The environmental sustainability effects of financial development and urbanization in Latin American countries

The present study assesses the impact of urbanization, economic growth, energy consumption, and financial development on CO₂ emissions in Latin American countries using a dataset spanning between 1980 and 2017. The current paper employs utilized panel econometric techniques such as CIDF, panel unit test, the Westerlund panel cointegration, fully modified ordinary least squares (FMOLS), dynamic ordinary least squares (DOLS), and Dumitrescu Hurlin panel causality test to assess these associations. The outcomes from the FMOLS and DOLS estimation reveal that (i) economic growth impacts CO₂ emissions positively, (ii) energy consumption exerts a positive impact on CO₂ emissions, and (iii) urbanization impacts CO₂ emissions positively. Furthermore, the outcomes of the causality test reveal that energy consumption and economic growth can predict CO₂ emissions in Latin countries. The findings highlight the importance of policymakers actively coordinating strategies to address Latin America's severe environmental degradation.

Intensified ozonation in packed bubble columns for water treatment: Focus on mass transfer and humic acids removal

Ozonation has been widely applied for the oxidation of contaminants in wastewater, and the disinfection of water. However, low ozone (O₃) mass transfer efficiency in common ozonation reactors requires high O₃ doses and causes high energy consumption. In this study, to intensify the O₃ mass transfer and oxidation of humic acids (HA) solution, a lava rock packed bubble column (LBC) and a metal pall ring packed bubble column (MBC) were developed and evaluated. In comparison with non-packed bubble column (BC), both LBC and MBC enhanced the O₃ mass transfer efficiency and the generation of hydroxyl radicals, thereby increasing the HA removal from an aqueous solution. At applied O₃ dose of 33.3 mg/(L_column h), the HA removal efficiency in BC was only 47%. When MBC and LBC were applied, it increased to 66% and 72%, respectively. Meanwhile, the O₃ utilization efficiency in LBC reached 68%, which was higher than that in MBC (50%) and BC (21%). Consequently, LBC has the lowest energy consumption (E_EO) for HA removal (1.4 kWh/m³), followed by MBC (1.6 kWh/m³) and BC (2.9 kWh/m³). LBC had better performance than MBC due to the adsorptive and catalytic roles of lava rock on the ozonation process. This study demonstrates the advantages of using lava rocks as packed materials in O₃ bubble column over metal pall rings in intensifying O₃ mass transfer and organic matters removal, which provides some insights into promoting the industrial application of O₃.

The impact of carbon market pilots on air pollution: evidence from China

As China's economic development enters a transitional stage, the government has put forward higher requirements for efficient air pollution control. Different from the traditional environmental regulation methods, China's carbon market pilots (CMP) can use market mechanism to achieve carbon emission reduction policy goals while also providing more efficient control methods for air pollution. Using the unique daily air pollution data of 324 prefecture-level and above cities in China from December 1, 2013, to December 18, 2017, and matching them with the daily data of carbon allowance trading in each CMP, we employ the time-varying difference-in-differences (DID) method to explore the casual relationship between CMP and air pollution, and its influence mechanism. Our results show that (1) the establishment of CMP can reduce air pollution by at least 4.9%, especially on sulfur dioxide, inhalable particulate matter, fine particles, and carbon monoxide. This conclusion is still robust after we use the instrumental variable (IV) method to deal with endogeneity. (2) Mechanism analysis shows that the reducing effect of CMP on air pollution is achieved mainly through three channels, including energy consumption reducing, technological progressing, and industrial structure upgrading. (3) Since CMP have just been established, government regulation plays a stronger role than the market mechanism in the process of CMP affecting air pollution. However, with the continuous improvement of CMP, the market mechanism has also played an increasingly important dynamic effect.

