Search Results (15,865)

In the context of the tangible consequences of climate change, this paper develops strategies for the energy-efficient transformation of high-rise post-war buildings of the 1950s and 1960s, taking the Asemwald housing estate in Stuttgart as a case study. The objectives are full decarbonization while under occupation, while preserving the architecture of the buildings. The main aim is the significant reduction in heating energy consumption, which can in turn enable the estate to be supplied with renewable energy. Revitalizing the estate completed in 1968 preserves important architectural designs and ideas and can serve as a model for sustainable refurbishment. Thermal bridge calculations and energy simulations are carried out to identify and evaluate energy inefficiencies. Based on this, two façade renovation concepts are developed. These concepts differ in the degree of invasiveness and combine architectural sensitivity with energy optimization. In addition, an analysis is carried out to determine which alternative environmentally friendly heating systems can be used. The results show an energy saving potential of up to 60% and that a conversion to a CO₂-neutral heating system is possible. It can be shown that a significant reduction in energy requirements is an important step towards converting to geothermal energy. The study emphasizes the relevance of integral and architecturally sensitive retrofitting to serve as a model for similar post-war high-rise housing estates. Full article

Coal gasification slag (CGS), a massive industrial solid waste, possesses inherent adsorptive potential that remains underutilized due to pore blockage by amorphous siliceous phases. Conventional modification strategies typically rely on energy-intensive high-temperature processes. Herein, we report a facile, low-temperature alkaline activation approach to transform CGS into a high-efficiency adsorbent (denoted NCGS) for Cd²⁺ removal. Sodium hydroxide (NaOH) solution was employed under mild conditions (90 °C) to selectively etch siliceous species, thereby generating a porous architecture and enriching surface oxygen-containing functionalities. Orthogonal experimental design identified optimal synthesis parameters (1 mol/L NaOH, solid–liquid ratio of 1:30 g/mL, 12 h), yielding NCGS with significantly enhanced textural properties. The adsorption isotherm was well described by the Langmuir model, with a maximum capacity of 87.06 mg/g at pH 6.0, while kinetic studies indicated the adsorption process could be described by pseudo-second-order kinetic model. Comprehensive characterization via SEM-EDS, FTIR, and XPS elucidated a multi-mechanistic adsorption pathway mainly involving ion exchange (Na⁺/Cd²⁺) and coordination complexation. Life cycle assessment analysis revealed that NCGS production generates 11.23 kg CO₂ eq emissions, with transportation accounting for 88%. This study presents an energy-saving and environmentally friendly strategy to unlock the adsorptive potential of CGS, providing a highly promising waste-based adsorption material for the remediation of Cd²⁺-contaminated water. Full article

Mangrove forests along China’s coastline serve as vital ecological barriers and blue carbon reservoirs. However, pests and diseases have become the primary biotic threats driving stand decline and diminished carbon sequestration capacity. This review synthesizes current knowledge on the major insect pests and plant diseases affecting Chinese coastal mangroves, focusing on their species profiles, characteristic damage symptoms, occurrence dynamics, and integrated control strategies. Fungal pathogens predominate among the diseases, with outbreaks most common during periods of high temperatures and humidity or low temperatures combined with high humidity; these often interact synergistically with insect pests. The dominant insect pests comprise leaf-feeding Lepidoptera, sap-sucking Hemiptera, and wood-boring Coleoptera, which spread through diverse pathways and can rapidly produce extensive “scorched” damage across mangrove stands during epidemic events. Control efforts follow the principle of “prevention first and integrated management,” incorporating cultural practices, chemical interventions, biological control agents, physical trapping methods, and rigorous quarantine-monitoring protocols. When applied in concert, these measures effectively limit damage to acceptably low levels. Recent studies identify pest–disease interactions and climate change as the foremost challenges in current management. Future priorities should include advancing molecular identification techniques, breeding disease-resistant varieties, and developing environmentally friendly biopesticides to establish precision ecological control systems. Such advances will deliver robust scientific support for mangrove conservation and the achievement of China’s dual-carbon goals. Full article

