活性氧化铅除砷动态吸附再生规律研究

本文报告了活性氧化铝除砷的动态吸附与再生的规律。结果表明:再生残留砷的蓄积规律与指数方程Log(k—y)=a—bx非常吻合,除砷容量的变化规律则与指数方程Log(q—k)=a—bx非常吻合;活性氧化铝最终能保持一个稳定而有效的除砷容量,用于饮水除砷在技术上是可行的、经济上是便宜的。     

活性氧化铝吸附法除砷再生规律初探

实验证明,用不同剂量的NaOH再生,再生均不彻底。活性氧化铝颗粒上再生残留砷与再生次数的关系可用指数方程表示。     

0.618法在指数曲线拟合中的应用

在医学统计学方法中，曲线的拟合常常是通过曲线直线化来完成的，有时会涉及Ｋ值的选择问题。例如，指数曲线ｌｇ（Ｋ－Ｙ）＝ａ＋ｂＸ、ｌｇ（Ｋ－Ｙ）＝ａ－ｂＸ、Ｙ＝ａ＋ｂｌｇ（Ｋ－Ｘ）和Ｙ＝ａ－ｂｌｇ（Ｋ－Ｘ）（图１）中都有Ｋ值的选择问题。Ｋ为一未知常数，需...     

乙型肝炎疫苗免疫后加强免疫时间的预测

以健康青年学生为观察对象，研究了抗－ＨＢｓ下降规律。结果表明，保护水平的抗－ＨＢｓ的持续时间与３１地免疫后抗－ＨＢｓ峰密切相关而抗ＨＢｓ的下降率与峰值无关。在此基础上又进行了回归分析，得到了预测模型；：Ｌｏｇ（ＭＩＵ）＝３．３０７７－０．３２４６Ｔ，换言之，由于ＭＩＵ值＝１０ｍＩＵ／ｍｌ为阴转临界点，可用此方程方程预测某个体阴转的时间：Ｔ＝「（ａ－Ｌｏｇ（ＭＩＵ）」／０．３４２６＝（ａ－１）／０．     

氟砷染毒对大鼠子代血清宏量元素的影响

采用两代一窝繁殖实验的方法,测定大量暴露于氟砷后其子代血液中宏量元素的水平。结果,随着暴露剂量的增加Ｎａ＾＋、Ｍｇ＾＋＋、Ｃａ＾＋＋随之降低,而Ｋ＾＋和Ｐ＾＋５变化不明显,停止氟砷暴露８周后Ｎａ＾＋、Ｍｇ＾＋＋、Ｃａ＾＋＋均明显增加。表明氟砷染毒对大鼠子代血清某些宏量元素有一定的影响。     

氟、砷联合发育毒性的体外实验研究

用全胚胎培养模型探讨了氟、砷联合染毒对体外培养４８ｈ大鼠胚胎的发育毒性。结果显示，不同浓度氟与砷的联合作用类型属协同作用（Ｐ＝０．０００１）。除２．５ｍｇ／Ｌ氟＋０．５ｍｇ／Ｌ砷组外，其它各联合组的反映胚胎生长发育的指标（颅臀长、头长、体节数和胚胎干重）与对照组比较，均具有显著性差异（Ｐ＜０．０５）。从氟砷联合胚胎毒性结果来看，二者相互增毒作用亦相当明显。例如３．０ｍｇ／Ｌ砷所致胚胎死亡率是１１．１％，但加２．５，１０和２０ｍｇ／Ｌ氟后，死胎率远大于二者单独作用之和，分别为３３．３％、４４．４％和１００％     

氟砷联合作用对大鼠肝脏抗氧化能力的影响

采用亚慢性动物实验方法，研究了氟、砷及其联合作用对大鼠肝脏ＳＯＤ、ＧＳＨ－Ｐｘ活性及ＭＤＡ、－ＳＨ含量的影响。结果显示：各实验组大鼠肝脏ＭＤＡ含量无明显差别，但染氟组（１５０ｍｇ／Ｌ，ＮａＦ）和染砷组（７５ｍｇ／Ｌ，Ａｓ２Ｏ３）ＳＯＤ、ＧＳＨ－Ｐｘ活性和－ＳＨ含量明显地低于对照组和氟砷联合组，后两组之间ＳＯＤ、ＧＳＨ－Ｐｘ活性无明显差异，氟砷联合组的－ＳＨ含量低于对照组。提示：氟和砷均可使肝脏的抗氧化能力降低；氟与砷同时存在时（氟、砷毒物剂量比为２：１），对肝脏ＳＯＤ、ＧＳＨ－Ｐｘ活性和－ＳＨ含量的影响存在拮抗作用，但对－ＳＨ的拮抗影响较弱。由于氟和砷之间的拮抗效应，使其联合作用对肝脏抗氧化能力的影响低于单纯氟和单纯砷。     

