Method and device for removing heavy metals in industrial wastewater by nanoscale zero-valent iron-multilevel reversed filter type system

A nano-zero-valent iron, industrial wastewater technology, applied in chemical instruments and methods, water/sewage multi-stage treatment, water pollutants, etc., can solve the problems of high cost and energy consumption, long operation time, complex equipment, etc. Simple structure, low cost and low energy consumption

Active Publication Date: 2013-03-06
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The biochemical method has low investment and operating costs and good treatment effect, but the amount of sludge is large, and the treatment effect is affected by temperature and cyanide in the wastewater, which is not stable enough; the chemical precipitation method produces a large amount of slu

Method used

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  • Method and device for removing heavy metals in industrial wastewater by nanoscale zero-valent iron-multilevel reversed filter type system
  • Method and device for removing heavy metals in industrial wastewater by nanoscale zero-valent iron-multilevel reversed filter type system
  • Method and device for removing heavy metals in industrial wastewater by nanoscale zero-valent iron-multilevel reversed filter type system

Examples

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Example Embodiment

[0036] Example 1:

[0037] The nano zero-valent iron used in the present invention is FeCl 3 Solution and NaBH 4 It is prepared by mixing the solution and undergoing oxidation-reduction reaction. The particle size ranges from 1 to 100 nm, the average particle size is 30 to 70 nm, and the specific surface area is 20 to 40 m. 2 / g, such as figure 1 The structure model diagram of nano-zero-valent iron, a typical core-shell double structure, with dense zero-valent iron inside, which plays a reducing role; the outer ring is covered with a thin layer of iron oxide (or FeOOH) for adsorption. To synthesize the ready-to-use nano-zero-valent iron, add ethanol, isopropanol and other organic reagents to fluidize into the compact reaction zone of the closed reactor. The wet nano-zero-valent iron has a solid content of 20-80 g / L, and nano-zero Valence iron must be stored in an oxygen-free environment.

[0038] A method and device for removing medium and low-concentration heavy metal-containing...

Example Embodiment

[0043] Example 2:

[0044] Take a copper mine wastewater effluent stock solution, first pretreat the copper mine wastewater stock solution: add a certain amount of PAM flocculant, stir quickly for 1 to 2 minutes to make the added flocculant mix evenly in the solution, and then reduce the stirring speed to slow down Slowly agitate the mining wastewater for 30-60 minutes to condense the suspended impurities in the copper mine wastewater stock solution into flocs. After the flocculation is completed, stop the stirring, and let the electroplating wastewater settle for 1 to 3 hours. After the precipitation is completed, filter it with filter paper. Clarified electroplating wastewater. Mining wastewater after pretreatment contains Cu 2+ 200~800 mg / L, Ni 2+ 50~100 mg / L, Zn 2+ 10-30 mg / L, pH between 7-8.5. The nano zero-valent iron used in this example is made of 0.050 mol / LFeCl 3 Solution and 0.25 mol / LNaBH 4 Prepared by equal volume mixing reaction, the prepared nano-zero-valent iro...

Example Embodiment

[0047] Example 3:

[0048] Take the electroplating wastewater stock solution at the exit of the electroplating workshop of an electroplating factory, first pretreat the stock solution of electroplating wastewater: add a certain amount of PAM flocculant, first stir quickly for 1~2min to mix the added flocculant in the solution evenly, and then reduce the stirring speed. Slowly stir the electroplating wastewater for 30-60 minutes to condense the suspended impurities in the electroplating wastewater stock solution into flocs. After the flocculation is completed, stop the stirring, and let the electroplating wastewater settle for 1 to 3 hours. After the precipitation is completed, filter with filter paper to obtain a clarified Electroplating wastewater. The electroplating wastewater after pretreatment contains 300~800mg / L of Pb and Ni, and the pH is between 6~8. The nano zero-valent iron used in this example is made of 0.050mol / L FeCl 3 Solution and 0.25 mol / L NaBH 4 Prepared by e...

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Abstract

The invention relates to a method and a device for removing heavy metals in industrial wastewater by a multilevel reversed filter type system. The invention provides unitized airtight reactors which can be connected with one another in series in a multilevel way. Each level of the reactor adopts a reversed filter type design, and is respectively to be a clarification region, a mixed reaction region and a compact reaction region from bottom to top, the bottom of each level of the reactor is provided with a water distributor, and the pretreated heavy metals-containing sewage enters into the compact reaction region to be mixed according to a certain hydraulic condition, and respectively passes through each region from bottom to top. Various heavy metals in sewage, such as Zn, Cu, Pb, Cd, Ni and the like can be removed by the nanoscale zero-valent iron for once due to the auxiliary functions of the absorption, the reduction and the like, the removed heavy metals are attached onto the nanoscale zero-valent iron, and the nZVI in the unit can be recovered and the fresh nanoscale zero-valent iron can be refreshed after the reaction of one reaction unit is saturated. The invention is simple to operate, and prominent in effect, various metals in the medium and low-concentration heavy metals-containing sewage can be removed for once, the water is stably discharged, and the device is easy to maintain. The method has the characteristics of being low in treatment cost, high in removal efficiency, free from secondary pollution and the like.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to the purification technology of wastewater containing heavy metals, in particular to a method and a device for removing heavy metals in industrial wastewater by a nanometer zero-valent iron-multistage reverse filter system. Background technique [0002] Metal wastewater refers to wastewater containing heavy metals discharged from industrial production processes such as mining and metallurgy, machinery manufacturing, chemical industry, electronics, and instrumentation. Heavy metal wastewater is one of the most serious environmental pollution and one of the most harmful industrial wastewater to humans. Its water quality and quantity are related to the production process. The main pollutants include cadmium, nickel, mercury, zinc, copper, chromium, lead, etc., and its content is also It can range from several to thousands of mg / L. With the rapid development of domesti...

Claims

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Application Information

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IPC IPC(8): C02F9/04C02F101/20
Inventor 张亚雷张伟贤周传龙代朝猛
Owner TONGJI UNIV
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