Method for preparing water-retaining agent for selectively fixing heavy metal in soil

Abstract

The invention relates to a method for preparing a water-retaining agent for selectively fixing heavy metal in soil. The method comprises steps of adding 1.0g of common water-retaining agent into water solution containing 0.5-10.0mmol of ferric salt, shaking so that iron ions are absorbed into the common water-retaining agent, then adding strong reducing agent to reduce the ferric salt into nano iron, vacuum stoving or freeze drying to obtain the water-retaining agent. According to the method, by utilizing the protective action of the common water-retaining agent, zero valent nano iron easy to be oxidized by air is wrapped so as to be prevented from oxidizing, after the common water-retaining agent absorbs water, the oxygen in air and nano iron react so as to generate high-activity ferric oxide or hydrogen oxide easy to adsorb heavy metal ions. The water-retaining agent capable of fixing heavy metal is especially applicable to heavy metal polluted soil, can prevent nano material from being interfered by humic acid and clay in soil, improves the effect in adsorbing and fixing heavy metal ions, has good water retention effect, and has important value in remediation of heavy metal polluted soil and agriculture application.

Description

technical field [0001] The invention relates to a method for preparing a water-retaining agent for adsorbing and fixing heavy metals, in particular to a method for preparing a water-retaining agent for selectively fixing heavy metals in soil. Background technique [0002] Due to the long-term input of heavy metal pollutants into the cultivated land system by mine smelting and chemical enterprises in various forms, coupled with the entry of heavy metals in fertilizers, a large area of ​​cultivated land has been severely polluted by heavy metals, which has seriously threatened my country's grain and other agricultural products. Safety. According to statistics, the area of ​​cultivated land polluted by heavy metals in my country is nearly 20 million hm 2 , accounting for about 1 / 5 of the total cultivated land area. Hunan Province is rich in non-ferrous metal deposits and is known as the "Hometown of Non-ferrous Metals". In addition, most of the cultivated land in the south is ...

AI Technical Summary

Problems solved by technology

Interference factors such as organic matter in soil are far more complex than those in groundwater, so its adsorption and fixation capacity will be even lower

The scientific community generally believes that the high specific surface area and unstable surface structure of nanomaterials make them extremely easy to aggregate in the complex system of soil, or be adsorbed by other minerals, or interfered by organic matter, salt ions and other substances, so nanomaterials The effect of adsorbing and fixing heavy metals in soil is far worse than that in water, or even has no effect

Images