Compound conditioner for soil pollution remediation and preparation method thereof

Abstract

The invention provides a safe and reliable compound conditioner for reducing the heavy-metal mobility and bioavailability of soil or sludge compost and a preparation method thereof. The compound conditioner is a powdery compound prepared by adding heavy-metal auxiliary passivating agent to alkaline agent, wherein, the heavy-metal auxiliary passivating agent includes precipitating agent and absorbing agent; and the compound conditioner comprises the following components by the mixing proportion (weight percentage): 78% to 91% of alkaline agent, 5% to 13% of precipitating agent and 4% to 9% of absorbing agent. The preparation method comprises the following steps: (1) drying and pulverizing one, two or more than two substances among soda-manufacturing waste residue, lime and fly ash and sieving by a 60-mesh sieve to obtain an alkaline powdery substance as the alkaline agent; (2) mixing the alkaline agent, the precipitating agent and the absorbing agent by the above mixing proportion; and (3) drying and pulverizing the mixed products and sieving by a 200-mesh sieve to obtain the powdery compound conditioner. The invention can greatly reduce the environmental risk caused by the prior art and realize the sustainable development of green circular economy, industry and agriculture by recycling the industrial waste at the same time.

Description

technical field [0001] The invention belongs to the field of solid waste recycling and soil heavy metal pollution restoration in the field of environmental protection, and particularly relates to a composite conditioner for soil pollution restoration and a preparation method thereof. technical background [0002] The phytoremediation technology used to remediate polluted soil has become a research hotspot in the field of environmental science for more than ten years. In the process of phytoremediation of soil with plants, because the heavy metals contained in the acidic soil in the south usually exist in the form of ions, with high concentration and strong toxicity, it is difficult for the crops planted on it or the plants for remediation to adapt to survive. [0003] When the final destination of sludge compost is farmland, long-term large-scale application will cause the accumulation of heavy metals in the soil, which will not only affect the growth of plants, but more ser...

AI Technical Summary

Problems solved by technology

[0006] ① Add complexing agent, through complexation in a very short period of time, the activity of heavy metals will increase rapidly, but within a certain period of time, plants can only absorb a small part of heavy metals in the soil, so that other large amounts of heavy metals that have not been absorbed by plants will be activated The heavy metals left in the soil still remain in the soil, and because of their enhanced mobility, they can gradually move down at any time, pollute the groundwater, and cause great environmental risks. The added complexing agent inevitably increases the environmental risk of groundwater pollution.

[0007] ②Under the action of soil microorganisms, etc., the complexing agent will gradually lose its effectiveness. At present, the reports in this area are not the same. According to Wu Long-hua, 2001's research on EDTA (ethylenediaminetetraacetic acid), the application of the complexing agent After 6 days, only about 62% of the complexing agent remained in the soil, and only about 25% after 12 days, which is also a waste of resources

The method of adding complexing agent solution causes the distribution of complexing agent in the space of soil and other polluted media to be scattered, and plants can only absorb heavy metals near the root zone, which reduces the use efficiency of complexing agent

Unused complexing agents can easily cause secondary pollution and pose potential hazards to the environment, ecology and human health

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