Study On The Enhanced Hydrolysis Of Spiramycin In Antibiotic Production Wastewater By Solid Acids

Spiramycin is a kind of widely used macrolide antibiotic and a large amount of production wastewater containing high concentration of spiramycin is produced during its production process.For spiramycin production wastewater,enhanced hydrolysis by solid acids is an effective pretreatment technique with high efficiency and high selectivity.In this study,spiramycin was selected as the target and the hydrolysis efficiency of spiramycin by solid acids enhanced by different methods was studied.The antibacterial potency of the hydrolysis products was evaluated and the hydrolysis mechanism of spiramycin was analyzed in acidic environment.Sulfamic acid was used to enhance the hydrolysis of spiramycin by heteropoly acids.The dosage of sulfamic acid and the hydrolysis temperature were optimized.When the dosage of sulfamic acid and heteropoly acids was 0.3 g/L and 1.0 g/L respectively and the temperature was 35℃,the effective hydrolysis of 20 mg/L of spiramycin can be achieved by the combination of heteropoly acids and sulfamic acid at 40 min.The removal ratio of spiramycin and its antibacterial potency can reach 100%when silicotungstic acid was combined with sulfamic acid.For the spiramycin production wastewater with a concentration of 433 mg/L,the complete removal of spiramycin and the significant reduction of its antibacterial potency were achieved when the dosage of heteropoly acids and sulfamic acid was 20 g/L and 6 g/L respectively.Microwave was used to enhance the hydrolysis of spiramycin by heteropoly acids and silicon-tungstic acid was identified as the optimal solid acid.When the dosage of silicotungstic acid was 1.0 g/L and the microwave power was 200 W,100 mg/L of spiramycin was completely removed at 8 min and the removal ratio of antibacterial potency can reached 98%.The identification of hydrolysis products and the analysis of hydrolysis pathway were carried out by ultra-performance liquid chromatography with time-of-flight mass spectrometry(UPLC-Q/TOF-MS),which showed that mycarose,forosamine and mycaminose were removed from the molecule structure of spiramycin as a result of the cleavage of glycoside bonds.For spiramycin production wastewater with a concentration of 433 mg/L,the complete removal of spiramycin and its antibacterial potency can be achieved at 6 min when microwave power was 500 W and the dosage of silicotungstic acid dosage was 10 g/L.A variety of sulfonated biochars were prepared by different sulfonating reagents and different sulfonation methods and the characterization was conducted.H3 and X3 had the highest total acidity and-SO3H acidity.The hydrolysis performance of spiramycin by sulfonated biochars was evaluated under microwave heating.When the microwave power was 200 W and the dosage of sulfonated biochars was 1.0 g/L,the removal ratios of 40 mg/L of spiramycin by H3 and X3 were 94%and 100%in 10 min,respectively.The removal ratios of its antibacterial potency were 93%and 99.5%,respectively.This study systematically explored the hydrolysis efficiency of spiramycin by different solid acids and evaluated the antibacterial potency of the hydrolysis products.The hydrolysis mechanism of spiramycin was analyzed as the cleavage of glycosidic bonds in the molecular structure leads to the detachment of its pharmacological functional groups,thereby reducing its antibacterial potency.Solid acids used in this study can effectively treat spiramycin production wastewater with high concentration in a short time.Technologies for rapid and efficient pretreatment of spiramycin production wastewater were initially established.