Bamboo is the fastest-growing plant and is abundant in Malaysia. It is employed as a starting material for activated carbon production and evaluated for its potential in CO2 capture. A single-stage phosphoric acid (H3PO4) activation is adopted by varying the concentrations of H3PO4 between 50 and 70 wt.% at a constant temperature and holding time of 500°C and 120 min, respectively. The bamboo-based activated carbons are characterized in terms of product yield, surface area, and porosity, as well as surface chemistry properties. Referring to the experimental findings, the prepared activated carbons have BET surface area of >1000 m2 g-1, which implies the effectiveness of the single-stage H3PO4 activation. Furthermore, the prepared activated carbon via 50 wt.% H3PO4 activation shows the highest BET surface area and carbon dioxide (CO2) adsorption capacity of 1.45 mmol g-1 at 25°C/1 bar and 9.0 mmol g-1 at 25°C/30 bar. With respect to both the characterization analysis and CO2 adsorption performance, it is concluded that bamboo waste conversion to activated carbon through H3PO4 activation method is indeed promising.
Degradation of amines is a significant issue allied to amine-based carbon dioxide (CO2) absorption in post-combustion CO2 capture. It becomes essential to have a detailed understanding of degradation products for advanced post-combustion CO2 capture technology. Identification and quantification of degradation products of amines help in practicability and environmental assessment of amine-based technology. Gas, liquid, and ion chromatographic techniques are the benchmark tools for qualitative and quantitative analyses of the amines and their derivatives. Among others, gas chromatography has been more in use for this specific application, especially for the identification of degradation products of amines. This review focuses on the critical elucidation of gas chromatographic analysis and development of methods to determine the amine degradation products, highlighting preparation methods for samples and selecting columns and detectors. The choice of detector, column, sample preparation, and method development are reviewed in this manuscript, keeping in view the industry and research applications. Furthermore, obtained results on the quantitative and qualitative analyses using gas chromatography are summarized with future perspectives.
The volumetric adsorption kinetics of carbon dioxide (CO2) onto the synthesized palm kernel shell activated carbon via single-stage CO2 activation and commercial Norit® activated carbon were carried out at an initial pressure of approximately 1 bar at three different temperatures of 25, 50, and 100 °C. The experimental kinetics data were modelled by using the Lagergren's pseudo-first-order model and pseudo-second-order model. Comparing these two, the non-linear pseudo-second-order kinetics model presented a better fit towards CO2 adsorption for both adsorbents, owing to its closer coefficient of determination (R2) to unity, irrespective of the adsorption temperature. In addition, kinetics analysis showed that the corresponding kinetics coefficient (rate of adsorption) of both activated carbons increased with respect to adsorption temperature, and thereby, it indicated higher mobility of CO2 adsorbates at an elevated temperature. Nevertheless, CO2 adsorption capacity of both activated carbons reduced at elevated temperatures, which signified exothermic and physical adsorption (physisorption) behaviour. Besides, process exothermicity of both carbonaceous adsorbents can be corroborated through activation energy (Ea) value, which was deduced from the Arrhenius plot. Ea values that were in range of 32-38 kJ/mol validated exothermic adsorption at low pressure and temperature range of 25-100 °C. To gain an insight into the CO2 adsorption process, experimental data were fitted to intra-particle diffusion model and Boyd's diffusion model, and findings revealed an involvement of both film diffusion and intra-particle diffusion during CO2 adsorption process onto the synthesized activated carbon and commercial activated carbon.
Mixed matrix membranes (MMMs) were fabricated by the hydrothermal synthesis of ordered mesoporous KIT-6 type silica and incorporating in polyimide (P84). KIT-6 and MMMs were characterized to evaluate morphology, thermal stability, surface area, pore volume, and other characteristics. SEM images of synthesized MMMs and permeation data of CO2 suggested homogenous dispersion of mesoporous fillers and their adherence to the polymer matrix. The addition of KIT-6 to polymer matrix improved the permeability of CO2 due to the increase in diffusivity through porous particles. The permeability was 3.2 times higher at 30% loading of filler. However, selectivity showed a slight decrease with the increase in filler loadings. The comparison of gas permeation results of KIT-6 with the well-known MCM-41 revealed that KIT-6 based MMMs showed 14% higher permeability than that of MMMs composed of mesoporous MCM-41. The practical commercial viability of synthesized membranes was examined under different operating temperatures and mixed gas feeds. Mesoporous KIT-6 silica is an attractive additive for gas permeability enhancement without compromising the selectivity of MMMs. Graphical abstract.
