Environmental Chemistry Letters最新文献

The rising aquaculture industry has induced an increase in aquaculture waste, calling for advanced methods to recycle waste in the context of the circular economy. Here, we review methods to treat aquaculture wastewater such as the biofloc technique, aquaponic-aquaculture, rice-fish co-culture, microalgae culture, algal–bacterial culture, membrane and moving bed bioreactors, and electrochemical techniques. We discuss nitrogen cycling, resources recovery, and nitrous oxide emission and mitigations. We observed that aquaculture wastewater irrigation allows for enhanced plant biomass, and biofloc technology improves fish biomass. Nitrogen removal processes, including anammox and partial nitrification, show improved performance. Nitrous oxide emission is mainly dependent on the total ammonia and nitrite concentration.

Pyrolysis of modern biomass is a sustainable technique to produce chemicals, yet efficient and selective conversion remains challenging. We studied biomass pyrolysis catalyzed by graphene oxide for the production of levoglucosan, a chemical with potential applications in biodegradable plastics and surfactants. We tested model compounds containing 40–100 wt% cellulose, poplar biomass, and we modelled the role of graphene oxide by calculations using the density functional theory. Results for model compounds show that levoglucosan production is higher for compounds containing less than 50% cellulose. By contrast, levoglucosan yield are reduced for model compounds having more than 60 wt% cellulose, because graphene oxide induced the breakdown of levoglucosan. Experiments show that pyrolysis of poplar biomass with 5 wt% graphene oxide increased about three times the yield of levoglucosan, compared to non-catalyzed pyrolysis. Enhanced levoglucosan formation is explained by the formation of a six-membered ring intermediate.

Toxic metals and metalloids pollution is a major ecological and human health issue, yet classical detection methods are limited. Here we review surface-enhanced Raman spectroscopy-based sensors using nanomaterial-based substrates for metal detection, with emphasis on substrate composition, functionalization, and assembly; metal sensing strategies; and analytical performance. Substrates include nobel metals, semiconductors, and composites. Substrate assembly can be done in solution or on solid supports. Sensing strategies comprise direct sensing, reporter recognition, reporter migration, substrate aggregation, and substrate modification. In general, the physicochemical properties of the substrates determine sensor sensitivity through electromagnetic and chemical enhancements of Raman scattering, whereas substrate surface functionalization, or lack thereof, determines sensor selectivity and the sensing mechanism. The main elements analyzed are mercury, lead, copper, arsenic, and chromium.

Water contamination is a major health issue that can be addressed by using carbonaceous materials to adsorb and filter pollutants, yet adsorption mechanisms need to be better understood to improve the adsorption efficiency. Here we review the models that are used to study the mechanisms of adsorption of drugs, dyes and metal ions on carbonaceous materials, with emphasis on classical and advanced isotherms. We discuss the fitting frequency, lignocellulosic and fossil fuel-derived adsorbents, biomass composition, activating agents, surface functions, the carbonization temperature, the medium temperature effect and the use of several isotherms to explain the same mechanism. The adsorption capacity can reach up to 2651 mg of contaminant per g of lignocellulosic materials and 1274 mg of contaminant per g of fossil materials. Isotherm validation commonly depends on several parameters. The adsorption on lignocellulosic carbonaceous materials is best described by the Langmuir isotherm. In contrast, adsorption on fossil materials is best described by the Redlich-Peterson isotherm. Advanced and classical isotherms are in good agreement in 44% of reports.

