CN-116773631-B - Biological cathode sensor and application thereof

CN116773631BCN 116773631 BCN116773631 BCN 116773631BCN-116773631-B

Abstract

The invention belongs to the technical field of environmental monitoring, and particularly relates to a biological cathode sensor and application thereof. The invention provides a biological cathode sensor, which comprises an electrolytic cell and a three-electrode system, wherein the three-electrode system comprises a working electrode, a counter electrode and a reference electrode, the working electrode comprises a modified electrode and an electroautotrophic cathode biological film loaded on the surface of the modified electrode, the modified electrode comprises a base electrode and a modified material, the modified material comprises riboflavin or ferriporphyrin, and the electroautotrophic cathode biological film is a mixed bacteria system mainly comprising Moheibacter. The biological cathode sensor provided by the invention can be used for monitoring and identifying non-toxic organic matters and toxic substances in water.

Inventors

WANG XIN
LIAO CHENGMEI
Han Yilian
LI NAN

Assignees

南开大学

Dates

Publication Date: 20260505
Application Date: 20230621

Claims (5)

1. A method for detecting the content of non-toxic organic matters and toxic substances in a water body, comprising the following steps: Placing a water sample to be detected in a biological cathode sensor, and performing electrochemical detection to obtain non-toxic organic matter response current density and toxic matter response current density respectively; Obtaining the content of non-toxic organic matters in the water sample to be detected according to the non-toxic organic matter response current density and a preset non-toxic organic matter standard curve, wherein the non-toxic organic matter response current density is the difference value between the recovery current density and the valley current density; Obtaining the content of toxic substances in the water sample to be detected according to the toxic substance response current density and a preset toxic substance standard curve, wherein the toxic substance response current density is the difference value between the baseline current density and the recovery current density; the biological cathode sensor comprises an electrolytic cell and a three-electrode system, wherein the three-electrode system comprises a working electrode, a counter electrode and a reference electrode; The working electrode comprises a modified electrode and a cathode biological film loaded on the surface of the modified electrode, wherein the modified electrode comprises a base electrode and a modified material, the modified material comprises riboflavin or ferriporphyrin, and the cathode biological film is a bacterial mixing system mainly comprising Moheibacter.
2. The method of claim 1, wherein the preparing of the working electrode comprises: under a three-electrode system with a modified electrode as a working electrode, a stainless steel mesh as a counter electrode and Ag/AgCl as a reference electrode, an organic carbon source is used as an electrolyte, and an inoculation source is subjected to acclimatization of the heterotrophic anode biomembrane to obtain an anode carrying the anode biomembrane; The inoculation source is MFCs effluent which stably runs for more than 3 years; And after electrode polarity inversion is carried out on the anode carrying the anode biomembrane, domesticating the electroautotrophic cathode biomembrane under the conditions of catholyte and dissolved oxygen to obtain the working electrode, wherein the base electrode is a carbon felt electrode, a carbon cloth electrode or a carbon brush electrode, and the load capacity of the modification material on the carbon felt electrode is 5-50 mg/cm 2 .
3. The method according to claim 1, wherein when the modified material is riboflavin, the method for producing a modified electrode comprises the steps of: Under the condition of avoiding light, soaking the base electrode in a mixed solution of sodium alginate and riboflavin, and carrying out the loading of the riboflavin to obtain an electrode loaded with the riboflavin and the sodium alginate; Immersing the electrode loaded with riboflavin and sodium alginate in an inorganic calcium salt solution, and carrying out ion exchange to obtain the modified electrode.
4. The method according to claim 1, wherein when the modification material is ferriporphyrin, the preparation method of the modification electrode comprises the steps of: And (3) taking H 2 SO 4 solution of ferriporphyrin as electrolyte, taking a basic electrode as a working electrode, and adopting a three-electrode system to carry out cyclic voltammetry scanning to obtain the modified electrode.
5. The method according to claim 4, wherein the voltage range of the cyclic voltammetry scanning is-1.1-2.2V, the number of turns of the cyclic voltammetry scanning is 4-6, and the scanning speed of the cyclic voltammetry scanning is 50-150 mV/s.