Dynamic nexus between energy consumption, economic growth, and urbanization with carbon emission: evidence from panel PMG-ARDL estimation

Carbon emission has been documented as a significant component of greenhouse gas that has been a significant source of environmental distortion globally. Based on panel data of 15 nations from 1980 to 2017, this study empirically investigates the impact of energy consumption, economic growth, urbanization, and energy consumption on carbon emission using panel co-integration tests and pooled mean group ARDL (PMG-ARDL) techniques. We augment the model with urbanization to establish the role urbanization plays in energy consumption, economic growth, and carbon emission nexus. Findings confirm that in the long run and short run, urbanization has no significant effect on the environment quality. On the other hand, energy consumption was found to enhance environmental destruction significantly in the short run and long run. Additional findings confirmed that economic growth causes environmental distortion in the long run for the sampled nations. Government officials and policymakers need to pay special attention to enhance adequate energy, urban planning, and emission reduction without affecting the economic development to achieve urban-economic-energy sustainability, which is key to attaining a green and clean environment.

Green standard model using machine learning: identifying threats and opportunities facing the implementation of green building in Iran

Residential buildings consume a major portion of energy resources and hence are seriously involved in environmental pollution. In Iran, fossil fuel consumption is growing, such that it increased by more than 400% from 1990 to 2018. One of the fundamental solutions for reducing fossil fuel consumption and creating a healthy environment inside and outside buildings is implementing and developing green buildings. This study seeks to examine the barriers to and opportunities for developing green buildings and proposes a localized green standard appropriate for the conditions of Iran. To this end, the required parameters were identified using the opinions of experts and the Delphi method. The opinions of 81 building experts, including the employers, consultants, and contractors, were obtained using a three-part questionnaire. Based on the results from the machine learning method, the score of the localized green building in five dimensions, namely, site, water, energy, materials, and quality of the indoor environment was calculated to be 77.2, while the energy dimension was determined to be the most important green standard dimension with a significance coefficient of 0.548. In the ranking analysis of all parameters using the Friedman test, the parameters of energy consumption management, renewable energy usage, and thermal zoning received the highest scores among other factors. Furthermore, a lack of awareness on green buildings (77%) and a high potential for renewable energy production (81%) were respectively identified as the biggest barrier to and opportunity for the implementation of green buildings in Iran.

Environmental Kuznets curve in Southeastern Europe: the role of urbanization and energy consumption

This paper investigates the dynamic short-term and long-term relationships among real GDP per capita, energy consumption, urbanization, and carbon dioxide emissions within the framework of the environmental Kuznets curve (EKC) hypothesis for Southeastern Europe (SEE) from 1997 to 2014. The evidence highlights an inverted U-shaped nexus between real GDP per capita and carbon dioxide emissions (i.e., the EKC hypothesis is verified in the long-run in the sample as a whole). The short-run estimates provide evidence of inverted U-shaped EKC only for Greece and Moldova. Two-way causal relationship between urbanization and pollutant emission was also established in the short-run, as well as one-way causality flowing from real GDP per capita to pollutant emission. The coefficients with the real GDP per capita and energy consumption are negative and statistically significant in the long-term. These findings indicate the existence of an error correction mechanism that drives the observed variables back to their equilibrium. Moreover, the findings show that the consistent increase in energy consumption has not reduced environmental pressures.

The role of food crop production, agriculture value added, electricity consumption, forest covered area, and forest production on CO2 emissions: insights from a developing economy

Several studies have quantified the carbon dioxide (CO₂₎ emissions associated with energy consumption, agriculture value added, food crop production, forest covered area, and forest production in various countries. However, past studies have ignored the long-term and short-term effects of these factors on CO₂. This study used data from 1980 to 2018 and applied the autoregressive distributed lag model (ARDL) technique to test long-run and short-run effects of these factors on CO₂ emission in the Pakistani context. The results revealed that in short-run food crop production, forest covered area and forest production have capacity to reduce CO₂ emission. However, in long run, energy consumption and agriculture value added along with food crop production, forest covered area, and forest production are negatively and significantly related to CO₂ emission which shows that these sectors, in long run, have capacity to mitigate emissions. Additionally, results also show that food crop production and forest covered area are more effective to reduce CO₂ emission as compared to other sectors. The robustness of the results was supported by using additional models and tests. This study provides scholars with valuable insights and also helps government authorities and policymakers to develop comprehensive strategies to reduce carbon emissions.

