Fenton试剂加硫酸处理高浓度含酚废水的研究

研究了硫酸、Fenton试剂对酚的催化降解作用，证实了硫酸与Fenton试剂对酚的催化降解具有协同作用。H_2SO_4－Fenton试剂对高浓度含酚废水的处理结果说明，在Fenton试剂中加入硫酸可大大增加其对酚的降解能力。与单独的Fenton试剂法比较，当H_2O_2∶COD（重量比）＜0．8时，本法对COD≥14000mg／L含酚废水COD去除率可提高40％以上，对高浓度含酚废水具有很好的处理效果。     

饵料加标研究二甲苯麝香在鱼体内的蓄积和清除能力

二甲苯麝香(musk xylene,MX)是一种人造麝香,具有强烈的麝香气,可用作化妆品香精和皂用香精等的定香剂。由于其持续不断地输入环境,它们在水、土壤、大气中的浓度逐渐升高,并且在动物和人体组织中产生了蓄积,其蓄积效应相当于有机氯农药(organochlorine pesticides,OCPs)等持久性有机污染物,因而研究MX在鱼体内的蓄积特征是十分必要的。本文用含浓度为50 mg·kg-1和100 mg·kg-1的MX的饵料投喂斑马鱼(Danio rerio)和稀有鮈鲫(Gobiocypris rarus)14 d,继而进入为期28 d的清除实验。通过快速溶剂萃取(accelerated solvent extraction,ASE)、凝胶渗透色谱(gel permeation chromatography,GPC)、气相色谱-质谱联用法(gas chromatography-mass spectrometry,GC-MS)测定斑马鱼和稀有鮈鲫体内MX的浓度,继而评估鱼对MX的清除能力。结果表明,饵料中MX浓度越高,鱼体内MX的蓄积水平越高,100 mg·kg-1浓度组的蓄积水平为50 mg·kg-1浓度组的蓄积水平的2~3倍。在整个试验阶段的不同时间点分析鱼的体重和脂肪与鱼体内MX浓度的关系,数据显示,MX在鱼体内的蓄积水平与鱼的体重存在正线性关系,而与鱼体内脂肪含量的关系还有待进一步研究。经28 d的清除,鱼体内的MX残留量接近于零,说明斑马鱼和稀有鮈鲫对MX的清除能力较强。     

Flow and transport in unsaturated fractured rock: effects of multiscale heterogeneity of hydrogeologic properties

The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site. Calibration results show a significant lateral and vertical variability in matrix and fracture properties. Hydrogeologic property distributions in a two-dimensional, vertical cross-section of the site are generated by combining the average layer-scale matrix and fracture properties with local-scale perturbations generated using a stochastic simulation method. The unsaturated water flow and conservative (nonsorbing) tracer transport through the cross-section are simulated for different sets of matrix and fracture property fields. Comparison of simulation results indicates that the local-scale heterogeneity of matrix and fracture properties has a considerable effect on unsaturated flow processes, leading to fast flow paths in fractures and the matrix. These paths shorten the travel time of a conservative tracer from the source (repository) horizon in the unsaturated zone to the water table for small fractions of total released tracer mass. As a result, the local-scale heterogeneity also has a noticeable effect on global tracer transport processes, characterized by an average breakthrough curve at the water table, especially at the early arrival time of tracer mass. However, the effect is not significant at the later time after 20% tracer mass reaches the water table. The simulation results also verify that matrix diffusion plays an important role in overall solute transport processes in the unsaturated zone at Yucca Mountain.     

Bimodal Cellular Structure Evolution in PBAT Foams Incorporated by Carbon Nanotubes and Graphene Nanosheets

Journal of Polymers and the Environment - Due to extensive concerns of tremendous environment pollutions, particularly microplastic as an emerging pollutant, the development and investigate on...     

Improving protected area effectiveness through consideration of different human-pressure baselines

Previous assessments of the effectiveness of protected areas (PAs) focused primarily on changes in human pressure over time and did not consider the different human-pressure baselines of PAs, thereby potentially over- or underestimating PA effectiveness. We developed a framework that considers both human-pressure baseline and change in human pressure over time and assessed the effectiveness of 338 PAs in China from 2010 to 2020. The initial state of human pressure on PAs was taken as the baseline, and changes in human pressure index (HPI) were further analyzed under different baselines. We used the random forest models to identify the management measures that most improved effectiveness in resisting human pressure for the PAs with different baselines. Finally, the relationships between the changes in the HPI and the changes in natural ecosystems in PAs were analyzed with different baselines. Of PAs with low HPI baselines, medium HPI baselines, and high HPI baselines, 76.92% (n=150), 11.11% (n=12), and 22.86% (n=8) , respectively, showed positive effects in resisting human pressure. Overall, ignoring human-pressure baselines somewhat underestimated the positive effects of PAs, especially for those with low initial human pressure. For PAs with different initial human pressures, different management measures should be taken to improve effectiveness and reduce threats to natural ecosystems. We believe our framework is useful for assessing the effectiveness of PAs globally, and we recommend it be included in the Convention on Biological Diversity Post-2020 Strategy.     

