• UV/O3 process had higher TAIC mineralization rate than O3 process.• Four possible degradation pathways were proposed during TAIC degradation.• pH impacted oxidation processes with pH of 9 achieving maximum efficiency.• CO32– negatively impacted TAIC degradation while HCO3– not.• Cl– can be radicals scavenger only at high concentration (over 500 mg/L Cl–). Triallyl isocyanurate (TAIC, C12H15N3O3) has featured in wastewater treatment as a refractory organic compound due to the significant production capability and negative environmental impact. TAIC degradation was enhanced when an ozone(O3)/ultraviolet(UV) process was applied compared with the application of an independent O3 process. Although 99% of TAIC could be degraded in 5 min during both processes, the O3/UV process had a 70%mineralization rate that was much higher than that of the independent O3 process (9%) in 30 min. Four possible degradation pathways were proposed based on the organic compounds of intermediate products identified during TAIC degradation through the application of independent O3 and O3/UV processes. pH impacted both the direct and indirect oxidation processes. Acidic and alkaline conditions preferred direct and indirect reactions respectively, with a pH of 9 achieving maximum Total Organic Carbon (TOC) removal. Both CO32– and HCO3– decreased TOC removal, however only CO32– negatively impacted TAIC degradation. Effects of Cl– as a radical scavenger became more marked only at high concentrations (over 500 mg/L Cl–). Particulate and suspended matter could hinder the transmission of ultraviolet light and reduce the production of HO· accordingly. 相似文献
• Magnetotactic bacteria (MTB) synthesize magnetic nanoparticle within magnetosomes.• The morphologic and phylogenetic diversity of MTB were summarized.• Isolation and mass cultivation of MTB deserve extensive research for applications.• MTB can remove heavy metals, radionuclides, and organic pollutants from wastewater. Magnetotactic bacteria (MTB) are a group of Gram-negative prokaryotes that respond to the geomagnetic field. This unique property is attributed to the intracellular magnetosomes, which contains membrane-bound nanocrystals of magnetic iron minerals. This review summarizes the most recent advances in MTB, magnetosomes, and their potential applications especially the environmental pollutant control or remediation. The morphologic and phylogenetic diversity of MTB were first introduced, followed by a critical review of isolation and cultivation methods. Past research has devoted to optimize the factors, such as oxygen, carbon source, nitrogen source, nutrient broth, iron source, and mineral elements for the growth of MTB. Besides the applications of MTB in modern biological and medical fields, little attention was made on the environmental applications of MTB for wastewater treatment, which has been summarized in this review. For example, applications of MTB as adsorbents have resulted in a novel magnetic separation technology for removal of heavy metals or organic pollutants in wastewater. In addition, we summarized the current advance on pathogen removal and detection of endocrine disruptor which can inspire new insights toward sustainable engineering and practices. Finally, the new perspectives and possible directions for future studies are recommended, such as isolation of MTB, genetic modification of MTB for mass production and new environmental applications. The ultimate objective of this review is to promote the applications of MTB and magnetosomes in the environmental fields. 相似文献
