Displaying publications 141 - 160 of 515 in total

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  1. Fulltext Supercritical fluid extraction of bioactive flavonoid from Strobilanthes crispus (pecah kaca) and its comparison with solvent extraction
    Liza, M.S., Abdul Rahman, R., Mandana, B., Jinap, S., Rahmat, A., Zaidul, I.S.M., et al.
    International Food Research Journal, 2012;19(2):503-508.
    MyJurnal
    Supercritical carbon dioxide extraction (SC-CO2) of bioactive flavonoid from Strobilanthes crispus (Pecah Kaca) was performed to study the effects of various parameters such as pressure, temperature and dynamic extraction time on the yield and composition of bioactive flavonoid. The results were also compared with those obtained by conventional Soxhlet extraction in lab conditions. The results from SFE showed that the effect of extraction variables on extraction yields decreased in the following order: pressure, temperature and dynamic extraction time. The extraction pressure played a dominant role in the yield of the sample while the effect of time could be ignored. This study also revealed that both Soxhlet extraction and SC-CO2 extraction can be used to obtain flavonoid compound. Under the optimum conditions, the highest bioactive flavonoid compound content was obtained at 3.98% and eight flavonoid compounds were identified by HPLC.
    Matched MeSH terms: Carbon Dioxide
  2. Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane
    Khairudin NF, Sukri MFF, Khavarian M, Mohamed AR
    Beilstein J Nanotechnol, 2018;9:1162-1183.
    PMID: 29719767 DOI: 10.3762/bjnano.9.108
    Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.
    Matched MeSH terms: Carbon Dioxide
  3. Carbon dioxide (CO2) emissions and economic growth: A systematic review of two decades of research from 1995 to 2017
    Mardani A, Streimikiene D, Cavallaro F, Loganathan N, Khoshnoudi M
    Sci Total Environ, 2019 Feb 01;649:31-49.
    PMID: 30170214 DOI: 10.1016/j.scitotenv.2018.08.229
    Understanding the nexus CO2 emissions and economic growth helps economies in formulating energy policies and developing energy resources in sustainable ways. Although during recent years, numerous of the previous studies have been very thoroughly investigated the nexus between economic growth and CO2 emissions, there is a lack of research regarding the qualitative systematic review and meta-analysis in these areas. The main purpose of this review paper is to present the comprehensive overview of the relationship between CO2 emissions and economic growth. In this regard, the Web of Science database has been chosen and a qualitative systematic and meta-analysis method which called "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" has been proposed. Therefore, a review of 175 published articles appearing in 55 scholarly international journals between 1995 and 2017 has been achieved to reach a broad review of the nexus between economic growth and CO2 emissions with other indicators. Consequently, the selected articles have been categorized by the author name, the year of publication, data duration, types of techniques, data analysis method, the name of indicators, country, scope (individual country and multi-countries), journals, results, and outcome in which they appeared. The results of this paper demonstrated that the nexus between CO2 emissions and economic growth gives reasons for policy options that have to reduce emissions by imposing limiting factors on economic growth as well. Given the fact that bidirectional causality exists, as far as economic growth increases or decreases, further CO2 emissions are stimulated in higher or lower levels and consequently, a potential reduction of the emissions should have an adverse influence on economic growth.
    Matched MeSH terms: Carbon Dioxide
  4. Fulltext Evaluation of the Properties, Gas Permeability, and Selectivity of Mixed Matrix Membrane Based on Polysulfone Polymer Matrix Incorporated with KIT-6 Silica
    Ding SH, Ng TYS, Chew TL, Oh PC, Ahmad AL, Ho CD
    Polymers (Basel), 2019 Oct 23;11(11).
