扬州古运河三湾段沉积物中重金属潜在生态风险评价及形态变化特征

扬州古运河是京杭大运河最古老的一段,为了解沉积物中重金属污染状况,采用Hakanson潜在生态风险评价扬州古运河三湾段沉积物中重金属Cr、Ni、Cu、Zn、Cd和Pb的风险水平,并对形态分布特征进行了研究。结果表明:扬州古运河六种重金属的含量均高于背景值,其中Cd含量为其背景值的13.15倍。沉积物中重金属的累积潜在生态风险指数RI高达456.55,沉积物的总体潜在生态风险等级为强。沉积物中Pb的主要赋存形态主要以铁锰氧化态存在,而Zn和Cd主要以酸可溶态形式存在,说明这三种重金属的潜在生态风险水平较高。     

电感耦合等离子体质谱法分析小麦中的稀土元素

为了研究稀土元素在小麦中的分布,建立了一种压力密闭消解电感耦合等离子体质谱分析Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb和Lu等15种稀土元素的方法。该方法被用于分析国际柑橘叶标准物质(NIST 1572)中的稀土元素,结果与标准值一致。该方法被用于研究稀土元素在小麦中的分布,稀土元素在小麦中的含量整体上遵循如下的顺序:麦粒<麦茎<麦壳<麦叶<麦根。     

黄河上中游表层沉积物中硅形态分布特征

研究了黄河上中游表层沉积物中总硅和形态硅的形态分布特征,研究结果表明:1各形态硅中,IEF-Si和CF-Si的占总硅比率较低,最高的是乌拉特Y2段。IMOF-Si和OSF-Si为形态硅的主要存在形式,且二者之间存在一定的相关性。2黄河上游表层沉积物样品中各形态硅含量总体变化规律是大致是,IMOF-SiOSF-SiIEF-SiCF-Si,但乌海Y1和托克托Y3点OSF-Si含量为该段最高,可能与沉积物中有机质增多有关。3黄河表层沉积物中总硅总量为2123.99~4727.484mg/kg,最低点和最高点分别出现在玛多X1和柳林Z1。     

湛江湾及邻近海域重金属污染研究进展

通过综述湛江湾海水、沉积物及海洋生物体中重金属的研究进展，梳理了湛江湾重金属的含量水平、赋存形态、时空分布特征和潜在生态风险，为湛江湾及国内其他海湾的污染防治提供借鉴。研究表明，湛江湾水体重金属浓度普遍较低，整体上低于Ⅲ类海水质量标准，湾内环境质量整体较好；海水中的重金属呈现出从内湾向湾口下降、岸边高于深海的规律；除Hg之外，湛江湾海水中重金属产生的生态系统风险均较小。湛江湾表层沉积物中重金属的平均浓度均低于其他海湾；除Cd、Hg及Cr存在中强或较强的生态风险外，湛江湾表层沉积物中其他重金属污染水平均较低；表层沉积物中重金属的空间分布呈现出岸边高于深海、从湾内向湾外降低的整体趋势；表层沉积物中重金属的主要赋存形态为氧化态和残渣态。湛江湾水生生物体内重金属含量平均水平呈现出Zn>Cu>Pb>Ni>Cd>Cr，湛江湾生物体中各重金属的含量整体上低于“海洋生物污染评价标准”。综合以上研究，后期应对湛江湾污染较重及生态风险较高的重金属加强重点监测，同时加强重金属与其他污染物复合污染的监测。     

延长探区南部盒8段稀土元素地球化学示踪

延长探区南部盒8段具有较大的天然气勘探开发潜力。通过分析延长探区南部盒8段泥岩样品中稀土元素地球化学特征,探讨了延长探区盒8段沉积环境及成岩物质来源。结果表明,研究区盒8段泥岩轻重稀土元素比值较大,分异程度较高,属于轻稀土中度富集型,δ(Ce)和Ceanom指示泥岩沉积时期水体整体处于缺氧的还原环境中,稀土元素特征和La/Yb-ΣREE判别图解指示延长探区南部盒8段构造环境稳定,存在多源分区性,源岩物质来自上地壳,源岩主要为花岗岩、沉积岩与钙质泥岩混合区,物源区主要为南部的祁连—秦岭古陆造山带的沉积岩母岩区和源自大陆边缘抬升基底型的花岗岩母岩区。     

内蒙古段黄河上游表层沉积物磷的形态分析

本文用改进的SEDEX方法,对内蒙古段黄河上游表层沉积物进行了磷的形态提取分析,研究了内蒙古黄河表层沉积物自然粒径的各形态磷的差异.分析结果表明可交换态磷、铁磷和有机磷含量都小,而钙磷、碎屑磷含量大.内蒙古段黄河沉积物无机磷的含量远远比有机磷的要高.其顺序为PCa＞PDe＞PFe＞Por＞Pex.     