The nexus amid foreign direct investment, urbanization, and CO2 emissions: Evidence from energy grouping along the ECOWAS community

The vision of every country or subregions is to achieve economic growth and sustainable economic growth. Thus, the Economic Community of West African States (ECOWAS) as an economic cooperation renders interaction among 16 relevant countries to increase economic development. However, CO₂ emissions as a result of economic growth are of great concern. Thus, this study delves into the determinants of CO₂ emissions along the ECOWAS community, taking into consideration if countries are energy exporters or energy importers. The analytical procedure applied indicated the presence of heterogeneity in the slope coefficient and cross-sectional dependencies across the various panels. Applying the Westerlund bootstrap co-integration unveiled, the employed variables have a long-run equilibrium association. The results from the augmented mean group (AMG) revealed that the contribution weight (order of importance) to CO₂ emissions varies across panel clusters. Finally, the causality results unveil a bidirectional causation in all panels between urbanization and CO₂ emissions, whereas foreign direct investment and CO₂ emissions have a bidirectional effect in energy importers and the main panel. These results obtained indicate that foreign direct investment, urbanization, energy consumption, trade openness, and gross domestic product are the determinants of CO₂ emissions along the community. Based on the outcome, the suggested policy implications indicate that (a) the need for a paradigm shift from fossil fuel sources to renewables be encouraged in the community and (b) again, the awareness of spillover of economic growth and energy transition on CO₂ emissions from foreign companies to local businesses must be promoted.

A Perspective Review of Security Challenges in Body Area Networks for Healthcare Applications

Body area network (BAN) connects sensors and actuators to the human body in order to collect patient's information and transmitting it to doctors in a confined space with limited users. wireless body area network (WBAN) is derived from wireless sensor networks (WSN) and enables to transfer of the patient's information with a wide range of communication due to the limitations of the wired body area network. It plays a vital role in healthcare monitoring, healthcare systems, medical field, sports field, and multimedia communication. Sensors and actuators lead to high energy consumption due to their tiny size. WBAN facilitates in securely storing patient information and transmitting it to the doctor without data loss at a specific time. This review examines and summarizes methodological approaches in WBAN relating to security, safety, reliability, and the fastest transmission. Flying body area networks (FBAN) utilizing unmanned aerial vehicles for data transmission are recommended to promote rapid and secure communication in WBAN. FBAN improve the security, scalability, and speed in order to transmit patient's information to the doctor due to high mobility.

COVID-19: The impact in US high-rise office buildings energy efficiency

The COVID-19 pandemic, through stay-at-home orders, forced rapid changes to social human behavior and interrelations, targeting the work environments to protect workers and users. Rapidly, global organizations, US associations, and professionals stepped in to mitigate the virus's spread in buildings' living and work environments. The institutions proposed new HVAC settings without efficiency concerns, as improved flow rates and filtering for irradiation, humidity, and temperature. Current literature consensually predicted an increase in energy consumption due to new measures to control the SARS-CoV-2 spread. The research team assumed the effort of validating the prior published outcomes, applied to US standardized high-rise office buildings, as defined and set by the key entities in the field, by resorting to a methodology based on software energy analysis. The study compares a standard high-rise office building energy consumption, CO₂ emissions and operations costs in nine US climate zones - from 0 to 8, south to north latitudes, respectively -, assessed in the most populated cities, between the previous and post COVID-19 scenarios. The outcomes clarify the gathered knowledge, explaining that climate zones above mixed-humid type tend to increase relative energy use intensity by 21.72%, but below that threshold the zones decrease relative energy use intensity by 11.92%.

