A novel BOD biosensor has been fabricated from a microbial membrane on an oxygen electrode; a porous inorganic Al2O3 sol-gel matrix was used to immobilize the yeast. Use of the sensor is convenient and rapid compared with the official BOD5 method. The gelation time required to form the microorganism membrane was less than 15 min. There was linear relationship between the response (sensor current) and BOD values ranging from 10-50 mg x L(-1). The lifetime of the BOD biosensor was more than 30 days at ambient temperature. 相似文献
The biological oxygen demand (BOD) may be the most used test to assess the amount of pollutant organic matter in water; however, it is time and labor consuming, and is done ex-situ. A BOD biosensor based on the microbial fuel cell principle was tested for online and in situ monitoring of biodegradable organic content of domestic wastewater. A stable current density of 282±23mA/m(2) was obtained with domestic wastewater containing a BOD(5) of 317±15mg O(2)/L at 22±2°C, 1.53±0.04mS/cm and pH 6.9±0.1. The current density showed a linear relationship with BOD(5) concentration ranging from 17±0.5mg O(2)/L to 78±7.6mg O(2)/L. The current generation from the BOD biosensor was dependent on the measurement conditions such as temperature, conductivity, and pH. Thus, a correction factor should be applied to measurements done under different environmental conditions from the ones used in the calibration. These results provide useful information for the development of a biosensor for real-time in situ monitoring of wastewater quality. 相似文献
A microbial sensor consisting of immobilized yeast or bacterial cells and an oxygen electrode was developed for the estimation of biochemical oxygen demand (BOD). A flow-through system was used, and the response time was within 20 min. A linear relationship was observed between the relative current decrease and the BOD of the sample solution within the range of 1-45 mg/L. The storage lifetime was > 1 yr. The reproducibility was quite good, within 6% fsd at a concentration of 20 mg/L BOD. Satisfactory results were attained when the biosensor was applied to the determination of BOD in brewery-plant and glutamate-plant wastewater and in a river.
The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion®. The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion®, resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria. 相似文献
A novel BOD biosensor fabricated with the microbial membrane on an oxygen electrode was introduced by using porous A12O3 sol-gel inorganic matrix to immobilize the yeast, which is convenient, rapid, correlating to the results of BOD5 and could be employed for commercial availability in the future. The induced culture technique was used to obtain high active yeast, and this point especially contribute to the higher selectivity and sensitivity, The gelation time to form microorganisms membrane is about 1 h, and the response time is 20min, the response current is steady rapidly, a linear relationship between the response of the sensor and BOD value ranging from 10~70 mg/L, the reproducibility of BOD estimation is good and the lifetime of BOD biosensor is over 30 day at 4℃. 相似文献
A preliminary study using gamma radiation on slaughterhouse wastewater samples was carried out. Chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) results were obtained at a dose rate of 0.9 kGy h−1. A decrease of COD, BOD and colour was observed after irradiation at high absorbed doses. The microbiological results, following irradiation in the same conditions, correlated with the BOD results. The results obtained highlight the potential of this technology for wastewater treatment. 相似文献
We determined a group of estrogenic compounds by solid-phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) with both ultraviolet (UV) and electrochemical detection (ED). A modified liquid chromatograph was used. Polyacrylate fibers (85 microns) were used to extract the analytes from the aqueous samples. Dynamic and static modes of desorption were compared and the variables affecting both absorption and desorption processes in SPME-HPLC were optimized. Static desorption gave the best recoveries and peak shapes. The performance of the SPME-HPLC-UV-ED method was checked with river water and wastewater. The method enabled estrogenic compounds to be determined at low-microgram l-1 levels in real water samples. Limits of detection were between 0.3 and 1.1 micrograms l-1 using UV detection and between 0.06 and 0.08 microgram l-1 using ED. beta-Estradiol was found in samples from a wastewater treatment plant at concentrations between 1.9 and 2.2 micrograms l-1. 相似文献
A μ-bis(tridentate) ligand named 2-phenyl-1,3-bis[3′-aza-4′-(2′-hydroxyphenyl)-prop-4-en-1′-yl]-1,3-imidazolidine (I) has been synthesized and scrutinized to develop iron(III)-selective sensors. The addition of sodium tetraphenyl borate and various plasticizers, viz., chloronaphthalene, dioctylphthalate, o-nitrophenyl octyl ether and dibutylphthalate has been used to substantially improve the performance of the sensors. The membranes of various compositions of the ligand were investigated and it was found that the best performance was obtained for the membrane of composition (I) (10 mg):PVC (150 mg):chloronaphthalene (200 mg):sodium tetraphenyl borate (9 mg). The sensor showed a linear potential response to iron(III) over wide concentration range 6.3 × 10−6 to 1.0 × 10−1 M (detection limit 5.0 × 10−6 M) with Nernstian slope (20.0 mV/decade of activity) between pH 3.5 and 5.5 with a quick response time of 15 s. The potentiometric selectivity coefficient values as determined by match potential method (MPM) indicate excellent selectivity for Fe3+ ions over interfering cations. The sensor exhibits adequate life of 2 months with good reproducibility. The sensor could be used in direct potentiometry. 相似文献
The authors describe a microsensor for the determination of biochemical oxygen demand. Different from established BOD detection schemes that incorporate a film of immobilized microbes, the sensitive element of this BOD microsensor consists of magnetite-functionalized Bacillus subtilis that can be immobilized and regenerated on an ultramicroelectrode array (UMEA). Modification and regeneration are magnetically controlled. The oxygen consumed is amperometrically quantified by using an UMEA modified with palladium nanoparticles and reduced carboxy graphene. The assay can be performed within 5 min owing to the fast mass transfer of the magnetite-functionalized microbes on the surface of the UMEA. The calibration plot, best acquired at a voltage of -0.4 V vs. Ag/AgCl, is linear in the 2 to 15 mg?L?1 BOD concentration range. A critical comparison with other BOD sensor shows the sensitivity of this sensor to be largely improved. It was successful applied to the determination of BOD in spiked water samples.
