Method and apparatus for removal and recovering of heavy metal ions from wastewater

Abstract

The present invention relates to a method and an apparatus for electrochemical processing of heavy metal ion-containing wastewater by use of an activated carbon basket as an electrode. According to the method, by combination of physical adsorption concentration, electrochemical reduction adsorption and electrochemical catalytic oxidation, heavy metal ion-containing wastewater is processed, and copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, molybdenum, and all other heavy metal pollutants in the wastewater can be effectively and thoroughly removed. The method not only can process wastewater containing a high concentration of heavy metal ions, is also suitable for processing wastewater containing extremely dilute concentrations of heavy metal ions (the concentration range is from 0 to hundreds of thousands of ppm), meanwhile compared with the traditional method, the method greatly reduces the processing cost, is inexpensive and simple in operation and equipment, can be recycled to run, and has great practical value.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment, in particular to a process for removing heavy metal ions in waste water, and relates to a treatment method and device for waste water containing heavy metal ions in a wide concentration range, in particular to an activated carbon basket used as an electrode for electrochemically assisted removal of heavy metal ions in waste water. Method and apparatus for heavy metal ions. Background technique [0002] Wastewater containing heavy metal ions mainly comes from industrial wastewater such as mining, nonferrous metals, electroplating, electrolysis, pesticides, medicine, tobacco, paints, and pigments. Heavy metal ions mainly include all heavy metal ions such as copper, lead, zinc, iron, cobalt, nickel, manganese, cadmium, mercury, tungsten, and molybdenum. Because heavy metal ions cannot be decomposed by themselves, they are easy to accumulate in organisms, disrupting the normal metaboli...

AI Technical Summary

Problems solved by technology

In the current treatment methods for wastewater containing heavy metal ions, the equipment and processes used are either slow in treatment speed and small in one-time treatment volume, or have high investment and large floor area, or are prone to secondary pollution and high cost.

For example: although the activated carbon adsorption method requires less investment and occupies a small area, the activated carbon adsorption speed is slow and the adsorption capacity is small, so it is not suitable for treating wastewater with high pollutant concentration; It produces secondary pollution, consumes a large amount of precipitant, and cannot completely remove heavy metal ions, and cannot treat wastewater with extremely dilute concentrations of heavy metal ions; the ion exchange method can achieve no wastewater discharge during the treatment process, but its investment is high and it occupies a large area. The concentration of pollutants in the wastewater should not be too high, and it cannot be effective for all ion exchanges; the raw materials of the biosorption method are cheap and easy to obtain, can effectively recover heavy metal ions, and the adsorption effect is good, but the bacteria used are slow in reproduction and the mechanical properties of the biosorbent Weak strength, poor chemical stability, and the valence of metal ions cannot be changed during the adsorption process, reducing the toxicity of heavy metal ions

In the prior art, there is also a process for separating heavy metal ions in wastewater by electrochemical methods. For example, the patent with the authorized notification number CN101088938B discloses a treatment method for heavy metal sewage. The pH value is adjusted to neutral by using electrochemical catalytic oxidation technology. The sewage is introduced into the reaction tower, the reaction tower is filled with air, and catalysts such as pig iron filings, activated carbon, and sponge iron oxygen scavenger are added to the reaction tower to cause oxidation-reduction reactions in the sewage, and the iron in the sewage is oxidized, and heavy metals Ions are reduced to heavy metals in a free state, but because heavy metal ions in sewage usually exist in the form of complexes and are difficult to decompose in a weak oxidative environment, the inventive method cannot completely remove heavy metal ions in sewage, and the method It has not broken the traditional iron-carbon micro-electrolysis treatment technology, and a high-voltage current is passed through the reaction tower, but the electrochemical reaction efficiency is still low due to the small contact area between the sewage and the electrode plate itself

In addition, the patent application with application number 201410325704.6 also discloses an electrode oxidation process for removing cyanide and heavy metals. Electrode oxidation technology is used to add catalytic carrier activated carbon to the bottom of the electrode oxidation tank to improve oxidation efficiency. However, the entire application document There is no clear description of the activated carbon catalytic carrier, that is, whether the activated carbon catalytic carrier is loaded with a catalyst, the type and amount of the catalyst, etc., nor how the activated carbon at the bottom of the electrode oxidation tank accelerates the metal complex. Therefore, the technical solution is unclear. In addition, this method uses platinum alloy series as electrodes, which is not only expensive, but also has a small contact area between the electrode plate and the wastewater, and the electrolysis efficiency is low.