| Oxidation-reduction reaction was adopted to prepare the adsorbent of manganese oxide coated zeolite (MOCZ) in this research. The characterization of MOCZ was analyzed by FTIR, XRD and specific surface area analysis and the adsorption properties for Rhodamine B (RhB) and p-Chlorophenol (p-CP) onto MOCZ were performed. The system of adsorption was innovative.There were large surface areas, high physical-chemical endurance for MOCZ. The pH at zero point charge (pHzpc) of MOCZ used in the present work was determined as 2.05. The content of MnO2 on the surface of MOCZ was 0.433%.The adsorption process for RhB and p-CP by MOCZ was operated in two ways of static and mobile adsorption. The effect of various experimental conditions, such as pH, adsorbent dosage, coexisting ions, contact time, initial concentration of the adsorbate and temperature were studied in batch adsorption. The results showed that the pH value of 2.00 was favorable for removal of RhB and p-CP. The presence of Na+and Ca2+had no obvious influence on the adsorption behavior. The adsorption capacity for RhB and p-CP was 12.5 mg·g-1 and 5.53 mg·g-1 at 295 K, respectively. The adsorption of RhB onto MOCZ was spontaneous and endothermic according to the thermodynamic parameters. But adsorption of p-CP was also spontaneous and the temperature had no obvious effect on adsorption. The equilibrium data for RhB and p-CP was all fitted well to the Langmuir and Redlich-Peterson isotherm models.The kinetics adsorption process of RhB and p-CP consisted of two phases:an initial rapid phase and a slower second phase. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of RhB and p-CP onto MOCZ. The adsorption rate had been found to be the adsorbate concentration and temperature dependent. The activation energy of adsorption (Ea) of RhB and p-CP onto MOCZ were determined as 28.0 and 12.0 kJ·mol-1, respectively. So it can be concluded that chemical adsorption may be predominant during the adsorption process of RhB and p-CP onto MOCZ.In the study of fixed-bed column, adsorption of RhB and p-CP onto MOCZ strongly depended on bed height, initial concentration of adsorbate, flow rate and pH. A variety of dynamic models were used to predict the breakthrough curves, and the Yan and BDST models were the best choices to describe the adsorption behavior of RhB and p-CP onto MOCZ.Through error analysis, some adsorption models were fitted according to experimental data by linear regressive analysis method and nonlinear regressive method and the errors were compared. The results implied that both methods can be used to predict the adsorption process.The regeneration research was also preformed. It was proved that 0.01 mol-L"1 NaOH solution was the best for the regeneration and reuse of MOCZ for removal of RhB from water. The desorption percentage and regeneration percentage increased with the increase of regeneration cycles. However, there were no efficient methods for the regeneration and reuse of MOCZ for removal of p-CP from water, so the more efforts should be taken to find them in the subsequent studies. |
