活性炭负载纳米TiO2对腐殖酸光催化降解动力学

采用溶胶-凝胶法制备了以颗粒活性炭(GAC)为载体的纳米TiO2/AC复合催化剂,并将其用于腐殖酸的光催化降解.动力学研究表明,TiO2/AC光催化降解腐殖酸过程可用Langmuir-Hinshelwood(L-H)动力学模式表示.L-H表观反应速率常数KLH=0.1124mg·L-·1min-1,吸附平衡常数K*=0.3402L·mg-1.活性炭负载TiO2对腐殖酸的光催化降解过程,体现了活性炭与TiO2的协同作用,活性炭的吸附作用提高了光催化反应速率.     

负载型纳米Bi2WO6/AC的制备及在可见光下降解邻硝基苯酚

采用水热法在160℃条件下以活性炭(AC)为载体合成了光催化剂Bi2WO6/AC,用X射线衍射仪(XRD)、电子扫描电镜(SEM)对催化剂进行了表征.同时,以邻硝基苯酚为目标污染物,在可见光照射下,讨论了催化剂用量、溶液的pH、污染物初始浓度等因素对催化剂光催化活性的影响.结果表明,当[Bi2WO6/AC]=5 g·L-1、pH=5[邻硝基苯酚]0=100 mg·L-1时,催化剂可见光降解活性最好,60 min后邻硝基苯酚的降解率可达到99.81%.     

改性纳米碳管的理化性质、毒性及风险研究进展

随着纳米材料的广泛应用,在生产加工过程中,各种改性后的纳米碳管(CNTs)进入环境。充分认识改性后CNTs的理化性质是对其进行客观风险评价的重要前提。主要分析了几种常用方法改性后的CNTs的悬浮、吸附特征及其理化性质差异,综述了目前CNTs毒理学实验的研究进展,评价了其潜在风险,并提出了今后研究的方向。     

纳米二氧化钛光催化净化空气的研究进展

摘要：光催化技术的诸多优点使其成为空气净化领域的研究热点之一,该论文综述了二氧化钛光催化氧化的机理、影响光催化反应的因素以及对二氧化钛的改性研究现状．并提出了应用前景。     

纳米Fe、Si体系对3,3′,4,4′-四氯联苯的脱氯降解

研究了纳米Fe、Si体系降解3,3′,4,4′-四氯联苯(PCB77)的动力学差异.结果表明,纳米Fe0、纳米Fe3O4和纳米Si0对PCB77均有降解作用,该降解为还原脱氯反应.降解过程符合准一级反应动力学,反应速率常数Kobs分别为0.0177,0.0038,0.0045h-1.PCB77初始浓度为5mg/L,纳米材料投加量为5g/L,溶液pH4.5条件下,纳米Fe0体系对PCB77降解效果最为显著,64h时PCB77残留率仅为19.83%,氯离子浓度为50.3μmol/L,反应体系pH值从4.5升至5.26.纳米双元体系Fe0和Si0、Fe3O4和Si0对PCB77降解过程也符合准一级反应动力学,反应速率常数Kobs分别为0.0114,0.004h-1,其中纳米Fe0和Si0体系降解效果优于纳米Fe3O4和Si0体系.PCB77残留率分别为34.91%和66.62%,氯离子浓度分别为40.07,20.47μmol/L,反应体系pH值变化不明显.随着溶液初始pH值增加,纳米Fe0、纳米Fe3O4降解PCB77效果明显降低,但溶液pH值升高有利于纳米Si0对PCB77的降解.两组纳米双元体系对PCB77的降...     

Effects of stable aqueous fullerene nanocrystal （nC60） on Daphnia magna： Evaluation of hop frequency and accumulations under different conditions

We investigated the e ects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60 by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using di erent environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D. magna in an aqueous system. Additionally, environmental factors may have a ected accumulation by changing nC60 properties, which are critical to understand the accumulation of fullerenes in aqueous systems.     

