Environmental Progress & Sustainable Energy最新文献

Residential carbon emissions have emerged as a primary driver of future carbon emissions in China. Investigating the influential factors affecting demand-side carbon emissions and elucidating future pathways for regional carbon reduction in consumption can provide a scientific basis for regional carbon peak and carbon-neutral action plans. This study incorporated the development of digital technology into the STIRPAT model. The technical components of the STIRPAT model were expanded upon to better understand the factors influencing the household consumption sector and the carbon emission reduction effects of these various factors. The results indicated that: (i) per capita residential carbon emissions in China exhibit a slow fluctuating rise followed by accelerated growth, with the sequence of emissions being highest in the eastern region, followed by the northeastern region, western region, and finally the central region; (ii) population size, shared prosperity, urbanization development, and digitalization collectively influence residential carbon emissions in different regions, with population size and consumption structure playing the most significant promoting and inhibiting roles, respectively; (iii) societal development scenarios and low-carbon development scenarios demonstrate a significant advantage in achieving the timely realization of China's overall residential carbon reduction plan. In most provinces, peak emissions are projected to occur around 2035 under various scenarios, necessitating substantial efforts for provinces to meet the 2030 carbon peak target.

Hydropower offers a means of generating electricity through the conversion of water flow's mechanical energy using rotors. The helical Savonius rotor is recognized as one of the most commonly employed rotor types. An approach employed to boost power output involves the utilization of guiding walls, positioned upstream of the Savonius rotor. In this specific study, an investigation is presented into a helical Savonius rotor equipped with an innovative deflector design composed of guiding walls in the form of NACA-profiled plates. Ansys Fluent is used to simulate the water flow around the helical Savonius turbine and the guiding walls. The geometric parameters of this design of guiding walls are adjusted to identify the most efficient configuration. When examining all considered configurations, an improvement is noted in the maximum power coefficient, with a significant increase compared with a conventional configuration. In fact, the power coefficient could be improved by 44% using optimal dimensions of the guiding walls. The inclusion of the proposed guiding walls in conjunction with the optimized geometric parameters emerges as a strategy to enhance the rotor's power coefficient.

Aquaponics is an integration of aquaculture and hydroponics systems, utilizing recirculating water to connect these two processes. Maintaining optimal water quality parameters is critical for the life of fish and plants and crucial for the optimal production in the aquaponics. However, this is difficult due to the complex dynamics in each system and the recirculations. Atmospheric temperature significantly impacts fish and plant growth by affecting water quality parameters. To address this, a mathematical model for key parameters, such as temperature and dissolved oxygen (DO), is introduced, along with a model predictive controller (MPC) that is designed to maintain these parameters at optimal levels. The ideal operating points for temperature and DO are identified by optimizing the aquaponics dynamics. The MPC's performance is compared to that of a traditional proportional-integral (PI) controller, utilizing two performance indices: relative absolute deviation (RAD) and mean relative deviation (MRD). The MPC demonstrates a reduction in RAD values for both FT and NFT water parameters by 40%–60%, and MRD values by 8%–43%. These results show that the MPC effectively mitigates disturbances and addresses model mismatches, outperforming the PI controller. Implementing the proposed strategies in aquaponic systems enhances overall performance, boosts food production rates, maximizes profit, and reduces labour.

The utilization of solar energy technology for obtaining clean water for use of society in remote locations will help in fulfilling the sustainable development goals of the United Nations. Also, promotion of solar energy for the use of society will subside dependency on the fossil fuel or conventional energy. This article deals with the annual energy, exergy, and efficiency analyses of N identical ETCs incorporated conical solar still (NETC-CSS). The thermal model for the proposed system has been developed based on equating input and output heats for different elements. The developed fundamental equations are fed to the MATLAB computational code. The four weather situations in each month of year for New Delhi climate is considered for the annual analysis. The annual energy, exergy, thermal efficiency, and exergy efficiency for NETC-CSS are computed to be 1796.61, 170.19 kWh, 38.79%, and 3.94% under optimized values of mass flow rate and number of collectors. Results are compared with earlier published research. Concludingly, the increase in annual energy, exergy, thermal efficiency, and exergy efficiency for NETC-CSS is 68.03% than modified solar still, 74.14% than conventional conical solar still, 61.12% than modified solar still, and 72.59% than solar still with parabolic trough collector.

