Synthesis Of Mg/Fe Hydrotalcite Compounds And Adsorption Of Sulfate Ions Water

China is a country with abundant water resources,but the per capita water resource is only 1/4 of the world standard.In addition,the geographical and climatic influence cause the uneven distribution of water resources and water resources supply and demand tension.Hence,groundwater become the main source water for drinking.Sulphate is a major anion occurring in natural water and industrial effluent,such as inorganic chemical industry wastewater and acid mine drainage.Naturally,it mainly originates from the processes of chemical weathering of sulphur containing minerals and the oxidation of sulphides and sulphur.The excess sulfate can cause adverse effects on human health and the natural sulfur cycle.In this paper,cheap magnesium nitrate,aluminum nitrate and iron nitrate are used as raw materials for preparing of Mg-Fe-CO3 hydrotalcite and Mg-Fe-N03 hydrotalcite by co precipitation method in suitable conditions.Under 200 ℃ 300 C,400 C and 500℃,respectively,two kinds of calcined hydrotalcite are calcined and then obtain their calcined products,and then these are used to characterize the structure by X ray diffraction.Sulfate ions could be adsorbed by Mg-Fe-N03 hydrotalcite and calcined Mg-Fe-CO3.In this paper,effects of reaction time,material dosage,roasting temperature,reaction temperature and initial concentration on the adsorption of sulfate ions are studied.Moreover,the adsorption mechanism of X ray diffraction of Mg-Fe-N03 hydrotalcite and calcined Mg-Fe-CO3 hydrotalcite on sulfate ion is discussed.The main results of this experiment:there are obvious characteristics in Mg/Fe carbonate type hydrotalcite and Mg/Fe nitrate type hydrotalcite,that means the two types of hydrotalccite have good layered structure and after calcination two kinds of hydrotalcite form metal oxide;the result of Reaction time,material for adsorption amount,calcination temperature and reaction temperature on the calcined Mg/Fe carbonate type hydrotalcite iron and calcined nitrate type hydrotalcite on effect of sulfate ions are basically the same,the difference is only in certain data,such as calcined Mg/Fe carbonate type hydrotalcite to the adsorption of 4h on sulfate ion from the beginning of the adsorption reaction process,adsorption quantity’s upward trend is uniform,while the Mg/Fe nitrate type adsorption process of adsorption of hydrotalcite on sulfate ions increases the amount is uneven,the rapid rise in the phenomenon of phase;adsorption process of two adsorbent on sulfate ion will fit the pseudo-second-order model and Langmuir isotherm model,controlled by the intra particle diffusion and chemical reaction mechanism.These two kinds of adsorbents’ surface are uniform and adsorption processes belong to monolayer adsorption.The performance of adsorption of sulfate ions in groundwater by calcined Mg/Fe carbonate type hydrotalcite and Mg/Fe nitrate type hydrotalcite are excellent.What’s more,their adsorption mechanism on sulfate ions is sulphate ions are the interlayer anion after adsorbing to restore the original layered structure of hyderotalcite compounds.Compared the Mg/Fe carbonate type hydrotalcite and Mg/Fe nitrate radical type hydrotalcite under the same conditions of adsorption of sulfate ions,the result can be found that anions changes anions changes are not caused by the nature of change on the adsorption itself,affected mainly roasting product in magnesium iron carbonate type hydrotalcite adsorption of sulfate ions is higher than that of magnesium iron nitrate radical type hydrotalcite adsorption of sulfate ions.