[Characteristics of U (VI) biosorption by biological adsorbent of platanus leaves].

The platanus leaves were used as adsorbent to study uranium removal efficiency from aqueous solution on the basis of adsorption kinetics and isotherm equations. Static adsorption affected by initial pH values and contact time was analyzed, and surface characteristics of platanus leaves and uranium removal mechanism were investigated with the help of SEM, FTIR, XRD and XRF. The adsorption process fits pseudo-second-order kinetic model and Freundlich isotherm equation, and the maximum adsorption capacity for uranium was 19.68 mg x g(-1). Results showed that hydroxyl groups, amides II belt and carboxyl active functional groups were important for uranium removal. Structure characteristic adsorption band of cellulose was found in XRD spectra, uranium was detected, and also Ca and Na elements of the content increased. Mg element content relative decrease was found on platanus leaves after adsorption by XRF, and it proved the reaction feasibility. Speculation for the behavior of uraniu adsorption by platanus leaves was both physical adsorption and chemical adsorption, exhibiting joint action of electrostatic attraction, redox reaction, chelating ligand and ion exchange.