    PMID: 31652828 DOI: 10.3390/polym11111732
    Mixed matrix membranes (MMMs) separation is a promising technology for gas permeation and separation involving carbon dioxide (CO2). However, finding a suitable type of filler for the formation of defect-free MMMs with enhancement in gas permeability remains a challenge. Current study focuses on synthesis of KIT-6 silica and followed by the incorporation of KIT-6 silica as filler into polysulfone (PSF) polymer matrix to fabricate MMMs, with filler loadings of 0-8 wt %. The effect of KIT-6 incorporation on the properties of the fabricated MMMs was evaluated via different characterization techniques. The MMMs were investigated for gas permeability and selectivity with pressure difference of 5 bar at 25 °C. KIT-6 with typical rock-like morphology was synthesized. Incorporation of 2 wt % of KIT-6 into PSF matrix produced MMMs with no void. When KIT-6 loadings in the MMMs were increased from 0 to 2 wt %, the CO2 permeability increased by ~48%, whereas the ideal CO2/CH4 selectivity remained almost constant. However, when the KIT-6 loading in PSF polymer matrix was more than 2 wt %, the formation of voids in the MMMs increased the CO2 permeability but sacrificed the ideal CO2/CH4 selectivity. In current study, KIT-6 was found to be potential filler for PSF matrix under controlled KIT-6 loading for gas permeation.
    Matched MeSH terms: Carbon Dioxide
  5. Fulltext Latest development in microalgae-biofuel production with nano-additives
    Hossain N, Mahlia TMI, Saidur R
    Biotechnol Biofuels, 2019;12:125.
    PMID: 31139255 DOI: 10.1186/s13068-019-1465-0
    Background: Microalgae have been experimented as a potential feedstock for biofuel generation in current era owing to its' rich energy content, inflated growth rate, inexpensive culture approaches, the notable capacity of CO2 fixation, and O2 addition to the environment. Currently, research is ongoing towards the advancement of microalgal-biofuel technologies. The nano-additive application has been appeared as a prominent innovation to meet this phenomenon.

    Main text: The main objective of this study was to delineate the synergistic impact of microalgal biofuel integrated with nano-additive applications. Numerous nano-additives such as nano-fibres, nano-particles, nano-tubes, nano-sheets, nano-droplets, and other nano-structures' applications have been reviewed in this study to facilitate microalgae growth to biofuel utilization. The present paper was intended to comprehensively review the nano-particles preparing techniques for microalgae cultivation and harvesting, biofuel extraction, and application of microalgae-biofuel nano-particles blends. Prospects of solid nano-additives and nano-fluid applications in the future on microalgae production, microalgae biomass conversion to biofuels as well as enhancement of biofuel combustion for revolutionary advancement in biofuel technology have been demonstrated elaborately by this review. This study also highlighted the potential biofuels from microalgae, numerous technologies, and conversion processes. Along with that, the study recounted suitability of potential microalgae candidates with an integrated design generating value-added co-products besides biofuel production.

    Conclusions: Nano-additive applications at different stages from microalgae culture to end-product utilization presented strong possibility in mercantile approach as well as positive impact on the environment along with valuable co-products generation into the near future.

    Matched MeSH terms: Carbon Dioxide
  6. CO2 utilization: Turning greenhouse gas into fuels and valuable products
    Anwar MN, Fayyaz A, Sohail NF, Khokhar MF, Baqar M, Yasar A, et al.
    J Environ Manage, 2020 Apr 15;260:110059.
    PMID: 32090808 DOI: 10.1016/j.jenvman.2019.110059
    This study critically reviews the recent developments and future opportunities pertinent to the conversion of CO2 as a potent greenhouse gas (GHG) to fuels and valuable products. CO2 emissions have reached an alarming level of around 410 ppm and have become the primary driver of global warming and climate change leading to devastating events such as droughts, hurricanes, torrential rains, floods, tornados and wildfires across the world. These events are responsible for thousands of deaths and have adversely affected the economic development of many countries, loss of billions of dollars, across the globe. One of the promising choices to tackle this issue is carbon sequestration by pre- and post-combustion processes and oxyfuel combustion. The captured CO2 can be converted into fuels and valuable products, including methanol, dimethyl ether (DME), and methane (CH4). The efficient use of the sequestered CO2 for the desalinization might be critical in overcoming water scarcity and energy issues in developing countries. Using the sequestered CO2 to produce algae in combination with wastewater, and producing biofuels is among the promising strategies. Many methods, like direct combustion, fermentation, transesterification, pyrolysis, anaerobic digestion (AD), and gasification, can be used for the conversion of algae into biofuel. Direct air capturing (DAC) is another productive technique for absorbing CO2 from the atmosphere and converting it into various useful energy resources like CH4. These methods can effectively tackle the issues of climate change, water security, and energy crises. However, future research is required to make these conversion methods cost-effective and commercially applicable.