• Pd nanoparticles could be reduced and supported by activated sludge microbes.• The effect of biomass on Pd adsorption by microbes is greater than Pd reduction.• More biomass reduces Pd particle size, which is more dispersed on the cell surface.• When the biomass/Pd add to 6, the catalytic reduction rate of Cr(VI) reaches stable. Palladium, a kind of platinum group metal, owns catalytic capacity for a variety of hydrogenations. In this study, Pd nanoparticles (PdNPs) were generated through enzymatic recovery by microbes of activated sludge at various biomass/Pd, and further used for the Cr(VI) reduction. The results show that biomass had a strong adsorption capacity for Pd(II), which was 17.25 mg Pd/g sludge. The XRD and TEM-EDX results confirmed the existence of PdNPs associated with microbes (bio-Pd). The increase of biomass had little effect on the reduction rate of Pd(II), but it could cause decreasing particle size and shifting location of Pd(0) with the better dispersion degree on the cell surface. In the Cr(VI) reduction experiments, Cr(VI) was first adsorbed on bio-Pd with hydrogen and then reduced using active hydrogen as electron donor. Biomass improved the catalytic activity of PdNPs. When the biomass/Pd (w/w) ratio increased to six or higher, Cr(VI) reduction achieved maximum rate that 50 mg/L of Cr(VI) could be rapidly reduced in one minute. 相似文献
Environmental Science and Pollution Research - In this study, porous activated carbon balls supported by nanoscale zero-valent iron composites (Fe@PACB-700) were used for the first time for the... 相似文献
In this study, farmland and mining ecotypes of Solanum photeinocarpum (a potential cadmium (Cd) hyperaccumulator plant) were reciprocally hybridized each other, and the Cd accumulation characteristics of the F1 hybrids were studied. In pot experiments, higher biomasses and Cd extraction abilities were found for two S. photeinocarpum F1 hybrids than for the parents, but the Cd contents in various organs were lower in the hybrids than the parents. However, the differences between the Cd contents in the two hybrids were not significant. The antioxidant enzyme (superoxide dismutase and peroxidase) activities were higher for the S. photeinocarpum F1 hybrids than the parents. Less DNA methylation was found in the hybrids than the parents because more demethylation occurred in the hybrids than the parents. The biomass, Cd content, and Cd extraction ability effects in field experiments were similar to the effects in the pot experiments. It was concluded that reciprocally hybridizing different S. photeinocarpum ecotypes improved the ability of S. photeinocarpum to be used to phytoremediate contaminated land.
基于土地评价和立地条件评估(Land Evaluation and Site Assessment, LESA)框架构建以耕地自然质量、生态敏感性、区位条件、耕作条件和土壤环境安全风险组成的指标体系,以决策树归纳法将浦东新区耕地划分为工业污染、生态农业、轮作休耕、农业连片、休闲农业和非农转化6类管护区,根据各区管护重点提出规模经营及绿色生产、休闲观光及农田保育、非农管控及发展限制型耕地生态补偿模式。上海市浦东新区耕地自然质量优良,约50%的耕地可规模经营及连片生产,但仍有10%左右的耕地面临着工业污染和非农占用的风险。建议对以稳产高产和生态协调为目标的农业连片区和生态农业区采取规模经营及绿色生产型生态补偿模式,对发展农业生产新形态的轮作休耕区和休闲农业区采取休闲观光及农田保育型生态补偿模式,对非农化风险较高的工业污染区和非农转化区采取非农管控及发展限制型生态补偿模式。 相似文献
The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore “red tides” happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area. 相似文献
Dietary uptake is the major way that inorganic arsenic (iAs) enters into benthic fish; however, the metabolic process of dietborne iAs in fish muscle following chronic exposure remains unclear. This was a 40-day study on chronic dietborne iAs [arsenite (AsIII) and arsenate (AsV)] exposure in the benthic freshwater food fish, the crucian carp (Carassius auratus), which determined the temporal profiles of iAs metabolism and toxicokinetics during exposure. We found that an adaptive response occurred in the fish body after iAs dietary exposure, which was associated with decreased As accumulation and increased As transformation into a non-toxic As form (arsenobetaine). The bioavailability of dietary AsIII was lower than that of AsV, probably because AsIII has a lower ability to pass through fish tissues. Dietary AsV exhibited a high potential for transformation into AsIII species, which then accumulated in fish muscle. The largely produced AsIII considered more toxic at the earlier stage of AsV exposure should attract sufficient attention to human exposure assessment. Therefore, the pristine As species and exposure duration had significant effects on As bioaccumulation and biotransformation in fish. The behavior determined for dietborne arsenic in food fish is crucial for not only arsenic ecotoxicology but also food safety. 相似文献