CN109179634B

Movatterモバイル変換

Info

Publication number: CN109179634B
Application number: CN201811043122.3A
Authority: CN
Inventors: 杨士红; 江赜伟; 庞晴晴; 徐俊增
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2018-09-07
Filing date: 2018-09-07
Publication date: 2022-01-28
Anticipated expiration: 2038-09-07
Also published as: CN109179634A

Abstract

Translated fromChinese

本发明公开了一种用于测量CW‑MFC反应速率的装置，包括电池耦合装置、测量电路、单片机；所述电池耦合装置为上端开口的半封闭腔体，从一侧至另一侧分别为进水口、阴极室、薄膜、第一滤料区、阳极室、第二滤料区、卵石层和出水口，上端开口处铺设植物层；所述测量电路两端分别连接电池耦合装置的阴极室和阳极室，用于测量其内部电压值，所述电池耦合装置通过测量电路与单片机相连，还公开该装置的测量方法，该装置可准确测得内部氧气浓度变化速率，即为CW‑MFC的反应速率。

The invention discloses a device for measuring the reaction rate of CW-MFC, comprising a battery coupling device, a measuring circuit and a single-chip microcomputer; the battery coupling device is a semi-closed cavity with an open upper end, and from one side to the other side are respectively Water inlet, cathode chamber, membrane, first filter material area, anode chamber, second filter material area, pebble layer and water outlet, a plant layer is laid at the upper opening; both ends of the measuring circuit are respectively connected to the cathode chamber of the battery coupling device and anode chamber for measuring its internal voltage value, the battery coupling device is connected with the single-chip microcomputer through a measuring circuit, and a measurement method of the device is also disclosed, the device can accurately measure the change rate of the internal oxygen concentration, which is the CW-MFC reaction speed.

Description

Device and method for measuring CW-MFC reaction rate

Technical Field

The invention relates to the field of reaction rate measurement, in particular to a device and a method for measuring the reaction rate of a CW-MFC.

Background

The constructed wetland-microbial fuel cell (CW-MFC) is a system for coupling the constructed wetland and the microbial fuel cell, and has been widely applied in various fields such as printing and dyeing wastewater degradation, rural domestic sewage purification and the like at present due to the innovativeness and excellent environmental benefit. The constructed wetland-microbial fuel cell can not only utilize the alternate aerobic and anaerobic environments in the constructed wetland, but also utilize the advantage that the microbial fuel cell can convert chemical energy into electric energy, and can realize biological electricity generation while removing pollutants.

However, the constructed wetland-microbial fuel cell still has many problems, and needs to be improved and adjusted in time: for example, the power generation performance of the constructed wetland-microbial fuel cell is influenced by factors such as organic load, redox gradient, wetland plants and substrates, and the like, and when the volume of the device is increased, the problems of too low power density, too high internal resistance, low coulombic efficiency and the like also occur. And the reaction rate of the constructed wetland-microbial fuel cell can be used for evaluating the water quality purification effect of the device and the activity of nitrobacteria and denitrifying bacteria. Therefore, the real-time reaction rate of the constructed wetland-microbial fuel cell needs to be intuitively and conveniently measured, and then the water purification and electricity generation performance of the device is timely improved and adaptively adjusted, but an effective method is still lacked at present. For example, chinese patent CN201610273268 provides a CW-MFC coupling system for degrading azo dyes and a degradation method thereof, which optimizes the cathode region structure and performance, creates an aerobic environment to improve the treatment efficiency, but cannot evaluate the reaction rate of the device operation in time, and does not solve the problem of evaluation of the treatment effect of CW-MFC that may be encountered in actual operation.

