CleanMat最新文献

The mounting global waste crisis demands forward-looking solutions rooted in circular economy principles and sustainable material flows, as well as resource efficiency. This review examines emerging technological approaches in recycling, upcycling, and downcycling, emphasizing their roles in enhancing environmental sustainability, economic viability, and social equity. Recycling is transforming through the integration of artificial intelligence–driven sorting, advanced material separation, and chemical recycling technologies, which enable the recovery of high-purity materials from complex waste streams. Upcycling leverages design thinking, biotechnology, and creative engineering to generate higher-value products from waste, reducing dependency on virgin materials and contributing to sustainable production systems. Downcycling, although resulting in lower value outputs, remains essential for diverting residual waste from landfills and supplying secondary materials for industries such as construction, textiles, and agriculture. This review critically evaluates how policy instruments, market-based incentives, and community participation shape the success of waste valorization efforts across diverse socio-economic contexts. Comparative insights from both industrialized nations and the Global South reveal that integrated, context-specific waste management approaches can significantly improve material recovery rates while minimizing environmental footprints. Key findings highlight the importance of harmonizing technological innovation with participatory governance and life cycle thinking. The review concludes with recommendations for advancing systems-based modeling, expanding life cycle assessment tools, and fostering interdisciplinary collaborations to optimize the performance, profitability, and sustainability of circular waste management systems in the face of climate change and growing urbanization.

Basic sanitation and access to drinking water are critical challenges for developing countries. By 2025, water scarcity could affect 50% of the global population. Given this scenario, the search for sustainable and cost-effective water purification methods has driven research into the application of biologically synthesized silver nanoparticles (AgNPs). In this study, AgNPs were produced using the filamentous fungus Aspergillus niger IBCLP20 and encapsulated in calcium alginate (AgNP_IBCLP20/CA) for use in a packed-bed reactor (PBR) to treat water contaminated with Escherichia coli IPT245 and Pseudomonas aeruginosa IPT365. To evaluate the process parameters for water disinfection, the following variables were assessed: influent bacterial concentration (10³, 10⁴, and 10⁵ CFU·mL⁻¹), temperature (25°C, 30°C, 37°C, and 40°C), reactor occupancy (50%, 75%, and 100%), and volumetric feed flow rate (1.0, 4.0, 7.0, and 10.0 mL·min⁻¹). In the experiments, P. aeruginosa IPT365 exhibited greater resistance compared to E. coli IPT245. For both bacteria, the best antimicrobial results were obtained at an influent concentration of 10³ CFU·mL⁻¹. Temperature had no significant impact on the system for either of the bacterial strain. The antimicrobial activity against E. coli IPT245 was observed for all reactor occupancy levels tested, whereas the bactericidal effect against P. aeruginosa IPT365 was only achieved when the PBR was filled to 100% of the catalyst mass. The optimum volumetric flow rate was determined to be 4.0 mL·min⁻¹. These findings confirm that the PBR with encapsulated AgNP_IBCLP20/CA is a promising approach for water disinfection. The maintenance of antimicrobial activity after nanoparticle encapsulation, along with a detailed analysis of operational parameters, supports the feasibility of this method for environmental applications.

Hydrochar–metal composites exhibit significant potential in catalysis and energy storage due to their tunable pore structures, high surface areas, and adjustable physicochemical properties. This review systematically examines preparation methods, phase equilibrium behavior, and thermophysical properties of these composites. Microstructural control is achieved by varying biomass types, hydrothermal conditions (temperature, time, pH), and metal incorporation approaches (direct addition or pretreatment). Metal type and content critically influence phase equilibrium, governing thermal conductivity (TC), specific heat capacity (SHC), and thermal expansion coefficient (CTE). Uniform metal dispersion and stable integration with the carbon matrix enhance catalytic activity and energy storage performance. High TC improves thermal management in catalysis, while high SHC and low CTE enhance energy storage stability by mitigating thermal fluctuations and mechanical stress. Challenges include phase equilibrium modeling, thermophysical characterization under extreme conditions, and scalable synthesis optimization. Future research should leverage machine learning, multifield coupling experiments, and advanced characterization to guide high-performance composite design.

