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1.
利用凹凸棒土比表面积大,吸附能力强的特点,以火焰原子吸收光谱(FAAS)法为检测手段,探讨了凹凸棒土对Cd(Ⅱ)和Ni(Ⅱ)的吸附行为,考察了静态饱和吸附容量,研究了影响其吸附和解吸的主要因素,以及共存离子的影响情况。当pH 4.0、凹凸棒土用量为0.50g时,凹凸棒土对Cd(Ⅱ)、Ni(Ⅱ)的吸附率达到94%以上;以20 mL 0.5 mol/L的HCl可将吸附在凹凸棒土上的Cd(Ⅱ)、Ni(Ⅱ)定量洗脱。凹凸棒土对Cd(Ⅱ)和Ni(Ⅱ)的静态饱和吸附容量分别为32.5 mg/g、25.0 mg/g;本法对Cd(Ⅱ)和Ni(Ⅱ)的检出限分别为31 ng/mL、0.19 ng/mL;相对标准偏差分别为1.1%和0.94%(Cd(Ⅱ):0.30μg/mL,n=11;Ni(Ⅱ):0.80μg/mL,n=11)。在优化的实验条件下,本法用于天然水样中Cd(Ⅱ)和工业废水中Ni(Ⅱ)含量的测定,加标回收率分别为92%~98%和87%~102%。  相似文献   

2.
纳米TiO2用二苯基硫脲修饰后得到改性纳米TiO2,改性纳米TiO2对Au3+、Pd2+和Rh3+有很强的吸附能力,被用于Au3+、Pd2+和Rh3+分离富集。将该分离富集方法与电感耦合等离子体原子发射光谱法(ICP AES)相结合建立了测定地质样品中Au、Pd和Rh的新方法。考察了溶液酸度、洗脱条件和干扰离子等因素对分析物的分离富集影响。结果表明,在pH 40,Au3+、Pd2+和Rh3+可被改性纳米TiO2定量富集,吸附率在95%以上;而K+、Na+、Ca2+、Mg2+、Zn2+、Ni2+、Ba2+、Co2+、Cd2+和Mn2+不被吸附,Fe2+、In3+和Ga3+部分被吸附,但对测定没有影响。吸附的贵金属离子可用20 g/L CS(NH2)2 和 2 mol/L HCl溶液完全洗脱。在优化的实验条件下,吸附剂对Au3+、Pd2+ 和Rh3+的吸附容量分别为2163 mg /g, 1282 mg/g和1956 mg/g。本法对Au3+、Pd2+和Rh3+的检出限(3σ)分别为:061 ng/mL, 058 ng/mL和189 ng/mL,样品测定结果的相对标准偏差(RSD)分别为17%, 26%和18 (n=11)。该法应用于标准样品(GBW07293)中Au3+、Pd2+和Rh3+的测定,测定值与认定值相符。  相似文献   

3.
用火焰原子吸收光谱(FAAS)法探讨了纳米二氧化钛对Zn2+,Cu2+的吸附行为,研究了影响其吸附和解脱的主要因素及共存离子的干扰。以0.1 mol/L的盐酸为解脱剂,可将吸附在纳米二氧化钛上的铜、锌定量洗脱。本法测得纳米二氧化钛对Cu2+,Zn2+的静态吸附容量分别为:12 000μg/g,7 400μg/g。Cu2+在0.1~2.0μg/mL之间线性良好,Zn2+在0.1~1.0μg/mL范围内线性良好,方法的检出限分别为23 ng/mL,39 ng/mL。本法用于环境样品中Cu2+,Zn2+的测定,相对标准偏差为0.9%~3.2%,加标回收率为93.4%~102.4%。  相似文献   