    Matched MeSH terms: Carbon Dioxide
  7. Rational Design of Carbon-Based 2D Nanostructures for Enhanced Photocatalytic CO2 Reduction: A Dimensionality Perspective
    Ong WJ, Putri LK, Mohamed AR
    Chemistry, 2020 Aug 06;26(44):9710-9748.
    PMID: 32511824 DOI: 10.1002/chem.202000708
    Photocatalytic CO2 reduction is a revolutionary approach to solve imminent energy and environmental issues by replicating the ingenuity of nature. The past decade has witnessed an impetus in the rise of two-dimensional (2D) structure materials as advanced nanomaterials to boost photocatalytic activities. In particular, the use of 2D carbon-based materials is deemed as highly favorable, not only as a green material choice, but also due to their exceptional physicochemical and electrical properties. This Review article presents a diverse range of alterations and compositions derived from 2D carbon-based nanomaterials, mainly graphene and graphitic carbon nitride (g-C3 N4 ), which have remarkably ameliorated the photocatalytic CO2 performance. Herein, the rational design of the photocatalyst systems with consideration of the aspect of dimensionality and the resultant heterostructures at the interface are systematically analyzed to elucidate an insightful perspective on this pacey subject. Finally, a conclusion and outlook on the limitations and prospects of the cutting-edge research field are highlighted.
    Matched MeSH terms: Carbon Dioxide
  8. Distinctive correlations between cell concentration and cell size to microalgae biomass under increasing carbon dioxide
    Lim YA, Khong NMH, Priyawardana SD, Ooi KR, Ilankoon IMSK, Chong MN, et al.
    Bioresour Technol, 2022 Mar;347:126733.
    PMID: 35074462 DOI: 10.1016/j.biortech.2022.126733
    Carbon capture and storage (CCS) via microalgae cultivations is getting renewed interest as climate change mitigation effort, owing to its excellent photosynthetic and CO2 fixation capability. Microalgae growth is monitored based on their biomass, cell concentrations and cell sizes. The key parametric relationships on microalgae growth under CO2 are absent in previous studies and this inadequacy hampers the design and scale-up of microalgae-based CCS. In this study, three representative microalgae species, Chlorella, Nostoc and Chlamydomonas, were investigated for establishing key correlations of cell concentrations and sizes towards their biomass fluctuations under CO2 influences of 0% to 20% volume ratios (v/v). This revealed that Chlorella and Chlamydomonas cell concentrations significantly contributed towards increasing biomass concentration under CO2 elevations. Chlorella and Nostoc cell sizes were enhanced at 20% (v/v). These findings provided new perspectives on growth responses under increasing CO2 treatment, opening new avenues on CCS schemes engineering designs and biochemical production.
    Matched MeSH terms: Carbon Dioxide
  9. A molecular simulation study on amine-functionalized silica/polysulfone mixed matrix membrane for mixed gas separation
    Asif K, Lock SSM, Taqvi SAA, Jusoh N, Yiin CL, Chin BLF
    Chemosphere, 2023 Jan;311(Pt 1):136936.
    PMID: 36273613 DOI: 10.1016/j.chemosphere.2022.136936
    Polysulfone (PSF) based mixed matrix membranes (MMMs) are one of the most broadly studied polymeric materials used for CO2/CH4 separation. The performance of existing PSF membranes encounters a bottleneck for widespread expansion in industrial applications due to the trade-off amongst permeability and selectivity. Membrane performance has been postulated to be enhanced via functionalization of filler at different weight percentages. Nonetheless, the preparation of functionalized MMMs without defects and its empirical study that exhibits improved CO2/CH4 separation performance is challenging at an experimental scale that needs prior knowledge of the compatibility between the filler and polymer. Molecular simulation approaches can be used to explore the effect of functionalization on MMM's gas transport properties at an atomic level without the challenges in the experimental study, however, they have received less scrutiny to date. In addition, most of the research has focused on pure gas studies while mixed gas transport properties that reflect real separation in functionalized silica/PSF MMMs are scarcely available. In this work, a molecular simulation computational framework has been developed to investigate the structural, physical properties and gas transport behavior of amine-functionalized silica/PSF-based MMMs. The effect of varying weight percentages (i.e., 15-30 wt.%) of amine-functionalized silica and gas concentrations (i.e., 30% CH4/CO2, 50% CH4/CO2, and 70% CH4/CO2) on physical and gas transport characteristics in amine-functionalized silica/PSF MMMs at 308.15 K and 1 atm has been investigated. Functionalization of silica nanoparticles was found to increase the diffusion and solubility coefficients, leading to an increase in the percentage enhancement of permeability and selectivity for amine-functionalized silica/PSF MMM by 566% and 56%, respectively, compared to silica/PSF-based MMMs at optimal weight percentage of 20 wt.%. The model's permeability differed by 7.1% under mixed gas conditions. The findings of this study could help to improve real CO2/CH4 separation in the future design and concept of functionalized MMMs using molecular simulation and empirical modeling strategies.
