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Method for removing complexed lead by using ferrous phosphate under anoxic condition

A ferrous phosphate, complex state technology, applied in chemical instruments and methods, oxidized water/sewage treatment, neutralized water/sewage treatment, etc., can solve the problems of impact and high degradation cost

Active Publication Date: 2022-01-07
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Muhammad V et al. utilize TiO 2 Auxiliary photocatalytic way to degrade EDTA-Pb, the degradation cost is high (MuhammadV.TiO 2 -Assisted photocatalysis of lead-EDTA[J].Water Research,2000,34(3):952-964.)
Moreover, the advanced oxidation method is seriously affected by the coexistence of anions and protonation, which has certain limitations.

Method used

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  • Method for removing complexed lead by using ferrous phosphate under anoxic condition
  • Method for removing complexed lead by using ferrous phosphate under anoxic condition
  • Method for removing complexed lead by using ferrous phosphate under anoxic condition

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Example 1: Fitting of ferrous phosphate to the adsorption capacity of EDTA-Pb under anoxic and aerobic conditions.

[0024] In this application, EDTA-Pb is first mixed with ethylenediaminetetraacetic acid and lead nitrate at a ratio of 1:1, and a 10mM EDTA-Pb stock solution is prepared under boiling conditions. In the experiment, 10, 30, 50, 70, 100, 200, 300, 400, 500mg / L EDTA-Pb was selected as the target pollutant to fit the isotherm, the EDTA-Pb stock solution was diluted to the preset value, and nitrogen gas was filled in the target contaminated solution for 10 minutes to achieve the target pollutant. Oxygen environment, then add ferrous phosphate at 1g / L, seal the Erlenmeyer flask, stay in the reactor for 1h, the temperature is 25±1°C, and the rotation speed is 250r / min. Another set of experiments was similar, and the process of filling nitrogen gas was removed. available from figure 1 It can be seen that the maximum adsorption capacity of ferrous phosphate has ...

Embodiment 2

[0025] Example 2: The removal effect of ferrous phosphate on EDTA-Pb under the inhibition of methanol in anoxic environment.

[0026] In this application, the selected initial concentration of EDTA-Pb is 300mg / L. Before adding ferrous phosphate after filling nitrogen, add a certain amount of methanol to remove possible hydroxyl radicals. In the process of removing EDTA-Pb with ferrous phosphate, due to the presence of Fe 2+ , may generate OH. Methanol was chosen as the masking agent for OH to explore whether OH was generated during this process. available from figure 2 It can be seen that EDTA-Pb can be removed relatively thoroughly without adding methanol, and the removal effect is inhibited to a certain extent after adding 10mM methanol, and the removal efficiency is only about 75%. After adding 50mM methanol, the removal efficiency is only 20%, which is equivalent to the removal effect under aerobic conditions, so it can be inferred that under anoxic conditions due to F...

Embodiment 3

[0027] Example 3: The removal effect of ferrous phosphate on lead in different complexed states.

[0028] There are a large number of different ligands in natural water bodies and industrial wastewater. This example studies the removal of lead in different complexed states by ferrous phosphate. The complexed Pb formed by common organic ligands and Pb is selected, the preparation method is consistent with that in Example 1, the initial concentration of complexed lead is selected as 50mg / L, and other operations are consistent with the batch processing in Example 1. From image 3 It can be seen that ferrous phosphate has a good removal effect on lead in various complex states, especially for carboxylic acids with strong binding capacity (such as DTPA), Pb can still be removed to 0.62mg / L. For lead citrate, it can even be removed below 0.1mg / L.

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Abstract

The invention discloses a method for removing complexed lead by using ferrous phosphate under anoxic conditions, belonging to the field of industrial wastewater treatment. The present invention uses ferrous phosphate to remove complexed lead under anoxic conditions, wherein the release of ferrous ions can act to generate hydroxyl radicals, which oxidize carboxyl groups to release lead ions, and at the same time, the oxidized ferric iron can be replaced The lead in the complex state can achieve the effect of releasing lead at the same time, and the phosphate can be used as a capture agent for lead ions to precipitate and separate lead ions. The invention is simple in operation and low in cost, uses ferrous phosphate to quickly remove complexed lead, and can reach a complexed lead removal rate of 99.67% within 60 minutes under anaerobic conditions, and removes lead to sub-ppm level. It has application prospects in the treatment of combined lead wastewater.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, and relates to a method for removing complexed lead by using ferrous phosphate under anoxic conditions. Background technique [0002] Currently, most heavy metal removal methods focus on the removal of free metal ions. However, heavy metals usually exist in nature and industrial wastewater in complex forms. Compared with free metal ions, metal complexes have higher solubility and stability in a wider pH range. Usually the stability constant of the metal complex is several orders of magnitude higher than that of its hydroxide, in which case the most common chemical precipitation method is relatively weak. There is an urgent need to develop effective and commercial methods to deal with complexed heavy metals. [0003] Lead is the most common toxic heavy metal, which is widely used in textile printing and dyeing, electroplating, ceramics, glass industry, petroleum refining...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/62C02F1/66C02F1/72C02F101/20
CPCC02F1/66C02F1/62C02F1/72C02F2101/20
Inventor 孙秀云李瑞王连军李桥沈锦优韩卫清李健生刘晓东
Owner NANJING UNIV OF SCI & TECH