A kind of green rust material and its preparation method and application

Abstract

The invention discloses a green rust material and its preparation method and application. Weigh ferrous sulfate and ferric sulfate respectively, mix and stir evenly to obtain an iron-based reagent; dissolve the iron-based reagent in water, and stir until the iron The base reagent is completely dissolved to obtain an iron-based solution; the β-cyclodextrin is added to the sodium hydroxide solution, and stirred under sealed conditions until the β-cyclodextrin is completely dissolved to obtain a cyclodextrin lye; the cyclodextrin lye Mix with iron-based solution, stir evenly under sealed conditions, age for 5-15 minutes, centrifuge, vacuum dry, grind into powder, and obtain green rust material. Compared with traditional green rust materials, the novel green rust adsorption material prepared by the invention has larger specific surface area, better heavy metal adsorption performance, larger pH applicable range, and higher material recovery rate.

Description

technical field [0001] The invention relates to the field of heavy metal polluted wastewater treatment, in particular to a patina material and its preparation method and application. Background technique [0002] Patina is a typical layered double hydroxide, which contains ferrous and ferric ions. Common patina includes patina mixed with sulfate, patina mixed with carbonate, and patina mixed with chloride ions. The molecular structure of green rust is [Fe(II) 1-x Fe(III) x (OH) 2 ] x+ ·[(x / n)A n- , mH 2 O] x- , where A n- Represents the anion doped in the green rust layer, x represents the molar ratio of ferric iron to total iron (0.25-0.33). The surface of the iron hydroxide layer is positively charged due to the substitution of ferric ions for ferrous ions. Based on the charge balance mechanism, a series of anions can be incorporated into the layered double hydroxide structure during the synthesis. Different anions have a great influence on the interlayer struct...

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Problems solved by technology

However, the synthesis process of nano-ZVI requires the use of a large amount of reducing agent, which not only makes the loading efficiency of cyclodextrin low, but also produces a large amount of reducing agent to pollute the waste liquid.

At the same time, the added cyclodextrin did not change the physicochemical properties of the nano-zero-valent iron itself

The green rust material synthesis process itself does not require the use of reducing agents, but the specific surface area of ​​the green rust material synthesized by the hydrothermal method is small, and the adsorption capacity for heavy metal pollutants is limited.

At the same time, the applicable pH range of existing green rust materials is narrow, and it is difficult to simultaneously remove various heavy metal pollutants under various pH water environments.

And in an acidic environment, part of the patina is easy to dissolve, resulting in a low recovery rate of patina and poor removal effect of heavy metals

In an alkaline environment, the surface of the existing green rust material is prone to hydrolysis to form flocs, which reduces the adsorption active sites on the green rust surface.

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