CleanMat最新文献

Diclofenac (DCF) is one of the prevalent pharmaceutical contaminants detected in municipal wastewater treatment plants. This research aimed to study the role of adsorption mechanisms in DCF removal in wastewater and the potential of using dried activated sludge (AS) as an adsorbent. Wastewater obtained from the facility was spiked with 1 and 10 mg L⁻¹ of DCF, and the removal was observed in batch experiments conducted in the laboratory. The DCF removal efficiencies of 90.9% and 89.7% by AS were obtained in 48 h for 1 and 10 mg L⁻¹ of DCF, respectively. Role of adsorption was then observed by adsorption experiments with dried biomass of the AS at the same DCF concentrations. The adsorption process was found to be pH and sludge dosage dependent. Sludge had the highest adsorption capacity in the DCF solution at the neutral pH 7 (14.4 × 10⁻² mg g⁻¹), followed by pH 10 (12.3 × 10⁻² mg g⁻¹), then pH 4 (4.0 × 10⁻² mg g⁻¹). The adsorption capacity reduced as the sludge dose increased whilst the removal percentage increased as the sludge dosage increased from 35.1% to 53.5%, and 71.3% for 1, 2, and 4 g of sludge, respectively. The adsorption was better fitted to a pseudo-second-order kinetic model with R² values > 0.98 and was dominated by the chemisorption process. The findings from this study have shown that adsorption is one of the key mechanisms of DCF removal in a municipal wastewater treatment plant, and the dried activated sludge has a potential as a DCF adsorbent.

At present, the increasing discharge of hazardous and toxic pollutants into freshwater bodies has become a major global concern due to its detrimental effects on human health and aquatic ecosystems. The growing challenges and a complex suite of problems related to water pollution and scarcity demand technological innovations, reuse strategies, and sustainable solutions. Therefore, developing efficient, affordable, and eco-friendly wastewater treatment technologies is crucial. An oleaginous photosynthetic organism “microalga” has emerged as a valuable feedstock for wastewater treatment, carbon neutrality, and nutrient recovery. On the other hand, setting up microalgal biorefineries support resource recovery and biomass utilization, offering diverse bio-based products across industries. For instance, the global microalgal biofuel market is projected to reach USD 8.7 billion by 2030, while microalgal nutraceuticals including omega-3 fatty acids already command a market value of over USD 2.5 billion annually, with pigments like astaxanthin valued at USD 1500–7000 per kg. Similarly, microalgal biomass for biofertilizers and animal feed additives contributes to a market share exceeding USD 1.2 billion globally. This multifaceted approach facilitates the reduction of waste generation by enhancing production of microalgae bioproducts. Unlike terrestrial crops like soybean that require 2000–3000 L of freshwater per kg biomass, microalgae cultivation in wastewater systems can reduce the water footprint to less than 100 L per kg biomass, achieving > 95% reduction in freshwater demand. Keeping this in mind, present review instigates the integrated phycoremediation approach that aligns with circular economy goals, promoting resource recovery and reducing the carbon footprints and water footprints in the framework of regenerative and zero waste valorization.

Polyethylene terephthalate (PET) is one of the major polymeric plastic products, with an annual production of over 24 million tons. Revalorization of plastic waste holds the promise of transforming end-of-life plastic materials towards cleaner and more sustainable product use. Cement is essential to shape the built environment by developing long-lasting, stable structures. While plastic materials have shown low adhesion with cement, the functionalization of PET (FPET) surfaces can enhance the interaction with a cementitious matrix. Herein, we present a new functionalization strategy that enables polymer-cementitious composites while enhancing the energy absorption capacity and ductility of cementitious beams. This cleaner manufacturing technique can provide an alternative application of waste polymeric products while enabling alternative market opportunities in construction. Complete standard rheological and mechanical characterization of composite cement, including fracture tests, are presented. A significant improvement in modulus of rupture, energy absorption, and ductility was observed when 12% FPET and 16% FPET were included. This suggests that the FPET is strongly bonded to cement, enabling stress transfer across the cracked surfaces, increasing ductility and energy absorption.

A methodology for the radiological characterization of organic radioactive liquid wastes (OLRWS) adsorbed into soils, generated in the 80s and 1990s is developed to define their management. The methodology is based on the recovery of radioactive organic liquids from their solid matrix using a solvent and their subsequent quantification. It is established on the basis of controlled tests with samples prepared with radioactive scintillation liquids mixed with soil, using different scintillation liquids, solvents, radionuclides and process types (percolation or batch). Thinner is selected as the extraction agent because it is inexpensive, easily accessible and offers good performance in the removal of radioactive organic liquids from soil. The recovery of the scintillation liquids depends mainly on their miscibility with the solvent and the affinity of the radionuclides to the soil. The method was applied to OLRWS containing only H-3 with average activities of 39 Bq g⁻¹ and can therefore be released from regulatory control.

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.