Behaviors and mechanisms of cadmium/lead adsorption by natural bamboo fibers modified with succinic acid
After pretreatments of alkalization and acidification,the natural bamboo fibers underwent esterification reaction with succinic acid to produce modified bamboo fibers.Infrared spectroscopy(FTIR)and scanning electron microscopy(SEM)analysis indicated that,after modification,the electronegative carboxyl and ester groups in bamboo fibers increased,and their microstructure changed from dense and flat to wrinkled and porous simultaneously.The adsorption experiments showed that the modified bamboo fibers achieved significantly higher adsorption rates of cadmium(Cd)and lead(Pb)than natural bamboo fibers(up to 47.37％and 44.57％,respectively),and could also be applied to a wider pH value range.The adsorption of Cd and Pb by modified and unmodified bamboo fibers conformed to both Langmuir and Freundlich thermodynamic models.Besides,after modification the maximum adsorption capacity(Qm)of the bamboo fibers for Cd and Pb increased from 8.9687mg/g and 11.5075mg/g to 26.1780mg/g and 32.3625mg/g respectively,indicating that the modification process of succinic acid increased the adsorption sites of the bamboo fibers,and thus improved their adsorption capacity of Cd/Pb,which can provide a new idea for the modification and upgrading of biosorbent materials.
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维普