Engineering microbial metabolic energy homeostasis for improved bioproduction

Metabolic energy (ME) homeostasis is essential for the survival and proper functioning of microbial cell factories. However, it is often disrupted during bioproduction because of inefficient ME supply and excessive ME consumption. In this review, we propose strategies, including reinforcement of the capacity of ME-harvesting systems in autotrophic microorganisms; enhancement of the efficiency of ME-supplying pathways in heterotrophic microorganisms; and reduction of unessential ME consumption by microbial cells, to address these issues. This review highlights the potential of biotechnology in the engineering of microbial ME homeostasis and provides guidance for the higher efficient bioproduction of microbial cell factories.

Energy-efficient removal of PFOA and PFOS in water using electrocoagulation with an air-cathode

Electrocoagulation (EC) with a zinc anode demonstrated promising results to remove perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from an aqueous solution. However, the energy requirement for EC is usually very high due to water electrolysis or aeration. This study aims to reduce energy consumption using an air-cathode in EC (ACEC) to supply oxygen electron acceptor without aeration for attenuating PFOA/PFOS in this new configuration. For the high PFOA concentration (0.25 mM), ACEC with 45 min of the reaction time exhibited an excellent PFOA removal (99.8 ± 0.3% removal) comparable to an EC with aeration (EC-aeration, 100% removal) while achieving much less energy consumption (0.14 kWh/m³). For the low PFOA concentration (0.1 μM), only 41.1 ± 11.6% was removed by the ACEC due to the low concentration gradient for adsorption. EC-aeration achieved higher PFOA removal (81.9 ± 15.1%) for the low PFOA concentration, possibly because air bubbles floated PFOA to the water surface, thereby concentrating PFOA. The PFOS removals in the ACEC and EC-aeration (76.4-88.5%) at the high concentration (0.25 mM) were lower than PFOA due tentatively to its micelle formation. However, PFOS was removed better than PFOA at the low concentration (0.1 μM) due to its higher hydrophobicity.

The effect of energy consumption on the environment in the OECD countries: economic policy uncertainty perspectives

In this paper, we investigate the impact of energy use and economic policy uncertainties on the environment. To achieve this objective, we use the pooled mean group-autoregressive distributed lag methodology (PMG-ARDL) and Dumitrescu and Hurlin causality test on 22 Organisation for Economic Co-operation and Development (OECD) countries between 1985 and 2017. The PMG-ARDL estimation shows that energy use and economic policy uncertainties have a positive relationship with carbon dioxide emission (CO2) emission, while a negative relationship is confirmed between renewable and CO2 emissions in the long run. The short-run estimation shows a positive relationship between energy use, real gross domestic product, and per capita on CO2 emissions. The Dumitrescu and Hurlin causality results highlight a unidirectional running from real GDP and GDP per capita square to CO2 emissions. Furthermore, one-way causality exists between CO2 emissions to economic policy uncertainties. These results have policy implications on the macroeconomy which are discussed in detail in the concluding section.

Transitioning towards cleaner cooking fuels: an analysis of consumer preferences in Ghana's cookstoves market

Globally, attention has been paid to policies that promote the manufacturing, distribution, and usage of 'cleaner stoves' to minimise the negative impact of inefficient cooking. The key objective of this study is to understand the factors that affect consumer preferences for local or imported improved stoves, identify the underlying factors that influence the performance of locally made improved stoves, and ascertain the weaknesses and strengths of locally made improved stoves. A survey method was applied to collect data across 10 regions of the country from households, restaurants, institutions, retailers, and manufacturers. The survey had a response rate of 86% out of a total of 1500 respondents (consumers). In addition, data was collected from 196 distributors and 35 manufacturers. The study finds that the critical strengths of imported improved stoves are relatively lower emissions, efficiency, and quality. On the other hand, their weaknesses include high prices, inability to meet traditional cooking requirements, limited rural market penetration, long supply chain, and repair turnaround. Locally manufactured improved cookstoves thrive on lower prices, proximity to market and easy repair if needed, potential for new entrants, distribution partnership, and access to rural market.