Graphical Abstract Schematic presentation of the novel biochemical oxygen demand (BOD) microsensor. The sensitive element can be modified and renewed on ultramicroelectrode array by using a magnet. The response time and the sensitivity of the microsensor are largely improved.
A simple and highly sensitive cartridge type nitrate sensing system was developed using titanium trichloride (TiCl(3)) in hydrochloric acid to reduce nitrate to ammonium ion. The system primarily consisted of a nitrate reduction section using titanium trichloride and an ammonia detection section. The nitrate was reduced in a simply made cartridge equipped with filter units and the resulting ammonium ion solution was directly introduced into a flow injection system, where it was neutralized to ammonia and allowed to react with o-phthalaldehyde (OPA). The isoindole thus formed was detected by virtue of its fluorescence, allowing quantitation of the nitrate in the initial sample. Our sensing system has a detection limit of 0.01 mg l(-1) and a dynamic linear range from 0.05 to 2.5 mg l(-1) with response times of less than 5 min for the entire procedure. The system had a relative standard deviation (RSD) of less than 2.56% after more than 30 consecutive measurements of 0.5 mg l(-1) NO(3)(-). The system is unaffected by FeCl(3), Na(2)SO(4) and NaCl at concentrations of 200 mg l(-1) or by biological oxygen demand (BOD) values as high as 110 mg O l(-1). The effects of reaction time and titanium trichloride concentration were also investigated. Furthermore, several river water samples were examined. 相似文献
An electrochemical sensor for paracetamol (PC) based on the hexacyanoferate(III) intercalated Ni−Al layered double hydroxide (Ni−Al−HCF) was presented. The as‐prepared LDH structurally and morphologically was characterized by scanning electron microscopy, X‐ray diffraction, and Fourier transform IR. Electrochemical studies revealed that Ni−Al−HCF film modified glassy carbon (GC) electrode exhibited remarkable electrocatalytic activity toward the oxidation of paracetamol. The electrochemical behavior of PC on the Ni−Al−HCF film was investigated in detail. Under optimum experimental conditions, the electrocatalytic response of the modified GC electrode was linear in the PC concentration range 3×10−6−–1.5×10−3 mol L−1, with a detection limit of 8×10−7 mol L−1 (S/N=3), using hydrodynamic amperometry. In addition, the modified electrode exhibited good reproducibility, long‐term stability and anti‐interference property. The fabricated sensor was successfully applied to determination of PC in various pharmaceutical preparations such as tablets, oral solution, and oral drops. Finally, the method was validated by the analysis of paracetamol spiked human serum samples, and good recoveries were obtained in the range of 99.2–103 %. 相似文献
A novel high-selective potentiometric sensor for molybdate was prepared with a PVC membrane combining mu-oxo-bis[5,10,15,20-tetra(p-methylphenyl)porphinatomanganese(III)] [[Mn(p-Me)TPP](2)O] as an electroactive material and 2-nitrophenyl octyl ether (o-NPOE) as a plasticizer in the percentage ratio of 3:65:32, [Mn(p-Me)TPP](2)O:o-NPOE:PVC (w:w). The sensor exhibited a linear response with a Nernstian slope of 30.5 mV per decade within a concentration range of 2.1 x 10(-6) to 1.0 x 10(-1) M MoO4(2-), with a working pH range from 5.0 to 12.5, and a fast response time of less than 15 s. The electrode showed improved selectivity toward molybdate with respect to common coexisting anions compared to monometalloporphyrin counterparts. Several electroactive materials and solvent mediators were compared and the experimental conditions were optimized. The sensor is preliminary applied to the assay of MoO4(2-) in corrosion inhibitor samples with satisfactory results. 相似文献
A selective oxygen biosensor based on bilirubin oxidase (BOx) was developed. The sensor was used for determining oxygen profiles in a membraneless, single‐chamber microbial fuel cell (SCMFC), fed with raw wastewater. The linear response of the sensor was optimized by a diffusion layer of silica gel. A computer‐controlled stage was used to obtain accurate and precise measurements. Oxygen concentration in biofilms covering electrodes was measured, showing 3 mg L?1 of O2 in the bulk solution, decreasing to 0 mg L?1 in the cathodic biofilm. The MFC generated power in the range of 0–0.08 mW, associated to the oxygen content. 相似文献
Fatty hydroxamic acid (FHA) immobilized in polyvinyl chloride (PVC) has been studied as a sensor element of an optical fibre chemical sensor for V(V). By using this instrument, V(V) in solution has been determined in the log concentration range of 0-2.5 (i.e. 1.0-300 mg/L). The detection limit was 1.0 mg/L. The relative standard deviation (R.S.D.) of the method for the reproducibility study at V(V) concentration of 200 mg/L and 300 mg/L were calculated to be 2.9% and 2.0%, respectively. Interference from foreign ions was also studied at 1:1 mole ratio of V(V):foreign ions. It was found that, Fe(III) ion interfered most in the determination of vanadium(V). Excellent agreement with ICP-AES method was achieved when the proposed method was applied towards determination of V(V). 相似文献