4.
六钛酸钾晶须对钴吸附性能的研究   总被引:2,自引:1,他引:1       下载免费PDF全文
以火焰原子吸收光谱法(FAAS)为检测手段,探讨了六钛酸钾晶须对Co2+的吸附行为以及影响其吸附和解脱的主要因素,考察了共存离子的影响以及六钛酸钾晶须对Co2+的吸附容量。结果表明:在pH 5.0的溶液中,振荡时间为5 min,静置时间为0.5 h时,Co2+的吸附率可达到100%;以3 mol/L H2SO4作为解脱剂,振荡5 min,静置1 h,可将吸附在六钛酸钾上的钴定量洗脱。六钛酸钾晶须对Co2+的吸附性能良好,静态饱和吸附容量可达81.9 mg/g。Co2+的浓度在0.1~2.5μg/mL范围内线性良好,检出限为2.6 ng/mL;对浓度为0.5μg/mL的Co2+进行测定,相对标准偏差为3.4%。用于水样中钴的测定,加标回收率为95.3%~96.6%。  相似文献   

5.
以处理过的氟罗里硅土为微柱吸附材料,采用流动注射技术进行锑的分离富集,系统地考察了氟罗里硅土微柱对Sb(Ⅲ)的吸附性能,探讨了溶液的pH值、试样流速、试样体积、洗脱液浓度和用量以及干扰离子等因素的影响。实验结果表明,pH值为5.0,试样流速为1.5 mL/min时,氟罗里硅土对Sb(Ⅲ)具有良好的吸附性能,吸附率接近99%,动态饱和吸附容量为6.76 mg/g;选用5 mL 5 mol/L NaOH溶液可将吸附的Sb(Ⅲ)完全洗脱。本法的检出限(3σ)为0.085μg/mL,相对标准偏差为RSD=0.85%(n=11,ρ=10 mg/L)。将本法应用于实际样品中锑的测定,结果满意。  相似文献   

6.
研究了介孔分子筛SBA-15材料对痕量Pb2+的分离富集性能,探讨了溶液pH值、温度、洗脱条件及共存离子对铅分离富集的影响。在最佳实验条件下,介孔分子筛SBA-15能定量、快速吸附试液中的痕量Pb2+,其静态饱和吸附容量为5.36 mg/g,吸附在介孔分子筛SBA-15上的Pb2+可用0.05 mol/L HNO3-CH3COOH完全洗脱,洗脱下来的Pb2+用火焰原子吸收法测定,方法线性范围为0.05~25.00μg/mL,铅的检出限为35 ng/mL。该方法已用于标准矿样和日常矿样中铅的测定,两个标准矿样测定结果的相对标准偏差(RSD)分别为3.8%和4.5%(n=5),日常矿样的加标回收率在98.7%~106%之间。  相似文献   

7.
高俊杰  余萍 《冶金分析》2007,27(9):42-44
硅藻土粉末经盐酸(1 1)预处理后,与1-(2-吡啶偶氮)-2-萘酚(PAN)的丙酮溶液混合,形成了负载PAN的硅藻土。研究了负载PAN硅藻土的富集柱对痕量镉离子的吸附和富集行为,确立了负载PAN硅藻土对镉的吸附洗脱条件,据此建立了硅藻土负载PAN吸附、富集-原子吸收光谱法测定水中镉的分析方法。结果表明,在中性溶液下,负载PAN硅藻土的富集柱对镉离子有较好的吸附能力,其吸附容量为0.5mg/g;用8mL100g/L的酒石酸溶液洗脱,洗脱率达到100%,方法的富集倍率为80倍;测定镉的线性范围为0.0554~4.000mg/L,检出限为0.0168mg/L;大量共存离子对测定无明显影响。方法用于测定地表水中镉,回收率为94.2%~96.0%,相对标准偏差为2.7%~3.3%。  相似文献   

8.
应用氯化银沉淀法分离银后,超声雾化ICP-AES法测定高纯银中Al,Ca,Cr,Fe,Mg,Mo,Ni,Ti,Ba,Bi,Cd,Co,Cu,In,Li,Mn,Pb,Sn,V,Y及Zn21种痕量元素。对银沉淀时待测杂质元素的损失、光谱测定条件进行试验。结果表明,当试液中10mg/mL的银被沉淀时,待测元素几乎不与氯化银共沉淀;在所选定的波长下测定,当铁、铬、钙、镍、镁、铅的质量浓度小于10μg/mL时没有明显光谱干扰。本法测定范围为10~320μg/g,回收率在93%~105%之间,相对标准偏差在19%~1  相似文献   

