Environmental Chemistry Letters最新文献

Anaerobic digestion constitutes a sustainable method for waste management and renewable energy generation, addressing significant environmental and societal challenges. The growing global waste crisis and the increasing momentum toward sustainable energy solutions emphasize the critical need to enhance anaerobic digestion technology for improved efficiency and environmental advantages. This process mitigates waste accumulation, enhances energy security, and reduces greenhouse gas emissions, providing a feasible solution within the framework of a circular bioeconomy. Here, we review the principles of anaerobic digestion and biogas production, focusing on agricultural waste and the utilization of biogas for energy within a sustainable framework. We specifically explore biogas applications in rural and industrial settings, assess the environmental impacts, and discuss the regulatory landscape with insights from China and Europe. This study reveals that the strategic implementation of anaerobic digestion can markedly improve energy yield and sustainability, demonstrating how focused policies and advanced technological practices can optimize biogas utilization. The review enhances comprehension of environmental impacts, emphasizing insights from China and Europe as key examples.

Tetracyclines are broad-spectrum antibiotics used as human and veterinary ailments, anticancer and antiviral agents, and for treating inflammations including arthritis and the Huntington’s disease. However, their inappropriate usage and disposal induce environmental pollution due to their persistency, hydrophilicity and limited volatility, requiring advanced remediation methods. Here, we review techniques for tetracycline removal, including adsorption, advanced oxidation and filtration. Materials to treat tetracycline pollution include aged microplastics, green materials, chemical compounds, sonocatalysts and membranes. Complete tetracycline removal is achieved by using membranes, sonocatalysis and composites. Green composites appear eco-friendly for wastewater treatment. Chemically-synthesized composites are mainly used in photocatalysis, oxidative and enzymatic degradation.

Biogenic volatile organic compounds are emitted by plants and influence human and environmental health. They contribute to the formation of pollutants such as ozone and secondary organic aerosols, thereby influencing air quality and climate. Here we review biogenic volatile organic compounds with focus on biosynthesis, release to the atmosphere, distribution at various scales, tropospheric chemical processes, and secondary organic aerosols. Biogenic volatile organic compounds are emitted primarily through enzymatic pathways in response to environmental factors, varying across plant species and ecosystems. These emissions exhibit heterogeneity at multiple scales, influenced by meteorological conditions and plant structure.

Although analytical methodologies are known to generate pollution, universal strategies to decrease their environmental, safety, and health burdens while maintaining performance are lacking. Separation science techniques including sample preparations and chromatography require large amounts of solvent and power to separate, identify, and quantitate pure constituents from their matrices. Recent advancements to green analytical chemistry have now provided comprehensive metrics, such as the analytical method greenness score (AMGS), that allow researchers to better understand their method’s environmental burden, compare it to other methods, and indicate what areas can be addressed to enhance sustainability. Here, we review approaches and technologies that can be used to green analytical separations with a focus on improving the method’s analytical figures of merit. Approaches to green sample preparation are first considered including microextraction techniques in liquid, solid, and supercritical phases and the ability to automate such techniques. We focus on high-performance liquid chromatography and sub- or super-critical fluid chromatography, where it is shown that changing the column dimensions and packing can reduce environmental impact while preserving chromatographic resolution. We review equations to calculate the greenest flow rate at which to operate a separation method, then we discuss of modern ultrafast and high throughput separations. Finally, we describe digital signal processing for analytical signals as a major green technology for the first time. We observed that, using digital signal processing, an ultrafast liquid chromatographic separation of 101 components in just one minute produced an AMGS of 0.12 which is, to our best knowledge, the lowest ever reported.

Microplastics are contaminating air, water, soils, both in populated megacities and in remote areas. Here we review analytical methodologies and occurrence of suspended airborne microplastics in Asia. Forty-three studies on suspended airborne microplastics were examined in thirteen countries across Asia. Abundance of suspended airborne microplastics ranged from 0.93 to 8,865 particles/m³ in indoor locations, 0.017 to 18,880 particles/m³ in outdoor areas, and 0.39 to 19 particles per 100 m³ in the oceanic environment. Suspended airborne microplastics mostly had the shape of fibers and fragments. Polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, and polystyrene polymers were commonly found. The size of plastic particles ranged from 0.43 to 9,555 µm, and the strategies used in sampling and analytical methods can influence the size of suspended airborne microplastics. Occurrence of suspended airborne microplastics in Asia demonstrates a critical pollution issue in the region.

