Removal of acid red 151 dye from water by iron-impregnated heat treated egg shell bio-adsorbent

摘要

Acid red 151 (AR151) dye adsorption on iron-impregnated heat treated egg shell (Fe-HTES) with FeCl2, Fe(NO3)(3) and K2FeO4 as iron precursors was studied by using a simple pyrolysis technique. The Fe-HTES performance was analyzed by utilizing scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction, Brunauer-Emmett-Teller, and Barrett-Joyner-Halenda (BJH) surface analysis. The effective parameters on the adsorption process such as pH, point of zero charge (pH(pzc)), initial dye concentration, dose and type of adsorbents raw egg shell (RES), heat treated egg shell (HTES) and Fe-HTES in addition to the adsorption time the dye removal and chemical oxygen demand (COD) removal have been investigated. The results obtained for the dye concentration in the range of 20-100 mg/L, indicated that the experimental adsorption data obeyed the Freundlich model (n < 1, R-2 = 0.981). At optimum pH 3, the adsorbent dose of 2 g/L and the equilibrium adsorption time of 15 min, the maximum dye removal efficiency were obtained as 98.9%, 88% and 78%, respectively, for Fe-HTES, HTES and RES. For the adsorbent Fe-HTES, the maximum adsorption capacity and COD removal efficiency were obtained as 50 mg/g and 93%, respectively. The results also indicated that the adsorption rate of AR151 dye onto the Fe-HTES can be expressed by a first-order rate equation.