Using agricultural waste pineapple peel as raw material,pineapple peel powder was modified by ultrasonic wave and thermal wave respectively with citric acid,and the removal effect of methylene blue by modified pineapple peel was explored.The pore and surface structures of pineapple peels before and after modification were characterized by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR),and the effects of dosage,pH,reaction time and dye mass concentration on the adsorption of methylene blue were also investigated before and after modification.The experimental results showed that carboxyl functional groups were introduced on the surface of pineapple peel modified with citric acid,and the adsorption effect on methylene blue was significantly increased.The removal of methylene blue by citric acid ultrasonically modified pineapple peel(PA-US)and citric acid thermally modified pineapple peel(PA-TM)could reach 65%and 98%under the conditions of adsorbent dosage of 1.2 g·L-1,starting pH of 6.52,modification time of 90 min,and starting concentration of 100 mg·L-1,respectively.The adsorption isotherm studies showed that both PA-US and PA-TM conformed to the Langmuir isotherm model,indicating that the adsorption process was monomolecular layer adsorption,and the maximum adsorption of methylene blue was 56.05 mglu-1 and 333.33 mg·g-1,which were 1.39 times and 8.08 times higher compared with that of the maximum adsorption of unmodified pineapple peel(PA),respectively.The adsorption kinetic studies showed that the adsorption of methylene blue by both PA-US and PA-TM conformed to the quasi-secondary kinetic equation model.From the adsorption isotherms and kinetic modeling results,it was inferred that the adsorption process belonged to chemisorption.
NETL
NSTL
万方数据
