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A method for removing arsenic from drinking water

A technology of drinking water and iron salt, applied in chemical instruments and methods, water pollutants, water/sewage treatment, etc., can solve the problems of secondary pollution of arsenic, difficult to control, low arsenic concentration, etc., to ensure safety and process The effect of ecological safety and simple operation

Active Publication Date: 2021-10-22
YUNNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this lime method for arsenic removal requires a higher pH and a longer precipitation time, which has limitations in application; and it is difficult to control the pH of the water body with lime, and it needs to be adjusted back to a certain pH when it is discharged. range, which increases the complexity of operation and treatment cost; the concentration of arsenic treated is low, and the simulated water body treated is difficult to meet the discharge standard
[0005] Existing drinking water systems such as lakes, ponds, and reservoirs mainly use flocculation to remove arsenic in water, but these flocculation methods end up letting the arsenic-containing flocs sink to the bottom of the water, and do not treat the flocs due to limited conditions.
When the flocculated solid is subjected to external force, strong acid and alkali or high temperature, it is easy to deflocculate, causing secondary pollution of arsenic

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041]Take 2mL arsenic (As5+) standard solution (As5+ concentration is 1000mg / L) in a 2000mL beaker, add 998mL deionized water to dilute to 1000mL, make the As5+ concentration 2.0mg / L, adjust the pH to about 7.5 with HCl to prepare a simulated water sample Weigh 0.252g NaHCO3 in a beaker, stir on a stirrer until it is completely dissolved, add 2.5mL of FeCl3·6H2O solution with a concentration of 108.2g / L under stirring conditions, stir for 5min, and let stand at 20°C for 0.5h, Capture and separate flocs, and detect the concentration of arsenic and its acidity in water samples. The measurement results are: pH = 7.8, the arsenic concentration drops to 0.008mg / L, and the arsenic removal rate is 99.6%, which meets the requirement that the arsenic concentration in drinking water is not higher than 0.010mg / L, and the pH variation range is small.

Embodiment 2

[0043] Take 2mL arsenic (As3+) standard solution (As3+ concentration is 1000mg / L) in a 2000mL beaker, add 998mL deionized water to dilute to 1000mL, make the As3+ concentration 2.0mg / L, adjust the pH to about 7.5 with HCl to prepare a simulated water sample ; Weigh 0.252gNaHCO in a beaker, stir until it dissolves completely on a stirrer, add 2.5mL concentration of 108.2g / L FeCl3 6H2O solution under stirring condition and stir for 5min, leave standstill under sunlight for 4h, capture Collect and separate flocs, and detect the concentration of arsenic and its acidity in water samples. The measurement results are: pH = 7.7, the arsenic concentration drops to 0.006mg / L, and the arsenic removal rate is 99.7%, which meets the requirement that the arsenic concentration in drinking water is not higher than 0.010mg / L, and the pH variation range is small.

Embodiment 3

[0045] Take 1000mL of water from a well in the Hetao area of ​​Inner Mongolia with an arsenic concentration of 0.102mg / L and a pH of 8.2 in a 2000mL beaker, weigh 0.010gNaHCO3 in the beaker, stir on a stirrer until it is completely dissolved, and add 1mL of NaHCO3 with a concentration of 10.82 under stirring conditions. The g / L FeCl3·6H2O solution was stirred for 5 minutes, and after standing at 30°C for 4 hours, the flocs were collected and separated, and the concentration of arsenic and its acidity in the water samples were detected. The measurement results are: pH = 8.3, the arsenic concentration drops to 0.009mg / L, and the arsenic removal rate is 91.2%, which meets the requirement that the arsenic concentration in drinking water is not higher than 0.010mg / L, and the pH variation range is small.

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Abstract

The invention provides a method for removing arsenic in drinking water, specifically: adding a system regulator (coagulant) to drinking water, then adding a flocculant, stirring, heating and standing under sunlight or at 20-30°C for 0.5 After ~4h, flocs are produced, and the arsenic in drinking water can be removed by removing the flocs. Among them, the system regulator (coagulation accelerator) is bicarbonate, and the flocculant is iron salt. By adding a system regulator, the present invention does not need to repeatedly adjust the pH of the water body in the process of treating the water body, and can maintain the relative stability of the system or ecosystem, ensuring the safety of the water body after treatment; and the flocs will emerge from the water surface, By trapping and separating the flocs to replace the existing method of allowing the flocs to sink to the bottom of the water, the arsenic in the water can be permanently removed, and the arsenic pollution phenomenon will not occur repeatedly. The invention is safe, cheap and easy to operate, the arsenic removal rate is as high as 99%, and the arsenic in drinking water can be reduced to below the upper limit concentration of 0.010 mg / L stipulated in the Hygienic Standard for Drinking Water (GB5749‑2006).

Description

technical field [0001] The invention belongs to the technical field of drinking water treatment, and in particular relates to a method for removing arsenic in drinking water. Background technique [0002] Arsenic (As) is a toxic element that exists widely in nature. The World Health Organization (WHO) and the International Agency for Cancer Research (IARC) have listed it as a carcinogenic element. Huge harm can cause skin diseases such as hyperkeratinization and abnormal pigmentation, vascular diseases such as high blood pressure and arteriosclerosis, and cancers such as skin cancer and lung cancer. In 1993, WHO reduced the allowable arsenic concentration in drinking water from 0.050 mg / L to 0.010 mg / L, and my country also stipulated that the arsenic concentration in drinking water be reduced to the WHO standard on July 1, 2007. The removal of arsenic in drinking water is a key measure to prevent and control arsenic poisoning. [0003] Shreemoyee Bordoloi et al. studied th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/52C02F101/10
CPCC02F1/5236C02F1/5245C02F2101/103
Inventor 王世雄白慧萍杨项军汤立红李声剑季四平张艮林陈景
Owner YUNNAN UNIV
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