The oxygen concentration can affect the activity of nitrobacteria and denitrifying bacteria, and further affect the artificial wetland-microbial fuel cell on COD and NO₃^--N、NH₄⁺And (4) removing effects of indexes such as-N and the like, and meanwhile, oxygen is consumed at the cathode of the constructed wetland-microbial fuel cell to generate water, so that the change rate of the oxygen concentration can reflect the reaction rate of the constructed wetland-microbial fuel cell. Common dissolved oxygen measuring methods include a current measuring method, an iodometry method and the like, but the iodometry method has long measuring period and complicated procedure, is easily interfered by external environment, and the current measuring method needs to stir a sample constantly, change electrolyte and activate electrodes, has complex operation and maintenance, and has the problem of secondary pollution because common electrodes of the current method are heavy metals such as silver, platinum and the like.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the disadvantages of the background art, the first object of the present invention is to disclose an apparatus for measuring the reaction rate of a CW-MFC; a second object is to disclose the method of the apparatus for measuring the CW-MFC reaction rate.

The technical scheme is as follows: the device for measuring the CW-MFC reaction rate comprises a battery coupling device, a measuring circuit and a singlechip; the battery coupling device is a semi-closed cavity with an opening at the upper end, the water inlet, the cathode chamber, the film, the first filter material area, the anode chamber, the second filter material area, the pebble layer and the water outlet are respectively arranged from one side to the other side, and a plant layer is laid at the opening at the upper end; the two ends of the measuring circuit are respectively connected with the cathode chamber and the anode chamber of the battery coupling device and used for measuring the internal voltage value of the battery coupling device, and the battery coupling device is connected with the single chip microcomputer through the measuring circuit. The film is an oxygen permeable film, and ensures that oxygen dissolved in water is gathered to the vicinity of the cathode chamber to be reduced.

Further, including current-limiting resistor, triode, thermistor, voltmeter in the measuring circuit, the base of triode passes through current-limiting resistor and is connected with the cathode chamber, the projecting pole and the cathode chamber lug connection of triode, the collecting electrode of triode passes through thermistor and is connected with the anode chamber, the singlechip is connected to the voltmeter and is connected with thermistor parallel, and the triode is with measuring circuit's electric current and voltage amplification, and then improves measurement accuracy, and the signal of telecommunication that the singlechip received the sensor passes to the computer, and then draws real-time chart.

Further, the filler of the cathode chamber and the anode chamber is granular activated carbon with the grain diameter of 1-8 mm; the first filtering material area and the second filtering material area are both composed of gravels with the particle size range of 4-10 mm; the pebble layer is composed of cobbles with the grain diameter of 20-35 mm; the plant layer is herba Typhae or medulla Junci.

Furthermore, the thickness of the filler in the cathode chamber is 4-6cm, the thickness of the filler in the first filter material area is 25-30cm, the thickness of the filler in the anode chamber is 8-12cm, the thickness of the filler in the second filter material area is 5-10cm, and the thickness of the filler in the pebble layer is 10-20 cm.

Further, the current limiting resistor is an external resistor of 800-1500 Ω, and the thermistor is an external resistor of 1000 Ω to determine the influence of temperature on the relationship between current and oxygen partial pressure.

A method for measuring the CW-MFC reaction rate, comprising the steps of:

A. the battery coupling device is built and connected with the measuring circuit and the single chip microcomputer;

B. enabling the artificial wastewater to enter the battery coupling device through the water inlet, and stopping water inflow when the water level rises to a position 3-5cm away from the top of the device;

C. reading and recording the resistance R of the thermistor and the voltage representation number U during the reaction, wherein the amplification factor of the triode is n, the Faraday constant is F, the surface area of the cathode chamber is A, the permeability coefficient of the film is Pm, the thickness of the film is L, and the dissolved oxygen concentration is obtained according to ohm law and Faraday law:

D. calculating the concentration change rate of the dissolved oxygen and feeding back to the computer through a sensor and a single chip microcomputer so as to obtain the real-time oxygen concentration change rate of the CW-MFC battery coupling device, namely the reaction rate of the CW-MFC battery coupling device:

E. after the device runs for 6-7 hours, the running is finished, and water is discharged from the water outlet of the device.

