biomass. Existing Challenges, future goals, and the development of these technologies at the pilot level are also discussed.


Assuntos
Poluentes Ambientais , Metais Pesados , Microalgas , Adsorção , Biomassa , Cátions , Carvão Vegetal , Corantes/química , Indústria Têxtil , Águas Residuárias
12.
Environ Dev Sustain ; : 1-39, 2022 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-35530442

RESUMO

Abstract: The global market for fuel pellets (FPs) has been steadily growing because of a shift to coal substitutes. However, sustainability and the availability of biomass are the main issues. Various kinds of bio-wastes can be valorized through cutting-edge technologies. In the coffee industry, a valuable organic waste called spent coffee grounds (SCGs) is generated in bulk. SCG can be divided into two components, namely spent coffee ground oil and defatted spent coffee grounds (DSCG). SCG and DSCG can be used to produce FPs with excellent higher heating values. This review highlights that burning FPs composed of 100% SCG is not feasible due to the high emission of NOx. Moreover, the combustion is accompanied by a rapid temperature drop due to incomplete combustion which leads to lower boiler combustion efficiencies and increased carbon monoxide emissions. This was because of the low pellet strength and bulk density of the FP. Mixing SCG with other biomass offers improved boiler efficiency and emissions. Some of the reported optimized FPs include 75% SCG + 20% coffee silverskin, 30% SCG + 70% pine sawdust, 90% SCG + 10% crude glycerol, 32% SCG + 23% coal fines + 11% sawdust + 18% mielie husks + 10% waste paper + 6% paper pulp, and 50% SCG + 50% pine sawdust. This review noted the absence of combustion and emissions analyses of DSCG and the need for their future assessment. Valorization of DSCG offers a good pathway to improve the economics of an SCG-based biorefinery where the extracted SCGO can be valorized in other applications. The combustion and emissions of DSCG were not previously reported in detail. Therefore, future investigation of DSCG in boilers is essential to assess the potential of this industry and improve its economics. Supplementary Information: The online version contains supplementary material available at 10.1007/s10668-022-02361-z.

13.
J Biotechnol ; 345: 30-39, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-34995559

RESUMO

The economic viability of microalgae as a bioenergy source depends on many factors. High CO2 fixing rate, improved lipids yield, and minimum water footprint are few key parameters. This study investigates the effect of four initial nitrogen concentrations (1-, 2-, 6- and 10-mM as nitrate) on lipids yield, their classification and composition, CO2 fixation rate, and water quality for further reuse after first cultivation. The initial 6 mM nitrate was found optimum for the growth and overall lipid productivity of Chlorella vulgaris. The maximum quantum efficiency (as Fv/Fm ratio) for algae decreases along with the cell growth profile and depletion of the initial nitrate concentration. CO2 fixation rate increased initially and peaked during exponential growth and then declined for the rest of the cultivation period. A higher CO2 fixation rate was recorded at 6 mM, and an overall fixation rate of CO2 was high at 6 mM. A higher total organic carbon (TOC) is produced in recycled water at a low nitrogen concentration of 1 and 2 mM. TOC changes during the cultivation period and with each reuse of water. Water was recycled twice successfully, while growth was inhibited during the 3rd cycle. Based on all these investigations, 6 mM of initial nitrogen was found optimal at given growth conditions.


Assuntos
Chlorella vulgaris , Microalgas , Biocombustíveis , Biomassa , Dióxido de Carbono , Lipídeos , Nitrogênio/análise , Águas Residuárias
14.
Chemosphere ; 286(Pt 2): 131730, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34364231

