Fe3O4纳米磁性微粒对全氟辛烷磺酸盐的吸附

采用共沉淀法合成Fe3O4纳米磁性颗粒,用透射电子显微镜（TEM）、X射线衍射仪（XRD）以及振动样品磁强计（VSM）对Fe3O4纳米磁性颗粒的粒径、形貌和磁性进行表征并研究Fe3O4纳米磁性微粒对全氟辛磺酸盐的吸附。结果表明：在PFOS初始浓度4 mg/L,pH为3,反应时间24 h,Fe3O4纳米磁性微粒投加量1.25 g/L,对全氟辛磺酸盐去除率达到90%。Fe3O4纳米磁性微粒对PFOS的吸附符合Freundlich吸附方程。     

Enhanced visual detection of pesticides using gold nanoparticles

The presence of parts per billion (ppb) levels of chlorpyrifos (O,O-Diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) and malathion (S-1,2-bis(ethoxycarbonyl) ethyl O,O-dimethyl phosphorodithioate), two common pesticides found in the surface waters of developing countries, have been visually detected using gold nanoparticles. Visual detection of the presence of pesticide is possible when the color change occurring by the adsorption of pesticides on gold nanoparticles is enhanced by sodium sulfate. The method presented here is simple and there is no need of sample preparation or preconcentration. The response occurs within seconds and the color change is very clear. The detection is possible if chlorpyrifos and malathion are present up to a concentration of 20 and 100 ppb, respectively. The method shows great potential for on-site pesticide monitoring. The method is also applicable as a qualitative technique for the performance evaluation of various household water filters, which claim pesticide removal.     

TiO_2晶体的微波水热法制备及光催化性能研究

以TiSO4和尿素为主要原料,EDTA为控制剂,采用微波水热法制备纳米TiO2光催化剂,并分析了纳米TiO2晶粒的最佳形成条件。利用XRD、TEM等技术对制备产物进行表征。结果表明,TiSO4和尿素混合物在微波水热条件下晶化150 min后,产物为锐钛矿型TiO2,且产物粒径小、大小均匀。在紫外光照射下,以自制的锐钛矿型纳米TiO2为催化剂,酸性橙为降解目标物,进一步研究了其光催化性能。结果表明,该TiO2在紫外光照射下表现出稳定的光催化活性。     

纳米Fe_3O_4磁性粒子的制备及吸附性能研究

采用共沉淀法制备了纳米Fe3O4磁性粒子。应用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)和振动样品磁强计(VSM)等对纳米磁性粒子的粒径、结构、形貌、磁性能进行了表征,进行了磁分离沉降性能和腐殖酸吸附去除实验研究。结果表明:在未添加任何分散剂的条件下,制得的纳米Fe3O4磁性粒子主要呈球状,平均粒径约11 nm,为典型的反尖晶石结构;饱和磁化强度、矫顽力和剩余磁化强度分别为73.10 emu/g、159.2 A/m和0.41 emu/g;磁分离沉降速度为重力场的50倍;纳米Fe3O4磁性粒子对腐殖酸的吸附符合Langmuir型吸附等温线。     

In vivo genotoxicity assessment of titanium,zirconium and aluminium nanoparticles,and their microparticulated forms,in Drosophila

As in vivo system, we propose Drosophila melanogaster as a useful model for study the genotoxic risks associated with nanoparticle exposure. In this study we have carried out a genotoxic evaluation of titanium dioxide (TiO₂), zirconium oxide (ZrO₂) and aluminium oxide (Al₂O₃) nanoparticles and their microparticulated forms in D. melanogaster by using the wing somatic mutation and recombination assay. This assay is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3, can lead to the formation of mutant clones in treated larvae, which are expressed as mutant spots on the wings of adult flies. Third instar larvae were feed with TiO₂, ZrO₂ and Al₂O₃ nanoparticles, and their microparticulated forms, at concentrations ranging from 0.1 to 10 mM. Although a certain level of aggregation/agglomeration was observed in solution, it must be noted than the constant digging activity of larvae ensures that treated medium pass constantly through the digestive tract ensuring exposure. The results showed that no significant increases in the frequency of all spots (e.g. small single, large single, twin, total mwh and total spots) were observed, indicating that these nanoparticles were not able to induce genotoxic activity in the wing spot assay of D. melanogaster. Negative data were also obtained with the microparticulated forms. This indicates that the nanoparticulated form of the selected nanomaterials does not modify the potential genotoxicity of their microparticulated versions. These in vivo results contribute to increase the genotoxicity database on the TiO₂, ZrO₂ and Al₂O₃ nanoparticles.     

Relevance study of bare and coated zero valent iron nanoparticles for lindane degradation from its by-product monitorization

Zero-valent iron nanoparticles (NZVI) as well as polymer–stabilized nanoparticles were synthesized and used for lindane (γ-hexachlorocyclohexane) degradation in aqueous solution. To study the effectiveness of the different coated nanoparticles, simple and rapid analytical methods have been developed to measure and to detect lindane and its by-products. For the monitorization of lindane degradation solid-phase extraction (SPE) was used, while volatile by-products formation measurement was carried out by headspace-solid phase microextraction (HS–SPME) followed by GC/MS. The SPE–GC/MS method provides low detection limits (0.2 μg L⁻¹), high recovery (above 95%) and it is a valuable tool for kinetic studies of the degradation process for each polymer used, while HS–SPME–GC/MS has proved to be an effective tool for the extraction and evaluation of volatile degradation by-products.     

Titanium dioxide nanoparticles relieve biochemical dysfunctions of fifth-instar larvae of silkworms following exposure to phoxim insecticide

Phoxim insecticide is widely used in agriculture, which is toxic to insect pests and nontarget organisms. The phoxim poisoning is hard to prevent for silkworms. TiO₂ NPs have been widely applied in whitening, brightening foods, toothpaste or sunscreens, and orally-administered drugs. However, whether TiO₂ NPs can increase resistance of silkworm to phoxim poisoning has not been reported. The results demonstrated that added TiO₂ NPs significantly decreased reduction of protein, glucose and pyruvate contents, lactate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activities, and attenuated increases of free amino acids, urea, uric acid and lactate levels, activities of protease, alanine aminotransferase and aspartate aminotransferase in the hemolymph of silkworms caused by phoxim exposure. From the present study, it is clearly evident that added TiO₂ NPs may relieve toxic impacts of phoxim insecticide on silkworm metabolism, which in turn may result in an increase in silk yield.     

Interaction of engineered nanoparticles with various components of the environment and possible strategies for their risk assessment

Nanoparticles are the materials with at least two dimensions between 1 and 100 nm. Mostly these nanoparticles are natural products but their tremendous commercial use has boosted the artificial synthesis of these particles (engineered nanoparticles). Accelerated production and use of these engineered nanoparticles may cause their release in the environment and facilitate the frequent interactions with biotic and abiotic components of the ecosystems. Despite remarkable commercial benefits, their presence in the nature may cause hazardous biological effects. Therefore, detail understanding of their sources, release interaction with environment, and possible risk assessment would provide a basis for safer use of engineered nanoparticles with minimal or no hazardous impact on environment. Keeping all these points in mind the present review provides updated information on various aspects, e.g. sources, different types, synthesis, interaction with environment, possible strategies for risk management of engineered nanoparticles.     

Behavioural and biochemical responses of two marine invertebrates Scrobicularia plana and Hediste diversicolor to copper oxide nanoparticles

Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10 μg L⁻¹) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO₃. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves.