Composite heavy metal chelating agent containing dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer

Abstract

The invention provides a composite heavy metal chelating agent containing a dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer, and relates to the technical fieldof chemical engineering and environmental protection. The composite heavy metal chelating agent provided by the invention is prepared from a dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer and micromolecular alkylene diamine-N, N'-dithiocarboxylate in a molar ratio of 1:(1.0-10.0), and the two components of different structure types have a synergistic positive effect, cooperate with heavy metals to be alternately combined with the heavy metals to form super-large molecular insoluble chelate precipitates while chelating the heavy metals, and have chelating-self-flocculation dual properties. The composite heavy metal chelating agent provided by the invention can treat heavy metal wastewater, especially low-concentration heavy metal wastewater, in a standard reaching manner, is wide in application range, and does not need to add a coagulant aid; and the preparation method is simple in process, easily available in raw materials, low in cost and easyto industrialize.

Description

technical field [0001] The invention relates to the technical fields of chemical engineering and environmental protection, in particular to a compound heavy metal chelating agent containing a dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer, a preparation method and an application. Background technique [0002] In recent years, heavy metal pollution has become the most important environmental crisis in China, posing a serious threat to the ecosystem and public health. With the continuous upgrading of national environmental protection monitoring, the electroplating and steel industry has begun to implement the special discharge of heavy metals in Table 3 of "Electroplating Pollutant Discharge Standard (GB21900-2008)" and "Steel Industry Water Pollutant Discharge Standard (GB13456-2012)" Limit standard. More stringent heavy metal discharge indicators, such as copper discharge from 0.5mg / L to 0.3mg / L; nickel in the electroplating industry...

AI Technical Summary

Problems solved by technology

Although inorganic precipitants (hydroxides, sulfides) are simple and low in cost, they have their inherent limitations: (1) they need to use a large amount of alkali to adjust the pH value; (2) they are easy to form colloids; (3) the precipitation is fine, A large amount of flocculant needs to be added, and the amount of heavy metal sludge is large; (4) Complex heavy metal wastewater cannot be treated; (5) The concentration of residual heavy metals is far from meeting the current discharge standards

Multi-DTC linear polymer chelating agent, there are multiple DTC groups on the linear molecular chain, after chelating with heavy metals, it can quickly flocculate to form large volume, fast sedimentation, and easy to separate deposits, good flocculation, but its linear molecular chain is easy to curl , the DTC group cannot be fully exposed to generate steric hindrance, and the utilization efficiency is low

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