    Matched MeSH terms: Carbon Dioxide
  10. An integrated life-cycle greenhouse gas protocol accounting on oil palm trunk and empty fruit bunch biofuel production
    Chew ZL, Tan EH, Palaniandy SA, Woon KS, Phuang ZX
    Sci Total Environ, 2023 Jan 15;856(Pt 1):159007.
    PMID: 36167122 DOI: 10.1016/j.scitotenv.2022.159007
    Improper discard of oil palm trunk and empty fruit bunch renders massive greenhouse gases. Turning these palm wastes into solid biofuels could aid in carbon reduction. The embodied environmental impacts of the solid biofuel densification process are neglected in carbon emission quantification studies applying Greenhouse Gas Protocol while the significance of classifying the system's direct and indirect carbon emissions were overlooked in those utilising life cycle assessment. Despite the prospect of both methodologies to complement their limitations for carbon emissions quantification, no study integrates both methodologies to investigate direct and indirect emissions systematically from a life cycle perspective. An integrated framework of life cycle assessment and Greenhouse Gas Protocol is developed to quantify the direct and indirect carbon emissions of oil palm trunk and empty fruit bunch densification from cradle-to-gate for three pellet plants in Indonesia and Malaysia. The emissions are categorised into three emission scopes: Scope 1, Scope 2, and Scope 3 according to the Greenhouse Gas Protocol, integrated with avoided emissions which are quantified via life cycle assessment. The pellet plants generate 534.7-732.3 kg CO2-eq/tonnepellet per hour, in which Scope 1 (i.e., direct emissions) is the major emission scope due to high emissions from wastewater production and drying fuel combustion. Washing equipment (169.2-439.0 kg CO2-eq/tonnepellet per hour) and burners (87.1-214.5 kg CO2-eq/tonnepellet per hour) are the hotspots found in the pellet plants. Producing empty fruit bunch pellets could reduce 62.0-74.1 % of emissions than landfilling the empty fruit bunch. Empty fruit bunch pellet and oil palm trunk pellet are recommended to co-fire with coal to phase down coal usage in achieving COP26 pledge. This study provides data-driven insights for quantifying carbon emissions through the integrated framework and could be a reference in future life cycle carbon footprint studies of the biomass densification process.
    Matched MeSH terms: Carbon Dioxide
  11. Effect of process parameters over carbon-based ZIF-62 nano-rooted membrane for environmental pollutants separation
    Mubashir M, Ashena R, Bokhari A, Mukhtar A, Saqib S, Ali A, et al.
    Chemosphere, 2022 Mar;291(Pt 3):133006.
    PMID: 34813846 DOI: 10.1016/j.chemosphere.2021.133006
    The paper evaluates the routes towards the evaluation of membranes using ZIF-62 metal organic framework (MOF) nano-hybrid dots for environmental remediation. Optimization of interaction of operating parameters over the rooted membrane is challenging issue. Subsequently, the interaction of operating parameters including temperature, pressure and CO2 gas concentration over the resultant rooted membranes are evaluated and optimized using response surface methodology for environmental remediation. In addition, the stability and effect of hydrocarbons on the performance of the resulting membrane during the gas mixture separation are evaluated at optimum conditions to meet the industrial requirements. The characterization results verified the fabrication of the ZIF-62 MOF rooted composite membrane. The permeation results demonstrated that the CO2 permeability and CO2/CH4 selectivity of the composite membrane was increased from 15.8 to 84.8 Barrer and 12.2 to 35.3 upon integration of ZIF-62 nano-glass into cellulose acetate (CA) polymer. Subsequently, the optimum conditions have been found at a temperature of 30 °C, the pressure of 12.6 bar and CO2 feed concentration of 53.3 vol%. These optimum conditions revealed the highest CO2 permeability, CH4 permeability and CO2/CH4 separation factor of 47.9 Barrer, 0.2 Barrer and 26.8. The presence of hydrocarbons in gas mixture dropped the CO2 permeability of 56.5% and separation factor of 46.4% during 206 h of testing. The separation performance of the composite membrane remained stable without the presence of hydrocarbons for 206 h.
