Method for removing cadmium in wastewater and recovering calcium and cadmium

A recovery method and waste water technology, applied in chemical instruments and methods, water pollutants, multi-stage water treatment, etc., can solve problems such as chronic poisoning of organisms, high toxicity of cadmium compounds, etc., and achieve separation recovery and resource reuse , Calcium and cadmium element recovery is convenient, the effect of simple operation

Active Publication Date: 2022-01-07
FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] Cadmium compounds are very toxic. If cadmium-containing wastewater is not treated up to the standard and discharged randomly, it will easily cause chronic poisoning of organisms.

Method used

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  • Method for removing cadmium in wastewater and recovering calcium and cadmium
  • Method for removing cadmium in wastewater and recovering calcium and cadmium
  • Method for removing cadmium in wastewater and recovering calcium and cadmium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Prepare 2mg / L of Cd 2+ Solution, take 500mL of the solution, add 2.22g of calcium chloride and 2.3g of sodium carbonate, react at room temperature for 2h, separate the solid and liquid of the reaction product, and obtain a solid product and the remaining cadmium-containing solution.

[0046]Take 5 mL of the remaining cadmium-containing solution, filter it through a 0.22 μm syringe filter, and send the clarified solution to an inductively coupled plasma optical emission spectrometer (ICP-OES) for detection. The concentration of cadmium ions in the remaining cadmium-containing solution is 0.0014 mg / L, and Cd 2+ The removal efficiency is 99.93%. After the solid product is dried, X-ray powder diffraction (XRD) is carried out for phase detection, and the results are as follows: figure 1 As shown, the phase is consistent with the standard card 01-072-1938 and 01-085-1108, and the solid powder is Ca 0.67 CD 0.33 CO 3 and CaCO 3 mixture.

Embodiment 2

[0048] Prepare 10mg / L of Cd 2+ Solution, take 50mL of the solution, add 0.222g of anhydrous calcium chloride and 0.320g of sodium hydroxide, react at room temperature for 2 hours, separate the solid and liquid of the reaction product, and obtain a solid product and the remaining cadmium-containing solution.

[0049] Take 5mL of the remaining cadmium-containing solution, filter it through a 0.22μm syringe filter, and send the clarified solution to an inductively coupled plasma optical emission spectrometer (ICP-OES) for detection. The concentration of cadmium ions in the remaining cadmium-containing solution is 0.038mg / L, Cd 2+ The removal efficiency is 99.62%. After the solid product is dried, X-ray powder diffraction (XRD) is carried out for phase detection, and the results are as follows: figure 2 As shown, the phase is consistent with the standard card 00-050-02468, and the solid powder is CaCd(OH) 4 .

Embodiment 3

[0051] Prepare 1000mg / L of Cd 2+ Solution, take 100mL of the solution, add 2.22g of anhydrous calcium chloride and 4.48g of potassium hydroxide, stir and react for 1d, and separate the solid and liquid of the reaction product to obtain a solid product and the remaining cadmium-containing solution.

[0052] Take 5 mL of the remaining cadmium-containing solution, filter it through a 0.22 μm syringe filter, and send the clarified solution to an inductively coupled plasma optical emission spectrometer (ICP-OES) for detection. The concentration of cadmium ions in the remaining cadmium-containing solution is 0.74 mg / L, and Cd 2+ The removal efficiency can reach 99.93%. Add anhydrous calcium chloride and potassium hydroxide to the remaining solution until Cd 2+ The detected concentration is lower than 0.05mg / L.

[0053] Add hydrochloric acid to the obtained solid precipitate to completely dissolve the precipitate at room temperature to obtain a clear solution with high concentratio...

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Abstract

The invention discloses a method for removing cadmium in wastewater and recovering calcium and cadmium. The method for removing cadmium in wastewater comprises the following steps of mixing composite calcium salt with cadmium-containing wastewater for reaction to generate precipitate, thereby removing cadmium ions in the cadmium-containing wastewater. According to the method, the calcium and cadmium mixed precipitate is formed in the wastewater, the cadmium ions in the wastewater are removed, and then separation is carried out according to the performance difference of the calcium and cadmium ions, so that separation and recovery of the calcium and cadmium ions and resource reuse can be realized. The method has the advantages of simplicity in operation, low cost, convenience in calcium and cadmium element recovery and the like.

Description

technical field [0001] The invention belongs to the field of water treatment technology and chemistry, and in particular relates to a method for removing cadmium in waste water and recovering calcium and cadmium. Background technique [0002] Cadmium compounds are very toxic. If cadmium-containing wastewater is not treated up to the standard and discharged randomly, it will easily cause chronic poisoning of organisms. Long-term drinking of water and food contaminated by cadmium can lead to "bone pain disease". Cadmium entering the human body can cause osteomalacia, which can lead to fractures and even death in severe cases. In 1931, the world-famous "bone pain disease" occurred in Jinzugawa, Toyama Prefecture, Japan, and cadmium environmental pollution attracted the attention of countries all over the world. "Comprehensive Wastewater Discharge Standard" (GB8978-1996) clearly lists cadmium as the first type of pollutant, the maximum allowable discharge concentration is 0.1m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C02F101/20
CPCC02F1/5236C02F2101/20C02F2301/08
Inventor 吴智诚林璋
Owner FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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