This work describes an efficient and environmentally friendly method for the synthesis of silver-based nanostructures through a green route using Aloe vera extract as a reducing agent, silver nitrate (AgNO₃) as a precursor, and polyvinylpyrrolidone (PVP, 10 kDa molecular weight) as a stabilizing agent. The formation of these structures was supported by UV–Vis spectroscopy, where a surface plasmon resonance (SPR) band was observed between 425 and 460 nm. Scanning electron microscopy revealed predominantly spherical features in the 300–500 nm range; however, the distinction between primary nanoparticles and aggregates cannot be conclusively established from SEM alone. EDX analysis indicated a silver content of 59.96 wt%. Antibacterial assays performed in Z8 medium demonstrated a reduction in cyanobacterial growth with increasing dosage, with complete inhibition observed at ≥20 $\mu$L (nominal MIC = 1.77 mg mL⁻¹, based on precursor estimation). Total dissolved solids and absorbance measurements exhibited a decreasing trend with increasing concentration (effect size = 0.87, $p<0.001$), supporting an inhibitory effect under the tested conditions. These findings suggest potential antibacterial activity. However, this study should be considered exploratory, and further work is required to elucidate the underlying mechanisms. Full article

Citrus fruits are a significant source of flavonoids. Of all the citrus fruits, Citrus paradisi (grapefruit) presents the highest concentration of the flavonoid naringin, a compound offering a variety of human health benefits and applications in the pharmaceutical, food, and cosmetic industries. Commonly, when a citrus fruit is consumed, the peel and seeds are discarded, resulting in approximately 50% waste, making the potential use of citrus waste in order to reduce environmental impact a research priority. The present study used fresh grapefruit albedo to extract naringin via eco-friendly methods, such as ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), which were compared against the conventional reflux extraction procedure. Furthermore, the presence of naringin was confirmed by nuclear magnetic resonance (NMR) spectroscopy, while naringin content was determined via HPLC-DAD analysis. The results obtained show that the pink grapefruit variety was the optimal source for extracting the flavonoid of interest, producing the highest content (3.41 g/kg), followed by the red (2.47 g/kg) and white (1.70 g/kg) varieties. The UAE method was observed to reduce the extraction time significantly, to only 10 min, which is up to 30-and -fold times less than the extraction times obtained using conventional (5 h) and MAE (40 min) methods, respectively. These results prove the usefulness of UAE as a simple, fast, efficient, and eco-friendly method for extracting naringin from fresh grapefruit albedo, via the use of a green solvent such as ethanol. In addition, the present study is the first to conduct a comparative analysis of naringin content in the three main grapefruit varieties grown in Mexico. Full article

The present study reports the application of a gold microelectrode array to determine copper(II) ions by anodic stripping voltammetry (ASV). The microelectrode characterization of the presented working electrode was investigated. Moreover, the way of its preparation ensures its reusability and eco-friendly character, thanks to the use of environmentally benign electrode material. The procedure does not require modification of the surface of the working electrode. Main experimental parameters were optimized, including pH and a concentration of the supporting electrolyte, activation and deposition conditions, and square wave parameters. The calibration graph was linear in the range of Cu(II) concentrations from 2 × 10⁻⁹ to 2 × 10⁻⁷ mol L⁻¹ (with a deposition time of 30 s) and from 5 × 10⁻¹⁰ to 5 × 10⁻⁸ mol L⁻¹ (with a deposition time of 90 s; RSD was 4.7% (n = 3) for a 1 × 10⁻⁸ mol L⁻¹ of Cu(II)). The limit of detection was equal to 1.93 × 10⁻¹⁰ mol L⁻¹ (t_acc = 90 s). The correctness of the developed procedure was successfully checked by analysis of certified reference material and a tap water sample, confirming the possibility of its practical application. Satisfactory recovery values were also obtained during the analysis of an environmental water sample. Full article