    Matched MeSH terms: Carbon Dioxide
  12. Oxygen vacancy induced Bi2WO6 for the realization of photocatalytic CO2 reduction over the full solar spectrum: from the UV to the NIR region
    Kong XY, Choo YY, Chai SP, Soh AK, Mohamed AR
    Chem Commun (Camb), 2016 Dec 06;52(99):14242-14245.
    PMID: 27872917
    Photocatalytic CO2 reduction over the UV-Vis-NIR broad spectrum was realized for the first time. The presence of surface oxygen vacancy defects on Bi2WO6 resulted in significant photocatalytic enhancement over the pristine counterpart under UV and visible light irradiation. Meanwhile, the photocatalytic responsiveness of Bi2WO6-OV was successfully extended to the NIR region.
    Matched MeSH terms: Carbon Dioxide
  13. Improvising humidified rapid-insufflation ventilatory exchange during rigid bronchoscopy
    Chan WK, Liu CY
    Br J Anaesth, 2023 Jan;130(1):e27-e29.
    PMID: 35738940 DOI: 10.1016/j.bja.2022.05.016
    Matched MeSH terms: Carbon Dioxide
  14. Performance evaluation of phosphonium based deep eutectic solvents coated cerium oxide nanoparticles for CO2 capture
    Ahmad T, Iqbal J, Bustam MA, Babar M, Tahir MB, Sagir M, et al.
    Environ Res, 2023 Apr 01;222:115314.
    PMID: 36738770 DOI: 10.1016/j.envres.2023.115314
    The critical challenge being faced by our current modern society on a global scale is to reduce the surging effects of climate change and global warming, being caused by anthropogenic emissions of CO2 in the environment. Present study reports the surface driven adsorption potential of deep eutectic solvents (DESs) surface functionalized cerium oxide nanoparticles (CeNPs) for low pressure CO2 separation. The phosphonium based DESs were prepared using tetra butyl phosphoniumbromide as hydrogen bond acceptor (HBA) and 6 acids as hydrogen bond donors (HBDs). The as-developed DESs were characterized and employed for the surface functionalization of CeNPs with their subsequent utilization in adsorption-based CO2 adsorption. The synthesis of as-prepared DESs was confirmed through FTIR measurements and absence of precipitates, revealed through visual observations. It was found that DES6 surface functionalized CeNPs demonstrated 27% higher adsorption performance for CO2 capturing. On the contrary, DES3 coated CeNPs exhibited the least adsorption progress for CO2 separation. The higher adsorption performance associated with DES6 coated CeNPs was due to enhanced surface affinity with CO2 molecules that must have facilitated the mass transport characteristics and resulted an enhancement in CO2 adsorption performance. Carboxylic groups could have generated an electric field inside the pores to attract more polarizable adsorbates including CO2, are responsible for the relatively high values of CO2 adsorption. The quadruple movement of the CO2 molecules with the electron-deficient and pluralizable nature led to the enhancement of the interactive forces between the CO2 molecules and the CeNPs decorated with the carboxylic group hydrogen bond donor rich DES. The current findings may disclose the new research horizons and theoretical guidance for reduction in the environmental effects associated with uncontrolled CO2 emission via employing DES surface coated potential CeNPs.
    Matched MeSH terms: Carbon Dioxide
  15. Microalgae-based biotechnological sequestration of carbon dioxide for net zero emissions
    Ma Z, Cheah WY, Ng IS, Chang JS, Zhao M, Show PL
    Trends Biotechnol, 2022 Dec;40(12):1439-1453.
