从金属切削废料中回收镍和钴生产硫酸镍和氧化钴

以镍钴合金切削废料为原料，通过酸溶、除铁、除铬、镍钴分离等一系列步骤，回收镍和钴，生产硫酸镍和氯化钴，通过试验确定了最佳工艺条件，并对经济效益进行了分析。     

改性硅酸钙(CSH)对重金属废水中Ni2+的吸附特性研究

以硅灰石和氧化钙为原料制备改性硅酸钙(CSH),为了探讨改性硅酸钙对Ni~(2+)的吸附特性和机理,考察了初始p H值、吸附剂投加量、初始Ni~(2+)质量浓度和硅酸钙使用次数等因素对模拟废水中Ni~(2+)去除率的影响。结果表明,p H值在3.0~6.0、吸附剂投加量为1g/L、含Ni~(2+)废水质量浓度小于200 mg/L、硅酸钙前两次使用时,CSH对Ni~(2+)均有较高的去除效果。采用Langmuir等温吸附模型拟合CSH对Ni~(2+)的吸附,得到CSH对Ni~(2+)的最大吸附量为417 mg/g。结合吸附前后的扫描电镜-能谱(SEM-EDS)和X射线衍射(XRD)图谱分析,推测出CSH的主要结构为Ca Si2O5,CSH对Ni~(2+)的吸附主要发生在CSH表面并且是通过离子交换作用进行的。通过对CSH吸附去除Ni~(2+)过程中溶液离子浓度变化的研究推断出97%的Ni~(2+)通过离子交换作用被去除,剩余的Ni~(2+)通过表面络合作用去除。     

碳纳米管修饰泡沫镍空气扩散电极电-Fenton法降解水中对硝基酚

采用涂覆焙烧法制备碳纳米管修饰泡沫镍空气扩散电极,并用环境扫描电子显微镜和循环伏安法对其表面形貌和氧化还原特性进行了表征。考察了该电极还原O2产生H2O2的性能及对水中对硝基酚的降解性能。表征结果表明:碳纳米管修饰泡沫镍空气扩散电极具有多级孔道结构;在-0.6 V处具有较强的氧双电子还原峰。实验结果表明:当电流为150 m A、反应时间为120 min时,产生的H2O2的质量浓度为321.38 mg/L;在外加0.1 mmol/L Fe SO4形成的电-Fenton体系中,反应30 min后对硝基酚去除率可达95.90%;且该电极重复使用10次的对硝基酚去除率为92%~96%。     

Fuel cell system with sodium borohydride hydrogen generator for small unmanned aerial vehicles

A 100 W proton exchange membrane fuel cell (PEMFC) system with a sodium borohydride (NaBH₄) hydrogen generator was investigated for small unmanned aerial vehicles (UAVs). The performance of a cobalt–phosphorous/nickel foam catalyst was evaluated to determine the change in catalytic activity under real operating conditions. The response time increased owing to oxidation of the metals and accumulation of sodium; however, the catalyst remained active at high reaction temperatures. A NaBH₄ hydrogen generator with the catalyst was developed for a 100 W PEMFC system. The hydrogen generation rate was stable for 3 h, and the conversion efficiency was 97.8%. Finally, a 100 W PEMFC system with the NaBH₄ hydrogen generator was investigated for small UAVs. The maximum power and energy density of the PEMFC system were 95.96 W and 185.2 Wh/kg, respectively.     

Heavy metals in surface water and stream sediments in Jamaica

The levels of heavy metals in water and stream sediments in Jamaica are presented and compared to levels in soils and environmental standards. Heavy metals (cadmium, chromium, copper, mercury, nickel, lead and zinc) appear to be less of a problem to Jamaica's freshwater environment than might be expected given the concentrations in soils. This can be explained by taking into account the dynamics of the Jamaican water environment and the relative absence of anthropogenic sources. The dynamics of the freshwater system on the other hand, could pass any environmental threat to the coastal environment. Because the stream sediments are relatively coarse and contain little organic material the bio-availability of micropollutants such as heavy metals from the sediments can be expected to be relatively high.     