Accelerating greenhouse gas emission particularly carbon dioxide (CO2) in the atmosphere has become a major concern. Adsorption process has been proposed as a promising technology for CO2 adsorption from flue gas, and the carbonaceous adsorbent is a potential candidate for CO2 adsorption at atmospheric pressure and ambient temperature. Biochar derived from palm kernel shell waste was applied as a potential precursor for activated carbon production. This research study employed the response surface methodology coupled with Box-Behnken design to optimize the parameters involved in producing exceptional activated carbon with high yield (Y1) and CO2 adsorptive characteristics (Y2). Specifically, parameters studied include the activation temperature (750-950 °C), holding time (60-120 min), and CO2 flow rate (150-450 mL/min). The activated carbon at the optimum conditions was characterized using various analytical instruments, including elemental analyzer, nitrogen (N2) physisorption analyzer, and field emission scanning electron microscopy. Overall, utilization of biochar as the activated carbon precursor is practical compared with the traditional non-renewable materials, due to its cost efficiencies and it being more environment-friendly ensuring process sustainability. Besides, this research study that incorporates physical activation with CO2 as the activating agent is attractive, because it directly promotes CO2 utilization and capture, in addition to the absence of any chemicals that may result in the secondary pollution problems.
The study aims to address the dynamic common correlated effects of trade openness, FDI, and institutional performance on environmental quality in OIC countries. Mostly, pollutants like CO2 and SO2 emissions are considered as the environmental indicators. However, for this study, we have selected ecological footprint as the indicator of environmental quality. The new econometric approach Dynamic Common Correlated Effects (DCCE) by Chudik and Pesaran (2015) has been used to measure the cross-sectional dependence among cross-sectional units. Results confirm that previous techniques for long panel data, like MG and PMG, give ambiguous outcomes in the presence of cross-sectional dependence. According to DCCE estimation, trade openness, FDI, and urbanization have a positive and significant relationship with ecological footprint while a significant and negative association is found between institutional performance and ecological footprint. The OIC countries must encourage green technology, clean production, and improved institutions for sustainable development and better environmental quality.
Against the backdrop of current global collaboration on mitigating carbon emissions, how to reduce the energy uses in the Belt and Road Initiative area becomes an urgent and big challenge facing the global community. Using the Eora input-output database, this paper accounts the embodied energy trade between Belt and Road countries in 2015, followed by an investigation of the factors influencing the embodied energy trade through a panel gravity model. Global value chain participation and position are two newly considered factors in analyzing the determinants of embodied energy flow. We find that the main bilateral embodied flow paths are from South Korea to China, China to South Korea, Singapore to China, Ukraine to Russia, and Malaysia to Singapore. Five percent embodied energy flow paths account for 80% of the total bilateral embodied energy flow volume between Belt and Road countries. The gravity model results indicate that gross domestic product (GDP) per capita, population, global value chain participation are the key drivers of bilateral embodied energy trade, while the industrial share of GDP and global value chain position are negatively related to the trade. Energy intensity plays a crucial role in reducing the bilateral embodied energy flow. These results are useful in the policymaking of sustainable development for the Belt and Road Initiative.
