Persulphate combined heating and activation method for environmental restoration

Abstract

A persulphate combined heating and activation method for environmental restoration comprises the steps that soil or a soil layer, containing organic pollutants, of a target restoration site is heatedto the temperature interval of 20-45 DEG C; under the condition of continuous heating and heat preservation, synergistic activation of hydrogen peroxide and chelating transition metal is implemented,the activation process is short in duration time but high in effect, the organic pollutants in the soil are promoted to be desorbed, and the degradation process of the organic pollutants is accelerated; and heating continues being conducted, and the continuous heat activation stage is started in a transition mode until the concentration of the target pollutants is decreased to be below a restoration target value. The restoration method adapts to environment restoration of soil and groundwater under cold regions / the low temperature environment, and is also an enhanced improved technology for semi volatile organic compound (SVOC) polluted soil which is difficult to restore through a general activation technology, the treatment effect can be effectively improved, thus engineer operation is not influenced by seasonal change, or the seasonal change influence is reduced, and the regional using range is expanded.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a persulfate combined heating activation method for environmental restoration. Background technique [0002] With the promulgation of the "Soil Pollution Prevention and Control Action Plan", the curtain of soil pollution prevention and control has officially opened. In recent years, domestic soil pollution incidents have occurred frequently, showing the characteristics of high pollution degree, great harm, complex pollution components, and difficult governance. The domestic soil organic pollution is very serious, and there are many kinds of pollutants. The pollutants in a single site may include one or more of benzene series, chlorinated solvents, polycyclic aromatic hydrocarbons, petroleum hydrocarbons, and pesticides, which increases soil environmental restoration. The difficulty of the work puts forward higher requirements for different restoration techniques...

AI Technical Summary

Problems solved by technology

Alkali activation technology has a wide range of applications, but there are still the following deficiencies in the application process: (1) If the temperature of the project site is low, the reaction will be limited, resulting in a slow reaction rate and affecting the repair effect; (2) Alkali activation requires Stabilizing the pH in the optimal alkaline range is the most conducive to oxidation. However, in general projects, the pH needs to be restored to neutral after restoration to avoid soil alkalization, which requires higher alkali dosage in practical operations; (3) Alkaline pH may drop with the continuation of the reaction, and it is necessary to add alkali in time to maintain the best reaction conditions, otherwise the oxidation efficiency will be reduced; Hydrophobic pollutants such as PAHs, pesticides, PCBs, etc. are less effective

[0006] It can be seen that the commonly used single activation method has certain limitations. At the same time, in some specific sites, the oxidation effect will also be affected by seasonal changes, which puts forward higher requirements for the activation method.

Although the strong oxidation technology based on activated persulfate is a chemical process, it is also very sensitive to the external temperature, and its reaction efficiency will be greatly reduced below 10°C

In China, especially in the north, the outdoor temperature is below 10°C for about 4-6 months, which makes this technology unable to be effectively applied and the implementation of the project is hindered.

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