The invention discloses a leaching method for remediation of arsenic polluted soil by using magnetic separation. The method is characterized by comprising the following steps: pre-treating polluted soil to be treated, entering a leaching system, successively adding prepared leacheate and a prepared auxiliary agent, and after thorough mixing leaching, obtaining arsenic pollutants by magnetic separation through powerful magnetic separation equipment in a stirring rolling pattern; and performing solid-liquid separation on the remaining soil and leacheate, directly backfilling or using clean soil, after coagulation sedimentation is performed on waste leacheate, recycling the waste leacheate for preparing the leacheate, and performing follow-up treatment on precipitated waste residues and waste residues obtained after magnetic separation together. Through the adoption of the method disclosed by the invention, the problem that heavy metal, especially arsenic, pollutes the soil can be thoroughly solved, the polluted soil can be treated stably, continuously and efficiently, and the method is suitable for remediation of the arsenic polluted soil with different pollution concentrations or other composite polluted soil.

Leaching method for remediation of arsenic polluted soil by using magnetic separation

The invention relates to a preparation method and the application of a biochar-based conditioner for cadmium contaminated soil The preparation method comprises the following steps: firstly, mixing biologic materials with sludge, or separately using the sludge and adjusting the moisture content to 10 to 90 percent; adding calcareous materials, carrying out high-temperature carbonization in the oxygendeficit or oxygen-free environment to obtain calcium-loaded biochar; secondly, adding a zeolite powder into a soluble phosphorus solution, carrying out soaking treatment, standing and carrying outair drying to obtain phosphorus modified zeolite; thirdly, uniformly mixing the calcium-loaded biochar obtained in the first step with the phosphorus modified zeolite obtained in the second step according to the ratio of 2-5 to 1, moisturizing, aging and drying, so as to obtain a finished product The preparation method disclosed by the invention has the advantages of simple technology, low energyconsumption and no pollution discharge in the processing process The biochar-based conditioner for the cadmium contaminated soil is mixed with the soil for use according to a certain proportion, sothat the absorption of plants to heavy metal cadmium can be reduced by 30 to 50 percent

Preparation method and application of biochar-based conditioner for cadmium contaminated soil

The invention relates to a purification method for removing active heavy metals from soil. The purification method comprises: 1, soaking heavy metal-polluted soil with heavy metal-free water; 2, repeatedly plowing the soaked soil to achieve a muddy state; 3, standing the plowed soil for 3-48 h; 4, placing the clarified water at the upper layer of the stand soil into a sammns heavy metal removing device to remove heavy metals; and 5, soaking the soil in the step 1 with the water being subjected to the heavy metal removing step, and repeatedly performing the steps 2-4 until 80% of the heavy metals in the soil is removed. According to the present invention, the whole treatment process does not affect the structure and the characteristic of the soil, the normal farming and the normal planting of the soil are not hampered, the heavy metal removing is permanent, and the method can be widely used for heavy metal polluted farmland and soil restoration.

Method for removing active heavy metals from soil

The invention relates to the technical filed of restoring of contaminated soil in the environment, and in particular relates to a method for removing lead and zinc in the contaminated soil by leaching with biologic materials. According to the method, distilled water is used for the vibration digestion on air-dried plant powders, the filter liquor is added into the soil, then the pH value of mixed solution is adjusted using dilute nitric acid and sodium hydroxide solution, and finally lead and zinc in the soil are vibrated and leached out. According to the method for removing lead and zinc in the contaminated soil by leaching with biologic materials, coriaria sinica maxim, pistacia weinmannfolia, castor-oil plant or euphorbia helioscopia are used as flushing agent, the cost is low, the source is wide, the leaching effect on the soil is obvious, and the secondary pollution does not occur on the environment.

Method for removing lead and zinc in contaminated soil by leaching with biologic materials

The invention provides a method for reducing accumulation quantity of arsenic in crops and belongs to the fields of heavy metal pollution remediation and agricultural product safety. According to the technical scheme adopted by the invention, deep ploughing is performed on soil before crops are planted, soil moisture content is reasonably controlled, and an appropriate amount of clay minerals and an arsenic precipitate adsorbent are added into arsenic-polluted surface soil to improve soil; surface soil and an improver are turned over and are uniformly mixed, and are aged for 20 days; and a base fertilizer is added and crops are planted, and a leaf phosphorus fertilizer is sprayed after crops normally grow to reduce arsenic accumulation of the crops and increase the crop yield. The method is strong in operability, is environmentally friendly, and can realize continuous and safe planting of crops on medium-light arsenic polluted soil.

Method for reducing accumulation quantity of arsenic in crops

The invention discloses a method for treating heavy metal contaminated soil. The method comprises the steps of breaking a heavy metal contaminated paddy field, irrigating the paddy field until a water logging layer on a soil layer is 10-15cm deep after breaking the 0.5-0.6m deep soil on the surface layer into soil lumps with sizes less than 2-3mm, adding a modified clay mineral adsorbent, mechanically stirring the adsorbent, standing for 6-8 hours, removing the supernatant, and carrying out solid-liquid separation; then uniformly adding magnetic nano materials to the soil with adjusted moisture content, mechanically stirring the materials, standing for 3-8 hours, and collecting the magnetic nano materials in the soil by way of magnetic separation, thus achieving solid-solid separation; preparing leachate for leaching, adding carbon microspheres while leaching, and then, leaching 1-3 times by using pure water as an eluent, thus obtaining the treated soil, wherein the amount of water used each time is 0.6-1 times the leachate added for the first time by volume. The method is simple to operate, is low in cost, has high removal efficiency, meets the actual requirements, and has good popularization and application values.

Niu Xiaojun

Papers

Method for treating heavy metal contaminated soil