六盘水地区煤岩稀土元素特征

通过对六盘水地区3个煤矿14种稀土元素的含量分布规律的研究,认为研究区煤岩中稀土元素La、Ce、Nd、Sm含量相对较高,其余元素均低于1．5&#215;10^-6;煤岩稀土元素总量为39．78--92．92&#215;10^-6,轻稀土元素分量与重稀土元素分量比值（LREE／HREE））94．39～7．70,La、Yb球粒陨石标准化比值（（La／Yb）n）为3．7725～8．3699,显示该煤岩属轻稀土富集型。铈异常系数（δCe）为0．7591～0．9447,销异常系数（δEu）为0．4179--0．8065,显示Ce略微亏损,Eu相对亏损。     

黄河包头、临河河段沉积物中磷的化学形态

文章采用改进的化学连续提取法,将所提取的黄河中游(包头河段、临河河段)沉积物中的样品用磷钼蓝分光光度法测定其中六种形态磷的含量,以便为该河段防治水污染提供基础依据。测定结果表明:(1)黄河包头段、临河段沉积物中的磷主要以钙结合磷和有机磷为主;(2)包头河段六种化学形态排序:Ca-POrg-PAl-PFe-PEx-PObs-P,临河河段沉积物中磷的六种化学形态排序:Ca-POrg-PAl-PEx-PFe-PObs-P。     

蛇绿岩地质地球化学特征研究

该研究在详述了蛇绿岩岩石组成及岩石特征后,对蛇绿岩岩石地球化学特征进行分析,结果表明:蛇绿岩岩石属钙碱性系列,富集高场强元素,稀土元素含量较低,略微富集轻稀土元素,显示岩浆来源于亏损地幔源,并有富集地幔物质的加入。     

原生磷矿及其风化矿中微量和稀土元素特征分析

本文对织金原生磷矿及其风化矿中的微量元素、稀土元素进行了研究,并结合前期研究成果对矿床矿石的地球化学特征进行了分析。原生矿与风化矿中微量元素的富集主要有Ba、Ce、La、Nd、Sr、Y等的富集;w(U)/w(Th)值表明原生矿后期受热液沉积作用的影响较大,风化矿具有明显的残积富集特征;w(Sr)/w(Ba)值表明该磷矿属于碎屑岩性磷矿;w(Zr)/w(Hf)值表明原生矿与热液活动早期有关,风化矿与热液活动后期有关。无论风化矿还是原生矿,轻稀土相对更富集,LREE/HREE平均为1.35,元素Ce、Eu均出现明显的负异常,稀土元素特征表明该磷矿属于正常海相沉积岩磷矿。     

白云鄂博稀土共生矿超重力梯级分离稀土元素的工艺研究

我国白云鄂博矿稀土储量居世界首位,其稀土矿物以轻稀土为主,Ce, La, Pr, Nd占稀土氧化物总量的97%以上,具有重要的工业价值。由于四种稀土元素具有极其相似的物化性质,因此在目前的处理工艺中很难实现不同稀土元素的彼此分离。本工作基于稀土精矿的矿相演变及元素迁移规律,在降温熔析过程中不同温度区间内会析出不同稀土相：在1400~1500℃的温度区间只有氧化稀土相析出,随着温度降至1200~1400℃,铁酸稀土相开始析出,当温度降至1100~1200℃时铈磷灰石相析出。利用超重力技术进行氧化稀土相、铁酸稀土相、铈磷灰石相的梯级分离实验,结果表明,98.38%的Ce元素优先以氧化稀土相形式析出并实现分离,97.70%的La元素进入铁酸稀土相作为第二相被分离,而Pr和Nd元素最终以铈磷灰石相的形式分离,以此实现了稀土精矿中Ce, La, Pr, Nd的梯级分离。     

地球化学参数在沉积古盐度中的应用

在对沉积物进行沉积古盐度分析时,微量元素分析能够起到很好的作用,它们对沉积盐度的变化具有很高的灵敏度,此外稀土元素具有很好的稳定性,能够保存沉积时的古盐度信息,生物标志化合物是生物的化学化石,具有稳定的结构,不易受成岩作用影响,能够记录生物沉积时的古盐度。通过阅读大量的文献,系统的总结了主微量元素、稀土元素和生物标志化合物在不同沉积盐度中的特征及其地质应用。对于沉积相分析不明确的地层,利用地球化学参数能够更直观地分析出沉积盐度。但沉积物在沉积过程中很容易受其他因素影响,因此在利用地化参数对沉积盐度判别时还应与地质背景、岩性岩相等相结合,以便能最大限度反映出沉积时的古盐度。     

稀土元素对脂肪醇胺化催化剂性能的影响

无论是作为脂肪醇胺化催化剂的活性组分还是载体 ,La和Gd均能提高目前工业用Cu—Ni催化剂的活性和选择性 ,可以使生成的高沸物小于 2 % ,二甲基叔胺的收率大于 97% ,而Nd和Ce则无明显的促进作用。这些稀土元素均对催化剂的稳定性没有改善     

Determination of rare earth elements in Niger Delta crude oils by inductively coupled plasma-mass spectrometry

