Removal of Eriochrome Black T dye from aqueous solution using base activated typha grass (Typha latifolia) as an adsorbent

Abstract

Adsorption of Eriochrome Black T (EBT) dye from aqueous solution by activated typha grass (T. latifolia) was studied using batch system. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) methods, as well as the point of zero charge (PZC). Adsorption parameters including effect of contact time, adsorbent dose, initial dye concentration and pH were studied and the adsorption capacity (qe) was found to be 47.619mg/g. The adsorption isotherm for the adsorption processes were also modelled and evaluated and the data fitted Freundlich isotherm model with R2 of 0.9943 relative to other models tested. The kinetic data were best described by pseudo-second order model with R2 values of 0.999 and rate constant (k) of 6.30mol-1dm3s-1 out of the four models tested. The thermodynamic quantities of the adsorption process including the entropy change (ΔS) which describe the degree of disorderliness of the dye-adsorbent interphase was found to be 2.108Jmol- 1K-1 indicating an increase in the interphase disorderliness, the enthalpy change (ΔH) describing the nature of energetic interaction between the dye molecules and the adsorbent surface has a value of -9.223kJmol-1 proving an exothermic process and the Gibbs free energy change (ΔG) of the range -8.563 to -8.718kJmol-1 were obtained indicating the process to be feasible and spontaneous in nature. Hence, the activated carbon produced from typha grass can be a potential adsorbent for the removal of hazardous dyes such as Eriochrome Black T from industrial effluent.