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1.
Environ Geochem Health ; 46(5): 163, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38592574

RESUMO

Microplastics leaching from aging biodegradable plastics pose potential environmental threats. This study used response surface methodology (RSM) to investigate the impact of temperature, light, and humidity on the aging characteristics of polylactic acid (PLA). Key evaluation metrics included the C/O ratio, functional groups, crystallinity, surface topography, and mechanical properties. Humidity was discovered to have the greatest effect on the ageing of PLA, followed by light and temperature. The interactions between temperature and light, as well as humidity and sunlight, significantly impact the aging of PLA. XPS analysis revealed PLA underwent aging due to the cleavage of the ester bond (O-C=O), resulting in the addition of C=O and C-O. The aging process of PLA was characterized by alterations in surface morphology and augmentation in crystallinity, resulting in a decline in both tensile strength and elongation. These findings might offer insights into the aging behavior of degradable plastics under diverse environmental conditions.


Assuntos
Ésteres , Plásticos , Poliésteres
2.
Environ Sci Pollut Res Int ; 28(14): 17417-17430, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33394404

RESUMO

In this study, 18S rRNA high-throughput sequencing was applied to investigate the eukaryotic community in a full-scale drinking water treatment plant. Eukaryotic species and microbial functions in raw water and filter biofilms were identified by metagenomic sequencing. The eukaryotic species richness and diversity presented declining trends throughout the treatment process. The lowest eukaryotic species richness was observed in disinfected water. Arthropoda, Ciliophora, Ochrophyta, and Rotifera were the dominant eukaryotic phyla and exhibited high variations in relative abundance among the different treatment units. Sedimentation significantly decreased the abundance of all eukaryotes except Arthropoda. Biological activated carbon (BAC) filtration and chlorine disinfection exerted strong effects on community composition. The eukaryotic communities in water were distinct from those in filter biofilms, as were the communities of different filter biofilms from each other. In contrast, communities were functionally similar among different filter biofilms, with the category metabolism being the dominant category represented, within which amino acid transport and metabolism (E) and energy production and conversion (C) dominated among subcategories. Seventy-one eukaryotic species pathogenic to humans were identified in raw water and filter biofilms. Quantitative PCR (qPCR) results showed that Acanthamoeba spp. and Vermamoeba vermiformis were present during some treatment processes, with concentrations of 12-1.2 × 105 copies/mL and 1 copy/mL, respectively. Neither of the two pathogenic amoebae was found in disinfected water. Canonical correspondence analysis (CCA) showed that pH was the most important environmental factor affecting eukaryotic community composition. Overall, the results provide insights into the eukaryotic community diversity in drinking water treatment plants and the potential eukaryotic hazards involved in drinking water production.


Assuntos
Água Potável , Purificação da Água , Biofilmes , Água Potável/análise , Eucariotos/genética , Humanos , Metagenoma , RNA Ribossômico 18S/genética
3.
RSC Adv ; 10(15): 9103-9115, 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-35496570

RESUMO

The purpose of this focus review is to provide a comprehensive overview of the direct synthesis of five-membered cyclic carbonates via oxidative carboxylation of the corresponding olefins and carbon dioxide with particular attention on the mechanistic features of the reactions. The review is divided into two main sections. The first section is a discussion of the single-step reactions, while the second consists of an overview of one-pot, two-step sequential reactions.

4.
RSC Adv ; 10(18): 10806, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-35503548

RESUMO

[This corrects the article DOI: 10.1039/C9RA10755J.].

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