Degradation kinetics

降解动力学
  • 文章类型: Journal Article
    水成分之间的结合(溶解的有机物,阴离子和阳离子)和药物会影响污染物的迁移和转化。在这里,水基质对药物降解的影响,以及紫外线期间的电能需求,UV/催化剂,UV/O3,UV/H2O2基,对UV/过硫酸盐和UV/氯工艺进行了系统评价。水成分的增强作用是由于强大的反应性物种的形成,催化剂的电子和空穴的复合还原和催化剂的再生;光衰减导致的抑制,目标污染物和活性物质激发态的猝灭效应,稳定的络合生成和催化剂失活。同一污染物在各种AOPs中的转化途径具有很高的相似性。同时,每种氧化剂还可以充当特殊的亲核试剂或亲电试剂,取决于目标化合物的官能团。药物降解的每阶电能(EEO)可以遵循EEOUV>EEOUV/催化剂>EEOUV/H2O2>EEOUV/PS>EEOUV/氯或EEOUV/O3的顺序。同时,平衡成本效益评估和有毒副产品形成至关重要,在存在不同水基质的情况下,污染物降解途径和产量的比较仍然缺乏。
    The binding between water components (dissolved organic matters, anions and cations) and pharmaceuticals influences the migration and transformation of pollutants. Herein, the impact of water matrices on drug degradation, as well as the electrical energy demands during UV, UV/catalysts, UV/O3, UV/H2O2-based, UV/persulfate and UV/chlorine processes were systemically evaluated. The enhancement effects of water constituents are due to the powerful reactive species formation, the recombination reduction of electrons and holes of catalyst and the catalyst regeneration; the inhibition results from the light attenuation, quenching effects of the excited states of target pollutants and reactive species, the stable complexations generation and the catalyst deactivation. The transformation pathways of the same pollutant in various AOPs have high similarities. At the same time, each oxidant also can act as a special nucleophile or electrophile, depending on the functional groups of the target compound. The electrical energy per order (EEO) of drugs degradation may follow the order of EEOUV > EEOUV/catalyst > EEOUV/H2O2 > EEOUV/PS > EEOUV/chlorine or EEOUV/O3. Meanwhile, it is crucial to balance the cost-benefit assessment and toxic by-products formation, and the comparison of the contaminant degradation pathways and productions in the presence of different water matrices is still lacking.
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  • 文章类型: Journal Article
    花青素是有色的有价值的生物化合物,其中提取量在全球范围内增加,尽管功能应用受到其有限的环境稳定性的限制。温度是食品工业加工的关键参数,会影响食品基质,特别影响热敏化合物,如花青素。由于花色苷热稳定性领域的显着科学进展,需要对已发布的数据进行分析和综合整合。本文综述了花色苷在加热过程中降解的分子机制和动力学参数。提取物和真正的食物基质。几个动力学模型(阿伦尼乌斯,Eyring,球)对花色苷的降解进行了研究。粗提物比纯化的花色苷提供更多的热稳定性。由于与某些营养素(蛋白质,多糖)。总结了使用经典和创新方法通过与其他分子的连接来稳定花色苷的最新研究。确保加工富含花青素的食品的适当的热条件将为未来开发稳定的功能产品提供合理的设计,在很大程度上保留了这些生物活性分子及其功能。
    Anthocyanins are colored valuable biocompounds, of which extraction increases globally, although functional applications are restrained by their limited environmental stability. Temperature is a critical parameter of food industrial processing that impacts on the food matrix, particularly affecting heat-sensitive compounds such as anthocyanins. Due to the notable scientific progress in the field of thermal stability of anthocyanins, an analytical and synthetic integration of published data is required. This review focuses on the molecular mechanisms and the kinetic parameters of anthocyanin degradation during heating, both in extracts and real food matrices. Several kinetic models (Arrhenius, Eyring, Ball) of anthocyanin degradation were studied. Crude extracts deliver more thermally stable anthocyanins than purified ones. A different anthocyanin behavior pattern within real food products subjected to thermal processing has been observed due to interactions with some nutrients (proteins, polysaccharides). The most recent studies on the stabilization of anthocyanins by linkages to other molecules using classical and innovative methods are summarized. Ensuring appropriate thermal conditions for processing anthocyanin-rich food will allow a rational design for the future development of stable functional products, which retain these bioactive molecules and their functionalities to a great extent.
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  • 文章类型: Journal Article
    High levels of toxic organic pollutants commonly detected during domestic/industrial wastewater treatment have been attracting research attention globally because they seriously threaten human health. Sulfate-radical-based advanced oxidation processes (SR-AOPs) have been successfully used in wastewater treatment, such as that containing antibiotics, pesticides, and persistent organic pollutants, for refractory contaminant degradation. This review summarizes activation methods, including physical, chemical, and other coupling approaches, for efficient generation of sulfate radicals and evaluates their applications and economic feasibility. The degradation behavior as well as the efficiency of the generated sulfate radicals of typical domestic and industrial wastewater treatment is investigated. The categories and characteristics of the intermediates are also evaluated. The role of sulfate radicals, their kinetic characteristics, and possible mechanisms for organic elimination are assessed. In the last section, current difficulties and future perspectives of SR-AOPs for wastewater treatment are summarized.
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