Cu-based catalysts have been extensively adopted for catalytic oxidation of volatile organic compounds (VOCs). Nevertheless, the poisoning effect of alkali metals over Cu-based catalysts has received insufficient consideration despite that alkali metals are common components in the coal-fired fuel gas. In this study, the poisoning effect of Na₂O and NaCl on CuO/Al₂O₃ catalysts during toluene oxidation is studied. Experimental results show that Na₂O and NaCl cause an increase in the temperature corresponding to 90% of toluene conversion by 38°C and 87°C, respectively. After being poisoned by Na₂O and NaCl, the CO₂ selectivity decreases by 0.67%–8.15% and 12.76%–42.99%, respectively. The significant inhibition effect arises from the formation of Cu-O-Na and O-Cu-Cl structures. Cu-O-Na structure reduces toluene adsorption capacity, surface acidity, the ratio of surface adsorbed oxygen to total oxygen (marked as O_A ratio), and the quantity of active oxygen species. O-Cu-Cl structure reduces O_A ratio, the quantity of active oxygen species, and low-temperature reducibility. Besides, the following changes in toluene oxidation pathway are identified. Cu-O-Na structure promotes the generation of benzene. O-Cu-Cl structure inhibits the benzaldehyde oxidation and causes the generation of chlorinated aromatics. These results well explain the decrease of CO₂ selectivity after the catalyst is poisoned by Na₂O and NaCl.

Chromium-bearing tannery sludge poses both environmental and resource challenges, but current methods often rely on high-temperature calcination with inorganic Ca sources. To address this gap, this study investigates the synergistic effects of oyster shell (OS), a natural biomineralized calcium material, in chromium recovery from dewatered tannery sludge (TS) through co-pyrolysis, with comparative analysis against inorganic calcium carbonate (CaCO₃). Laboratory-scale experiments were conducted at pyrolysis temperatures ranging up to 900°C, with varying OS concentrations. The results demonstrate that OS incorporation significantly influenced chromium phase transformation, effectively converting Cr₂O₃ (exclusive to TS) into chromate salts during the co-pyrolysis process. The optimized co-pyrolysis conditions achieved remarkable chromium recovery efficiency exceeding 95%, substantially outperforming the CaCO₃-assisted pyrolysis system. Mechanistic analysis revealed that the organic matrix proteins inherent in OS played a crucial role in facilitating chromium adsorption and subsequent phase transformation processes. This work provides a new way to recover chromium using OS powder, which performs better than CaCO₃ and also utilizes marine waste material. The process improves chromium recovery and supports resource reuse in the tannery industry. This innovative co-pyrolysis approach utilizing OS powder offers a sustainable and economically viable solution for chromium recovery, simultaneously addressing environmental concerns and resource utilization challenges in the tannery industry. Furthermore, the oxidation of Cr(III) to Cr(VI) in tannery wastewater not only enhances chromium recyclability but also promotes the conversion of waste streams into valuable resources, thereby advancing circular economy principles within the leather manufacturing sector.

The upstream petroleum industry significantly contributes to environmental pollution through the use of fossil-derived chemicals. This study explores the potential of green alternatives by synthesizing and evaluating chitosan-based polymers for enhanced oil recovery (EOR) applications. A native chitosan salt (S0) and its hydrophobically modified derivatives (S1–S4), grafted with linear alkyl chains (C5–C8), were synthesized and systematically characterized. Key parameters investigated include thermal stability in seawater, interfacial tension (IFT), rheological behavior, and wettability alteration of carbonate rock surfaces. The performance of these materials was found to correlate with their critical aggregation concentration (CAC) and hydrophobicity. While the unmodified chitosan (S0) exhibited no interfacial activity, HM-chitosan displayed surfactant-like behavior with characteristic L-shaped IFT profiles. Despite limited viscosity enhancement, all HM-chitosan significantly reduced water contact angles by up to 46%, indicating effective wettability alteration. These findings show the promise of HM-chitosan as an environmentally friendly EOR agents due to their biocompatibility, structural tunability, and surface activity. The study establishes a fundamental framework linking molecular structure, CAC, and performance, supporting future applications in porous media systems.

