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Method for removing hexavalent chromium in wastewater

A technology of hexavalent chromium and hexavalent chromium ions, applied in chemical instruments and methods, water pollutants, water/sewage treatment, etc. The effect of specific surface area and good adsorption performance

Inactive Publication Date: 2020-12-15
青岛蓝色地球大数据科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hexavalent chromium is an ingestion poison / inhalation poison, and skin contact may cause allergies; it is more likely to cause genetic defects, inhalation may cause cancer, and has a persistent danger to the environment
But the application of electrochemical method is more expensive; the application of reverse osmosis requires high pressure, and the membrane is easy to block, so the price is more expensive; the resin used in the ion exchange method is expensive

Method used

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  • Method for removing hexavalent chromium in wastewater
  • Method for removing hexavalent chromium in wastewater
  • Method for removing hexavalent chromium in wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Accurately weigh 0.5g of low-rank coal after passing through a 200-mesh sieve with an electronic balance, add it to 40mL of hexavalent chromium ion solution with a concentration of 100mg / L, and absorb different times, and then centrifuged at 12,000 rpm for 5 minutes.

[0028] Take the supernatant after centrifugation, and use a UV spectrophotometer to test the concentration change of its absorbance before and after adsorption, and calculate the adsorption amount of the adsorbent at different times according to the following formula.

[0029] q t =(c 0 -c t )V / m

[0030] In the formula, q t Indicates the adsorption amount at time t (mg / g); c 0 and c t respectively represent the concentration of hexavalent chromium ions in the initial solution (mg / L) and the concentration of hexavalent chromium ions in the solution at time t (mg / L); V is the volume of the solution containing hexavalent chromium (L); m is the mass of the adsorbent (g).

[0031] The effect of low-ra...

Embodiment 2

[0033] Adsorption isotherm test, the steps are as follows:

[0034] Use an electronic balance to accurately weigh 0.5g of low-rank coal adsorbent after passing through a 200-mesh sieve, and add it to 40mL of hexavalent chromium ion solution with a concentration range of 20-1000mg / L. Under the conditions of 40°C, rotating speed 150rpm and pH=2.0, adsorb for 24 hours, and use a UV spectrophotometer to test the change of absorbance before and after adsorption, so as to calculate the concentration of chromium ion remaining in the solution of each concentration solution after adsorption, and draw The adsorption isotherm curve, to obtain the maximum adsorption capacity of low-rank coal adsorbed chromium ions, see figure 2 .

[0035] from figure 2 It can be seen that the unit adsorption capacity of the adsorbent increases with the increase of the initial chromium ion concentration in the solution until the adsorption reaches equilibrium. When the chromium ion concentration is lo...

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Abstract

The invention discloses a method for removing hexavalent chromium in wastewater. The method comprises the following steps: sieving low-rank coal with a 200-mesh sieve to obtain a hexavalent chromium adsorbent; adding the sieved low-rank coal into a wastewater solution containing hexavalent chromium, adjusting the pH value of the solution to 0.5-4.0, and performing stirring; and centrifuging the reacted solution, and collecting the centrifuged supernatant to obtain the treated wastewater. The low-rank coal has the advantages of being wide in source, low in cost, short in adsorption time, high in efficiency and the like, has a large specific surface area and good adsorption performance, and can rapidly adsorb hexavalent chromium ions from high-concentration chromium-containing wastewater ina high-dose mode.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a method for removing hexavalent chromium in wastewater. Background technique [0002] Chromium is widely used in industrial processes such as leather tanning, stainless steel manufacturing and electroplating. Cr(VI) compounds are highly toxic, and have high biological carcinogenic and toxic effects on the human body and biological systems, and compounds containing Cr(VI) cannot be degraded naturally, and will accumulate and enrich in organisms and human bodies for a long time. It is a heavy polluting substance. Hexavalent chromium is an ingestion poison / inhalation poison, and skin contact may cause allergies; it is more likely to cause genetic defects, inhalation may cause cancer, and has a long-lasting danger to the environment. At present, Cr(VI) is listed by the Ministry of Environmental Protection as one of the eight most harmful chemical substances to human h...

Claims

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Application Information

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IPC IPC(8): C02F9/02C02F101/22
CPCC02F1/281C02F1/38C02F2101/22
Inventor 邹星云付晓爽梁泽浩邹文健
Owner 青岛蓝色地球大数据科技有限公司