饮水除氟和含氟废水处理

用0.1M硫酸降原水pH至6.0～6.5,通过φ0.45～1.2或2mm活性氧化铝滤罐。出水平均含氟量0.5mg/L,补充原水调至0.90mg/L供饮用。除氟容量为4.5mgF~-/g Al_2O_3,比不降pH旧工艺(1.2mgF~-/g Al_2O_3)提高近四倍。1m~3供水的化学品、电力费0.28～0.10元,比旧工艺(0.29元)节约72～66％。以0.80～0.85％氢氧化钠再生滤料。含氟含碱再生废水经中和后,加氯化钙处理。     

氟砷染毒对大鼠子代脂质过氧化的影响

目的 为揭示氟砷共存时对子代健康影响提供有价值的资料。方法 采取两代一窝繁殖实验的方法,测定Ｗｉｓｔａｒ大鼠暴露于氟砷后其子代血液中脂质过氧化水平和抗氧化能力。要随着暴露剂量的增加,超氧化物歧化酶（ＳＯＤ）和谷胱甘肽过氧化物酶活性随之降低,而脂质过氧化物（ＬＰＯ）含量却逐渐增加,Ｆ２代ＳＯＤ活性在不同的剂量组分别为１４．５６、１３．７４、１１．８９和１１．２１μｍｏｌ．ｍｉｎ＾－１．ｍｇＨｂ＾－１     

活性氧化铝滤层吸附法饮水除砷现场半生产性试验研究

本文研究了现场饮水除砷及再生废水处理的工艺。用稀酸将原水pH降至6.0～6.5,再通过一个充填粒径为0.35～1.20mm、厚度为750mm的活性氧化铝滤罐。进水平均砷浓度为0.34～0.53mg/L,出水的平均砷浓度为0.014～0.028mg/L,平均除砷效率为94.7～95.9％。周期单位产水量≥4360m~3水/T·Al_2O_3。每立方米水的处理费用(包括化学品、滤料补充、废水处理)仅0.076元,低于饮水除氟的费用。强碱性含砷废水经中和及氯化铁混凝沉淀3天后,上清液中砷浓度降至0.009mg/L(远远低于0.5mg/L的排放标准),完全可以排放。     

集中式饮水除砷装置的研制

为验证本专题研制的强化除砷剂的除砷效果、除砷容量以及再生效果 ,必须有中试规模的试验装置及其运行状况 ,以便推进饮水除砷剂及其除砷技术的产业化进程 ,中试基地选在源水含砷量超标的浙江省某天然泉水饮料厂 ,该集中式饮水除砷装置的处理能力为 1m3 h ,自 1999年 4月起连续运行至今 ,处理后出水符合国家生活饮用水有关卫生标准的要求 ,除砷容量高 ;成本低 ,设备管理简单 ,进水和出水均无需调节pH ;再生剂安全、价廉、效果好 ,适宜用于水砷高的农村或含砷的自备水厂     

骨炭除氟方法及其设施的研究

骨炭的吸附容量比活性氧化铝高2.6倍,接触时间短,滤速快,价格便宜,是一种性能良好的新型除氟剂。采用简单的处理工艺,成功地解决了集中式除氟的技术问题,处理水氟含量≤1.0mg/L,为高氟水地区推广骨炭除氧提供了实践经验。     

饮水复合材料除砷滤芯的研制与效果评价

目的　研制饮水复合材料除砷滤芯并在高砷饮水地区进行模拟现场效果评价。方法　以载铁活性炭粉与超细聚乙烯树脂为主要成分制备复合材料除砷滤芯 ,现场使用加标高砷饮水为原水 ,测定了滤芯的安全性、除砷效果以及其它净水作用。结果　以等量载铁活性炭粉和超细聚乙烯树脂制备的复合材料除砷滤芯可安全用于饮用水处理对砷含量为 0 4mg L的实验原水 ,除砷容量可达 2 5 6mg g ,同时对水质浊度和耗氧量指标有明显改善。结论　以载铁活性炭粉与超细聚乙烯树脂为主要成分制备复合材料除砷滤芯适合于农村高砷饮水的除砷     

Optimization of regenerated bone char for fluoride removal in drinking water: a case study in Tanzania

