Preparation And Adsorption Properties Of Rape Straw/hydrotalcite Composites

Phosphorus is a major factor of eutrophication pollution, At present our country eutrophication situation is grim. Based on the current biomass resources composites, we used composite preparated by biomass materials and clay mineral approach to the removal of phosphorus and humic acid in water. The Mg/Al hydrotalcite and rape straw were used as raw materials to prepare rape straw/hydrotalcite composites through a solution intercalation technique in this paper. The morphology and structure of the composites were characterized by scanning electron microscope(SEM), X-ray diffraction(XRD), infrared spectroscope(FTIR), and the effect of the BET. The optimum adsorption properties of the composites were explored by changing the way they complex, calcination temperature, the mass ratio of rape straw and Mg/Al hydrotalcite and so on. The optimum adsorption conditions of the composites were determined by changing the adsorption temperature, dosage, the initial concentration and so on. On this basis, the adsorption kinetics and thermodynamics of the composites were exprlored. It reveals the adsorption mechanism of phosphorus and humic acid and other anionic contaminants. At the same time, We study Environmental friendliness and reusable performance of composite in the water. The research results of this paper were summarized as follows:(1)The morphology and structure analysis: the composite of hydrotalcite andrape straw material, the average pore size in the composite material(1937.16 nm) is bigger than the average pore diameter of hydrotalcite(432.56 nm), the formation of porous intercalated composite. The composite improves the adsorption properties of composites phosphorus and humic acid after it formed the intercalated structure.(2)The adsorption properties: It found that the adsorption properties of rapestraw and calcined hydrotalcite composite preparated by mass ratio of 1/1 is better than other materials, and it has stable and good adsorption by comparing the effect of adsorption between materials prepared by different methods, such as calcination, physically mixed with uncalcined composite materials, composite of different mass ratio.The material adsorpting humic acid is 0.6/1 mass ratio. The adsorption results indicated that the best adsorption conditions of rape straw/hydrotalcite composites: dosage for phosphorus removal composite is 0.6 g/L, the dosage of humic acid is 0.7 g/L, adsorption temperature is 20℃, the initial concentration of phosphorus is 5mg/L, the initial concentration of humic acid solution is 10mg/L, coexisting ions have a certain impact on the adsorption of phosphorus, the removal rate of phosphorus is more than 94%, the removal rate of humic acid is more than 77%.(3)Adsorption mechanism: the composite adsorption of phosphorus are in linewith second-order kinetic model and Langnmuir isotherm mode. And the presence of HA reduces the adsorption effect when composite adsorpted phosphorus.(4)Environmental friendliness and reusable performance: the determination of dissolution of the compsite in an aqueous solution provides the basis for a new composite as an anion adsorbent possess Environmental friendliness. And we explore the effects of reusing materials in the adsorption experiments by reusing the composite.