Kinetic and equilibrium modeling of liquid‐phase adsorption of lead and lead chelates on activated carbons

The sawdust (SD) waste generated in the timber industry was converted to a low‐cost activated carbon (SDAC) using a simpler and cheaper activation process, single‐step steam pyrolysis activation. The possibility of utilizing SDAC for the removal of lead (Pb(II)) in the absence of ligands and nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) chelated Pb(II) complexes from the liquid phase was examined and the results were compared with those for commercial activated carbon (CAC). SDAC shows a high adsorption capacity for Pb(II) and Pb(II) chelates compared with CAC. The extent of adsorption of Pb(II) and Pb(II) chelates on activated carbons was found to be a function of solution pH and species distribution of Pb(II) and Pb(II) chelates. The optimum pH range for the removal of Pb(II) in the absence of ligands by SDAC was 6.5–8.0, whereas its maximum removal by CAC was observed at pH 6.5. In the presence of ligands, the extent of Pb(II) adsorption was enhanced in the pH range 2.0–5.0 and was reduced significantly in the pH range 6.0–8.0. The maximum uptake of Pb(II) chelates for both carbons was observed at pH 5.0. Kinetic models such as pseudo‐first‐order, pseudo‐second‐order and pore diffusion were tested to investigate the adsorption mechanism. Batch kinetic studies showed that the adsorption of Pb(II) from aqueous solutions with and without ligands could be best described by a psuedo‐first‐order model for both carbons. The effect of pH on the adsorption isotherms of Pb(II) and Pb(II) chelates was also investigated. The applicability of the Langmuir and Freundlich isotherms, established for various initial concentrations of the adsorbate and for different pH values, was tested at 30 °C. Copyright © 2003 Society of Chemical Industry     

EDTA络合溶胶-凝胶法制备Y2O3:Eu纳米晶

以金属硝酸盐和EDTA为原料，用EDTA络合溶胶-凝胶法制备出Y2O3:Eu纳米晶，并对合成条件进行了优化。分别用TG-DTA、FTIR、XRD、SEM、荧光分光光度计等手段对凝胶的热分解机理、Y2O3:Eu的形成过程以及纳米晶的性质进行了研究。结果表明：硝酸根离子可以加速EDTA凝胶的热分解，仅600℃焙烧即可得到颗粒细小、组分均匀、纯立方相的Y2O3:Eu纳米晶，颗粒基本呈球形，粒径随温度升高逐渐长大，600℃时，约为20nm,1000℃时，约为70nm。     

印制电路废水处理工艺分析

分析了通常采用混凝法处理印制电路废水达不到国家一级排放水标准的原因，提出了相应的解决问题的方法。     

苏打渣中铜量的测定──EDTA解蔽法

本文提出EDTA解蔽法测定苏打渣中的钢量，着重研究了如何将苏打渣中的铜掩蔽与解蔽的方法。通过试验，提出了切实可行的方法。实践证明本方法的精密和准确度均很好，可满足科研和生产的要求。本法具有流程短，分析速度快，劳动强度小等优点。     

测定饲料及其原料中钙的方法改进

本文提出了在测定不同饲料及原料中钙含量的改进方法对含磷样品,采用三乙醇胺和洒石酸盐作掩蔽剂,进行 EDTA 滴定分析,而对含重金属离子的样品而言,则需添加氰化钾及盐酸羟胺,以消除重金属离子的干扰。     

Conformational changes of Mal d 2, a thaumatin-like apple allergen,induced by food processing

Mal d 2, a thaumatin-like protein from apple was previously described to react to almost 75% of the apple allergic patient sera. Based on the molecular structure of this protein, the present study focused on the conformational stability of Mal d 2 in relation to in vitro IgE-binding under different physico-chemical conditions and proteolysis. The structural integrity of Mal d 2 was monitored using SDS–PAGE, Western blotting using polyclonal antibodies and human sera, fluorescence spectrometry and circular dichroism. Results confirmed the stability of Mal d 2. However, Mal d 2 was reactive to human serum IgEs mainly after reduction of disulphide bridges fixing the α-helical domain II. Contrary to previous assumptions, the current findings suggest that the allergenic epitopes of Mal d 2 are hidden inside the protein structure and none of the rigorous conditions applied in industrial juice processing or digestive proteolysis enhance or reduce the binding to IgE molecules.     

EDTA滴定法快速分析碳化钙中碳化钙

试样以硝酸、氢氟酸溶解,高氯酸冒烟,定容。取部分溶液,在pH≥12.5碱性介质中,以钙试剂为指示剂,用EDTA标准溶液滴定钙量。     

EDTA提高含金多金属硫化矿选别指标的研究

本文通过EDTA在含金多金属硫化矿浮选中应用的研究,论证了应用EDTA提高选别指标的优越性,为含金硫化矿矿石浮选找到了一种新的调整剂。     

丙烯酰胺中浓度水溶液的辐射聚合——EDTA二钠体系的研究

本文研究了用~(60)Coγ射线引发丙烯酰胺水溶液的聚合体系中,添加乙二胺四乙酸二钠盐(EDTA),对提高聚合物分子量,改善水溶性和掩蔽铜、铁等有害杂质的作用。同时也对剂量率、剂量、辐照温度等因素进行了探讨。制得了分子量高,水溶性好的聚丙烯酸胺(PAM)。本实验结果为中间试验和工业化生产提供了科学依据。     

EDTA及其中间体类似物合成新工艺研究

以羟基乙腈和乙二胺为原料,用一锅法制得EDTN,进一步水解得到EDTA。同时,对底物进行了扩展,在相同的反应条件下,用其它含氨基以及二氨基的底物与羟基乙腈反应,合成了系列氨基腈类化合物。