Research Of Nano-zeolite Composite As Adsorbent For The Removal Of Benzene Hydrocarbons In Water

Because of the great specific surface area, nano-zeolite and diatomite have good adsorption performance. Compared with zeolite or diatomite, the composite compounded reasonably by zeolite and diatomite has better adsorption capacity on benzene hydrocarbons in water. Besides, the weight of zeolite used is decreased, and the cost reduced correspondingly. The main experiment and conclusions are as follows:(1) Using single-factor analysis and perpendicular experiment, we confirmed the best proportion, the best condition and the removal rate under the optimal condition of composite on each benzene hydrocarbon respectively. And then we analyzed the adsorption mechanism elementarily through the adsorption isotherm. We found that the adsorption isotherm of composite on benzene accords with Langmuir model. And the adsorption isotherm of composite on toluene, xylene and styrene have great deviation from this model. The adsorption isotherm of benzene and styrene are type-â…¡according to the Brunauer classification, and the adsorption isotherm of xylene shows more steps. So we could draw the conclusion that the adsorption isotherm of composite on each benzene hydrocarbon are different. Besides, the results suggest that the adsorption capacity of composite on benzene, toluene and xylene increase as the molecular weight increasing. This result shows that Keesom force play an important role on the adsorption.(2) The optimal parameters of coagulation for treating composite in water was acquired by experiment, when coagulation time is 20 min, the proportion of PFS:PAM is 1:2, the usage of coagulation is 1ml and the settlement time is 20min. Under these conditions the turbidity of the disposal water is below 3, moreover, the removal rate of xylene reaches 84% and the retrieve rate of composite increases also.(3)After comparision, we chose heating method to regenerate the composite. When the tempe- rature is 400 degree centigrade, and the regeneration time is 2 hours, the regeneration effect is optimized. Under this condition, even the fourth regeneration rate still could reaches 89%.(4) Material is characterized. Observing through SEM and TEM, we could found that the diameter of zeolite particle is during 10²0nm, the diameter of straight chain diatomite is between 8μm and 20μm, and the diameter of discoid diatomite is between 15μm and 20μm. From the diagram of TGA and DGA, we could draw the conclusion that the adsorption capacity of diatomite could be increased by heating method under appropriate temperature. The results of FTIR analysis show that there are several libration between 1510 cm^-1 and 1529 cm^-1, and this result can sufficiently prove the adsorption of benzene hydrocarbons.