The working principle is as follows: in the anode chamber of the constructed wetland-microbial fuel cell, organic matters are degraded by microbes under anaerobic conditions, generated electrons are captured by the microbes and transferred to the anode, the electrons reach the cathode, a loop is formed, current is generated, and oxygen is consumed in the cathode chamber to generate water. According to Faraday's law, the current flowing through the electrodes is in direct proportion to the oxygen partial pressure, and the current and the oxygen concentration are in a linear relation under the condition of unchanged temperature, so that the resistors at different temperatures can be obtained by arranging the thermistors, then the corresponding voltage is measured to obtain the current, the measurement precision is improved by amplifying the current through the triode, the oxygen concentration can be calculated by the current, and the current is transmitted to a computer through the sensor and the singlechip, so that the real-time oxygen concentration change rate, namely the reaction rate of the constructed wetland-microbial fuel cell device is obtained.

Has the advantages that: compared with the prior art, the invention has the advantages that: the current between the cathode and the anode of the artificial wetland-microbial fuel cell device is simply and intuitively measured by a thermistor and a voltmeter after being amplified by utilizing an electrochemical method, so that the change condition of the oxygen concentration is reflected, the redox reaction speed of the coupling device and the activities of denitrifying bacteria and nitrifying bacteria are related to the change condition of the oxygen concentration, therefore, the measurement problem of the reaction rate is converted into the change of the voltmeter indicating number, the water inlet process of the device plays the roles of stirring and replacing electrolyte, the possibility of blocking and damaging a thin film is reduced, the service cycle is prolonged, the measurement precision is improved, and the device is simple and easy to operate and has low cost.

Drawings

FIG. 1 is a schematic diagram of the structure of the apparatus of the present invention;

fig. 2 is a schematic flow chart of the present invention.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

The device for measuring the CW-MFC reaction rate as shown in FIG. 1 comprises abattery coupling device 1, ameasuring circuit 2, asingle chip microcomputer 3; thebattery coupling device 1 is a semi-closed cavity with an opening at the upper end, thewater inlet 101, thecathode chamber 102, thefilm 103, the firstfiltering material area 104, theanode chamber 105, the secondfiltering material area 106, thepebble layer 107 and thewater outlet 108 are respectively arranged from the left side to the right side, and aplant layer 109 is paved at the opening at the upper end; the filling material of thecathode chamber 102 is granular activated carbon with the grain diameter of 4mm, the filling material thickness is 5cm, the filling material of theanode chamber 105 is granular activated carbon with the grain diameter of 5mm, the filling material thickness is 10cm, and thefilm 103 is an oxygen permeable film, so that dissolved oxygen in water is concentrated on the cathode to be reduced. The first filteringmaterial area 104 and the second filteringmaterial area 106 are both composed of 10mm gravel filtering materials, and the thicknesses of the filling materials are 25cm and 5cm respectively; thepebble layer 107 is cobblestones with the grain diameter of 25mm and is paved on the right side of the second filtering material area, and the thickness of the filler is 10 cm; theplant layer 109 is made of herba Typhae. Wherein the water inlet is high and the water outlet is low.

The two ends of themeasuring circuit 2 are respectively connected with thecathode chamber 102 and theanode chamber 105 of thecell coupling device 1 for measuring the internal voltage value thereof, and thecell coupling device 1 is connected with thesinglechip 3 through themeasuring circuit 2.

Themeasuring circuit 2 comprises a currentlimiting resistor 201, atriode 202, athermistor 203 and avoltmeter 204, the base of thetriode 202 is connected with thecathode chamber 102 through the currentlimiting resistor 201, the emitter of thetriode 202 is directly connected with thecathode chamber 102, the collector of thetriode 202 is connected with theanode chamber 105 through thethermistor 203, and thevoltmeter 204 is connected with thesinglechip 3 and connected with thethermistor 203 in parallel.

The right ends of thecathode chamber 102 and theanode chamber 105 are each provided with a 40-60 μm thick copper mesh, preferably 50 μm, to collect electrons, which are collected by the copper mesh and then looped through a copper wire.

The current limitingresistor 201 is an external resistor of 900 Ω, and thethermistor 203 is an external resistor of 1000 Ω. Themeasuring circuit 2 amplifies the current and the voltage through thetriode 202, and further improves the measuring precision. And the single chip microcomputer transmits the electric signals received by the sensor to a computer, so as to draw a real-time chart.