RESUMO

Coffee is a globally consumed beverage that produces a substantial amount of valuable organic waste known as spent coffee grounds (SCG). Although SCG is a non-edible biomass, research initiatives focused on valorizing/utilizing its organic content, protecting the environment, and reducing the high oxygen demand required for its natural degradation. The integration with biorefinery in general and with pyrolysis process in specific is considerered the most successful solid waste management strategy of SCG that produce energy and high-value products. This paper aims at providing a quantitative analysis and discussion of research work done over the last 20 years on SCG as a feedstock in the circular bioeconomy (CBE). Management stratigies of SCG have been thoroughly reviewed and pyrolysis process has been explored as a novel technology in CBE. Results revealed that explored articles belong to Chemical, physical., biological and environmental science branches, with Energy & Fuels as the most reporting themes. Published works correlate SCG to renewable energy, biofuel, and bio-oil, with pyrolysis as a potential valorization approach. Literature review showed that only one study focused on the pyrolysis of defatted spent coffee grounds (DSCG). The insightful conclusions of this paper could assist in proposing several paths to more economically valorization of SCG through biorefinery, where extracted oil can be converted to biofuels or value-added goods. It was highlighted the importance of focusing on the coupling of SCG with CBE as solid waste managment strategy.


Assuntos
Café , Gerenciamento de Resíduos , Biocombustíveis , Pirólise , Resíduos Sólidos
15.
ACS Omega ; 6(33): 21316-21326, 2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34471736

RESUMO

It is extremely prudent and highly challenging to design a greener bifunctional electrocatalyst that shows effective electrocatalytic activity and high stability toward electrochemical water splitting. As several hundred tons of catalysts are annually deactivated by deposition of carbon, herein, we came up with a strategy to reutilize spent methane reforming catalysts that were deactivated by the formation of graphitic carbon (GC) and carbon nanofibers (CNF). An electrocatalyst was successfully synthesized by in situ deposition of noble metal-free MoS2 over spent catalysts via a hydrothermal method that showed exceptional performance regarding the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). At 25 mA cm-2, phenomenal OER overpotentials (η25) of 128 and 154 mV and modest HER overpotentials of 186 and 207 mV were achieved for MoS2@CNF and MoS2@GC, respectively. Moreover, OER Tafel slopes of 41 and 71 mV dec-1 and HER Tafel slopes of 99 and 107 mV dec-1 were obtained for MoS2@CNF and MoS2@GC, respectively. Furthermore, the synthesized catalysts exhibited good long-term durability for about 18 h at 100 µA cm-2 with unnoticeable changes in the linear sweep voltammetry (LSV) curve of the HER after 1000 cycles. The carbon on the spent catalyst increased the conductivity, while MoS2 enhanced the electrocatalytic activity; hence, the synergistic effect of both materials resulted in enhanced electrocatalysts for overall water splitting. This work of synthesizing enhanced nanostructured electrocatalysts with minimal usage of inexpensive MoS2 gives a rationale for engineering potent greener electrocatalysts.

16.
Expert Syst Appl ; 185: 115695, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34400854

RESUMO

During the current global public health emergency caused by novel coronavirus disease 19 (COVID-19), researchers and medical experts started working day and night to search for new technologies to mitigate the COVID-19 pandemic. Recent studies have shown that artificial intelligence (AI) has been successfully employed in the health sector for various healthcare procedures. This study comprehensively reviewed the research and development on state-of-the-art applications of artificial intelligence for combating the COVID-19 pandemic. In the process of literature retrieval, the relevant literature from citation databases including ScienceDirect, Google Scholar, and Preprints from arXiv, medRxiv, and bioRxiv was selected. Recent advances in the field of AI-based technologies are critically reviewed and summarized. Various challenges associated with the use of these technologies are highlighted and based on updated studies and critical analysis, research gaps and future recommendations are identified and discussed. The comparison between various machine learning (ML) and deep learning (DL) methods, the dominant AI-based technique, mostly used ML and DL methods for COVID-19 detection, diagnosis, screening, classification, drug repurposing, prediction, and forecasting, and insights about where the current research is heading are highlighted. Recent research and development in the field of artificial intelligence has greatly improved the COVID-19 screening, diagnostics, and prediction and results in better scale-up, timely response, most reliable, and efficient outcomes, and sometimes outperforms humans in certain healthcare tasks. This review article will help researchers, healthcare institutes and organizations, government officials, and policymakers with new insights into how AI can control the COVID-19 pandemic and drive more research and studies for mitigating the COVID-19 outbreak.

