Barazandeh, Asma and Karyab, Hamid (2021) Optimization of malathion and diazinon adsorption from aqueous solution by nano polypropylene titanium dioxide (Nano-PP/TiO2). Masters thesis, Qazvin university of medical sciences, Qazvin, Iran.
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Abstract
Background Aim: One of the most important environmental problems is the pollution of aquatic environments due to human activities. Among the pollutants in aquatic environments, we can mention pesticides caused by agricultural runoff. The results of several studies have shown that the use of pesticides causes human health problems such as abortion, mental retardation, fetal defects and carcinogenic potential and mutations. The capability of PP/ TiO2 nanosorbent has been proven in previous studies in the adsorption of organic compounds from water; but so far this adsorbent has not been used to remove organic toxins. Therefore, the aim of this study was to evaluate the adsorption of organophosporous pesticides, including Malathion and Diazinon, by Nano-PP/Tio2. Materials and methods: Polypropylene fibers were exposed to humid heat for 90 minutes at an optimum temperature of 64 ° C. The fibers were coated using immersion in the vicinity of ultrasonic waves with a power of 50 watts and a frequency of 10 kHz at a temperature of 40 ° C. At each stage of the experiment, the amount of one gram of adsorbent was placed in polyamide packages with an aperture diameter of 200 μm. A shocking device (shaker) with a speed of 100 rpm was used for proper mixing of the adsorbent and adsorbent material. After the desired contact time, the residual concentrations of toxin in the solution were analyzed using gas chromatography. Stock solution of 20,000 mg / l of diazinon and malathion was prepared using methanol solvent and toxin standard prepared by Sigma Aldrich. To draw the calibration curve, standard diazinon and malathion solutions with concentrations in the range of 1000 μg / l to 1 μg / l were prepared and the samples were injected by gas chromatography (FID detector and CAPILARY column) with 3 repetitions. In the continuation of the study, according to the calibration curve, the concentration of unknown samples was determined. Absorption optimization was investigated using Design expert software. The parameters studied for entering the software included contact time, adsorbent dose and initial concentration of diazinon and malathion toxins. The study time was limited to 5 to 60 minutes. The initial concentration of toxins was in the range of 2 to 1000 micrograms per liter. The adsorbent dose in the range of 0.5 to 4 g / l was evaluated. Results: Experimental data showed that the removal rate of diazinon by Nano-PP/TiO2 was 64.8%. In addition, the removal percentages in different concentrations of 20 mg/l, 10 and 0.005 were 79.55 ± 74.20, 53.79 ± 53.23, 13.55 ± 36.28 respectively. Batch adsorption studies showed that the Langmuir Type 2 model is suitable with equilibrium adsorption data on Nano-PP/TiO2. In addition, the results showed that the adsorption kinetics follow the quasi-second-order model. This means that adsorption processes can be described by two-step propagation. In summary, it can be concluded that Nano-PP/TiO2 has a good affinity for organophosphate pesticides and has made nano-pp/TiO2 a suitable and efficient adsorbent for the treatment of water and wastewater sources containing such contaminants. Conclusion: The present study shows that Nano-PP/TiO2, a recently developed adsorbent, is an effective adsorbent for the removal of diazinon, an organophosphate pesticide, from water and wastewater sources.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | R Medicine > RN Health > RN1002 Enviromental Health |
| Divisions: | University Thesis > Faculty of Health > Environmental Health |
| Depositing User: | Health School Students |
| Date Deposited: | 30 Jun 2021 07:31 |
| Last Modified: | 30 Jun 2021 07:31 |
| URI: | http://eprints.qums.ac.ir/id/eprint/10857 |
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