    PMID: 36216714 DOI: 10.1016/j.tibtech.2022.09.002
    Excessive carbon dioxide (CO2) emissions into the atmosphere have become a dire threat to the human race and environmental sustainability. The ultimate goal of net zero emissions requires combined efforts on CO2 sequestration (natural sinks, biomass fixation, engineered approaches) and reduction in CO2 emissions while delivering economic growth (CO2 valorization for a circular carbon bioeconomy, CCE). We discuss microalgae-based CO2 biosequestration, including flue gas cultivation, biotechnological approaches for enhanced CO2 biosequestration, technological innovations for microalgal cultivation, and CO2 valorization/biofuel productions. We highlight challenges to current practices and future perspectives with the goal of contributing to environmental sustainability, net zero emissions, and the CCE.
    Matched MeSH terms: Carbon Dioxide
  16. Carbonated ground granulated blast furnace slag stabilising brown kaolin
    Mohammed AMA, Mohd Yunus NZ, Hezmi MA, A Rashid AS, Horpibulsuk S
    Environ Sci Pollut Res Int, 2021 Oct;28(40):57308-57320.
    PMID: 34086175 DOI: 10.1007/s11356-021-14718-4
    Proposals have been made by several researchers to conduct the sequestration of carbon dioxide (CO2) through calcium and magnesium-rich materials. From these materials, ground granulated blast furnace slag (GGBS) containing 5% magnesium and 45% calcium is seen to be a good candidate and is available to sequester CO2. This study intends to ascertain the ability to absorb CO2, sequester it, and increase treated kaolin strength with different content of GGBS under various carbonation periods with varying CO2 pressure. The impacts of carbonated GGBS on the mechanical attributes of soil were examined by conducting the unconfined compressive strength (UCS) test, and microstructure analysis was conducted to identify the changes in the structure and Crestline phase. Stationary carbonation in a triaxial test with pure CO2 was conducted to accelerate the carbonation process. The outcome indicates that the strength rises as the carbonation period rises. Likewise, UCS rises as the CO2 pressure rises from 100 to 200 kPa. It could be concluded that augmentation of the strength is because of carbonated calcium and magnesium products which stuff the soil voids. Changes occur on the microstructure level due to carbonation as well.
    Matched MeSH terms: Carbon Dioxide
  17. Does tradeoff between financial and social indicators matters in environmental consideration: evidence from G7 region
    Van Song N, Phuong NTM, Oanh TTK, Chien DH, Phuc VQ, Mohsin M
    Environ Sci Pollut Res Int, 2021 Apr;28(16):19911-19925.
    PMID: 33410000 DOI: 10.1007/s11356-020-12041-y
    The study tries to discover the impact of financial and social indicators' growth towards environmental considerations to understand the drivers of economic growth and carbon dioxide emissions change in G7 countries. The DEA-like composite index has been used to examine the tradeoff between financial and social indicator matters in environmental consideration by using a multi-objective goal programming approach. The data from 2008 to 2018 is collected from G-7 countries. The results from the DEA-like composite index reveals that there is a mixed condition of environmental sustainability in G-7 countries where the USA is performing better and Japan is performing worse among the set of other countries. The further result shows that the energy and fiscal indicators help to decrease the dangerous gas emissions. Divergent to that, the human and financial index positively contributes to greenhouse gas emissions. Fostering sustainable development is essential to successfully reduce emissions, meet established objectives, and ensure steady development. The study provides valuable information for policymakers.
    Matched MeSH terms: Carbon Dioxide
  18. An investigation on the relationship between physicochemical characteristics of alumina-supported cobalt catalyst and its performance in dry reforming of methane
    Khairudin NF, Mohammadi M, Mohamed AR
    Environ Sci Pollut Res Int, 2021 Jun;28(23):29157-29176.