17.
PLoS One ; 16(7): e0254485, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34270603

RESUMO

Application of advanced pyrolysis processes to agricultural waste for liquid production is gaining great attention, especially when it is applied to an economic crop like tobacco. In this work, tobacco residues were pyrolyzed in an ablative reactor under vacuum. The maximum bio-oil yield of 55% w/w was obtained at 600°C with a particle size of 10 mm at a blade rotation speed of 10 rpm. The physical properties of the products showed that the oil produced was of high quality with high carbon, hydrogen, and calorific value. Two-dimensional gas chromatography/time-of-flight mass spectrometric analysis results indicated that the oils were complex mixtures of alkanes, benzene derivative groups, and nitrogen-containing compounds. In addition, 13C NMR results confirmed that long aliphatic chain alkanes were evident. The alkanes were likely converted from furans that were decomposed from hemicelluloses. Ablative pyrolysis under vacuum proved to be a promising option for generating useful amount of bio-oils from tobacco residues.


Assuntos
Nicotiana/química , Óleos de Plantas/química , Pirólise , Resíduos , Alcanos/química , Benzeno/química , Celulose/análogos & derivados , Carvão Vegetal/química , Furanos/química , Vácuo
18.
J Hazard Mater ; 418: 126381, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329008

RESUMO

As plastics have been omnipresent in society ever since their introduction in 1907, global plastic production has ballooned in the 20th century or the Plasticene Era (Plastic Age). After their useful life span, they deliberately or accidentally, are disposed of in the environment. Influenced by different factors, plastics undergo fragmentation into microplastics (MPs) and present hazardous risks in all life forms including humans. Obliterating MPs from the environment has been a global challenge for the attainment of sustainable development goals (SDGs). This review aims to present MP degradation routes with a great focus on the thermodegradation and biodegradation routes as sustainable routes of MP degradation. These routes can achieve the reduction and obliteration of MPs in the environment, thus reducing their hazardous effects. Moreover, the thermodegradation of MPs can produce fuels that help solve the dilemma of energy security. Overall, continued research and development are still needed, however, these novel approaches and the increased awareness of the microplastics' hazards give us hope that we can achieve sustainable development in the near future.


Assuntos
Microplásticos , Poluentes Químicos da Água , Biocombustíveis , Monitoramento Ambiental , Humanos , Plásticos , Poluentes Químicos da Água/análise
19.
Chemosphere ; 285: 131382, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34329141

RESUMO

Agro-Wastes are identified as to manufacture potential valuable organic biochar fertilizer product economically while also managing the waste. Biochar (BC) produced from agriculture waste is helps to improve the soil because of its neutral pH, addition of organic carbon to the soil and lower salt index values. This study focused on the development of nano-biochar into a more enhanced biochar product where it was checked whether the biochar derived from wheat straw can absorb nutrients and then act as support matter for releasing micro-nutrients and macro-nutrients for the plants on slow liberation basis. Wheat biochar (WBC) and wheat nano-biochar (WBNC) were synthesized by pyrolysis at two different temperatures and nutrients were fused into the WBC via impregnation technique. Physical parameters such as Proximate, Ultimate analysis & other were also studied and inspected by standard control procedures. Studies were also carried out on water retention (WR), water absorbance (WA), swelling ratio (SR) and equilibrium water content (EWC) for all samples; data was collected and compared for the better sample. Slow-release studies performed portrayed the release pattern of nutrients for prolonged periods, which are very important for the plant growth, yield and productivity. Overall, the experimental results displayed that BNC produced at 350 °C showed promising features of (SI:0.05, SR: 3.67, WA:64%, EWC:78.6%, FC:53.05% and pH:7.22), is a good substance however the nano-biochar has improved results; environmental friendly & could be utilized as a potential fertilizer on slow release for sustainable and green agriculture application.


Assuntos
Fertilizantes , Triticum , Agricultura , Carvão Vegetal
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