Foreign direct investment inflow, economic growth, energy consumption, globalization, and carbon dioxide emission around the world

This study for the first time examined the link of foreign direct investment inflow, globalization, energy consumption, economic growth, export of fuel resources, and export of ore and metal resources with carbon dioxide emission in 170 countries around the world by using panel data from 1990 to 2018. The examined results of GMM and fixed effect model show that greenhouse gas emissions reduce due to exports of natural resources, export of fuel resources and export of ore and metal resources, urbanization, economic globalization, and political globalization, but the use of energy, social globalization, foreign direct investment, and economic growth have boosted the carbon dioxide emissions. This study suggests that policy makers should focus to implement environment-friendly equipment to reduce carbon dioxide emissions.

Impacts of reducing air pollutants and CO2 emissions in urban road transport through 2035 in Chongqing, China

The road transport sector in megacities is confronted with pressing local air pollution and carbon dioxide (CO₂) control issues. To determine effective policy instruments for saving energy and the co-control of air pollutants and CO₂, several mainstream measures were examined and compared in Chongqing's road transport sector from 2017 to 2035. An integration assessment framework was developed by combining the Long-range Energy Alternatives Planning (LEAP) system and a set of quantitative methods for evaluating the co-benefits of emission reductions (including the air pollutant equivalent (AP_eq), co-control coordinate system, and pollutant reduction cross-elasticity (Els_a/b)). Results showed that the shifting transportation modes scenario presented the most significant potential for energy-saving and emission reductions, reducing energy use by 30.9% and air pollutants and CO₂ emissions by approximately 27-32% compared with the business as usual (BAU) scenario in 2035. The improving energy efficiency scenario also provided significant co-benefits for reducing air pollutants and CO₂ emissions. Nevertheless, the promoting alternative fuel scenario may increase fine particulate matter (PM_2.5) emissions by 2.2% compared to BAU in 2035 under the cleanness of regional electricity in 2017. Our findings suggest that the shifting transportation modes were effective measures to reduce air pollutants and CO₂ in the short term synergistically, and highlighted the importance of cleaner electricity generation to develop electric vehicles in the medium and long term.

The impact of energy consumption on environmental quality: empirical evidence from the MINT countries

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.

Enhancement of sludge electro-dewatering by anthracite powder modification

Electro-dewatering of sludge has received considerable attention due to its low energy consumption for sludge deep-dewatering. However, prior studies have shown the resistance of dried sludge near anode significantly hinders electro-dewatering. The dewatering performance may be improved by reducing the resistance with the addition of conductive material into sludge. We conditioned municipal sludge by anthracite powder, an inexpensive product, to increase solid conductivity, followed by electro-dewatering. After running for 20 min under a constant voltage of 30 V, when the anthracite powder mass was 10%-22% of raw sludge dry solids mass (DS), the final dry solids content of the mud cake after dehydration was 6.2%-12.9% higher than that from dehydration of unconditioned sludge. The average filtrate flow rate ranged from 0.0243 to 0.0285 g s^-1. The lowest unit energy consumption, 0.19 kW h·kg_water^-1, which was 14% lower than that of control, was reached when 18% DS of anthracite was added. Our theoretical analysis indicates that properly increasing solid conductivity of sludge can reduce the adverse effect caused by the high electrical resistance of sludge near anode. The experimental results, along with the theoretical analysis, show that using anthracite powder for sludge modification is an economical approach to improve sludge dewatering rate and reduce energy consumption.

Economic growth, fiscal imbalance, and environmental sustainability: What is desirable and undesirable for developing economies?

Developing economies are suffering to fulfill the sustainable environment's commitments in fiscal imbalance. This study attempted to highlight the core issue of fiscal imbalance in developing economies and its impact on a sustainable environment. For this purpose, the study utilized generalized least squares (GLS) and quantile autoregressive distributive lag (QARDL) on a 19-year dataset (2000-2018) of the South Asian region. The results of GLS indicate that fiscal imbalance contributing positively to South Asia's environmental degradation process. Here, energy consumption (due to dirty sources of energy) and energy intensity (due to inefficient energy conversion technology) are also sources of environmental degradation in this region. The results of QARDL confirm that economic and political fluctuations can be the long-run source of fiscal imbalance in this region, which ultimately slows down the process of the environmental Kuznets curve (EKC) theory and contributes positively to environmental degradation. Based on the empirical analysis, this study provides a comprehensive set of policy guidance for developing and developed economies for the smooth transition of sustainable environmental conditions in South Asia.

