4A沸石去除水中Pb~(2+)的研究

在静态条件下,研究了4A沸石对废水中Pb2+的吸附性能,并探讨了影响吸附的因素。实验表明:当温度为30℃,废水pH为5~6,0.01 g4A沸石对100 mg/LPb2+溶液10 mL吸附20 min,Pb2+的去除率可达到99%以上。在实验研究条件下,4A沸石对Pb2+的吸附符合Langmuir和Freundlich等温吸附方程,相关系数为0.9819和0.9998。经计算,4A沸石对Pb2+的饱和吸附量为125 mg/g。4A沸石吸附水中Pb2+,达到吸附平衡的时间较短;溶液pH值的变化对吸附效果影响不显著;温度从室温略微升高,Pb2+的去除率略有增大。吸附在4 A沸石上的Pb2+可回收利用,处理后的4A沸石可以再生,且重复使用性能较好。     

氢化物发生—电加热石英管原子吸收法测定环境水样中痕量铅的研究

研究了将氢化物发生技术用于电加热石英管原子吸收法测定环境水样中痕量铅 ,讨论了最佳测定条件和干扰元素的消除。方法的线性范围为 0～ 2 5 ng/m l,检出限为 0 .48ng/ml,相对标准偏差小于 2 .5 % ,回收率在 95 %～ 116%之间。     

兰州市小儿血铅水平与环境铅污染关系调查

采用随机抽样的方法对兰州市103对新生儿及其母亲、1月至36月的146名婴幼儿以及808名3～7岁儿童的毛细血管血铅进行了分析,同时对上述幼儿园室内外尘土或土壤样品采用石墨炉原子吸收法进行了铅分析测定,通过相关分析,说明城市环境铅污染是小儿血铅升高的主要原因之一。     

氢化物发生-原子荧光光谱法测定废水中痕量铅

运用氢化物发生-原子荧光光谱法,经过各种条件试验,建立测定地面水与废水中痕量铅的分析方法,在0.0004～0.05mg/L线性范围内,铅的最低检出限为0.4μg/L,标液变异系数＜2%,样品变异系数＜8%,样品回收率100%～105%.     

Comparative equilibrium studies of sorption of Pb(II) ions by sodium and calcium alginate

The absorption of Pb(II) ions from aqueous solution by di erent alginate compounds was studied in a batch sorption system. Water soluble sodium alginate and insoluble calcium alginate beads were investigated. The lead-binding capacity of both alginate compounds was highest within the pH range 6–8. The binding capacities and rates of Pb(II) ions by alginate compounds were evaluated. The Langmuir, Freundlich, and Bruneaur, Emmet and Teller (BET) sorption models were applied to describe the isotherms and isotherm constants. Sorption isothermal data could be well interpreted by the Langmuir model. The results obtained through the study suggest that alginate compounds are favorable sorbents. The largest amount of Pb(II) ions were bound by sodium alginate although the di erence between two compounds was slight. Therefore, alginate substances may be considered as an alternative for sorption and removal of Pb(II) ions from wastewaters.     

Calcium alginate accelerates elimination of environmental lead in preschool children

Environmental lead poses a serious threat for public health, particularly, for children. The use of substances with metal-binding properties, such as natural alginates, may be a potentially effective method for elimination of toxic metal ions from human body. In present study, effect of calcium alginate isolated from brown algae on distribution of the lead ions in preschool children was investigated. In the beginning of the study, lead concentration in urine, feces, and hair was determined. Then these children were administered a dietary supplement containing calcium alginate for four weeks. The results showed that all children participated in the study had a high baseline median lead level in urine (1.1 µg/L), feces (4.6 µg/g), and hair (5.0 µg/g). Administration of calcium alginate resulted in twofold increase of the urine lead level within two weeks from the start of the treatment. At the end of alginate administration, significant decrease of lead concentration in hair was registered. These results suggest that calcium alginate can potentially prevent accumulation of the lead ions in the body and may be used as an active agent for elimination of this toxic metal from human body.     