A profile for rare earth elements (REE) of crude oils from the offshore – shallow water and onshore fields in the Niger Delta, analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) is reported. The oil samples were prepared for ICP-MS measurement by acid digestion into colourless aqueous solution. The analysis method was validated using standard reference materials SLRS-4 and NIST-1640. Results showed percentage recovery values that ranged from 81.8% to 115.4% for Co, Cu, Fe, Mn, Ni, Sb and U and from 98.8% to 104.7% for Co, Cu, Fe, Mn, Ni and Sb. The magnitude of deviation recorded in SLRS-4 for Co and Fe suggests that it may not be a suitable standard for these elements using the ICP-MS method outlined in this study. The concentrations of the detected REE; La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er and Yb ranged from 0.01 to 1.58 ppb with an average of 0.98 ppb (%RSD < 5) for the oil samples analyzed. Light REEs (LREE) were identified in all the oil samples while heavy rare earth elements (HREE) were identified in offshore oil samples only. LREE patterns constructed from chondrite-normalized values for the oils show some similarities among the oils, which suggest common origin of the oils and that the REE got into the oils from similar source. While those with different chondrite-normalized REE patterns suggest different source input of the REE. This indicates that REE will be a useful tool in oil–oil correlation. Statistical evaluation of these oils by cluster analysis using the REE as variables clearly discriminated according to their geographic sources. Biodegradation has pronounced effect on the concentration of REE in oils. Therefore, REE contents of oils will be useful in oil classification. ICP-MS proved to be a versatile method for the determination of rare earth elements in Niger Delta oils.     

Rare earth elements leaching from Chadormalu apatite concentrate: Laboratory studies and regression predictions

The extraction of rare earth elements from apatite concentrate of Chadormalu plant of Iran was studied with the dissolution of ore in nitric acid. The parameters of acidity: 60%, solid to liquid ratio: 30%, leaching time: 30 minute, agitation rate: 200 rpm, temperature: 60 °C and particle size (d₈₀): 50 microns were determined as the optimum operational conditions. The recoveries of lanthanum, cerium, neodymium and yttrium were achieved at 74, 59, 72 and 73%, respectively, in the optimized conditions. Multivariable regression was used to predict La, Ce, Nd, Y and total REEs (Y+Nd+Ce+La) leaching recoveries, using experimental data from laboratory studies. It was achieved quite satisfactory correlations of 0.93, 0.98, 0.99, 0.97 and 0.99 for the prediction of Y, Nd, Ce, La and total REEs recoveries, respectively. It was shown that the proposed equations accurately reproduce the effects of operational variables on the different REEs recoveries, and can be used to optimize the REEs leaching plant.     

Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets

Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO₃ acid (0.1 M) after a short contact time (15 min).     

Selective recovery of lanthanides,uranium and thorium from Rosetta monazite mineral concentrate

An innovative procedure for the selective recovery of lanthanides using (NH₄)₂SO₄ from hydrous oxide cake produced after the alkali breakdown of monazite mineral concentrate was proposed. By applying this procedure, 94.6% of the rare earth elements (REEs) content would be dissolved. In this context, partial precipitation of light rare earth elements (LREEs) as their double sulfate took place. To separate uranium completely from thorium and the remaining REEs (5.4%) from hydrous oxide cake, an alkaline leaching procedure has been carried out by using a mixture of 1/3 (Na₂CO₃/NaHCO₃) solution. Finally, the remaining hydrous oxide cake was then dissolved in 4M HCl to separate either Th or REEs contents.     

稀土离子(Gd~(3+),Ce~(3+)/Ce~(4+),Eu~(3+))对Tb~(3+)掺杂硅酸盐玻璃发光性能的影响

研究了(Gd3+,Ce3+/Ce4+,Eu3+)对Tb3+掺杂硅酸盐玻璃发光性能的影响.结果表明:Tb3+掺杂硅酸盐玻璃可以发出弱蓝光(400～460 mm)和较强的绿光(480～600mm).Gd3+对Tb3+的发光起敏化作用,可提高TB3+掺杂硅酸盐玻璃的发光强度.在空气中熔制的玻璃中Ce3+和Ce4+同时存在,Ce3+对Tb3+发光起敏化作用;而Ce4+对Tb3+发光起淬灭作用.由于Ce4+比例比较高,CeO2加入导致TB3+发光强度降低,同时也缩短了Tb3+发光余辉.加入Eu2O3时,Eu3+自身发光分散了激发Tb3+发光的能量,使Tb3+的特征发射强度降低.     

七种稀土元素对酸性化学镀镍-磷合金镀层影响

在酸性化学镀镍镀液中分别加入Ce、La、Y、Sm、Sc、Lu和Tm七种稀土元素,对基材进行化学镀镍,探究稀土元素对沉积速率、镀层孔隙率及表面形貌的影响.结果证明,七种稀土元素对沉积速率以及镀层性能影响各不相同.其中,Ce、Y和Lu三种稀土元素在一定质量浓度范围内有加速作用,加入4 mg/L Ce的加速比最大,为18.05％.七种稀土元素对镀层孔隙率均有抑制作用,最低能达到0.32个/cm2.