A method for measuring the CW-MFC reaction rate as shown in fig. 2, comprising the steps of:

A. thebattery coupling device 1 ofclaim 2 is constructed, and themeasuring circuit 2 and thesinglechip 3 are connected;

B. the artificial wastewater enters thebattery coupling device 1 through theleft water inlet 101, and the water inlet is stopped when the water level rises to a position 5cm away from the top of the device;

C. during the reaction, the resistance R of thethermistor 203 is read and recorded, the number U is indicated by thevoltmeter 204, the amplification factor of the triode is n, the Faraday constant is F, the surface area of thecathode chamber 102 is A, the permeability coefficient of thefilm 103 is Pm, the thickness of the film is L, and the dissolved oxygen concentration is obtained according to ohm's law and Faraday's law:

D. calculating the concentration change rate of the dissolved oxygen and feeding back to the computer through a sensor and a single chip microcomputer, and further obtaining the real-time oxygen concentration change rate of the CW-MFC battery coupling device 8, namely the reaction rate of the CW-MFC battery coupling device 8:

E. after the device runs for 6 hours, the running is finished, and water is discharged from a water outlet on the right side of the device.

Claims

1. A method for measuring the CW-MFC reaction rate, characterized by: the device comprises a battery coupling device (1), a measuring circuit (2) and a singlechip (3); the cell coupling device (1) is a semi-closed cavity with an opening at the upper end, a water inlet (101), a cathode chamber (102), a film (103), a first filtering material area (104), an anode chamber (105), a second filtering material area (106), a pebble layer (107) and a water outlet (108) are respectively arranged from one side to the other side, and a plant layer (109) is laid at the opening at the upper end; the two ends of the measuring circuit (2) are respectively connected with a cathode chamber (102) and an anode chamber (105) of the battery coupling device (1) and used for measuring the voltage value inside the battery coupling device, and the battery coupling device (1) is connected with the singlechip (3) through the measuring circuit (2);

the measuring circuit (2) comprises a current limiting resistor (201), a triode (202), a thermistor (203) and a voltmeter (204), the base electrode of the triode (202) is connected with the cathode chamber (102) through the current limiting resistor (201), the emitter electrode of the triode (202) is directly connected with the cathode chamber (102), the collector electrode of the triode (202) is connected with the anode chamber (105) through the thermistor (203), and the voltmeter (204) is connected with the singlechip (3) and connected with the thermistor (203) in parallel;

the method comprises the following steps:

A. the battery coupling device (1) is built and connected with the measuring circuit (2) and the single chip microcomputer (3);

B. enabling artificial wastewater to enter the battery coupling device (1) through the water inlet (101), and stopping water inflow when the water level rises to a position 3-5cm away from the top of the device;

C. reading and recording the resistance R of the thermistor (203) during the reaction, reading U of a voltmeter (204), the amplification factor n of the triode, the Faraday constant F, the surface area A of the cathode chamber (102), the permeability coefficient Pm of the film (103), the film thickness L, and obtaining the dissolved oxygen concentration according to ohm's law and Faraday's law as follows:

2. A method for measuring the CW-MFC reaction rate according to claim 1, characterized in that: the filling materials of the cathode chamber (102) and the anode chamber (105) are granular activated carbon with the grain diameter of 1-8 mm; the first filtering material area (104) and the second filtering material area (106) are both composed of gravels with the particle size range of 4-10 mm; the pebble layer (107) is composed of cobblestones with the particle size of 20-35 mm; the plant layer (109) is cattail or juncus effusus.

3. A method for measuring the CW-MFC reaction rate according to claim 1, characterized in that: the filler thickness of the cathode chamber (102) is 4-6cm, the filler thickness of the first filtering area (104) is 25-30cm, the filler thickness of the anode chamber (105) is 8-12cm, the filler thickness of the second filtering area (106) is 5-10cm, and the filler thickness of the pebble layer (107) is 10-20 cm.

4. A method for measuring the CW-MFC reaction rate according to claim 1, characterized in that: the current limiting resistor (201) is an external resistor of 800-1500 omega, and the thermistor (203) is an external resistor with a nominal resistance of 1000 omega.