This paper presents findings of a study on optimization and application of the regenerated bone char media for the defluoridation of drinking water in Tanzania where more than 30% of all water sources have fluoride concentrations above the 1.50 mg/I which is recommended by the World Heath Organization (WHO). In this study, regeneration temperature, regeneration duration, contact time, regenerated bone char dosage and particle size were investigated. Results indicate that the highest fluoride removal and adsorption capacity were 70.64% and 0.75 mg-F/g-bc, respectively, for a sample with bone char material that was regenerated at 500 degrees C. In this study the optimum burning duration was found to be 120 min, which resulted in residual fluoride that varied from a maximum value of 17.43 mg/I for a 2 min contact time to a minimum value of 8.53 mg/I for a contact time of 180 min. This study further indicated that the smallest size of regenerated bone char media (0.5-1.0 mm diameter) had the highest defluoridation capacity, with residual fluoride which varied from 17.82 mg/I at 2 min contact time to 11.26 mg/I at 120 min contact time. In terms of dosage of the regenerated bone char media it was established that the optimum dosage was 25g of bone char media with a grain size of 0.50-1.0 mm. This had a fluoride removal capacity of 0.55 mg-F/g-BC. Column filter experiments indicated that regenerated bone media is capable of removing fluoride from dinking water to meet both WHO and Tanzania recommended values.     

Urinary arsenic species, toenail arsenic, and arsenic intake estimates in a Michigan population with low levels of arsenic in drinking water

The large disparity between arsenic concentrations in drinking water and urine remains unexplained. This study aims to evaluate predictors of urinary arsenic in a population exposed to low concentrations (≤50?μg/l) of arsenic in drinking water. Urine and drinking water samples were collected from a subsample (n=343) of a population enrolled in a bladder cancer case-control study in southeastern Michigan. Total arsenic in water and arsenic species in urine were determined using ICP-MS: arsenobetaine (AsB), arsenite (As[III]), arsenate (As[V]), methylarsenic acid (MMA[V]), and dimethylarsenic acid (DMA[V]). The sum of As[III], As[V], MMA[V], and DMA[V] was denoted as SumAs. Dietary information was obtained through a self-reported food intake questionnaire. Log(10)-transformed drinking water arsenic concentration at home was a significant (P<0.0001) predictor of SumAs (R(2)=0.18). Associations improved (R(2)=0.29, P<0.0001) when individuals with less than 1?μg/l of arsenic in drinking water were removed and further improved when analyses were applied to individuals who consumed amounts of home drinking water above the median volume (R(2)=0.40, P<0.0001). A separate analysis indicated that AsB and DMA[V] were significantly correlated with fish and shellfish consumption, which may suggest that seafood intake influences DMA[V] excretion. The Spearman correlation between arsenic concentration in toenails and SumAs was 0.36 and between arsenic concentration in toenails and arsenic concentration in water was 0.42. Results show that arsenic exposure from drinking water consumption is an important determinant of urinary arsenic concentrations, even in a population exposed to relatively low levels of arsenic in drinking water, and suggest that seafood intake may influence urinary DMA[V] concentrations.     

杞县饮水型地方性氟中毒病区饮水氟砷含量与井深关系的探讨

目的探讨杞县农村饮水型地方性氟中毒病区分散式供水水氟、水砷含量与井深的关系,寻找适宜氟砷含量的饮水层,为地方病防治提供基础资料和科学依据。方法采集杞县氟中毒病区饮用井水样,测定水中氟、砷的浓度,分析浓度分布特点以及水氟、水砷、水井深度三者之间的关系。结果杞县地方性氟中毒病区水井深度在66 m以内,水氟含量与饮水井深度之间呈正相关关系,相关系数为0.108。水砷浓度与饮水井深度呈负相关关系,相关系数为-0.170。水氟含量与水砷含量之间无相关关系。结论饮水型地方性氟中毒病区水氟、水砷含量与井深之间有密切关系。水氟含量随饮水井深度的增加而增高;水砷含量随饮水井深度的增加而降低;而水氟、水砷浓度间不具有相关性。杞县饮水型地方性氟中毒病区饮水应避开现用水层,选择地表水或深层地下水。     

活性氧化铝吸附法饮水除砷研究

活性氧化铝的除砷机理以吸附为主,其除As~(5+)的效率非常显著地高于As~(3+).水中As~(3+)用氯氧化后的去除率和As~(5+)相同.含砷0.75mg/L左右的原水将pH调至6.0～6.5的条件下,除砷容量为1.4～2.0mg/g Al_2O_3,处理1m~3水的化学品费用为0.221元.1m~3 Al_2O_3每个周期可处理水1700m~3以上.     

活性氧化铝吸附法饮水除砷研究

活性氧化铝的除砷机理以吸附为主,其除As~(5+)的效率非常显著地高于As~(3+)。水中As~(3+)用氯氧化后的去除率和As~(5+)相同。含砷0.75mg/L左右的原水将pH调至6.0～6.5的条件下,除砷容量为1.4～2.0mg/g Al_2O_3,处理1m3水的化学品费用为0.221元。1m~3 Al_2O_3每个周期可处理水1700m~3以上。