Adsorption studies of etherdiamine onto modified sugarcane bagasses in aqueous solution.

In this study sugarcane bagasse was modified with succinic anhydride and EDTA dianhydride to obtain SCB 2 and EB adsorbents, respectively. These adsorbents were used to remove etherdiamine, which is used for iron ore flotation from single aqueous solutions. The removal and recovery of etherdiamine is important for environmental and economic reasons due to its toxicity and high cost. The results demonstrated that adsorption of etherdiamine by SCB 2 and EB was better fitted by a pseudo-second-order kinetic model than pseudo-first-order and Elovich models. Adsorption isotherms were better fitted by the Langmuir model rather than the Freundlich, Sips, and Temkin models. The maximum adsorption capacities (Qmax) of SCB 2 and EB for etherdiamine adsorption were found to be 869.6 and 1203.5 mg/g, respectively. The calculated ΔG° values for adsorption of etherdiamine on SCB 2 (-22.70 kJ/mol) and EB (-19.10 kJ/mol) suggested that chemisorption is the main mechanism by which etherdiamine is removed from the aqueous solution for both adsorbents. The high Qmax values showed that SCB 2 and EB are potential adsorbents for recovering the etherdiamine and treating effluents produced from iron ore flotation.

Adsorption studies of methylene blue and gentian violet on sugarcane bagasse modified with EDTA dianhydride (EDTAD) in aqueous solutions: kinetic and equilibrium aspects.

In this study the adsorption of cationic dyes by modified sugarcane bagasse with EDTA dianhydride (EB) was examined using methylene blue (MB) and gentian violet (GV) as model compounds in aqueous single solutions. The synthesized adsorbent (EB) was characterized by FTIR, elemental analysis, and BET. The capacity of EB to adsorb dyes was evaluated at different contact times, pH values, and initial dye concentrations. According to the obtained results, the adsorption processes could be described by a pseudo-second-order kinetic model. The adsorption isotherms were well fitted by the Langmuir model. Maximum adsorption capacities for MB and GV on EB were found to be 202.43 and 327.83 mg/g, respectively. The free energy change during adsorption of MB and GV was found to be -22.50 and -24.21 kJ/mol, respectively, suggesting that chemisorption is the main mechanism controlling the adsorption process.