With increasing global concerns about industrial wastewater treatment and the need for sustainable practices, this study explores the potential of softwood sawdust as an eco-friendly, cost-effective adsorbent for removing heavy metal ions, specifically zinc (Zn²⁺) and lead (Pb²⁺), from synthetic model solutions. Factors affecting adsorption include adsorbent particle size, pH, adsorbent dosage, and contact time. A remarkable removal efficiency of 98.2% for Zn²⁺ and 98.1% for Pb²⁺ under optimal adsorption conditions of −106 µm average particle size at 8 pH and 0.3 g of adsorbent dosage using 50 (mg/L) initial concentrations for 60 min at ambient temperature. Characterization of the adsorbent used by XRD, FTIR, SEM, and BET analysis confirmed the structural integrity and surface properties of wood sawdust. It is clear that there is a gradual decline in adsorption capacity over multiple reuse cycles due to the depletion of active functional groups. The results confirm wood sawdust’s effectiveness as a locally available, low-cost, and biodegradable option for treating wastewater, eliminating metal ions, supporting environmental conservation, and aligning with sustainability goals. Full article

The high silica content of coal fly ash (CFA) poses a significant challenge for alumina extraction, resulting in high material and energy consumption. To reduce the silica content and improve alumina extraction efficiency, a novel process combining pre-desilication, vacuum reduction, and alkali dissolving is proposed. In the pre-desilication stage, amorphous silica in CFA is effectively removed by NaOH solution, increasing the Al₂O₃/SiO₂ mass ratio from 0.78 to 1.27. The desilicated coal fly ash (D-CFA) is then subjected to vacuum carbothermal reduction with the addition of Fe₂O₃ and CaO to produce Fe-Si alloys and CaO·xAl₂O₃. The resulting CaO·xAl₂O₃ can be dissolved via alkali dissolving to extract alumina, achieving an alumina dissolving rate of over 90%. The Fe-Si alloys remaining in the dissolved residue are subsequently recovered by magnetic separation. Compared with the process without pre-desilication, the current process reduces material input by 30.25% and energy consumption by 35.18%, demonstrating that this approach offers a low-cost, energy-efficient, and environmentally friendly route for high-value-added utilization of CFA. Full article

The urgency for sustainable propagation methods is increasing as anthropogenic disturbances threaten global biodiversity and plant productivity. This study focused on the cutting propagation of Campanula pelviformis and Petromarula pinnata, two local endemic species of Crete (Greece) with known multipurpose crop potential. For C. pelviformis, the effects of cutting type and indole-3-butyric acid (IBA) treatments applied with or without the commercially available and environmentally friendly fertilizer Theocopper and population were investigated. For P. pinnata, the effects of cutting type and IBA treatments were examined. Rooting success and root dry mass were assessed three weeks after propagation onset, while root number and length were measured in the third week to evaluate overall rooting performance. Vegetative propagation of P. pinnata was straightforwardly achieved across cutting types (>90% rooting success), and superior root traits were observed in young shoot cuttings. In C. pelviformis, high rooting success (90%) was recorded in four of the six treatments using adventitious shoot cuttings, while the combined application of 1% Theocopper and IBA efficiently enhanced both rooting percentages and root traits in young shoot cuttings and sub-apical stem sections. The results further indicated a population effect on rooting success and traits among cutting types. The data produced may guide conservation purposes and/or sustainable utilization of these neglected species as novel multipurpose crops, especially in landscaping design with native plants. Full article

Consumer behavior evolves unexpectedly, and understanding new perspectives according to market trends is a key factor in identifying the most commonly recurring consumption demands. In this context, this study aimed to examine the associations among green consumption orientation, consumer ethical beliefs and green purchasing intention. Based on a quantitative and explanatory study with the participation of 411 Peruvian consumers, this study demonstrated that green consumption orientation has a direct and negative association with consumers’ ethical beliefs, while green consumption orientation has a direct and positive association with green purchasing intention. Finally, green purchasing intention has a direct and negative association with the ethical beliefs of Peruvian consumers. These findings reveal a reconfiguration of the ethical framework of Peruvian consumers, where green consumption orientation acts as a catalyst for the intention to purchase eco-friendly products, but at the same time generates tensions with traditional ethical beliefs. This phenomenon suggests that consumers are developing new value systems that prioritize environmental sustainability over conventional ethical considerations, which represents both a challenge and an opportunity for companies seeking to position themselves in the green market. Full article

