Some aspects in testing and assessment of metal dust explosions

The dust explosion committee of the Association of Powder Process Industry and Engineering, Japan recently established two testing standards for dust explosions. In the investigations for the standardization, many experimental data have been obtained for the dusts currently used in Japanese industries. Data for zirconium, tantalum and silicone dusts are presented to discuss the use of test methods, which have been accepted internationally. The test methods for dust explosions have to consider a variety of kinds and forms of dusts to be tested.     

Gravity orientation in social wasp comb cells (Vespinae) and the possible role of embedded minerals

Social wasps and hornets maintain their nest in the dark. The building of the combs by all Vespinae is always in the direction of the gravitational force of Earth, and in each cell's ceiling, at least one 'keystone' is embedded and fastened by saliva. The sensory mechanisms that enable both building of sizeable symmetrical combs and nursing of the brood in the darkness merit investigation, and the aim of the present study was to identify and characterize the 'keystones' that exist in the ceiling and in the walls of the social wasp comb cells. Bio-ferrography was used to isolate magnetic particles on slides. These slides, as well as original cells, were analyzed in an environmental scanning electron microscope by a variety of analytical tools. It was found that both the roof and the walls of each comb cell bear minerals, like ferrites, as well as Ti and Zr. The latter two elements are less abundant in the soil around the nest. Ti and Zr are known to reflect infrared (IR) light. IR imaging showed a thermoregulatory center in the dorsal thorax of the adult Oriental hornet. It is not known yet whether these insects can sense IR light.     

锆改性膨润土对废水中大红染料去除率的研究

用Zr2＋对膨润土改性,并用改性后的膨润土对大红染料废水进行处理,考察了pH值、反应温度、反应时间、改性膨润土用量等因素对大红染料去除率的影响,研究了其吸附动力学及等温吸附。     

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.     

Microwave-assisted preparation of two-dimensional amphiphilic nanoplate herding surfactants for offshore oil spill treatment

Oil spills are the uncontrolled release of liquid hydrocarbon by ruptured pipelines and tanker hulls, or blowouts and leaks from offshore storage facilities and drilling rigs, either by faulty human behaviors or inevitable natural aging processes. Spills cause disastrous environmental and economic consequences, with the effects of marine habitat damage for lasting decades, necessitating a critical need for efficient oil spill mitigation and leakage treatment. In this study, we develop a two-dimensional (2D) amphiphilic nanoplate as the herding surfactant for retracting spilled oil offshore on the seawater surface with various temperature and saline concentrations. Applying 2D nanoplate herding surfactant causes areas of thin oil slick floating on water to largely shrink and form a thick bulk layer. This transformation lays the foundation for the next-step oil treatment and recovery. Microwave-assisted synthesis method was used to fabricate the surface-modified zirconium phosphate (ZrP) nanoplates as the oil herder, which has an amphiphilic characteristic, containing both hydrophilic and hydrophobic properties. The 2D nanoplate surfactants decrease the air-water surface tension to facilitate the oil herding process efficiently. Using this herding procedure, we propose a biocompatible, high herding efficiency and cost-effective 2D herding surfactant fabrication method and offer a new direction for oil treatment in the offshore process safety field.     

碱熔法生产二氧化锆污染的综合治理

采用新型反应器及胶凝除硅、直接酸溶重结晶、直接煅烧等技术对二氧化锆的生产工艺进行了改革 ,降低了原材料消耗及能耗 ,减少了废液排放量 ,并将回收的废物加工成副产品白炭黑 ,在生产过程中防治污染。     

高温老化气氛对单钯三元催化剂活性的影响

本文制备了一种含Y、Ce和Zr的单钯三元催化剂(Pd-YCZ).在1050℃下,分别于空气和配气中对这一催化剂进行了高温老化,并对其催化活性进行了测试.实验结果表明,Pd-YCZ在空气中老化后的活性优于其在配气中老化后的活性.     

癌症与土壤环境中锆元素的关系

利用土壤环境中锆元素资料 767个数据和癌症死亡调查资料 7870 80例 ,研究了癌症死亡率与人群生存区土壤环境中锆元素的关系。结果表明 :肝癌、肺癌、鼻咽癌、乳腺癌死亡率与锆元素有相关性 ,等级相关系数分别为 0 5 0 44 (P <0 0 0 5 )、0 3 3 99(P <0 0 5 )、0 3 164 (P <0 0 5 )、0 3 197(P <0 0 5 )。     

Enhanced phosphate removal using zirconium hydroxide encapsulated in quaternized cellulose

Zirconium-based materials are efficient adsorbent for aqueous phosphate removal. However, current zirconium-based materials still show unsatisfied performance on adsorption capacity and selectivity. Here, we demonstrate a zirconium hydroxide encapsulated in quaternized cellulose (QC–Zr) for the selective phosphate removal. Zirconium hydroxide nanoparticles were simultaneously generated in situ with the QC framework and firmly anchored in the three-dimensional (3D) cross-linked cellulose chains. The maximum P adsorption capacity of QC–Zr was 83.6 mg P/g. Furthermore, the QC–Zr shows high P adsorption performance in a wide pH range, generally due to the electrostatic effects of quaternized cellulose. The enhanced adsorption of P was also achieved in the presence of competing anions (including Cl^?, NO₃^?, ${\text{SO}}_4^{2?}$, ${\text{SO}}_4^{\mathrm{4}?}$) and humic acid (HA) even at a molar ratio up to 20 levels. The column adsorption capacity of QC–Zr reached 4000 bed volumes (BV) at EBCT = 0.5 min as the P concentration decreased from 2.5 to 0.5 mg/L. Mechanism study revealed that both –N⁺(CH₃)₃ groups and zirconium hydroxide were involved in phosphate adsorption via electrostatic interactions between –N⁺(CH₃)₃ and phosphate, and the formation of zirconium hydrogen phosphate (Zr(HPO₄)x). The ³¹P nuclear magnetic resonance (NMR) study implied that P surface–precipitated and inner–sphere complexed with zirconium hydroxide at a ratio of 3:1.