Description

Biological cathode sensor and application thereof Technical Field The invention belongs to the technical field of environmental monitoring, and particularly relates to a biological cathode sensor and application thereof. Background The traditional water pollution detection method depends on a large instrument, has low efficiency and convenience, and is difficult to realize real-time online monitoring of pollutants. The microbial electrochemical technology is a novel biological monitoring technology and can be used for monitoring toxic substances and organic matters in water. The monitoring process relies primarily on a unique pattern of electron transfer between the electroactive biofilm and the electrode, known as the extracellular electron transfer process (EET). When the target contaminant suddenly exists or the concentration changes, the metabolic activity or pattern of the electroactive microorganism may be affected, which is converted into a change in an electrical signal by the sensor. Microbial electrochemical sensing elements can be generally classified into anode type and cathode type. While in target analyte monitoring, bioanode sensors are often affected by various water quality parameters. Anaerobic treated water and carbon sources need to be replenished prior to monitoring to ensure that the bioanode sensor has a stable baseline signal. In addition, because organic matter is required as an electron donor, heterotrophic biofilms on the anode may limit mass transfer processes of target analytes, thereby reducing the sensitivity of the sensor. Compared with a biological anode, the biological cathode sensor can monitor the aerobic water environment without adding organic matters, and has lower detection limit and higher sensitivity. However, there is currently no biocathode sensor that can be used to monitor and distinguish between organic and toxic substances in a body of water. Disclosure of Invention In view of the above, the present invention is directed to a bio-cathode sensor and an application thereof, and the bio-cathode sensor provided by the present invention can be used for monitoring and identifying organic matters (non-toxic) and toxic substances in a water body. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a biological cathode sensor, which comprises an electrolytic cell and a three-electrode system, wherein the three-electrode system comprises a working electrode, a counter electrode and a reference electrode, and is characterized in that the working electrode comprises a modified electrode and a cathode biological film loaded on the surface of the modified electrode, wherein the modified electrode comprises a base electrode and a modified material; the cathode biological film is a mixed bacteria system mainly comprising Moheibacter. Preferably, the preparation of the working electrode includes: under a three-electrode system with a modified electrode as a working electrode, a stainless steel mesh as a counter electrode and Ag/AgCl as a reference electrode, an organic carbon source is used as an electrolyte, and an inoculation source is subjected to acclimatization of the heterotrophic anode biomembrane to obtain an anode carrying the anode biomembrane; The inoculation source is MFCs effluent which stably runs for more than 3 years; and (3) after electrode polarity inversion is carried out on the anode carrying the anode biomembrane, domestication of the electroautotrophic cathode biomembrane is carried out under the conditions of catholyte and dissolved oxygen, and the working electrode is obtained. Preferably, the base electrode is a carbon felt electrode, a carbon cloth electrode or a carbon brush electrode. Preferably, the load of the modification material on the carbon felt electrode is 5-50 mg/cm 2. Preferably, when the modification material is riboflavin, the preparation method of the modification electrode comprises the following steps: Under the condition of avoiding light, soaking the base electrode in a mixed solution of sodium alginate and riboflavin, and carrying out the loading of the riboflavin to obtain an electrode loaded with the riboflavin and the sodium alginate; Immersing the electrode loaded with riboflavin and sodium alginate in an inorganic calcium salt solution, and carrying out ion exchange to obtain the modified electrode. Preferably, the cross-linking agent comprises CaCl 2 solution and/or SrCl 2 solution. Preferably, when the modification material is ferriporphyrin, the preparation method of the modification electrode comprises the following steps: And (3) taking H 2SO4 solution of ferriporphyrin as electrolyte, taking a basic electrode as a working electrode, and adopting a three-electrode system to carry out cyclic voltammetry scanning to obtain the modified electrode. Preferably, the voltage range of the cyclic voltammetry scanning is-1.1-2.2V, the number of turns of the