Meningitis is an inflammation of the protective membranes called meninges and fluid adjacent the brain and spinal cord. The inflammatory progression expands all through subarachnoid space of the brain and spinal cord and occupies the ventricles. The pathogens like bacteria, fungi, viruses, or parasites are main sources of infection causing meningitis. Bacterial meningitis is a life-threatening health problem that which needs instantaneous apprehension and treatment. Nesseria meningitidis, Streptococcus pneumoniae, and Haemophilus flu are major widespread factors causing bacterial meningitis. The conventional drug delivery approaches encounter difficulty in crossing this blood-brain barrier (BBB) and therefore are insufficient to elicit the desired pharmacological effect as required for treatment of meningitis. Therefore, application of nanoparticle-based drug delivery systems has become imperative for successful dealing with this deadly disease. The nanoparticles have ability to across BBB via four important transport mechanisms, i.e., paracellular transport, transcellular (transcytosis), endocytosis (adsorptive transcytosis), and receptor-mediated transcytosis. In this review, we reminisce distinctive symptoms of meningitis, and provide an overview of various types of bacterial meningitis, with a focus on its epidemiology, pathogenesis, and pathophysiology. This review describes conventional therapeutic approaches for treatment of meningitis and the problems encountered by them while transmitting across tight junctions of BBB. The nanotechnology approaches like functionalized polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carrier, nanoemulsion, liposomes, transferosomes, and carbon nanotubes which have been recently evaluated for treatment or detection of bacterial meningitis have been focused. This review has also briefly summarized the recent patents and clinical status of therapeutic modalities for meningitis.
ICTs (information and communication technologies) have emerged as a potent new force. Digitalization, modernization, and automation of the manufacturing process are expected to facilitate ICT adoption, resulting in increased genuine environmental concerns. This research aims to examine the impact of ICTs on environmental quality and the relationship between ICTs, environmental quality, and economic growth. Dynamic panel threshold regression was employed, and the sample countries comprised 69 developing countries from 2010 to 2019. The threshold technique will identify the precise threshold value of ICTs and highlights the impacts of ICTs on the environmental quality nexus when above and below the threshold value in developing countries. Empirical evidence suggests that ICTs positively impact environmental quality (CO2) when above the ICTs threshold value. However, ICTs provide a positive but insignificant impact on environmental quality when below the ICTs threshold value of 4.699. Additionally, ICTs affect the economic growth and environmental quality nexus, with increasing economic growth resulting in a decrease in CO2 emissions in developing countries when ICTs are below the threshold value. Thus, the ICTs threshold value should be used to ensure that ICTs adoption promotes sustainable economic growth and resolves environmental degradation issues in developing nations.
In this study, luminescent bio-adsorbent nitrogen-doped carbon dots (N-CDs) was produced and applied for the removal and detection of Hg (II) from aqueous media. N-CDs were synthesized from oil palm empty fruit bunch carboxymethylcellulose (CMC) and urea. According to several analytical techniques used, the obtained N-CDs display graphitic core with an average size of 4.2 nm, are enriched with active sites, stable over a wide range of pH and have great resistance to photobleaching. The N-CDs have bright blue emission with an improved quantum yield (QY) of up to 35.5%. The effect of the variables including pH, adsorbent mass, initial concentration and incubation time on the removal of Hg (II) was investigated using central composite design. The statistical results confirmed that the adsorption process could reach equilibrium within 30 min. The reduced cubic model (R2 = 0.9989) revealed a good correlation between the observed values and predicted data. The optimal variables were pH of 7, dose of 0.1 g, initial concentration of 100 mg/L and duration of 30 min. Under these conditions, adsorption efficiency of 84.6% was obtained. The adsorption kinetic data could be well expressed by pseudo-second-order kinetic and Langmuir isotherm models. The optimal adsorption capacity was 116.3 mg g-1. Furthermore, the adsorbent has a good selectivity towards Hg (II) with a detection limit of 0.01 μM due to the special interaction between Hg (II) and carboxyl/amino groups on the edge of N-CDs. This work provided an alternative direction for constructing low-cost adsorbents with effective sorption and sensing of Hg (II).
Green growth is an extension of traditional economic growth. Financial fragility and ICT penetration are important pillars of green growth sustainability. However, very limited studies have explored this association and provided conflicting results. Thus, our study intends to fill this vacuum by exploring the impact of financial fragility and ICT penetration on renewable energy consumption and green growth for the top five polluting economies over the period 1996-2020. In this study, financial fragility is measured by bank costs and bank non-performing loans. Panel ARDL technique is used to find out long-run and short-run results estimates. Financial fragility reduces renewable energy consumption and green growth in the long run. However, internet penetration enhances renewable energy consumption and green growth in the long run. Our findings suggest imperative policy implications for the green economy.
