Effect of heating processes on Salvadora persica (Miswak) and its application for removal and determination of aniline blue from wastewater

Effect of heating processes of Salvadora persica (Miswak) with different temperature (308, 378 and 523 K) on the Miswak matrix was studied. Miswak after heating was characterized using different tools such as elemental analysis, IR spectroscopy, nuclear magnetic resonance and scanning electron microscopy. The sorption properties of Miswaks behavior for removal of aniline blue from aqueous solution were investigated using a batch processes. The maximum uptake of aniline blue was found to be in pH range 1–2. The kinetic behavior of the sorption of the aniline blue was found to be fast with average values of half-life of sorption (t1/2) of 30 s. The equilibrium process is well described by the Freundlich isotherm model, which attributed to the heterogeneous surface structure of the Miswak. The average capacity of the Miswak material was 0.37 mmol/g for aniline blue dye. The average values of thermodynamic parameters, ΔH and ΔG are −14.7 and −31.7 kJ/mol, respectively. The sorption data indicates that the sorption of aniline blue onto Miswak proceed via both solvent extraction and ion association mechanism. Miswak was verified as a good biosorbent by aniline blue removal from wastewater.