Sweet sorghum bagasse (SSB) is a promising feedstock for cellulosic ethanol production because of its composition and productivity. The use of SSB pretreated with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) before subcritical water hydrolysis (SWH) aiming the production of fermentable sugars and platform chemicals was investigated. Modifications in the composition of SSB at different conditions (100°C and 120°C; 2, 4, and 6 h) were evaluated by the thermogravimetric analysis. Sequentially, pretreated SSB was submitted to subcritical water hydrolysis, whose conditions were 220°C and 260°C, and solvent/feed ratios of 80 and 100 g water/g sample (R-80 and R-100) were considered. Maximum enrichment in hemicellulose content and minimum cellulose content was reached in 2 h for pretreatment at 100°C. SSB pretreated with [Bmim]Cl presented enrichment in hemicellulose content from 37.95 to 90.07%, and a 76.9% reduction in lignin content. Therefore, pretreated SSB from this condition was submitted to SWH, resulting in 19.18 g of fermentable sugars per 100 g of sample at 220°C and R-100. The yield of fermentable sugars using SSB pretreated with [Bmim]Cl increased 2.05 times compared with unpretreated under the same condition of SWH (220°C/R-100/10 min). The higher platform chemicals production from pretreated SSB was 15.25 g per 100 g of sample at 220°C and R-80, lower when compared with untreated SSB at 220°C and R-100. Optimizing the solvent/feed ratio is crucial for balancing fermentable sugar and platform chemical production via SWH. [Bmim]Cl pretreatment and ratio optimization enhance product yields significantly.

To promote the sustainable development of urban rail transit (URT) in China, it is necessary to quantitatively analyze the greenhouse gas (GHG) emissions and its internal driving factors. Based on the LMDI algorithm, this research constructs an assessment model and makes a quantitative analysis of internal driving factors for GHG emissions in the operational phase of the URT system in China. According to the official investigated data, the GHG emission of URT in the operational phase is between 600 × 10⁴ and 2000 × 10⁴ tons of carbon dioxide equivalent (CO₂e) per year from 2012 to 2023. The results of the driving factors decomposition showed that the passenger demand intensity was the key and positive factor affecting carbon emissions in the operational phase and the contribution rate was 12.93%–60.81% from 2013 to 2023. Therefore, it is necessary to formulate targeted policies in terms of management and technical means to reduce the average traveling distance demanded by passengers and reasonably control the scale of the line network for GHG reduction in the Chinese URT system.

The effective utilization and high-value bioproducts from agro-wastes make sense for a sustainable circular economy for agriculture. The article discusses the promising potential of utilizing agro-wastes to produce high-value bioproducts, particularly focusing on carbon dots (C-dots) derived from such wastes. These C-dots exhibit remarkable fluorescence properties and excellent biocompatibility, making them valuable nanomaterials for various applications. The dual sources of these C-dots: green precursors sourced from both edible and non-edible plant-based materials, and chemical precursors involving acid and non-acid reagents are highlighted. This diversity in precursor materials underscores the versatility and sustainability of C-dot production. Importantly, the synthesis of fluorescent C-dots achieved quickly and directly via hydrothermal carbonization, microwave technique, thermal pyrolysis carbonization, solvothermal technique, and ultrasonic process are review concisely intended for widespread application in fields ranging from bio-imaging to optoelectronic devices. Furthermore, the article discusses the challenges associated with synthesizing high-quality C-dots from agro-residues, indicating ongoing research efforts in this area. Likewise, key energy specific characteristics like optical, photoluminestic, photosimulated electron transfer, catalytic, mechanical, and carcinogenic attributes are discussed. Despite these energy specific characteristics, various energy applications of C-dots, including their potential use in light-emitting diodes, supercapacitors, and photovoltaics are outlined. This highlights the multifaceted nature of C-dots and their contribution to advancing sustainable practices in agriculture while simultaneously addressing energy needs in various sectors. Overall, the article underscores the importance of leveraging agro-wastes for the development of innovative and environmentally friendly bioproducts, contributing to the circular economy in agriculture.

Natural coagulants are a biodegradable and potential alternative to chemical coagulants. Cassia fistula seeds and Cactus opuntia f-indica are employed herein to reduce the concentration of methylene blue dye in aqueous solutions. Maximum removal efficiency was obtained by optimizing the process parameters by the Taguchi method in the design of experiments (DOE). At optimum conditions, the removal efficiencies of C. fistula seeds and Cactus opuntia f-indica were 98.27% and 92.75%, respectively. The adsorption kinetics data were fitted to pseudo-first-order, pseudo-second-order, Elovich, intra-particle diffusion, and Boyd kinetic models. Accordingly, intra-particle diffusion and pseudo-second-order kinetics suggested the coagulation process to be an adsorption process controlled by the solid-phase sorption with intra-particle diffusion as the rate-limiting step. A comparative study was also conducted using alum to determine its effectiveness in reducing dye concentration. Results suggested biocoagulants are appropriate alternatives for reducing dye concentrations in wastewater and treating textile and dye industrial effluents.