Concentrations, sources and interactions between black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were investigated in 42 sediment samples collected from riverine, coastal and shelf areas in Peninsular Malaysia. The concentrations of BC measured by benzene polycarboxylic acid (BPCA) method and PAHs showed broad spatial variations between the relatively pristine environment of the East coast and developed environment of the West and South coast ranging from 0.02 to 0.36% dw and 57.7 ng g-1 dw to 19,300 ng g-1 dw, respectively. Among diagnostic ratios of PAHs, the ratios of Ant/(Ant+Phe) and LMW/HMW drew the clearest distinctions between the East coast versus the West and South coast sediments indicating the predominance of petrogenic sources in the former versus pyrogenic sources in the latter. PAHs significantly correlated with BC and total organic carbon (TOC) in the sediments (p
Rapid increases in energy consumption and economic growth over the past three decades are considered the driving force behind rising environmental degradation, which remain a threat to people and healthy environment. This study investigates the impact of energy consumption on environmental quality in the MINT countries using a panel PMG/ARDL modelling technique, and the Granger causality test spanning from 1971 to 2017. The empirical results confirm the existence of long-run nexus among the variables employed. The results also reveal that economic growth, energy consumption and bio-capacity have a positive and statistically significant effect on environmental degradation during the long run period. We find that a 1% increase in primary energy consumption leads to 0.4172% increase in environmental deterioration in the long-run period, but it is insignificant in the short run. This implies that energy consumption deteriorates environmental quality through a negative effect of ecological footprint. The result also suggests that as MINT countries increase the use of energy to accelerate pace of economic growth, environmental quality would deteriorate through increased ecological footprints. The coefficient of the error correction term (ect) is negative and significant (- 0.2306), suggesting that ecological footprint, a measure of environmental degradation would converge to its long-run equilibrium in the MINT region by 23.06% speed of adjustment every year due to contribution of economic growth, energy consumption, urbanization and biocapacity. The Granger non-causality test results reveal a unidirectional causal relationship from economic growth, energy consumption, and urbanization to ecological footprint and from economic growth to biocapacity. The results further show bi-directional causality between biocapacity and ecological footprint as well as between biocapacity and economic growth. Moreover, urbanization causes economic growth and biocapacity Granger-causes urbanization. Based on these findings, policy implications are adequately discussed.
In the face of mounting climate change challenges, reducing emissions has emerged as a key driver of environmental sustainability and sustainable growth. Despite the fact that research has been conducted on the environmental Kuznets curve (EKC), few researchers have analyzed this in the light of economic complexity. Thus, the current research assesses the effect of economic complexity on CO2 emissions in the MINT nations while taking into account the role of financial development, economic growth, and energy consumption for the period between 1990 and 2018. Using the novel method of moments quantile regression (MMQR) with fixed effects, an inverted U-shape interrelationship is found between economic growth and CO2 emissions, thus validating the EKC hypothesis. Energy consumption and economic complexity increase CO2 emissions significantly from the 1st to 9th quantiles. Furthermore, there is no significant interconnection between financial development and CO2 emissions across all quantiles (1st to 9th). The outcomes of the causality test reveal a feedback causal connection between economic growth and CO2, while a unidirectional causality is established from economic complexity and energy use to CO2 emissions in the MINT nations. Based on the findings, we believe that governments should stimulate the financial sector to provide domestic credit facilities to industrialists, investors, and other business enterprises on more favorable terms so that innovative technologies for environmental protection can be implemented with other policy recommendations.
