Application Of Modified Electrode In Determination Of Industrial Wastewater

According to the nature of the main pollutants, industrial wastewater pollution can be classified into organic pollutants and inorganic pollutants. Once the water is polluted by industrial pollution a harmful effect would be made on people’s life and health. Though a great price has been paid for environment restoration, it is difficult to recover to its original state in a short period of time. In this paper, some fast and effective electrochemical methods were established to monitor the industrial wastewater pollution.6-benzyladenine and Pb2+, as the typical representative of organic and inorganic pollutants and pollution marker-DNA base have been monitored by this method. The method provides an important theoretical basis and effective guidance for the rapid detection of the industrial pollution with low cost.Part 1:Voltammetric determination of 6-benzylaminopurine (6-BAP)based on a grapheme film modified glassy carbon electrodeIn this paper, a novel electrochemical biosensor was built to determine 6-benzy laminopurine by graphene modified electrodes. Experiment showed cyclicvoltammograms that the graphene modified electrodes could significantly reduce the measuring potential and increase the response current during the determination process. The 6-benzylaminopurine experienced a diffusion control process at the surface of the electrode. A good linear relationship between the current and the concentration of 6-BAP in the range of 1.0×10-8-1.0×40-5 mol/L of with the detection limit of 5.0×10-9mol/L was obtained. The sensor was applied to actual samples and standard recovery with the rate ranging between recovery 91.3%-106.4% was obtained. This indicated an ideal result. At the same time, the electrode showed good stability and reproducibility.Part 2:Voltammetric determination of Pb2+using polyforchlorfenuron as internal standardA novel electrochemical method for the quantification of lead ions has been constructed by using the electrochemical signal of polyforchlorfenuron (pCPPU) as the internal standard. The anodic peak current of CPPU stayed stable after several times of scanning with the differential pulse voltammetry, which indicate that (pCPPU) could be used as an internal standard solution to determinate Pb2+ quantitatively. Under the optimized conditions, the peak current ratio between Pb2+ and pCPPU was proportional to the concentration of Pb2+in the range of 5.0×10-8-1.2×10-6mol/L and the detection limit was down to 2.0×10-8 mol/L. The proposed method was successfully applied to detect Pb2+ concentration in the wastewaters samples of Lead battery factory, the results showed that the Pb2+concentration was about 8.2×10-8 mol/L, which was close to the value of 8.5×10-8 mol/L of the national standard method (atomic absorption method). Therefore, this method is valid for real sample analysis.Part 3:Electrochemical detection of bases on carbon-doped Boron nitride modified carbon paste electrodeBoron nitride nanotubes possess two-dimensional hexagonal structure which is similar to graphene. It is also a type of semiconductor material with a wide band gap. In addition, h-BN exhibits an exciting ability to capture molecules and nanoclusters. These advantages show that h-BN is a promising substrate for self-assembly devices and biosensors. The result of boron nitride and only carbon modified carbon paste electrode for determination of the four bases was contrasted through experiment. The results show that boron nitride electrode has an obvious catalytic effects towards the oxidation of guanine and adenine, thymine and cytosine with high sensitivity, low detection limit. The peak separations between G and A, A and T, T and C are 244 mV,110 mV and 186 mV respectively. This means the four oxidation peaks were well separated.