Liquid phase adsorptions of Rhodamine B dye onto rawudand chitosan supported mesoporous adsorbents: isothermsudand kinetics studies

摘要

Irvingia gabonensis endocarp waste was charredud(DNc) and subsequently coated with chitosanud(CCDNc). Physicochemical characteristics of the twoudadsorbents were established, while Fourier transformudinfrared (FTIR), Scanning electron microscopy (SEM) andudBrunauer–Emmett–Teller (BET) surface area methodsudwere further employed for characterization. Efficiencies ofudthe prepared adsorbents in the uptake of Rhodamine Bud(RhB) from aqueous effluent were investigated andudadsorption data were tested using four isotherms and fourudkinetics models. The BET surface areas of the preparedudadsorbent were 0.0092 and 4.99 m2/g for DNc andudCCDNc, respectively, and maximum adsorption wasudrecorded at pH between 3 and 4, respectively. Whileudmonolayer adsorption dominates the uptake of RhB ontoudDNc, uptake of RhB onto CCDNc was onto heterogeneousudsurface. The maximum monolayer adsorption capacitiesud(qmax) obtained from the Langmuir equation are 52.90 andud217.39 mg/g for DNc and CCDNc, respectively. Pseudoudsecond order and Elovich kinetic models well described theudkinetics of the two adsorption processes. The mean sorptionudenergy (E) calculated from the D-R model and desorptionudefficiencies suggests that while the uptake of RhBudonto DNc was physical in nature, for RhB-CCDNc systemudchemisorption dominates