铅暴露的环境健康风险评估模型的本土化研究

我国现阶段重金属污染引发的群体事件频繁发生,其中铅污染事件尤为突出和严重。铅污染暴露对儿童健康损害的严重性、不可逆性以及铅污染后果的积累性和潜伏性特点,使得铅暴露的环境健康风险评估对中国的铅污染防治具有重要意义。目前,国际上最常用的铅污染暴露的儿童健康风险评估模型是美国EPA开发的IEUBK模型。为使IEUBK模型在中国得到更好的应用,本文首先对美国IEUBK模型系统做出如下本土化:1鉴于中国儿童的饮食结构、生活习惯及暴露参数等方面与欧美儿童存在的差异,对IEUBK模型暴露模块中的膳食模块和土壤-灰尘模块的数学模型进行改进;2探讨IEUBK模型中生理毒物代谢多隔室模型的高速精确的迭代算法。即针对生理毒物代谢多隔室模型的线性特征,通过离散化方法转化为线性方程组,引进中间变量,设计出了不需要进行高阶矩阵计算、存贮量较小、计算速度快且大样本模拟计算时优点明显的模型求解的一次迭代算法;3根据改进后的模型算法,编制模型的底层代码程序,并优化设计出友好的IEUBK模型系统中文输入界面。接着,对本土化IEUBK模型系统进行测试,测试结果表明:模型迭代算法的计算快速、结果准确,输入界面友好。然后,对本土化IEUBK模型进行实证分析,实证结果显示:本土化IEUBK模型的血铅预测值与血铅实测值的统计学差异并不显著。因此,本土化的IEUBK模型可在中国推广应用。最后,本文探讨了本土化的IEUBK模型系统的进一步改进方向及其在中国环评、环境标准制定及环境诉讼等方面的应用。     

菜籽粕对水溶液中Pb(Ⅱ)的吸附性能

以菜籽粕为吸附剂去除水溶液中Pb2+,考察了pH值、吸附剂投放量、反应时间对吸附性能的影响,研究了不同温度下菜籽粕对溶液中Pb2+吸附热力学和动力学。当Pb2+溶液浓度为100 mg/L时,吸附剂投放量为4 g/L,pH值3~5.5,吸附时间120 min,Pb2+去除率达到95%以上。铅吸附等温线很好地符合Langmuir等温方程,293 K时饱和吸附量达31.9 mg/g。对吸附热力学参数ΔGθ,ΔHθ,ΔSθ的计算表明,吸附过程属于熵驱动型的吸热自发过程。Pb2+在菜籽粕上动力学吸附符合准二级速率方程,表观吸附活化能Ea=49.6 kJ/mol。结合吸附前后红外光谱(FTIR)分析,Pb2+在菜籽粕上吸附主要发生在蛋白质的酰胺结构、-NH2、-C-S-上,具有化学吸附的显著特征。菜籽粕作为一种廉价的生物质吸附剂,对低浓度Pb2+溶液吸附量大,吸附速度快,具有良好的开发应用前景。     

阴极射线管锥玻璃真空碳热还原除铅机理研究

阴极射线管(cathode ray tube,CRT)玻璃附加值极低,毒性浸出实验表明CRT玻璃为危险废物,是当前我国电子垃圾处理处置中首要的必须解决的难题。废弃CRT玻璃安全处理处置的关键在于其含铅锥玻璃的处理处置。文章从锥玻璃的组成出发,探讨真空碳热还原除铅的可能性及可行性,计算表明真空碳热还原除铅完全可能,实验结果表明900℃,10 Pa下反应4 h铅的去除率可达93.53%,残余物中铅的质量分数仅为0.9%。该法为解决废弃危险电子垃圾CRT玻璃问题提供了新的思路,具有较强的应用价值。