Electric flocculation water treatment technology for retarding pole plate passivation

A technology of electrocoagulation and water treatment, applied in water/sewage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., can solve the problem of destroying the formation conditions of adsorbed flocs, weakening the degree of passivation, and reducing the yield of adsorbed flocs Reduce and other problems, achieve the effect of slowing down and anode passivation, eliminating anode passivation, and no maintenance time

Inactive Publication Date: 2014-03-05
JIANGSU UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The second method is to add acid to the electrolytic cell to adjust the pH value of the solution during the electrocoagulation electrolysis process, so that the pH value is between 3.5 and 5, which can weaken the passivation degree, but the lower pH value will destroy the adsorption Floc formation conditions, such that the yield of adsorbed flocs is reduced

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] 1. A mixed cadmium-containing heavy metal wastewater, the influent cadmium content is 100mg / L, adjust the pH value of the wastewater to 7, adjust the conductivity to 500us / cm, add sodium chloride to adjust the concentration of sodium chloride to 80mg / L, enter the intermittent electricity For flocculation system treatment, iron electrodes are used, the electrode distance is 5mm, the voltage of each pair of electrodes is set to 5V, and the anode and cathode are iron electrodes. After electrolysis for 60 minutes, the measured average current density is 8.3A / m 2 . After the electrocoagulation reaction, the mass concentration of heavy metal cadmium was reduced to 8.7mg / L, and the removal rate reached 92.3%.

[0015] Life test: The water inlet parameters are consistent with the above. After 200h of experiment, set the voltage of each pair of electrodes to 5V, electrolysis for 60min, and the measured average current density is 7.7A / m 2 , the mass concentration of metal cadmi...

Embodiment 2

[0018] A mixed chromium-containing heavy metal wastewater, the influent chromium content is 50mg / L, adjust the pH value of the wastewater to 3, adjust the conductivity to 300us / cm, add sodium chloride to adjust the concentration of sodium chloride to 40mg / L, and enter the intermittent electroflocculation system For the treatment, iron electrodes are used, the distance between the electrodes is 15mm, the voltage of each pair of electrodes is set to 3V, and the anode and cathode are aluminum electrodes. After electrolysis for 30 minutes, the measured average current density is 3.2A / m 2 . After the electrocoagulation reaction, the mass concentration of heavy metal cadmium was reduced to 5.1mg / L, and the removal rate reached 89.8%.

[0019] Life test: The water inlet parameters are consistent with the above. After 200h of experiment, set the voltage of each pair of electrodes to 3V, electrolyze for 30min, and the average current density is 4.4A / m 2 . The mass concentration of m...

Embodiment 3

[0022] A mixed nickel-containing heavy metal wastewater, the influent nickel content is 400mg / L, adjust the pH value of the wastewater to 5, adjust the conductivity to 3000us / cm, add sodium chloride to adjust the concentration of sodium chloride to 200mg / L, and enter the intermittent electrocoagulation system For the treatment, iron electrodes are used, the distance between the electrodes is 5mm, and the voltage of each pair of electrodes is set to 10V. After electrolysis for 40 minutes, the measured average current density was 29.3A / m 2 . After the electrocoagulation reaction, the mass concentration of heavy metal cadmium was reduced to 36.5mg / L, and the removal rate reached 92.7%.

[0023] Life test: The water inlet parameters are consistent with the above. After 200h of experiment, set the voltage of each pair of electrodes to 10V, electrolyze for 40min, and the measured average current density is 26.7A / m 2 . The mass concentration of metal cadmium was reduced to 60.90mg...

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Abstract

The invention discloses an electric flocculation water treatment technology for retarding pole plate passivation, and belongs to the technical field of water treatment. The technology comprises the following steps: adding electrolyte sodium chloride to wastewater one time before electrolysis of each batch of wastewater in an intermittent electric flocculation process, so that the mean mass concentration of the sodium chloride inside an electrolytic cell is 40-200mg/L; outputting an intermittent electric flocculation voltage by a constant-pressure control power supply; and setting the voltage of each pair of electrodes to be 3-10V, the distance between the pole plates to be 5-15mm and the electrolytic time to be 30-90 minutes by adopting a direct current power supply. The problem of electrode surface passivation is improved and removed by in-situ generation of an acid substance on the electrode surface. The electric flocculation water treatment technology is free of feeding acid and base, and free of dismantling the electrodes to clean, and has the advantages of being simple in structure, and convenient to operate.

Description

technical field [0001] The invention relates to an electrocoagulation water treatment process for slowing down the passivation of the polar plate, more specifically, it involves adding electrolyte into the electrolytic cell of electrocoagulation, and in the process of electrolysis, acidic substances are generated in situ by the electrode to slow down and eliminate the polar plate passivation process. Background technique [0002] Electrocoagulation is (referred to as: EC) the use of soluble anodes to generate metal cations (Al 3+ or Fe 2+ ), the cathode produces OH - , the combination of the two forms hydroxides and polynuclear hydroxyl complexes, and finally forms hydroxide flocs containing surface hydroxyl groups, which absorb heavy metal ions and organic substances in water through exclusive adsorption, net capture, sweeping, adsorption bridging, etc., and at the same time flocculate The body is attached to the H produced by electrolysis at the cathode 2 Air flotation...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/463C02F1/461
Inventor 陆君马晓云李艳
Owner JIANGSU UNIV OF SCI & TECH
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