Humic acid and metal ions accelerating the dechlorination of 4-chlorobiphenyl by nanoscale zero-valent iron

Transformation of polychlorinated biphenyls (PCBs) by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl (4-ClBP) by nanoscale zero-valent iron (NZVI) in the presence of humic acid or metal ions was investigated. The results showed that the dechlorination of 4-ClBP by NZVI increased with decreased solution pH. When the initial pH value was 4.0, 5.5, 6.8, and 9.0, the dechlorination efficiencies of 4-ClBP after 48 hr were 53.8%, 47.8%, 35.7%, and 35.6%, respectively. The presence of humic acid inhibited the reduction of 4-ClBP in the first 4 hr, and then significantly accelerated the dechlorination by reaching 86.3% in 48 hr. Divalent metal ions, Co2+, Cu2+, and Ni2+, were reduced and formed bimetals with NZVI, thereby enhanced the dechlorination of 4-ClBP. The dechlorination percentages of 4-ClBP in the presence of 0.1 mmol/L Co2+, Cu2+ and Ni2+ were 66.1%, 66.0% and 64.6% in 48 hr, and then increased to 67.9%, 71.3% and 73.5%, after 96 hr respectively. The dechlorination kinetics of 4-ClBP by the NZVI in all cases followed pseudo-first order model. The results provide a basis for better understanding of the dechlorination mechanisms of PCBs in real environment.     

纳米FeO作用下4-氯酚的脱氯特性及机理

采用化学还原法制备了纳米Fe^O, ESEM测定结果表明其颗粒在1～100 nm内. 实验表明这些纳米Fe^O能在20 h内将初始浓度为20 mg/L的4-氯酚完全降解, Fe^O对4-CP的还原脱氯是主要去除途径. 苯酚是脱氯反应的主要产物. 当4-CP的初始浓度由20　mg/L增大到50, 100, 150　mg/L时, 其相对去除率明显降低, 但绝对降解量有较大提高. 温度不仅影响脱氯速率, 而且影响4-CP去除的途径. 30℃时, 脱氯反应为主要反应; １０℃时, 较易产生氧化产物. Fe原子的迁移过程在4-CP的降解中也是一个重要的限速步骤. 此外, 纳米Fe^O具有很好的稳定性, 在受试的379　h内, 纳米Fe^O能够应对不同浓度冲击及反复投加的4-氯酚冲击的能力.     

纳米级二氧化锰材料阻控土壤砷向水稻迁移的研究

为了探究纳米级二氧化锰材料阻控土壤中砷向水稻迁移的影响,通过盆栽种植水稻,向砷污染土壤中分别添加0%(CK)、0.2%、0.5%、1.0%和2.0%的纳米级二氧化锰材料,分析土壤溶液p H值、砷和锰的含量变化,及水稻中砷和锰的含量变化.结果表明:添加不同浓度的纳米级二氧化锰材料,土壤溶液pH值没有显著变化,土壤溶液中砷、锰的浓度随着水稻生长的时间增加而降低;不同时期水稻中砷和锰的分布规律是根部茎部叶部糙米,水稻植株中锰和砷的含量呈显著负相关(p0.05);不同浓度的纳米级二氧化锰材料能有效控制水稻糙米中总砷含量,其中1.0%添加量的阻控效果最好,使糙米中总砷含量降低了65.4%,其无机砷含量低于《食品中污染物限量(GB2762—2012)》中砷限量.     

全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-ZnO)单独与联合暴露对斑马鱼胚胎的氧化损伤和细胞凋亡的影响

探讨全氟辛烷磺酸钾(PFOS)和纳米氧化锌(Nano-Zn O)复合暴露对斑马鱼机体氧化损伤和细胞凋亡的影响。将斑马鱼胚胎暴露于PFOS(0、0.4、0.8和1.6 mg·L-1)、Nano-Zn O(0、12.5、25和50 mg·L-1)、PFOS+Nano-Zn O(0、0.4+12.5、0.8+25和1.6+50 mg·L-1)溶液中6天后,检测相关的酶活性变化(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(Gpx)、脂质过氧化物(MDA)、半胱氨酸蛋白酶(Caspase-3和Caspase-9)和与细胞凋亡相关基因(Bax,p53和Bcl-2)表达情况。结果表明:PFOS和Nano-Zn O单独与复合暴露均可造成斑马鱼胚胎的氧化损伤和细胞凋亡,但复合暴露组的氧化损伤和细胞凋亡程度明显大于单独暴露组。在PFOS和Nano-Zn O单独和复合暴露组中,随着处理浓度的升高,SOD、Gpx、Caspase-3和Caspase-9酶的活性显著升高。而CAT酶活性随着处理浓度的升高抑制作用显著。PFOS与Nano-Zn O复合暴露组与单独暴露组相比,Bax和p53表达显著上调,而Bcl-2表达显著下调。因此,在实验浓度范围内,等毒性配比1:1条件下,推测NanoZn O可以增强PFOS对斑马鱼胚胎的氧化损伤和细胞凋亡毒性。