Study Of The Adsorption Of Methyl Orange And Methylene Blue In The Aqueous Solutions By Natural Zeolite

The adsorption technique is proved to be an effective and attractive process for the treatment of refractory pollutants from wastewaters. If the adsorbent material used is of cheaper cost and does not require any expensive additional pretreatment step, this method will become inexpensive and has economic, social and environmental meaning. The aim of this study is to develop a cheap technology for the removal of methyl orange(MO) and methylene blue(MB) from wastewater.The characteristics of natural zeolite are studied by thermogravimetry analysis(TGA), differential thermal analysis(DTA), Fourier-Transform Infrared Analysis spectroscopy(FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy/An energy dispersive X-ray Spectra(SEM/EDS). The FT-IR spectra of zeolite composed of the peaks of sorbed water, vibration of framework and Si-0 or Al-O. The analysis of XRD showed the zeolite is clinoptilolite. The surface of zeolite is rough and it is composed of some elements, such as silicon, oxygen, aluminum and potassium, etc. The natural zeolite is thermal stable and its surface and average diameter of pore is 24.9 m²Â·g^-1, 28.7 (?), respectively.Adsorption of the objective MO and MB by zeolite strongly depends on pH, contact time, initial concentration of the adsorbate and adsorbent dosage. The adsorptive process had nearly reached equilibrium after 300 contact time. The experimental data for MO and MB systems all fitted the Langmuir isotherm model excellently. The maximum adsorption capacities of MO and MB per gram zeolite were calculated as 5.96 mg(288K), 16.0 mg (298K), respectively. The process of MO and MB uptake onto zeolite followed the psuedo second-order rate expression and suggesting that the biosorption mechanism might be a chemisorption process. Using the equilibrium concentration contants obtained at different temperatures, various thermodynamic parameters, such asâ–³G⁰,â–³H⁰ andâ–³S⁰, have been calculated. The thermodynamics parameters indicate the spontaneous and endothermic process for dye/zeolite systemZeolite can adsorb MB from solution in fixed-bed column, and the effect of two important parameters, current velocity and the initial MB concentration of inflow, was discussed. The data were fitted to Thomas model equations using linear and non-linear regressive analysis, respectively. Present investigation showed that the linear and non-linear methods are both suitable to predict the breakthrough curves using Thomas model parameters and the non-linear method is better. The Effect of bed depth was also studied and BDST model was used to calculate the relative constants.The results show that zeolite as low cost adsorbent may be used effectively in removal of MO and MB from aqueous systems for environmental cleaning purposes.