Fossil fuel-based products should be replaced by products derived from modern biomass such as plant starch, in the context of the future circular economy. Starch production globally surpasses 50 million tons annually, predominantly sourced from maize, rice, and potatoes. Here, we review plant starch with an emphasis on structure and properties, extraction, modification, and green applications. Modification techniques comprise physical, enzymatic, and genetic methods. Applications include stabilization of food, replacement of meat, three-dimensional food printing, prebiotics, encapsulation, bioplastics, edible films, textiles, and wood adhesives. Starch from maize, potatoes, and cassava shows amylose content ranging from 20 to 30% in regular varieties to 70% in high-amylose varieties. Extraction by traditional wet milling achieves starch purity up to 99.5%, while enzymatic methods maintain higher structural integrity, which is crucial for pharmaceutical applications. Enzymatic extraction improves starch yield by of up to 20%, reduces energy consumption by about 30%, and lowers wastewater production by up to 50%, compared to conventional methods. Sustainable starch modification can reduce the carbon footprint of starch production by up to 40%. Modified starches contribute to approximately 70% of the food texturizers market. The market of starch in plant-based meat alternatives has grown by over 30% in the past five years. Similarly, the use of biodegradable starch-based plastics by the bioplastic industry is growing over 20% annually, driven by the demand for sustainable packaging.Kindly check and confirm the layout of Table 1.Layout is right

Pollution and the rising energy demand are two major society issues, requiring urgent solutions. Here, we review the simultaneous production of hydrogen and removal of pollutants, with a focus on mechanisms, synthesis of photocatalysts, and applications. Remarkably, this method utilizes organic pollutants as sacrificial agents for photocatalytic hydrogen production, thus both reducing pollution and producing energy. Metal-doped, cocatalyst-loaded, organic and inorganic composite, heterostructure and heterojunction photocatalysts are described. We present applications to the removal of antibiotics and organic dyes. Pollutant degradation rates range from 5.3 to 100%, with hydrogen evolution of 13.7–2724.89 μmol·g^–1h^–1.

Paracetamol, a common pain reliever, has seen a significant rise in use, particularly during the Coronavirus Disease 2019 (COVID-19) pandemic. This widespread consumption has led to increased levels of paracetamol in the environment through wastewater discharge. This raises concerns about its potential impact on aquatic ecosystems. Here, we review the state-of-the-art methods for removing paracetamol from wastewater, focusing on adsorption techniques. We explore how different materials and operational conditions influence the effectiveness of this approach. We also discuss the potential of combining adsorption with oxidative methods for enhanced removal. We further assess the environmental impact by critically examining the ecotoxicological effects of paracetamol on aquatic organisms. This analysis compares established toxicity values with those observed in studies using real wastewater samples. Finally, we highlight the specific needs for further research and development of efficient and sustainable strategies to mitigate paracetamol pollution, ensuring the safety of both human and aquatic life.

Lowering the adverse effects of climate change requires advanced methods to decrease atmospheric levels of carbon dioxide. Here, we review the use of carbonic anhydrase nanobiocatalysts for carbon dioxide sequestration, with emphasis on inorganic, organic, and polymeric nanomaterials. Inorganic nanomaterials include metal and metal oxide, carbon-based, and nonmetallic nanomaterials. Hybrid nanomaterials comprise metal–organic frameworks and nanoflowers. Factors influencing the properties of nanobiocatalysts such as interactions between carbonic anhydrase and the nanoscale support are presented. The immobilization of carbonic anhydrase onto nanomaterials overcomes the limitations associated with its free form, such as short shelf life, challenging separation, and poor reusability. We discuss the potential for large-scale applications.

Phosphorus is an essential element influencing both food security via plant fertilization, and water pollution through excessive phosphorus use, yet the phosphorus cycle in ecosystems is poorly known. In particular, beyond adsorption, the role of iron and manganese oxides in catalyzing the abiotic dephosphorylation of biomolecules is debated. Here, we studied the reactions of ribonucleotides, containing different phosphate bonding, with goethite, hematite, and birnessite. We employed both high-resolution mass spectrometry of solution species and molecular modeling simulations of ribonucleotide-mineral complexes. Results disclose an up to fivefold preferential hydrolytic cleavage of a phosphoanhydride bond over a phosphoester bond, indicating that mineral-catalyzed reactions reflect the hierarchy reported for the activity of phosphatase enzymes. The fourfold higher catalytic reactivity of goethite and birnessite versus hematite is explained by mineral-specific binding rather than surface area differences. Corresponding simulated adsorbate conformations at the water–mineral interfaces are proposed. Overall, our findings provide new insights on the catalytic recycling of organic phosphorus species by mineral oxides.