    PMID: 33550559 DOI: 10.1007/s11356-021-12794-0
    This study deals with the development of alumina-supported cobalt (Co/Al2O3) catalysts with remarkable performance in dry reforming of methane (DRM) and least carbon deposition. The influence of Co content, calcination, and reduction temperatures on the physicochemical attributes and catalyst activity of the developed catalysts was extensively studied. For this purpose, several characterization techniques including ICP-MS, H2 pulse chemisorption, HRTEM, H2-TPR, N2 adsorption desorption, and TGA were implemented, and the properties of the developed catalysts were carefully analyzed. The impact of reaction temperature, feed gas ratio, and gas hourly space velocity (GHSV) on the reactants conversion and products yield was investigated. Use of 10%Co/Al2O3 catalyst, calcined at 500°C and reduced under H2 at 900°C in DRM reaction at 850°C, CH4/CO2 ratio of 1:1, and GHSV of 6 L.g-1.h-1 resulted in a remarkable catalytic activity and sustainable performance in long-term operation where great CO2 (96%) and CH4 (98%) conversions and high H2 (83%) and CO (91%) yields with a negligible carbon deposition (3 wt%) were attained in 100-h on-stream reaction. The good performance of the developed catalyst in DRM reaction was attributed to the small Co particle size with well-dispersion on the alumina support which increased the catalytic activity and also the strong metal-support interaction which inhibited any serious metal sintering and enhanced the catalyst stability.
    Matched MeSH terms: Carbon Dioxide
  19. Decomposing the trade-environment nexus for Malaysia: what do the technique, scale, composition, and comparative advantage effect indicate?
    Ling CH, Ahmed K, Binti Muhamad R, Shahbaz M
    Environ Sci Pollut Res Int, 2015 Dec;22(24):20131-42.
    PMID: 26300360 DOI: 10.1007/s11356-015-5217-9
    This paper investigates the impact of trade openness on CO2 emissions using time series data over the period of 1970QI-2011QIV for Malaysia. We disintegrate the trade effect into scale, technique, composition, and comparative advantage effects to check the environmental consequence of trade at four different transition points. To achieve the purpose, we have employed augmented Dickey-Fuller (ADF) and Phillips-Perron (PP) unit root tests in order to examine the stationary properties of the variables. Later, the long-run association among the variables is examined by applying autoregressive distributed lag (ARDL) bounds testing approach to cointegration. Our results confirm the presence of cointegration. Further, we find that scale effect has positive and technique effect has negative impact on CO2 emissions after threshold income level and form inverted U-shaped relationship-hence validates the environmental Kuznets curve hypothesis. Energy consumption adds in CO2 emissions. Trade openness and composite effect improve environmental quality by lowering CO2 emissions. The comparative advantage effect increases CO2 emissions and impairs environmental quality. The results provide the innovative approach to see the impact of trade openness in four sub-dimensions of trade liberalization. Hence, this study attributes more comprehensive policy tool for trade economists to better design environmentally sustainable trade rules and agreements.
    Matched MeSH terms: Carbon Dioxide
  20. CO2 reforming of methane to syngas over multi-walled carbon nanotube supported Ni-Ce nanoparticles: effect of different synthesis methods
    Afandi NS, Mohammadi M, Ichikawa S, Mohamed AR
    Environ Sci Pollut Res Int, 2020 Dec;27(34):43011-43027.
    PMID: 32725565 DOI: 10.1007/s11356-020-10269-2
    Several multi-walled carbon nanotubes supported Ni-Ce catalysts were synthesized, and their performance in carbon dioxide reforming of methane (CDRM) for syngas production was evaluated. The attachment of Ni-Ce nanoparticles to the functionalized carbon nanotube (fCNT) support was carried out using four synthesis routes, i.e., impregnation (I), sol-gel (S), co-precipitation (C), and hydrothermal (H) methods. Results indicated that synthesis method influences the properties of the NiCe/fCNT catalysts in terms of homogeneity of metal dispersion, size of crystallites, and metal-support interaction. The activity of the catalysts followed the order of NiCe/fCNT(H) > NiCe/fCNT(S) > NiCe/fCNT(C) > NiCe/fCNT(I). The NiCe/fCNT(H) catalyst exhibited the highest catalytic activity with CH4 and CO2 conversions of 92 and 96%, respectively, and resulted in syngas product with consistent H2/CO ratio of 0.91 at reaction temperature of 800 °C without notable deactivation up to 30 h of reaction. Moreover, the growth of carbon on the spent catalyst was only 2% with deposition rate of 4.08 mg/gcat·h; this was plausibly due to the well-dispersed distribution of nanoparticles on fCNT surface and abundant presence of oxygenated groups on the catalyst surface.
    Matched MeSH terms: Carbon Dioxide
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