Treatment Of Wastewater From Amantadine Production By Fenton-Ultrasound Oxidation And Recovery Of Hydrobromic Acid By Bipolar Membrane Electrodialysis

Wastewater generated during amantadine production is a kind of pharmaceutical wastewater with poor biodegradability, complicated components, and high concentration of inorganic ions. There are a large amount of amantadine structure-containing organic matters in the wastewater, which makes the wastewater very hard to be treated. This study aims at breaking the amantadine structure and reducing the organic matters in the wastewater. To achieve the goal, advanced oxidation process was employed to treat the wastewater from amantadine production. For the high-concentration bromide ions existing in the wastewater, bipolar membrane electrodialytic was used to recover the HBr, which can realize the resourcezation of wastewater.Fenton oxidation was employed to treat simulated amantadine wastewater. Influences of initial pH, dosage of H2O2, reaction time and H2O2/Fe2+were studied. The optimum reaction conditions were initial pH of3.0, H2O2dosage of98mmol/L, FeSO4dosage of33mmol/L, and reaction time of40min. After the treatment under the optimum conditions, the COD removal reached about90%, and B/C rose from0.08to0.53. The intermediate products in the reaction process were detected by Excitation-Emission Matrix spectra and GC-MS. EEM results showed that aromatic protein-like substances, tryptophan protein-like substances, visible fulvic-like substances and UV fulvic-like substances were generated and further degraded during the Fenton process. GC-MS results showed that the cage structure of amantadine was firstly broken by Fenton reagent, and substituted aromatic aldehydes, aromatic esters or aromatic acids were generated as the main intermediates, then these intermediates were decomposed to long-chain alkanes and amides, and finally were converted into CO2and H2O. A degradation pathway of amantadine was proposed according to the intermediates.Fenton oxidation was adopted to treat the real wastewater from amantadine production, and the results showed that only17%of TOC was removed by Fenton process, which is much lower than the treatment efficiency of simulated amantadine wastewater. The results of wastewater treatment with Fenton-ultrasound process indicated that the TOC removal reached65.6%, which is18%higher than the sum of single ultrasound and single Fenton treatment, showing an obvious synergy effect. The optimum operating conditions were initial pH of3.0, H2O2dosage of2mol/L, H2O2/Fe2+molar ratio of20, ultrasound density of5W/ml. Fenton process reduced the toxicity of wastewater by50%while ultrasound process showed no obvious effect on toxicity reductiuon. The detection of treated wastewater by EEM and GC-MS showed that the Fenton-ultrasound process effectively removed the organic matters in the wastewater, especially the biodegradation-resistant matters containing benzene ring. The contaminants in the wastewater were reduced to a large extent.HBr in the wastewater was recovered by bipolar membrane electrodialysis process. The results showed that the recovery rate of HBr was above90%, average current efficiency reached about80%, and the energy consumption was0.135kWh/mol with the operating voltage of15V, initial solution volume ratio between salt chamber and acid chamber of1and Na2SO4concentration of0.4mol/L, which indicated that the bipolar membrane electrodialysis is suitable for the desalination and recovery of HBr in the wastewater.