Study On Surface Properties And Optimization Of Modified-pulullan Absorbent

In this study, surface complexation models have been used to study the surfaceproperties of composite adsorbent MgOP and calculate its intrinsic surface adsorptionconstants. Further more, a series of experiments has been taken to study the interactionbetween MgOP and pH in solution.The study of surface complexation models on MgOP showed that: the increase of Cl-concentration could promote the surface reaction of MgOP, and the changes of NO3-have no impact on its surface reaction. Experiments showed that the initial pH of thesolution has no effect on the adsorption capacity of MgOP, but it has a significant impacton its adsorption rate. The reason is that MgOP surface hydroxyl groups will react withthe H+or OH-and form electriferous groups when the solution is acidic or alkaline. Therank of fluoride-binding capacity of these electriferous groups is: positively electriferousgroups> negatively electriferous groups> unelectriferous groups, resulting in differentabsorption rates in different solution pH. But because the total surface active group has notchanged, so that the adsorption capacity is not influenced.Aluminum salts had been used with MgOP for defluorination to investigate theirregulation of the pH of the solution after the treatment. The results showed that: threecommonly used aluminum salts(aluminum chloride, aluminum nitrate, aluminum sulfate)could reduce the pH of treated solution in a certain proportion with MgOP, ensuring itsdefluorination performance.Artificial neural network model had been used to simulate the breakthrough curves ofMgOP dynamic adsorption in fixed bed. The results showed that: correlation of this modelis superior to Thomas model and Yan model. What`s more, this model is independent tothe changes of reaction conditions and parameters, so it is more suitable for MgOP’spractical applications.Finally, reactive red X-3B had been taken as adsorbate to investigate MgOPadsorption capacity of organics, the results showed that: MgOP has a adsorption capacityof99mg X-3B/g and the removal rate reached over99%in60min, with the initial X-3Bconcentration is200mg/L and MgOP dosage is2g/L. After all, MgOP, with an excellent adsorption performance, not only could be appliedto defluorination, also could be applied to remove other pollutants. Additionally, surfacecomplexation model and artificial neural network model can be applied to research anddevelopment of adsorbent.