The worldwide contamination of waters and food by herbicides is a major health issue, yet the toxic effects of herbicides to non-target organisms and ecosystems have been poorly summarized. Here we review the effects of herbicides belonging to the groups of chloroacetanilides, imidazolinones, sulfonylureas, and pyrimidinylcarboxylic, on small invertebrates, high vertebrates, plants, and the surrounding ecosystems. We describe toxicity in terms of behavioural changes, molecular biosynthesis, endocrine disruption, immunological responses, enzymatic alteration, and reproductive disorders. Strategies to decrease toxic effects are also presented. We observe widespread toxicity threats in amphibians and major aquatic species. Each herbicide group displays a different toxicity risk. For instance, chloroacetanilides display higher risks to soil, aquatic, algal, cyanobacteria, and terrestrial species, whereas alachlor, acetochlor, and metolachlor are highly carcinogenic to humans. Most imidazolinone herbicides cause phytotoxicity in non-target and succeeding crops. Sulfonyl-urea herbicides are severely toxic to soil microbes and succeeding crops. Pyrimidinylcarboxy herbicides are more toxic to soil microbes, aquatic species, and rats.

The world energy consumption has increased by + 195% since 1970 with more than 80% of the energy mix originating from fossil fuels, thus leading to pollution and global warming. Alternatively, pyrolysis of modern biomass is considered carbon neutral and produces value-added biogas, bio-oils, and biochar, yet actual pyrolysis processes are not fully optimized. Here, we review the use of machine learning to improve the pyrolysis of lignocellulosic biomass, with emphasis on machine learning algorithms and prediction of product characteristics. Algorithms comprise regression analysis, artificial neural networks, decision trees, and the support vector machine. Machine learning allows for the prediction of yield, quality, surface area, reaction kinetics, techno-economics, and lifecycle assessment of biogas, bio-oil, and biochar. The robustness of machine learning techniques and engineering applications are discussed.

Many organic pollutants are chemically stable and thus cannot be degraded by classical wastewater treatment techniques. To solve this issue, ozone-based advanced oxidation processes using hydroxyl radicals with strong oxidation ability have been recently developed. Here we review hydroxyl radicals in ozone-based advanced oxidation processes with focus on reaction characteristics, generation, detection, and quantitation of hydroxyl radicals. Hydroxyl radicals are generated using ozone micro/nano-bubbles, peroxymonosulfate-activated ozone, ozone coupled with Fenton oxidation, electro-peroxone, or catalytic ozonation. Hydroxyl radicals are detected by electron paramagnetic resonance and quenching experiments. We also present applications in wastewater treatment and reactor design. Ozone-based advanced oxidation combines direct oxidation by ozone molecules and indirect oxidation by reactive oxygen species; regulating these two pathways remains challenging. The generation of hydroxyl radicals depends on the environmental matrix and on the chemical structure, properties, and ozone reactivity of contaminants. Chain reactions among reactive oxygen species induce contradictions during the analysis of results obtained by electron paramagnetic resonance, quenching techniques, and probe methods.

Nitrogen pollution is a global issue impacting ecosystems, climate change, human health, and the economy. The challenge to reduce nitrogen pollution as a priority highlights the wastewater treatment system an important point of control. Coagulation, a common water treatment process, has a positive impact on the overall treatment process but often struggles to address nitrogen pollution effectively. Our study introduces a novel magnetic seed to enhance coagulation in treating nitrogen pollution, offering a new solution for the global water treatment industry. We focus on the efficiency, mechanistic detail, and recovery potential of a magnetic zirconium tannate in treating real-world wastewater nitrogen under coagulation conditions. Results show that 9 g/L of magnetic zirconium tannate effectively removes ammonia nitrogen, organic nitrogen, and total nitrogen from five different wastewater types. For low-concentration wastewater with ammonia nitrogen below 20 mg/L and organic nitrogen below 5 mg/L, removal rates reach up to 100%. For high-concentration wastewater with ammonia nitrogen below 98 mg/L and organic nitrogen below 86 mg/L, the maximum removal rate is 59% for ammonia nitrogen and 88% for organic nitrogen. Spectral analysis reveals that magnetic zirconium tannate adsorbs nitrogen compounds in water through both hydrogen bonding and electrostatic interactions, achieving excellent treatment outcomes. It can be efficiently recovered without using complex organic eluents and is easily separated from the flocculate. This technology offers non-disruptive supplement for current treatment approaches to meet the global nitrogen pollution challenge head on.