Hydrothermal deposition of titanate on biomass carbonaceous aerogel to prepare novel biomass adsorbents for Rb+ and Cs+

Biomass adsorbents derived from pomelo peels were synthesized by modifying biomass carbonaceous aerogels (BCA) and carbonized biomass carbonaceous aerogels (CBCA) with sodium titanate and potassium titanate through a hydrothermal deposition process. The prepared adsorbents were characterized by SEM, XRD, FTIR, TG-DTG, BET isotherm, XPS, and then used for the adsorption of Rb+ and Cs+ from the aqueous solutions. The effects of ion concentration, contact time, temperature, solution pH and ionic strength on the adsorption of Rb+ and Cs+ were investigated systematically. In addition, the adsorption kinetics and isotherms were studied and the adsorption data were better fitted with pseudosecond-order kinetics and Langmuir adsorption isotherm models, respectively. The characterization and adsorption data proved that the prepared adsorbents had excellent adsorption properties for Rb+ and Cs+ from the aqueous solutions. The maximum adsorption amounts of Rb+ and Cs+ are 1.84 and 1.60 mmol/g, respectively. From the analysis of adsorption mechanism, the ion exchange reaction could occur between Na+ of sodium titanate or K+ of potassium titanate on the adsorbents and Rb+ or Cs+ in the solution which enhanced the adsorption existed on the surface of adsorbents.