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Preparation method of cadmium removal agent of thiolated chitosan microsphere

A chitosan microsphere, chitosan technology, applied in chemical instruments and methods, water/sludge/sewage treatment, adsorbed water/sewage treatment, etc., can solve the loss of chitosan of adsorbent, loss of adsorbent It can improve the adsorption performance, improve the selective adsorption and improve the stability.

Active Publication Date: 2015-06-17
XIAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the actual application process, because the highly compact crystal structure of chitosan is insoluble in common solvents, chitosan is only soluble in dilute acids and some specific solvents, and the amine groups in chitosan are easily soluble in acidic solutions. Protonation leads to a large loss of chitosan as an adsorbent; at the same time, under acidic conditions, due to the electrostatic repulsion between the positive charge of chitosan and metal cations, the coordination ability is weakened, which affects the adsorption effect; Under alkaline conditions, metal cations tend to form hydroxide precipitates, making the adsorbent useless, so chitosan is rarely used in actual water purification at present.

Method used

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  • Preparation method of cadmium removal agent of thiolated chitosan microsphere
  • Preparation method of cadmium removal agent of thiolated chitosan microsphere

Examples

Experimental program
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Effect test

Embodiment 1

[0021] (1) Dissolve 3g chitosan in 200ml 5wt% acetic acid solution, add 1.5g cadmium chloride, magnetically stir for 3h, add 20wt% sodium hydroxide solution dropwise, form gel until maximum amount, filter, wash, Dried to obtain cadmium ion imprinted chitosan;

[0022] (2) Dissolve 3g of cadmium ion imprinted chitosan in 900ml 5wt% acetic acid solution, adjust to pH 6 with 20wt% sodium hydroxide solution, add 100ml 1wt% tripolyphosphate drop by drop, after magnetic stirring for 2h , then adjust the pH to 13 with 20wt% sodium hydroxide solution to form a red gel, filter, wash, and dry to obtain cross-linked chitosan;

[0023] (3) After the cross-linked chitosan is eluted with 0.1M hydrochloric acid until no cadmium ion is detected, it is washed with deionized water until neutral, and dried to obtain chitosan microspheres;

[0024] (4) Add 3g of chitosan microspheres into 300ml of 20wt% sodium hydroxide solution, alkalinize for 1 hour, add 2ml of carbon disulfide, stir magnetica...

Embodiment 2

[0026] (1) Dissolve 5g chitosan in 300ml 5wt% acetic acid solution, add 2.5g cadmium nitrate, magnetically stir for 3h, add 20wt% sodium hydroxide solution dropwise, form gel until the maximum amount, filter, wash, dry , to obtain cadmium ion imprinted chitosan;

[0027] (2) 5g cadmium ion imprinted chitosan was dissolved in 1500ml 5wt% acetic acid solution, adjusted to pH 6 with 20wt% sodium hydroxide solution, and 200ml 1wt% tripolyphosphate was added dropwise, after magnetic stirring for 2h , then adjust the pH to 13 with 20wt% sodium hydroxide solution to form a red gel, filter, wash, and dry to obtain cross-linked chitosan;

[0028] (3) After the cross-linked chitosan is eluted with 0.1M hydrochloric acid until no cadmium ion is detected, it is washed with deionized water until neutral, and dried to obtain chitosan microspheres;

[0029] (4) Add 5g of chitosan microspheres into 500ml of 20wt% sodium hydroxide solution, alkalinize for 1 hour, add 2ml of carbon disulfide, ...

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Abstract

The invention discloses a preparation method of a cadmium removal agent of a thiolated chitosan microsphere. The method comprises the steps of imprinting chitosan with a cadmium ion, then carrying out cross-linking forming with tripolyphosphate, eluting the cadmium ion with hydrochloric acid to prepare a chitosan microsphere, and modifying with carbon disulfide under an alkaline condition to prepare a finished product. A material prepared by the method has good absorption and chelation effects on the cadmium ion, is used for cadmium wastewater treatment, and can allow wastewater to reach the standard for discharge and recover the cadmium ion in the water.

Description

technical field [0001] The invention relates to a preparation method of a mercapto-chitosan microsphere cadmium-removing agent and its use in the treatment of cadmium-containing wastewater, which belongs to the field of environmental protection. Background technique [0002] Cadmium, mercury, lead, chromium, and arsenic are collectively known as the "five poisons" among heavy metals, which are seriously harmful to the ecological environment and human health. Cadmium has the characteristics of high stability, refractory degradation, bioaccumulation and toxicity. Since the discovery of cadmium in the early 20th century, the industrial output of cadmium has increased year by year, but the discarded cadmium is discharged into the environment through waste gas, waste water and waste residue, causing pollution. The pollution sources are mainly lead-zinc mines, non-ferrous metal smelting, electroplating and factories using cadmium compounds as raw materials or catalysts. At prese...

Claims

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Application Information

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IPC IPC(8): B01J20/24B01J20/30C02F1/28C02F1/62
Inventor 程爱华
Owner XIAN UNIV OF SCI & TECH
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