DTPA modified material and preparation method for rapid-full-dissociation type DGT (Diffusive gradients in thin films) coupling phase prepared therefrom

Abstract

The invention relates to a DTPA modified material and a preparation method for a rapid-full-dissociation type DGT (Diffusive gradients in thin films) coupling phase prepared therefrom. DTPA reacts with Mg<2+> and Al<3+> under alkaline conditions. The method comprises the steps: (1) adding 24.4ml of ammonia water (NH4(OH)) and methanol into 73.20ml of water, uniformly mixing the ammonia water, the methanol and the water, then, adding 32.78g of DTPA into the mixture, and thoroughly dissolving DTPA; (2) fetching another beaker, adding 593.34ml of water and 197.78ml of ammonia water into the beaker, uniformly mixing the water and the ammonia water thoroughly; and (3) simultaneously adding solutions obtained in the step (1) and the step (2) into a solution containing MgCl2.6H2O and AlCl3.6H2O so as to prepare the DTPA modified material, carrying out spray drying, then, sieving the dried DTPA modified material by a sieve with the pore size of 200 meshes (75 microns) so as to form a heavy-metal adsorption material for a DGT coupled film, then, adding the heavy-metal adsorption material into a polyacrylamide gel solution, and carrying out reaction at a certain temperature, thereby preparing the DGT coupled film. The gel film prepared by the method disclosed by the invention has the effects of heavy-metal adsorption and short-time full dissociation, and the disadvantage that the dissociation of the former heavy-metal coupling phase is slow and incomplete is overcome. The materials used are cheap and are easily prepared, and no secondary pollution is caused, so that the popularization and application of a DGT technology are facilitated.

Description

technical field [0001] The invention belongs to the field of heavy metal detection, and relates to a method for preparing a combined phase gel film of DGT (Diffusive gradients in thin films, DGT) for easy dynamic extraction of heavy metals in the analysis of environmental media such as water bodies, soils and sediments. Background technique [0002] In recent years, the problem of heavy metal pollution in soil, water and sediment has become more prominent, causing a series of environmental and ecological hazards, such as the cadmium rice incident caused by soil pollution, and the Minamata disease incident caused by water pollution. In order to more scientifically evaluate the real pollution status of heavy metals in different media and analyze their pollution hazards, in 1994, DGT (Diffusivegradientsinthin-films, DGT) technology came into being. , where the binding phase is one of the core components of DGT. Its role is to quickly adsorb the easily dynamic heavy metals passi...

AI Technical Summary

Problems solved by technology

[0003] Usually DGT binding phase adsorbs heavy metal materials mostly chelex-100, zirconium dioxide, titanium dioxide and nano-iron oxide. Although these materials can efficiently adsorb heavy metals and dissociate in acid or alkali solvents, the dissociation time is long and the decomposition Incomplete, the shortcomings are reflected in: on the one hand, it increases the detection time of DGT, and on the other hand, it is easy to cause deviations in the detection results

[0004] In view of the above problems, the present invention proposes a method for preparing DGT binding membrane based on DTPA modified material, which can effectively solve the problem of long dissociation time and incomplete dissociation of DGT binding membrane

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