Study On The Adsorption Behaviors Of Anion-cation Surfactants Modified Palygorskite For Organic Materials In Water

With the development of the composite materials, the requirement of the modified inorganic composite materials was increased rapidly. Because of its advantages of abundant reserves,low prices and the stability of the physical and chemical properties, the different composite materials prepared from clays attracted extensive attention. After being modified by organic materials, the inner and outer sueface of the clay transfer from hydrophobic to hydrophilic, the affinity between the clay and the organic materials is increased, which can not only effectively remove the organic matter in wastewater, but also to further expand the scope of application of clay. Based on the review of the properties, modified methods and the applications of the palygorskite, the dissertation include following contents:1. The anion-cation surfactants modified palygorskite were preparaed by adopting microwave assistant and the convention methods, and there were characterized by element analysis, FTIR spectra and the SEM.2. The sorption property of modified palygorskite for benzene,hydroquinone, p-nitrophenol and methyl orange in water were studied. The effects of type of the cation surfactant, the ratio of anionic surfactant to cationic surfactant, amount of the surfactant, microwave irradiation time, the amount of the adsorbent, pH, temperature and sorption time on the removal of benzene, hydroquinone, p-nitrophenol and methyl orange were investigated. Comparing to natural palygorskite, the adsorption capacity of anion-cation modified palygorskite is higher in the treatment of benzene, hydroquinone, p-nitrophenol and methyl orange.3. The maximum removal rate of benzene was 93.66% and the maximum adsorption capacity for benzene was 1276.57mg.g-1. The adsorption isotherms were regression analyses with the Freundlich equations and Langmuir equations, but the Langmuir equation is better. Thermodynamic function calculation shows that the adsorption is a spontaneous and endothermic process. Enthalpy and entropy change of the sorption of benzene are 61.05 kJ·mol-1 and 223.73J·mol-1·K-1 , respectively. Free energy of the adsorption decreases with the increase of temperature.4. The maximum adsorption capacity for hydroquinone was 137.47mg·g-1. The adsorption equilibrium was in accordance with the Langmuir isothermal adsorption equations. The thermodynamic parameters were calculated, and the enthalpy(△H) and entropy (△S) of the adsorption were -93.58kJ·mol-1, -299.32J·mol-1·K-1, respectively, which showes that the adsorption is a spontaneous and exothermic process.5. The maximum adsorption capacity for p-nitrophenol is 137.74mg·g-1. The adsorption equilibrium is in accordance with the Langmuir isothermal adsorption equations, but the Langmuir equation is better. Thermodynamic function calculated shows that the adsorption is a spontaneous and exothermic process. The adsorption enthalpy and entropy change of p-nitrophenol are 59.16 kJ·mol-1 and 205.48J·mol-1·K-1, respectively. Free energy of the adsorption increases with increasing of the temperature. The adsorption of p-nitrophenol is a pseudo-second-order process.6. The maximum sorption capacity for methy orange was 121.77mg·g-1,the maximum removal rate of methyl orange was 98.80%. The sorption isotherms were regression analyses with Langmuir equations better. Thermodynamic function calculation shows that the adsorption is a spontaneous and exothermic process. Enthalpy and entropy change of the adsorption of methy orange are -8.80kJ·mol-1 and -18.01J·mol-1·K-1, Free energy of the adsorption increases with the increase of temperature.