The growing urbanisation of India is a major contributor to the production of 72,368 million litres of wastewater daily. Unfortunately, not even 28 to 31% of the generated wastewater receives proper treatment before disposal, putting public health, water quality, and ecological conditions at risk. Traditional wastewater treatment technologies have been proven effective, but they cannot be applied in decentralised settings due to excessive initial investment costs, continuous power needs, and the need for expert supervision. Constructed wetlands (CWs) provide an efficient and environmentally friendly option for decentralised treatment, but these systems suffer from a gradual loss of effectiveness associated with the problem of media-clogging in traditional setups. This research investigates the functioning and efficiency of the Modified Towery Bio-rack Constructed Wetland (MTBRCW) technology designed specifically to mitigate media-clogging issues. The MTBRCW is tested on the basis of its performance under continuous operating conditions for thirteen months (January 2025 to January 2026), as well as on the effectiveness of the treatment at eight different hydraulic retention times (days 1 to 8). A pilot-scale MTBRCW system was monitored through two periodic sampling events (S1 and S2) conducted during each month of operation. The pilot-scale MTBRCW unit is made up of an inlet storage tank (volume 0.099 m³) followed by two wetland containers (volume 0.034 m³ each) planted with Typha angustifolia and Chrysopogon zizanioides (vetiver grass). In continuous testing mode, influent–effluent paired samples are collected for eight days at each HRT (totalling eighty samples), and samples are analysed according to APHA Standard Methods for pH, BOD, COD, TN, and TP. In continuous testing mode, the MTBRCW exhibits high removal efficiencies at the levels of 89.8% for BOD, 87.5% for COD, 78.2% for TN, and 74.4% for TP. The BOD/COD of the effluent was within the prescribed CPCB discharge limits for all thirteen months of the study, and the TN levels were adhered to in 12 out of 13 months, with one non-compliance event recorded only in July 2025 (effluent TN = 10.8 mg/L), coinciding with the peak monsoon hydraulic loading rate of 0.28 m³/m²·d. TP remained within CPCB limits in all thirteen months. In batch testing mode, removal efficiencies are 94.9% for BOD and 89.9% for COD by day 8. In addition, there were no indications of clogging or any reduction in hydraulic performance during the entire period of the tests through the use of visual inspections and measurement of the outlet flows, but this can only be seen as an observation in a field operation, and not as proof of the hydraulic performance of the system, since no tracer test or measurement of hydraulic conductivity was conducted. Full article

With the continuous development of China’s economy and technology, the number of urban transportation shield tunnels has been increasing. As tunnel depth and diameter grow, the geological conditions become increasingly complex, making leakage at segment joints of shield tunnels a more prominent issue, significantly affecting the sustainable development of urban transportation. To address the issue of water leakage, microbially induced calcium carbonate precipitation (MICP) technology offers a green and environmentally friendly solution. However, relying solely on MICP technology is insufficient to enhance the waterproofing performance of large segment joints of shield tunnel. To address this, this study proposes combining diatomite as both a carrier and filler material with MICP technology, using a diatomite–MICP composite grout to improve the waterproofing performance of tunnel segment joints. First, through laboratory macro-scale tests and micro-morphology analysis, the influence of diatomite dosage on the sealing performance of diatomite–MICP composite grout was systematically studied, and the optimal diatomite dosage was determined. Based on this, a self-developed segment joint waterproofing testing platform was adopted to conduct hydraulic tests on double-seal gasket joints, evaluating the enhancement effect of the composite grout on the overall waterproofing performance of tunnel segment joints. The results indicated that the dosage of diatomite significantly affects the sealing performance of the composite grout, with an optimal dosage of 20% by weight of the bacterial solution. At this dosage, the composite grout achieved the highest density, resulting in maximum unconfined compressive strength and shear strength, as well as the lowest permeability coefficient. The joint water pressure test confirmed that after grouting with a diatomite–MICP composite grout at the optimal dosage of 20%, the breakdown water pressures of the inner and outer seal gaskets at the segment joints reached 2011 kPa and 2019 kPa, representing increases of 15.91% and 16.64% compared to the control group without grouting. This study demonstrates the effectiveness and application potential of the green biomineralization technologies in waterproofing of shield tunnel joints. Full article

