Based On LPFG Sensor For Measurement Of Dissolved Oxygen Concentration In Microbial Fuel Cell

Microbial fuel cell is a new kind of clean energy device.It also has the ability to deal with wastewater while producing electricity,and has become a hot topic in recent years.Although the microbial fuel cells have many advantages,but the yield of microbial fuel cell electric power is low.The most important non-biological factors affecting the production of microbial fuel cells are temperature,p H,concentration of dissolved oxygen and substrate concontration,etc.Therefore,accurate and online monitoring of the microbial fuel cell to produce electricity performance of biological parameters,is particularly important for optimization control microbial fuel cell performance.At present,methods of dissolved oxygen concentration detection are time-consuming,laborious,oxygen consumption,real-time measurement problems and vulnerability to temperature,cannot be effectively applied to measurement of dissolved oxygen concentration in the microbial fuel cell.Therefore,explor8 ng a new kind of used for dissolved oxygen concentration accurate on-line measurement method is particularly important in the microbial fuel cell.This article uses the long period fiber grating(LPFG)and fiber Bragg grating(FBG)coupled way to implement dissolved oxygen concentration in the microbial fuel cell.The FBG mainly responds to the temperature change and LPFG mainly responds to the internal temperature and the concentration of dissolved oxygen in the battery.This paper carried out research from the following several aspects:(1)Based on dissolved oxygen concentration measurement of plastic optical fiber has carried on the related experimental research,explored the dissolved oxygen sensitive film optical fiber surface preparation scheme and the best condition to measure the effects of oxygen sensor.(2)Using sol-gel method of oxygen sensitive membrane fixed on the optical fiber,through the changes of spectral characteristic of optical fiber before and after the coating and coating of the tendency of the fluorescence spectrum and Phenanthroline ruthenium(?)agree the change trend of fluorescence spectrum,and the sensitive membrane was characterized(3)Mading good sensor is used to analyse the different dissolved oxygen concentration measurement.Based on the oxygen sensor of plastic fiber,the sensitivity of the oxygen is measured by measuring the fluorescence intensity,which indicates that the sensitive membrane is good.Making good sensitive membrane performance lays the foundation for LPFG based oxygen sensor,can through the center wavelength shift to measure the dissolved oxygen concentration,fitting coefficient R2 is 0.9564.(4)In order to improve accuracy of the LPFG dissolved oxygen measurement,the design and construction of the FBG-LPFG combined fiber optic oxygen sensor to eliminate the influence of temperature,it is concluded that: the center wavelength of the FBG,LPFG offset a certain linear relationship with temperature,the temperature sensitivity of FBG is 0.0063 nm / ?,the temperature of the LPFG sensitivity of 0.0588 nm / ?;When the concentration was measured,the center wavelength of LPFG was offset,LPFG's refractive index sensitivity was-56.66 nm/RIU,and the center wavelength of FBG was not offset.That FBG-LPFG combined fiber optic oxygen sensor can simultaneously measure the concentration and temperature.(5)Using the FBG-LPFG combined fiber optic oxygen sensor to measure the change of the microbial fuel cells dissolved oxygen concentration in the MFC,when oxygen concentration is 0.24 mg/L,the output power is maximum.In this paper,two methods of being designed can be effective for measuring the concentration of dissolved oxygen,but the use of plastic optical fiber measurement,is conducted under the condition of constant temperature,as a result of microbial fuel cell temperature is affected by the microbial metabolism,resistance,temperature change constantly,in the use of microbial fuel cells have certain limitations.But plastic optical fiber sensor is to explore the sensitive membrane,the optimal preparation methods and conditions for the LPFG sensors of prophase preparation,this article made to eliminate the influence of temperature oxygen sensor for the study of dissolved oxygen sensor has a certain significance.