The foremost purpose of the study is to establish a point that an economy of G-7 countries has an abundance of resources to tackle the environmental changes that occur in the world, but these countries are still behind the line because in this modern era, environmental performance changes their shape, dimension, and nature very frequently and create a huge impact on globalization of world economy. To fill this gap, we use green investment, institutional quality, and economic growth on environmental performance for this, we use four proxies for green investment and three proxies for greenhouse gas, and we also use six proxies of institutional quality to do this using period of 1997 to 2021. Moreover, we have used the panel nonlinear autoregressive distributed lag method to evaluate the long-run and short-run asymmetric effects of green investment, institutional quality, and economic growth on greenhouse gas emissions. The findings of the study affirm that the positive change of green investment has a positive and significant relationship with environmental performance, while the negative change of green investment has a significant and positive influence with environmental performance in the long run. Furthermore, the outcomes demonstrate that the positive shock of institutional quality has a positive and significant relationship with environmental performance, while the negative shock of intuitional quality has a significant and positive association with environmental performance in the long run, whereas positive change in economic growth has a positive and significant with the environmental performance, while the negative change of economic growth has a positive effect with environmental performance in the long run. This study finds future precautions that institutional quality has to perform exceptionally and shows results very rapidly, while green investment with economic growth has also made a deadly combination to control greenhouse gas emission, so the role of G-7 countries is pretty clear and straight. Furthermore, it is suggested that governments and policymakers take a proactive stance to promote resource acquisition and investment across all industries. To reduce gas emissions, public interest might also be complementary to private ones. So, economic policymakers, specifically in G-7 countries, should consider strategies that support sustainable economic growth.
Electrogenic microorganisms serve as important biocatalysts for microbial electrochemical sensors (MESes). The electrical signal produced is based on the rate of electron transfer between the microbes and electrodes, which represents the biotoxicity of water. However, existing MESes require complex and sophisticated fabrication methods. Here, several low-cost and rapid surface modification strategies (carbon powder-coated, flame-oxidized, and acid-bleached) have been demonstrated and studied for biosensing purposes. Surface-modified MESe bioanodes were successfully applied to detect multiple model pollutants including sodium acetate, ethanol, thinner, and palm oil mill effluent under three different testing sequences, namely, pollutant incremental, pollutant dumping, and water dilution tests. The carbon powder-coated bioanode showed the most responsive signal profile for all the three tests, which is in line with the average roughness values (Ra) when tested with atomic force microscopy. The carbon powder-coated electrode possessed a Ra value of 0.844, while flame-oxidized, acid-bleached, and control samples recorded 0.323, 0.336, and 0.264, respectively. The higher roughness was caused by the carbon coating and provided adhesive sites for microbial attachment and growth. The accuracy of MESe was also verified by correlating with chemical oxygen demand (COD) results. Similar to the sensitivity test, the carbon powder-coated bioanode obtained the highest R2 value of 0.9754 when correlated with COD results, indicating a high potential of replacing conventional water quality analysis methods. The reported work is of great significance to showcase facile surface modification techniques for MESes, which are cost-effective and sustainable while retaining the biocompatibility toward the microbial community with carbon-based coatings.
Tropical primary forests are being destroyed at an alarming rate and converted for other land uses which is expected to greatly influence soil carbon (C) cycling. However, our understanding of how tropical forest conversions affect the accumulation of compounds in soil functional C pools remains unclear. Here, we collected soils from primary forests (PF), secondary forests (SF), oil-palm (OP), and rubber plantations (RP), and assessed the accumulation of plant- and microbial-derived compounds within soil organic carbon (SOC), particulate (POC) and mineral-associated (MAOC) organic C. PF conversion to RP greatly decreased SOC, POC, and MAOC concentrations, whereas conversion to SF increased POC concentrations and decreased MAOC concentrations, and conversion to OP only increased POC concentrations. PF conversion to RP decreased lignin concentrations and increased amino sugar concentrations in SOC pools which increased the stability of SOC, whereas conversion to SF only increased the lignin concentrations in POC, and conversion to OP just increased lignin concentrations in POC and decreased it in MAOC. We observed divergent dynamics of amino sugars (decrease) and lignin (increase) in SOC with increasing SOC. Only lignin concentrations increased in POC with increasing POC and amino sugars concentrations decreased in MAOC with increasing MAOC. Conversion to RP significantly decreased soil enzyme activities and microbial biomasses. Lignin accumulation was associated with microbial properties, whereas amino sugar accumulation was mainly associated with soil nutrients and stoichiometries. These results suggest that the divergent accumulation of plant- and microbial-derived C in SOC was delivered by the distribution and original composition of functional C pools under forest conversions. Forest conversions changed the formation and stabilization processes of SOC in the long run which was associated with converted plantations and management. The important roles of soil nutrients and stoichiometry also provide a natural-based solution to enhance SOC sequestration via nutrient management in tropical forests.
