Potential bio-adsorbent synthesized using sugarcane bagasse for removal of cesium ions from aqueous media

Magnetic activated carbon was synthesized using sugarcane bagasse (SC400), and its physicochemical properties (the surface morphology, thermogravimetric–differential thermal behavior, FT-IR, specific surface area, acidic functional group content, and point of zero charge) were characterized. The specific surface area and pHpzc of SC400 was greater than that other SC samples. Amount of acidic functional groups were opposite trends. The amount of cesium ions adsorbed on SC400 was greater than those on other SC adsorbent samples. The adsorption kinetics data indicated that equilibrium was reached within 1 h, and the results fit the pseudo-second-order model (correlation coefficient: 0.996) more closely than the pseudo-first-order model (correlation coefficient: 0.178). Furthermore, the adsorption isotherm data were better described by the Langmuir model (correlation coefficient: 0.979–0.990) compared to the Freundlich model (correlation coefficient: 0.907–0.980). Hence, adsorption mainly occurred in a monolayer. Also, SC400 was a useful adsorbent for solid–liquid separation and cesium ion removal under our simulated experimental conditions. Following adsorption, the presence of cesium (Cs) on the SC400 surface was confirmed by elemental distribution and binding energy measurements. In addition, adsorption capacity of cesium ion onto SC400 increased with increasing pH. Collectively, the optimal conditions for cesium ion removal were as follows: temperature of 5 °C, adsorption time of 3 h, and pH between 6 and 8. Cations such as sodium ions and potassium ions affected the cesium ion adsorption capacity in complex solution systems. Finally, a desorption solution, namely sodium hydroxide or hydrochloric acid, made it easily desorbed the cesium ions adsorbed on SC400. Overall, SC400 showed promising properties as an adsorbent for the removal or recovery of cesium ions from aqueous media.