An electrochemical method for removing heavy metal cadmium in silkworm excrement

Abstract

The invention discloses an electrochemical method for removing heavy metal cadmium in silkworm excrement. The method is characterized by comprising the following steps: weighing the silkworm excrement containing heavy metal cadmium, extracting by adopting 0.1mol / L EDTA, citric acid and acetic acid as extractants, adjusting the pH value to 2-6 by using hydrochloric acid, putting into an electrochemical device taking graphite as an electrode, controlling the electrode plate distance to be 14cm, arranging a layer of cation exchange membrane at a position 10cm away from the anode, controlling the voltage gradient to 0.5V / cm-1.5V / cm and performing electrochemical treatment. According to the method, the electricity consumption is low, the pH range is relatively wide, the electrolysis time is short, the time is shortened, the cation exchange membrane is uniform, the electrode voltage is stable, and the performance is reliable; the removing rate of metal Cd in the silkworm excrement can be up to 63.4 or more. By using the method, the heavy metal Cd is enriched at the cathode, so that the heavy metal Cd is easy to treat, no secondary pollution is generated, no harm factors are generated, and the treated silkworm excrement can be used as drug or can be used as a fertilizer.

Description

technical field [0001] The invention belongs to the technical field of agricultural organic waste treatment and resource utilization, and specifically relates to an electrochemical method for removing heavy metal cadmium in silkworm excrement. Background technique [0002] my country is the birthplace and main producing country of sericulture in the world, and sericulture has a long history. Silkworm excrement (i.e. silkworm excrement) is the excrement of silkworm larvae, dark green, granular, about 5 mm in diameter. Because silkworm excrement contains many pathogenic bacteria and heavy metals, it cannot be used directly, and some silkworm farmers even pile it up everywhere to let the rain wash away, which not only wastes resources, but also pollutes the environment. In order to make silkworm excrement turn waste into wealth, turn harm into profit, and improve the comprehensive economic benefits of sericulture production, it is necessary to improve the removal technology of...

AI Technical Summary

Problems solved by technology

Electrochemical removal of heavy metals in silkworm excrement needs to solve the following problems: 1) During the electrolysis process, the pH of the medium is constantly changing, which is not conducive to the enrichment of heavy metals; 2) In the electrochemical process, different extraction agents are applied, and the removal rates of heavy metals are different; 3) During the electrolysis process, the migration speed of heavy metal cations is different, and the enrichment time in the cathode is different, and some heavy metals may not achieve the treatment effect; 4) Under different voltage gradients, the removal rate of heavy metals is different, so it is necessary to seek the best voltage gradient

At present, there is no report on the treatment of heavy metals in silkworm excrement, but some useful substances in silkworm excrement are extracted, such as pectin, chlorophyll, leaf protein, phytoalcohol, etc., to improve the comprehensive utilization value of silkworm excrement, such as feed, fertilizer, etc.

Images