新型杂环三氮烯类光度试剂与镍的显色体系研究

光度法检测微量镍发展的核心是制备高灵敏的显色剂,而杂环三氮烯类试剂由于其显色反应的灵敏度高、选择性好,是热点研究方向。本文以新合成的1-(偶氮苯基)-3-(3-硝基-2-吡啶)-三氮烯(简称AB-NPT)为显色剂,研究了它与镍的高灵敏显色体系,结果表明:在pH值为10.8~11.6范围内Na2B4O7-NaOH的缓冲溶液中,ABNPT在非离子表面活性剂Tween-100存在下与镍形成红色稳定的配合物,其最大吸收波长为535 nm。该显色体系大大提高了测定方法的选择性和抗干扰性,优于其它光度法测镍。采用此法用于矿样中微量镍的测定,结果令人满意,有较强的应用背景和社会效益。     

珠江三角洲典型区域农业土壤中镍的含量分布特征

对珠江三角洲典型区域农业土壤取样调查表明:研究区农业土壤中镍的含量范围在2.29～112.00mg·kg-1之间,平均值(27.79±18.39)mg·kg-1,有24.9%土壤样品的镍含量超过国家土壤环境质量标准(GB15618—1995)的二级标准;土壤中镍的含量主要受成土母质的影响,滨海沉积物和三角洲冲积物发育的土壤中镍含量明显高于其它成土母质的土壤;可能受到富含镍的西江和北江沉积物质的影响,西江和北江三角洲沉积区土壤中镍含量明显高于东江三角洲沉积区。调查结果为研究区域的土壤环境质量调查、评价和治理提供重要的基础资料和决策依据。     

Nickel and Cadmium Concentrations in Plasma and Na+/K+ATPase Activities in Erythrocyte Membranes of the People Exposed to Cement Dust Emissions

The aim of this study was to determine the concentrations of nickel and cadmium in blood plasma of the people exposed to cement dust emissions and to investigate the effects of exposure period on the activities of Na⁺/K⁺ ATPase enzymes in their erythrocyte membranes. The study was carried out on people living in Eskiehir Çukurhisar rural area, located near a cement factory. Blood samples of the individuals residing in this area were taken from 80subjects (30 for control) following a physical examination. The analysis of plasma samples showed that nickel concentrations in subject group were found to be significantly higher than those of the control group (p < 0.001). Cadmium concentrations were found to be within the reference values for both group and no difference was found between the subjects and controls (p > 0.05). Furthermore, no correlation was observed between the levels of Na⁺/K⁺ ATPase activity in erythrocyte membranes of the subject group and the ages of people living in the region (p > 0.05, r = 0.133). It was also observed that nickel concentrations increased by age (p < 0.001, r = 0.646) while no effect was observed in means of cadmium. Na⁺/K⁺ ATPase activities in the erythrocyte membranes were not affected.In conclusion although there was no difference between the Na⁺/K⁺ ATPase activity in means of age, there was an environmental pollution and may be it was due to the industrial plant.     

Chemical forms of cobalt and nickel extracted by M1,M3 and CaCl_2-DTPA

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高分子重金属絮凝剂PEX捕集Ni2+及除浊性能研究

以聚乙烯亚胺、NaOH、CS2为原料,在一定条件下合成了一种新型两性高分子重金属絮凝剂--聚乙烯亚胺基黄原酸钠(PEX),研究了其捕集Ni2 及除浊性能,并对几个影响因素作了考察.实验结果表明:(1)该絮凝剂对Ni2 有很好的捕集功能,Ni2 的最高去除率可达99%以上;(2)pH值对PEX投加量有一定的影响,但对Ni2 的最高去除率影响不大;(3)水中存在碱金属或碱土金属离子时在一定程度上会促进Ni2 的去除;(4)当有Fe3 存在时,在较低pH值下会明显降低Ni2 的去除,但当pH值升高时对Ni2 的去除有促进作用;(5)Cl-与NO3-的存在可促进PEX对Ni2 的去除,而SO42-的存在对Ni2 的去除有抑制作用,需增加投药量才能得到较好的去除;(6)Ni2 和致浊物质共存时,会互相影响彼此的去除.