A kind of molecular sieve ion exchange method

Abstract

The invention provides a molecular sieve ion exchange method. The method comprises the following steps: a bipolar membrane electrodialysis step comprising conducting bipolar membrane electrodialysis on an aqueous solution containing ions to obtain an acid liquid; an ion exchange step comprising enabling a molecular sieve and the acid liquid to be in contact with each other to implement ion exchange so as to obtain a molecular sieve slurry subjected to the iron exchange; a solid liquid separation step comprising conducting the solid liquid separation on the molecular sieve slurry subjected to the iron exchange to obtain a liquid phase and a solid phase, and conducting solid liquid separation after the pH of the liquid phase is regulated to be more than 8 to obtain a processing liquid; a step of circulating the processing liquid to the bipolar membrane electrodialysis step to replace at least part of the aqueous solution containing ions, and then conducting bipolar membrane electrodialysis to obtain an alkaline liquid and an acid liquid. In the method provided by the invention, the power consumption of the bipolar membrane electrodialysis step is low. In addition, the method can acquire higher ion exchange efficiency.

Description

technical field [0001] The invention relates to a molecular sieve ion exchange method, in particular to a clean and low-cost ion exchange method for molecular sieves. Background technique [0002] According to the data of the Ministry of Water Resources in 2005, 78% of the river sections flowing through cities in the country are no longer suitable for drinking water sources, and 50% of urban groundwater is polluted. Water pollution will not only directly affect industrial and agricultural production, but also cause serious harm to human health. In order to achieve the sustainable development of the country and the harmonious coexistence between man and nature, the country has formulated the national standard GB8978-1996 for industrial sewage discharge, which stipulates that the primary discharge standard of ammonium nitrogen in the petrochemical industry is 15mg / L, and the secondary discharge standard is 50mg / L. [0003] Molecular sieves have structural characteristics su...

AI Technical Summary

Problems solved by technology

However, the common problem with the ammonium exchange method is that the raw molecular sieve powder needs to be exchanged with ammonium to produce NH 4 Type molecular sieves can be transformed into hydrogen type molecular sieves by roasting again. However, due to the limitation of chemical balance, NH 4 + Cannot completely replace Na at one time + , to get low Na 2 Molecular sieve with O content, the ammonium exchange process needs to be repeated many times, resulting in a large amount of ammonium nitrogen waste water exceeding the standard

In order to meet the national standard that the discharge of ammonium nitrogen is less than 15mg / L, wastewater needs to be treated, but the process of treating the wastewater not only consumes a lot of energy but also costs a lot

In addition, the conventional ammonium ion exchange method needs to repeatedly adjust the acidity and alkalinity of the environment, the operation is complicated and the efficiency is low

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