Permeable reactive barrier (PRB) taking loaded nano zero-valence iron as filler and application thereof

Abstract

The invention relates to a permeable reactive barrier (PRB) taking a loaded nano zero-valence iron composite magnetic material as a filler. Magnets are placed at the two sides of the PRB so as to form a magnetic field, the magnetic field is vertical to a water flow direction, and the PRB is filled with a Hangjin clay 2# loaded nano zero-valence iron composite magnetic material, natural zeolite and persulfate, wherein the mass ratio of a nano zero-valence iron composite magnetic material to Hangjin clay 2# is 1: (4-5). The invention also discloses a method for in-situ remediation of polluted groundwater by using the PRB. Compared with the current methods for improving the reaction activity of nano zero-valence iron, the PRB provided by the invention has the advantages of being simple in use, not consuming any chemical substance, reducing dosage of medicament and being environmentally-friendly and energy-saving and has a very high popularization and application value in actual water pollution control machine repair engineering.

Description

technical field [0001] The invention belongs to the technical field of groundwater pollution restoration, and in particular relates to a permeable reaction wall with loaded nanometer zero-valent iron as filler. [0002] The invention also relates to a method for repairing groundwater nitrobenzene pollution by utilizing the above-mentioned permeable reaction wall. Background technique [0003] Groundwater pollution is a very serious environmental problem at present, which is characterized by complexity, concealment and difficulty of recovery. Among the three types of groundwater pollution, organic pollution has surpassed heavy metal pollution and radioactive pollution, and has become the main form of groundwater pollution. Nitrobenzene pollution is one of the organic pollution. Once an aquifer has been contaminated, recovery and purification is a lengthy process. [0004] Nitrobenzene is a widely used chemical primary raw material in the chemical market, mainly used in indu...

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Problems solved by technology

[0008] (1) The large specific surface area and strong magnetism of nano-zero-valent iron make it easy to agglomerate and form large particles in the process of preparation and application, resulting in a decrease in specific surface area and activity, which greatly affects its Value;

[0009] (2) The agglomeration of nano-zero-valent iron particles can also reduce its fluidity in water, making the detergent diffuse unevenly, making it difficult to completely contact with pollutants, reducing the possibility of its practical engineering application;

[0010] (3) The high activity of nano-ZVI also makes it easy to be oxidized by non-target pollutants in the environment (such as water and oxygen), that is, the "spontaneous combustion" of nano-ZVI, a phenomenon that contributes to the reactivity and effectiveness of ZVI Reduce, cannot degrade pollutants in the environment for a long time

[0013] (2) Partially loaded raw materials have limited sources and high raw material costs

[0015] (4) The adsorption / flocculation performance of the loading material itself is limited, and most of them have no catalytic performance. How to better exert the reduction / adsorption / catalysis synergistic effect of the material and improve its removal rate of pollutants requires further research and development.

In water treatment, although there are also reports on the application of magnetic fields, they are all based on the mechanism of magnetophysical effects (such as magnetic flocculation, which does not involve chemical reactions), and the use of magnetic fields to strengthen supported nano-zero-valent iron to remove nitrobenzene in groundwater has not yet been studied. see the report

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