Method for removing hexavalent chromium in wastewater through magnetic adsorbent compounded by chitosan and magnetic biological carbon

A magnetic adsorbent, chitosan technology, applied in the direction of adsorption water/sewage treatment, chemical instruments and methods, water/sewage treatment, etc., can solve the problem that the adsorption performance of magnetic biochar cannot meet the required standards, and achieve surface adsorption Easy site, low cost, simple preparation method and process

Inactive Publication Date: 2015-07-22
HUNAN UNIV
6 Cites 51 Cited by

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Problems solved by technology

However, it has been verified by research that the adsorption pe...
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Abstract

The invention discloses a method for removing hexavalent chromium in wastewater through a magnetic adsorbent compounded by chitosan and magnetic biological carbon. The compounded magnetic adsorbent comprises the magnetic biological carbon, and the chitosan is combined on a magnetic biological carbon matrix. The preparation method comprises the following steps: firstly, utilizing FeCl3.6H2O to soak water hyacinth biomass; secondly, performing pyrolysis and calcination on the soaked biomass to obtain the magnetic biological carbon; finally, compounding the chitosan onto the surface of the magnetic biological carbon. The application steps are as follows: adding a composite material into the wastewater containing the hexavalent chromium with the concentration of 20-500 mg/L, wherein the usage amount of the composite material is 1-2 g/L; carrying out an oscillation and adsorption reaction at 10-50 DEG C for a period of time, and then separating the compound from the wastewater with a magnet to finish the removal of hexavalent chromium ions. The method has the advantages of being low in cost, simple in process, high in absorption property, easy in separation process, environmentally-friendly and the like.

Application Domain

Technology Topic

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  • Method for removing hexavalent chromium in wastewater through magnetic adsorbent compounded by chitosan and magnetic biological carbon
  • Method for removing hexavalent chromium in wastewater through magnetic adsorbent compounded by chitosan and magnetic biological carbon
  • Method for removing hexavalent chromium in wastewater through magnetic adsorbent compounded by chitosan and magnetic biological carbon

Examples

  • Experimental program(5)

Example Embodiment

[0024] Example 1:
[0025] A chitosan/magnetic biochar composite material according to the present invention, the composite material is prepared by the following method:
[0026] (1) 40g FeCl 3 ·6H 2 O was dissolved in 120 mL of deionized water to prepare a certain concentration of ferric chloride solution, 20 g of water hyacinth biomass was immersed in the ferric chloride solution, stirred with a glass rod for 10 minutes, and then left to soak for 12 hours;
[0027] (2) drying the soaked water hyacinth biomass at 50-60°C, grinding, and passing through a 100-mesh sieve;
[0028] (3) Put the sieved water hyacinth biomass into the tube furnace, 600 ℃, pass N 2 , and burn for 1 h to obtain magnetic biochar. Wash the obtained magnetic biochar with deionized water for 2 to 3 times, dry at 50 to 60°C, grind, and pass through a 100-mesh sieve;
[0029] (4) Dissolving 6 g of chitosan in an acetic acid solution whose volume percentage is 2% is prepared into a chitosan solution whose mass percentage is 0.6%;
[0030] (5) Take 6g of magnetic biochar, add it to the chitosan solution obtained in step (4), stir at 40-50°C for 30-50min, add 1% glutaraldehyde, stir at 40-50°C for 30-50min, then Add 1 mol/L NaOH to adjust the pH to 9-10, continue stirring for 30-60 min, the obtained product is cooled, separated and washed, dried at 40-50°C, ground, and passed through a 100-mesh sieve to obtain chitosan/magnetic Biochar meets the material adsorbent.
[0031] The chitosan/magnetic biochar composite material obtained above was observed under a scanning electron microscope, and its structure was as follows: figure 1 It can be seen that a large number of magnetic Fe2O3 nanoparticles are distributed on its surface. figure 2 The XPS spectrum of the chitosan/magnetic biochar composite material shows that the chitosan/magnetic biochar composite material has rich functional groups, and it can be used as an adsorbent to adsorb heavy metal ions well.

Example Embodiment

[0032] Example 2:
[0033] The chitosan/magnetic biochar composite material prepared in Example 1 was applied to the treatment of hexavalent chromium ion wastewater, including the following steps: preparing 6 parts of 50mg/L lead solution, using 1mol/L NaOH or HNO 3 The pH was adjusted to 2, 3, 4, 5, 6, and 7, respectively. The above-mentioned chitosan/magnetic biochar composite material was added, and the amount of adsorbent was 1 g/L. They were placed in constant temperature shaking at 30°C. The rotating speed of the oscillator was 150 rpm, and the shaking time was 24 h. After the reaction is completed, it is placed on a magnet to separate the adsorbent from the solution, and the adsorption process ends. The content of unadsorbed hexavalent chromium in the wastewater was determined by ultraviolet spectrophotometry, and the calculated adsorption results are shown in Table 1.
[0034] Table 1: Effects of different pH values ​​on the removal of hexavalent chromium from wastewater by chitosan/magnetic biochar composites
[0035]
[0036] It can be seen from Table 1 that different pH conditions have a great influence on the adsorption. The lower pH is favorable for the removal of hexavalent chromium by the adsorbent. When the pH is 2, the adsorption capacity reaches the maximum value, and as the pH increases, the adsorption capacity gradually decreases.

Example Embodiment

[0037] Example 3:
[0038] The chitosan/magnetic biochar composite material prepared in Example 1 was applied to the treatment of hexavalent chromium ion wastewater, including the following steps: taking a hexavalent chromium solution with an initial concentration of 100 mg/L, adjusting the pH of the solution to 2.0, The chitosan/magnetic biochar composite material obtained in Example 1 was added, and the dosage of the composite was 1 g/L, and the adsorption reaction was carried out at 20, 30 and 40 °C air bath thermostatic oscillator respectively, and the rotation speed was 150 rpm, 24 After 1 hour, the composite was separated from the waste water with a magnet, and the content of unadsorbed hexavalent chromium in the waste water was determined by ultraviolet spectrophotometry. The results of the calculated adsorption amount are shown in Table 2.
[0039]Table 2: Chromium adsorption data of chitosan/magnetic biochar composites at different temperatures
[0040]
[0041] It can be seen from Table 2 that the adsorption capacity of the complex to chromium ions is 79.25 mg/g at the reaction temperature of 20 °C, and increases with the increase of the initial temperature, and the adsorption capacity reaches 85.58 mg/g when the temperature is 40 °C. g.
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PUM

PropertyMeasurementUnit
Adsorption capacity79.25mg/g
Adsorption capacity85.58mg/g
Adsorption capacity19.9mg/g
tensileMPa
Particle sizePa
strength10

Description & Claims & Application Information

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Owner:JIANGNAN UNIV
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