Pyrolysis is widely used as a sludge conversion technology, but the poor adsorption capacity on account of less surface functional groups limits its practical application. In this work, hydrothermal carbonation (HTC) technology was used as the pretreatment of pyrolysis to carbonize sewage sludge to prepare the sludge biochar (SDBC) for enhanced adsorption removal. It was certified that pretreatment with HTC promoted Cu²⁺ adsorption. At a HTC temperature of 120°C, the adsorption removal rate of Cu²⁺ was found to be the highest, achieving an maximum adsorption capacity of 22.5 mg/g for Cu²⁺, which was 1.23 times higher than that of SDBC. The adsorption better fitted with the Langmuir model and pseudo-second-order kinetic. Chemical adsorption was the predominant mechanism. The adsorption interactions include ion exchange, electrostatic effect, surface complexation and cation-π interaction. The HTC pretreatment increased surface oxygen-containing groups (−COOH or C=O, −OH), which was adsorption sites to promote Cu²⁺ adsorption.

The rapid emergence of lithium-ion batteries (LIBs) to satisfy our ever increasing energy demands will result in a significant future waste problem at their end of life. Lithium iron phosphate (LFP) as a cathode material is now widely used in LIBs with increasing market share. It is expected that there will be significant volumes of battery waste containing this material in the near future, and therefore it is important to develop methods for effectively repurposing this LFP waste to mitigate its impact on the environment. In this work we demonstrate the repurposing of LFP from spent LIBs as electrocatalysts for the oxygen evolution reaction (OER) which is critical to electrochemical water splitting and the production of green hydrogen. Our study has shown that the recovered LFP once immobilized onto a Ni substrate reconstructs into a mixed Fe/Ni oxide surface layer which is highly active for the OER. Promisingly, the LFP recovered from batteries that were cycled multiple times (up to 100 cycles) showed excellent electrocatalytic performance with a low Tafel slope of 58 mV dec⁻¹, overpotential values of 250 and 310 mV to reach 10 and 100 mA cm⁻², respectively and 24 h stability at over 200 mA cm⁻². This research provides potential motivation for recycling companies to isolate LFP from spent Li ion batteries for later use in water electrolysis technologies.

Vapor-phase molecular detection is an emerging approach in human-associated fields like environmental monitoring, human health, agriculture, and national defense. Recently, trace-level detection of molecules in the vapor phase has been recognized as a promising and extremely challenging approach. In this context, surface-enhanced Raman spectroscopy (SERS) is a potential technique that offers extremely high sensitivity and superior capability of finding molecular fingerprints down to the ppb level. This review critically delineates SERS's expansive progressions and engagement in the vapor-phase detection of explosives, volatile organic compounds (VOC), and gaseous molecules. Furthermore, we concisely describe the research landscape of vapor-phase detection in various fields and propose insights into potential prospects for imminent advancements. Additionally, the review emphasizes the future standpoints on technical and theoretical expansion and addresses the research gap to create a versatile platform for the betterment of society.

Research on the synthesis and uses of zero-dimensional (0D) carbon quantum dots (CQDs) has emerged as a dynamic and fascinating innovative area of study in current years. The exceptional characteristics of CQDs, such as their low cost, easy surface functionalization, nontoxicity, tunable photoluminescence, and chemical inertness, have drawn attention. Their possible uses span the biomedical, pharmaceutical, environmental, photocatalytic, and energy storage domains. Research on these has mainly concentrated on how they behave in biosensing, optoelectronics, and environmental sensing; however, energy storage systems are developing quickly as novel, capable approaches are coming up to address few of the unresolved problems with energy at affordable and ecological impact. Therefore, this review delves deeply into the effects of synthetic methods on the final product of CQDs and the fundamentals and properties of CQDs, including size-dependent properties and quantum confinement effects on electrochemical energy-related systems. This review also covers the design of CQD-based composites used as charge carriers in different energy storage materials (like batteries and supercapacitors) and as a catalyst in energy storage (like overall water splitting and oxygen reduction reaction). It also includes helpful recommendations for resolving the remaining issues in the field.