Impacts of continuously regenerating trap and particle oxidation catalyst on the NO2 and particulate matter emissions emitted from diesel engine

Two continuously regenerating diesel particulate filter (CRDPF) with different configurations and one particles oxidation catalyst (POC) were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO₂, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO₂/NO_x significantly. The results of smoke emissions and particle number (PN) emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter (PM) and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO₂/NO_x. The PN emission results from two CRDPFs indicated that more NO₂ generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO₂ exposure in atmosphere.     

MTBE装置职业病危害关键控制点及防护对策

通过职业病危害现场调查,分析了某MTBE装置的生产工艺、装置存在的主要职业病危害因素、检测结果、职业病危害防护措施,找出了职业病危害的关键控制点,并提出了防护对策.     

不同电化学法对双甘膦废水除磷效果的比较研究

采用电-芬顿、芬顿-微电解、三维电催化、微电解工艺对预处理双甘膦废水的效果进行了比较研究。试验结果表明:对于高浓度有机磷双甘膦废水,采用上述四种工艺处理后的总磷去除率分别为66.2%、88.1%、87.8%、92.2%。铁碳微电解除磷效果最优,进一步对其影响因素进行试验,结果表明:pH为3,反应时间为2h,铁碳比为1:1时微电解法对双甘膦废水的总磷去除率可达92.2%,微电解联用对废水总磷去除率为96.8%。     

五种挺水植物对矿山废水中锰的去除效能比较

以水葱、香蒲、芦苇、灯芯草和野茭白五种挺水植物为研究对象,通过实验室模拟人工湿地系统,研究在投加不同浓度梯度人工拟合酸性矿山废水条件下各植物对重金属锰的去除效能以及植物各部位对锰的富集能力。结果表明,野茭白和水葱的去除效能最显著,第七天的去除率达到90%和76%以上,香蒲的相对较差,为56%以上。五种植物各部位对重金属锰的富集能力均遵循同一规律:对于无茎植物,根富集浓度大于叶富集浓度;对于有茎植物,则为根大于茎大于叶。     

弥苴河口湿地植物残体与底泥资源化利用研究

应用双室堆沤肥技术,以弥苴河口湿地植物残体、湿地底泥和当地养殖业废物制成双室堆沤肥,按不同配比设计5种施肥处理方案进行还田试验。对比研究施肥前后的蔬菜产量、蔬菜品质、土壤肥力以及土壤根际微生物,发现:方案A[50%～60%植物残体(收割物)+40%～50%养殖业废物+微生物菌剂(3 kg/t),活性液体肥作追肥,农药同习惯施肥]对增加蔬菜产量、提高蔬菜品质、增加土壤肥力和改善土壤微生态环境效果最好。在实际应用中也可适当增加1 0%～20%的湿地底泥,相应减少养殖业废物量。     

Dynamics of antibiotic resistance genes and microbial community in shortcut nitrification–denitrification process under antibiotic stresses

In this study, the performance of shortcut nitrification–denitrification (SCND) at different TC and SD stress conditions (0 μg/L, 1–97 days; 100 μg/L, 98–138 days; 500 μg/L, 139–175 days) was investigated. Higher level antibiotic stress (500 μg/L) led to the serious deterioration of nitrogen removal, and denitrification was more sensitive to antibiotic stress than nitrification. The dynamics of antibiotic resistance genes (ARGs) and microbial community were revealed by quantitative real-time PCR and 16S rDNA high-throughput sequencing, respectively. Tet-genes (tetA, tetQ, tetW), sul-genes (sulI, sulII), and mobile genetic element (intI1) in activated sludge increased by 1.2?~?2.5 logs with long-term exposure of antibiotic stress, and sulI, tetA, tetQ, and tetW were significantly positively correlated with intI1. Long-term antibiotics stress caused the decrease of most denitrifiers, and five genera were identified as the potential host of ARGs. The key impact factors of SCND drove the dynamics of ARGs and microbial community. Except for sulII gene, DO and FA were significantly positively correlated with ARGs, while FNA, NAR, and NO₂^?-N showed opposite effects to ARGs. Overall, maintaining relative lower DO, higher FNA, NAR, and NO₂^?-N conditions are not only benefit to the stable operation of SCND, but may also conducive to the control of ARG dissemination. This study provides theoretical basis on the control of ARGs in the SCND process.

     

Effects of phosphorus-containing material application on soil cadmium bioavailability: a meta-analysis

Environmental Science and Pollution Research - Diverse phosphorus-containing materials (PCMs) were widely applied in remediation of cadmium-contaminated soils, and their effects on the change of...     

Preparation and related properties of geopolymer solidified uranium tailings bodies with various fibers and fiber content

Environmental Science and Pollution Research - Uranium tailing ponds are a potential major source of radioactive pollution. Solidification treatment can control the diffusion and migration of...     

How COVID-19 induced panic on stock price and green finance markets: global economic recovery nexus from volatility dynamics

Environmental Science and Pollution Research - This paper investigates the effect of different categories of essential COVID-19 data from 2020 to 2021 towards stock price dynamics and options...     

Characteristics and Bioactivities of Carrageenan/Chitosan Microparticles Loading α-Mangostin

Journal of Polymers and the Environment - This study attempted to develop carrageenan/chitosan based microparticles loading α-mangostin which was extracted from Vietnamese mangosteen skin. The...