Carbon emission trading is an important environmental policy tool to promote carbon emission reduction. With the panel data of carbon emissions trading (CET) pilots, this paper used the spatial difference-in-difference model (SDID) to test whether CET can affect the enterprise environmental responsibility and the spatial spillover effect of carbon emissions trading. The study found that CET can significantly improve the environmental responsibility level of enterprises in pilot areas. The environmental responsibility level of enterprises in surrounding areas are also improved driven by CET. In the time dimension, the role of CET in improving the enterprise environmental responsibility is gradually increasing. The impact of CET on enterprise environmental responsibility has significant heterogeneity in the dimension of ownership attributes and environmental regulation. Promoting corporate environmental protection investment is the main path for CET to improve the enterprise environmental responsibility.
Industrial revolution on the back of fossil fuels has costed humanity higher temperatures on the planet due to ever-growing concentration of carbon dioxide emissions in Earth's atmosphere. To tackle global warming demand for renewable energy sources continues to increase. Along renewables, there has been a growing interest in converting carbon dioxide to methanol, which can be used as a fuel or a feedstock for producing chemicals. The current review study provides a comprehensive overview of the recent advancements, challenges and future prospects of methanol production and purification via membrane-based technology. Traditional downstream processes for methanol production such as distillation and absorption have several drawbacks, including high energy consumption and environmental concerns. In comparison to conventional technologies, membrane-based separation techniques have emerged as a promising alternative for producing and purifying methanol. The review highlights recent developments in membrane-based methanol production and purification technology, including using novel membrane materials such as ceramic, polymeric and mixed matrix membranes. Integrating photocatalytic processes with membrane separation has been investigated to improve the conversion of carbon dioxide to methanol. Despite the potential benefits of membrane-based systems, several challenges need to be addressed. Membrane fouling and scaling are significant issues that can reduce the efficiency and lifespan of the membranes. The cost-effectiveness of membrane-based systems compared to traditional methods is a critical consideration that must be evaluated. In conclusion, the review provides insights into the current state of membrane-based technology for methanol production and purification and identifies areas for future research. The development of high-performance membranes and the optimization of membrane-based processes are crucial for improving the efficiency and cost-effectiveness of this technology and for advancing the goal of sustainable energy production.
Hydrogen (H2) is a possible energy transporter and feedstock for energy decarbonization, transportation, and chemical sectors while reducing global warming's consequences. The predominant commercial method for producing H2 today is steam methane reforming (SMR). However, there is still room for development in process intensification, energy optimization, and environmental concerns related to CO2 emissions. Reactors using metallic membranes (MRs) can handle both problems. Compared to traditional reactors, MRs operates at substantially lower pressures and temperatures. As a result, capital and operational costs may be significantly cheaper than traditional reactors. Furthermore, metallic membranes (MMs), particularly Pd and its alloys, naturally permit only H2 permeability, enabling the production of a stream with a purity of up to 99.999%. This review describes several methods for H2 production based on the energy sources utilized. SRM with CO2 capture and storage (CCUS), pyrolysis of methane, and water electrolysis are all investigated as process technologies. A debate based on a color code was also created to classify the purity of H2 generation. Although producing H2 using fossil fuels is presently the least expensive method, green H2 generation has the potential to become an affordable alternative in the future. From 2030 onward, green H2 is anticipated to be less costly than blue hydrogen. Green H2 is more expensive than fossil-based H2 since it uses more energy. Blue H2 has several tempting qualities, but the CCUS technology is pricey, and blue H2 contains carbon. At this time, almost 80-95% of CO2 can be stored and captured by the CCUS technology. Nanomaterials are becoming more significant in solving problems with H2 generation and storage. Sustainable nanoparticles, such as photocatalysts and bio-derived particles, have been emphasized for H2 synthesis. New directions in H2 synthesis and nanomaterials for H2 storage have also been discussed. Further, an overview of the H2 value chain is provided at the end, emphasizing the financial implications and outlook for 2050, i.e., carbon-free H2 and zero-emission H2.