The increasing global demand for energy has intensified the need for lithium, a critical component in rechargeable batteries and electric vehicles. However, conventional lithium extraction methods are associated with significant environmental impacts. In this study, a one-step bioleaching approach for lithium recovery from mineral concentrates was evaluated using native microbial consortia and isolated bacterial strains. A suitable culture medium was selected, individual strains were isolated, and bioleaching experiments were conducted using a Box–Behnken experimental design. Lithium solubilization and cell density were assessed under different agitation conditions, pulp concentrations, and initial pH values. The highest lithium solubilization (99%) was achieved under non-agitated conditions, with a pulp concentration of 30% and an initial pH of 6. Three bacterial strains (ITDB101, ITDR102, and ITDN103) were identified. The native microbial consortium and the biotic control exhibited the highest lithium solubilization efficiencies (94.5% and 96.3%, respectively), outperforming the individual strains, which achieved solubilization values ranging from 91.73% to 93.27%. X-ray diffraction analysis identified five mineral phases in the concentrate, and comparisons among treatments revealed changes in these phases following bioleaching, supporting the potential of this process as an environmentally friendly alternative for lithium extraction. Full article

The growing demand for safe and minimally processed fresh fruits and vegetables has highlighted the need for effective and environmentally friendly decontamination methods. Conventional washing techniques often fail to remove pesticide residues and microbial contaminants efficiently, while chemical disinfectants raise concerns related to toxicity and sustainability. In this context, natural surfactants and fermentation-derived solutions have emerged as promising alternatives. This critical review presents aspects regarding recent advances in the use of plant-based and microbial surfactants, for the decontamination of fresh products, with highlights on their mechanisms of action, ranging from enhanced removal of hydrophobic residues to disruption of microbial bio-films. Also, particular attention is given to the potential of combining surfactants with bioactive compounds obtained through fermentation processes, as well as to the valorization of agro-industrial waste as sustainable raw materials. The impact of these treatments will contribute to the improvement of product quality, safety, and environmental compatibility. Finally, current challenges related to scalability, standardization, and regulatory aspects are outlined, highlighting the need for further research to support the transition from laboratory studies to real-world applications. Full article

Rice cultivation generates a substantial amount of rice husks (RH) as agricultural waste from rice milling, which is not effectively utilized for environmentally friendly products. This study investigates the product yields and chemical characteristics of RH pyrolysis conducted at temperatures between 400 and 600 °C, at 50 °C intervals, with heating rates of 5, 10, and 20 °C/min. The highest liquid product yield (30.57%) was achieved at 600 °C under a heating rate of 20 °C/min. Gas chromatography–mass spectrometry (GC–MS) characterization revealed that the liquid product consisted predominantly of complex mixtures, with C6 compounds dominating the carbon number distribution, followed by C8 and C5 compounds. During the pyrolysis process, CO₂ and CO were the main components of the non-condensable gases, whereas total hydrocarbons (THC) were generated at pyrolysis temperatures of 500 °C and above. The carbon content of biochar increased as the pyrolysis temperature increased, while the oxygen and hydrogen contents decreased. These findings elucidate the influence of temperature and heating rate on the chemical properties of pyrolysis products derived from RH. In addition, the kinetic analysis of RH pyrolysis showed that the estimated activation energy varies depending on the applied method. Therefore, the combined use of multiple methods is considered desirable for providing a more reliable kinetic interpretation of RH pyrolysis. Full article