Does globalization affect the green economy and environment? The relationship between energy consumption, carbon dioxide emissions, and economic growth

This study analyzes the relationship between globalization, energy consumption, and economic growth among selected South Asian countries to promote the green economy and environment. This study also finds causal association between energy growth and nexus of CO₂ emissions and employed the premises of the EKC framework. The study used annual time series analysis, starting from 1985 to 2019. The data set has been collected from the World Development Indicator (WDI). The result of a fully modified ordinary least square (FMOLS) method describes a significantly worse quality environment in the South Asian region. The individual country as Bangladesh shows a positively significant impact on the CO₂ emissions and destroys the level of environment regarding non-renewable energy and globalization index. However, negative and positive growth levels (GDP) and square of GDP confirm the EKC hypothesis in this region. This study has identified the causality between GDP growth and carbon emission and found bidirectional causality between economic growth and energy use.

The nexus between health status and health expenditure, energy consumption and environmental pollution: empirical evidence from SAARC-BIMSTEC regions

Background

The COVID-19 pandemic has highlighted the need for the betterment of health status, while also considering health expenditure, energy, and environmental issues. This paper examines the nexus between health status and health expenditure (both public and private), energy consumption and environmental pollution in the SAARC-BIMSTEC region.

Methods

We utilized the panel autoregressive distributed lag (ARDL) model, the heterogeneous panel causality test, the cross sectional dependence test, the cointegration test and the Pesaran cross sectional dependent (CADF) unit root test for obtaining estimated results from data over 16 years (2002–2017).

Results

Our results authorize the cointegration among the variables used, where the coefficients of energy consumption, public and private health expenditures, and economic growth are 0.027, 0.014, 0.030, and 0.029, respectively, and indicating positive and statistically significant effects. The coefficient of environmental pollution is − 0.085, implying significant negative effect on the health status of these regions in the long-run. However, no panel wise significant impact is found in the short-run. Bidirectional and unidirectional causal links between the studied variables and the health status are also identified..

Conclusions

The improved health status in the SAARC-BIMSTEC region needs to be protected by articulating the effective policies. The attained results are theoretically and empirically consistent, and have important policy implications in the health sector.

Role of green technology innovation and renewable energy in carbon neutrality: A sustainable investigation from Turkey

After the Paris Climate Conference (COP21), many countries start progressing towards carbon neutrality targets. In doing so, green technology innovations (GTIs) and clean energy are the essential factors that can help to achieve the carbon neutrality goal. Therefore, this paper examines the linkages between green technology innovation and renewable energy and carbon dioxide emissions based on the STIRPAT model in Turkey during the time of 1990-2018. The study used testing like "unit-root" to verify the variables' integrative properties containing the information for structural breaks. Also, the bootstrapping ARDL-bound testing technique is used to analyze the relationship between the variables. The causal relationship between green technology innovation, energy consumption, renewable energy, population, income per capita, and carbon dioxide emissions is tested through a Granger causality test. The empirical findings show that green technology innovation, renewable energy, energy consumption, population, income per capita, and carbon dioxide emissions are co-integrated for the long-term association. Additionally, green technology innovation and renewable energy decline carbon dioxide emissions, whereas energy consumption, population, and per capita enhance carbon emissions. This paper helps the policymakers design a comprehensive policy for strengthening environmental sustainability through green technology innovation and renewable energy, specifically in the region of Turkey.