Effects of long-term nitrogen addition and precipitation changes on CH4 flux in an alpine steppe北大核心CSCD

土壤是甲烷(CH4)重要的源和汇.氮沉降和降水格局变化正在急剧改变土壤碳循环,进而可能对土壤CH4通量造成深刻影响.高寒生态系统是巨大的碳库,对氮沉降和降水变化十分敏感.然而,目前多数研究集中在短期实验上,缺乏对长期氮沉降和降水变化背景下CH4通量的响应及其调控因素的认识.以青藏高原高寒草原为研究对象,在2013年搭建模拟氮沉降和降水格局改变实验平台.基于静态箱–气相色谱法测定2020年生长季(5-10月)土壤CH4通量.结果显示,高寒草原土壤呈CH4的汇.氮添加没有显著改变生长季和植物生长高峰CH4通量.然而,降水变化显著改变了生长季和植物生长高峰CH4通量,其中降水增加(+50%降水)降低了CH4的吸收(分别为–16%和–45%),降水减少(–50%降水)增强了CH4的吸收(分别为+73%和+33%).进一步研究发现,与植物属性和功能基因丰度相比,土壤环境因子主导了CH4通量变化(解释率>90%).其中CH4通量与土壤含水量和温度显著正相关,与土壤pH显著负相关.综上所述,在未来全球变化情景下,降水格局改变更能调节青藏高原高寒草原CH4通量的变化.(图6表1参37)     

Distribution characteristics of dinoflagellate cysts in the Yantian Port,Shenzhen, China北大核心CSCD

An annual quarterly survey of six stations in Yantian Port, Shenzhen, China was conducted from January 2020 to October 2020 to investigate the spatial and temporal distribution of dinoflagellate cysts in the surface sediment of Yantian Port. In total, 36 species representing five groups and two uncertain taxa were identified. The dominant species were Scrippsiella trochoidea, Alexandrium spp., Gymnodinium catenatum, Cochlodinium spp., and Lingulodinium polyedrum. The seasonal difference was not obvious in terms of temporal distribution. The number of species ranged from 32 to 36, and the abundance varied from 297 to 996 cysts/g. The annual average values of the diversity index, richness index, and evenness index were 3.65, 1.55, and 0.93, respectively. The annual number and abundance of heterotrophic species were higher than those of autotrophic species. The number and abundance of species at stations near the dock zone were lower than those near the adjacent area. Notably, six toxic dinoflagellate cysts were found in the surface sediment of Yantian Port, indicating a potential outbreak risk for their vegetative cells in the local coastal area. This study provides a picture of the “Seed Bank” of dinoflagellates near Yantian Port, Shenzhen, and provides a reference value for predicting the occurrence of algal blooms. © 2022 Science Press. All rights reserved.     

Biocompatible self-healing hydrogels based on boronic acid-functionalized polymer and laponite nanocomposite for water pollutant removal

Environmental Chemistry Letters - Global water pollution by organic dyes and metals may be solved by adsorption. In particular, hydrogel adsorbents display unique...     

双酚A促进粪肠球菌中信息素调控质粒pCF10介导的耐药基因接合转移

粪肠球菌是一种在自然水体中广泛存在的革兰氏阳性细菌。信息素调控质粒介导的接合转移是造成粪肠球菌耐药基因快速扩散的重要方式。双酚A是一种内分泌干扰物,因其在工业中大量应用造成其在水环境中的广泛分布。本文以信息素调控质粒中比较有代表性的pCF10质粒作为研究对象,研究了双酚A对粪肠球菌中耐药基因接合转移的影响,证实了双酚A可以促进pCF10质粒介导的耐药基因接合转移,且这一结果同双酚A作用浓度和作用时间相关。双酚A影响耐药基因的扩散,是通过促进编码正调控信息素的ccfA基因表达实现的。本文旨在深入理解双酚A影响抗生素抗性基因扩散的环境行为,为耐药基因控制及双酚A环境效应的评估提供理论支持。