9.
以色谱柱填料二氧化硅为原料,首先采用3-氯丙基三乙氧基硅烷对二氧化硅进行硅烷化反应,再在二氧化硅表面接枝多胺基线性聚合物聚乙烯亚胺(PEI),得到一种多胺基树脂(Si-PEI)。利用胺基与2-氯甲基吡咯的功能化反应,合成了一种用于硫酸钴电解液深度净化除铜的新型二氧化硅基氨基吡咯螯合树脂(Si-AMP)。红外、元素分析结果表明,二氧化硅表面成功引入了氨基吡咯官能团。从料液pH、吸附动力学及分离性能等方面考察了树脂对Cu2+、Ni 2+、Co2+的吸附性能。树脂在溶液pH 3.8时对Cu2+、Ni 2+、Co2+的最大吸附量分别为0.35mmol/g、0.25mmol/g、0.22mmol/g。模拟钴电解液静态吸附试验得到树脂对铜钴的分离系数达3 167,净化后溶液铜离子含量低于1mg/L。  相似文献   

10.
以细菌Pseudomonas sp.产生的胞外高聚物PS-2作为吸附剂,利用火焰原子吸收光谱法研究了该吸附剂对镉的吸附性能,提出了用胞外高聚物PS-2作为吸附剂,富集、分离测定环境水样中痕量Cd(Ⅱ)的新方法。结果表明,在pH 6.0,PS-2用量为0.30 g时,吸附率可达到99.5 %,静态吸附容量为35.97 mg/g。以10 mL 1 mol/L HCl 作为解脱剂,可将吸附在PS-2上的镉定量洗脱。此方法的检出限为2.4 ng/L,相对标准偏差为2.5 % (c=0.30 μg/mL, n=9)。将其应用于自来水、玉带河水中痕量Cd(Ⅱ)的测定,方法回收率在95%~101%之间,测定结果与标准方法测定值吻合。  相似文献   

11.
12.
Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.  相似文献   

14.
BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.  相似文献   

15.
Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.  相似文献   

16.
OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.  相似文献   

17.
The constructs of intelligence and ego-resiliency are discussed. The personality implications of "pure intelligence" and "pure ego-resilience" were identified. Intelligence (IQ) was indexed by the Wechsler Adult Intelligence Scale-Revised (WAIS—R) and ego-resiliency by an inventory scale. Residual scores measuring "pure intelligence" and "pure ego-resilience" were correlated with the items of the observer based California Q-sort, used to describe participants. Persons relatively high on ego-resilience tend to be more competent and comfortable in the "fuzzier" interpersonal world; persons defined primarily by raw IQ tend to be effective in the "clearer" world of structured work but tend also to be uneasy with affect and less able to realize satisfying human connections. Gender differences exist in the relations of ego-resilience and intelligence and in their adaptive relevance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
Investigated the effects of modeling and corrective feedback on the conservation of equalities and inequalities, with items spanning 3 stimulus dimensions (length, number, and 2-dimensional space). Ss were 48 kindergartners (24 boys, 24 girls). Brief observation of a model, briefer correction training (joining positive feedback with verbal rule provision), and the combination of observation and correction were all successful in producing learning and, without further training, transfer and retention of conservation. Unlike the controls (who also never correctly answered any equality items), the trained experimental Ss gave evidence of spontaneously generalizing their new learning to a task that required nonverbal behavior to manifest conservation. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
根据深云立交桥梁的检测结果,对该桥目前的整体状况、工作状态,及其使用情况做出综合评价,对桥的病害原因进行了分析,并提出合理的加固方案。  相似文献   

20.
众所周知,国际单位制物质的量采用摩尔(mol)表示,近几年出版的给排水专业书籍,为了与国际单位制接轨,逐渐将摩尔的使用频率不断提高,被给排水技术人员广泛应用的新版给排水设计手册,将表示物质浓度的单位“当量/升”或“毫克当量/升”.改为mol/l或mmol/l,虽然编者对其基本单元定义作了说明,但在实际运用上仍会出现误解,  相似文献   

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