In situ potential measurement in a flow-electrode CDI for energy consumption estimation and system optimization

Flow electrode capacitive deionization (FCDI) is a promising electrochemical technique for brackish water desalination; however, there are challenges in estimating the distribution of resistance and energy consumption inside a FCDI system, which hinders the optimization of the rate-limiting compartment. In this study, energy consumption of each FCDI component (e.g., flow electrodes, membranes and desalination chamber) was firstly described by using in situ potential measurement (ISPM). Results of this study showed that the energy consumption (EC) of the flow electrodes dominated under most conditions. While an increase in the carbon black content in the flow electrodes could improve the energy efficiency of the electrode component, consideration should be given to the contribution of ion exchange membranes (IEMs) and the desalination chamber to the EC. Based on the above analysis, system optimization was carried out by introducing IEMs with relatively low resistance and/or packing the desalination chamber with titanium meshes. Results showed that the voltage-driven desalination capability was increased by 39.3% with the EC reduced by 17.5% compared to the control, which overcame the tradeoff between the kinetic and energetic efficiencies. Overall, the present work facilitates our understanding of the potential drops across an FCDI system and provides insight to the optimization of system design and operation.

Energy balance of torrefied microalgal biomass with production upscale approached by life cycle assessment

Torrefaction is a thermochemical process used to convert the biomass into solid fuel. In this study, torrefaction increased the raw microalgal biomass' energy content from 20.22 MJ⋅kg^-1 to 27.93 MJ⋅kg^-1. To determine if more energy is produced than energy consumption from torrefaction, this study identified the energy balance of torrefied microalgal biomass production based on a life cycle approach. The energy analysis showed that, among all processes, torrefaction had the least amount of energy demand. The experimental setup, defined as scenario A, revealed that the principal source of energy demand, about 85%, was consumed on the microalgal growth using a photobioreactor system. A sensitivity analysis was also performed to determine the varying energy demand for torrefied microalgal biomass production. The different types of cultivation methods and various production scales were considered in scenarios B to D. Scenario D, which represented the commercial production-scale, the energy demand drastically decreased by 59.46% as compared to the experimental setup (scenario A). The open-pond cultivation system resulted in the least energy requirement, regardless of the production scale (scenarios B and C) among all the given scenarios. Unlike scenarios A and D, scenarios B and C identified the drying process to consume a high amount of energy. All the scenarios have shown an energy demand deficit. Therefore, efforts to decrease the energy demand on the upstream processes are needed to make the torrefied microalgal biomass a viable alternative energy source.

Physicochemical, reconstitution, and morphological properties of red pepper juice (Capsicum annuum L.) powder

ABSTRACT

The aim of this study is to investigate the influence of the encapsulating agents (maltodextrin (MD), whey protein isolate (WP), and gum arabic (GA)) and their blends (MD + WP, MD + GA, WP + GA, and MD + WP + GA) on the powder yield, drying ratio, productivity, drying rate, physicochemical, bulk, reconstitution, and morphological properties of the red pepper juice powders (RPJP) and to calculate the energy efficiency of the spray dryer. A pilot-scale spray dryer (180/80 °C inlet/outlet air temperature, 392 kPa atomization pressure, 1.54 m³/min air flow rate, and a 12.0 ± 0.2°Bx feeding concentration) was used for the drying experiments. The acceptable powder yield (52.48-94.25%) and specific energy consumption values (7.39-9.72 MJ/kg H₂O) were obtained. The RPJP presented moisture content and water activity values lower than 10% and 0.367. The red pepper juice powders were found to be highly dispersible (88.34-95.18%), soluble (solubility time and index are 9.75-77.25 s and around 99%), and easly wetted (9.75-122.00 s). The average particle sizes of the RPJPs were 14.92 μm, 19.68 μm, 19.36 μm, 17.58 μm, 19.96 μm, 19.41 μm, and 18.72 μm for RPJP + MD, RPJP + WP, RPJP + GA, RPJP + MD + WP, RPJP + MD + GA, RPJP + WP + GA, and RPJP + MD + WP + GA respectively. Despite the low powder yield and high water activity value, RPJP + MD exhibited superior (bulk density, flowability, cohesiveness, wettability and solubility times) or statistically similar (productivity, moisture content, browning index, porosity, dispersibility, and hygroscopicity) properties compared to other powders.

GRAPHIC ABSTRACT