Study On Phosphorus Removal By Four Mineral Material Which Were Modified

Bentonite, Zeolite, Kaolin and Attapulgite were be choosed in this paper, and they were modified by hydrochloric acid, heating, AlCl3 and MgCl2 successively, the adsorption capacity of phosphorus by these samples were investigated, these materials were characterized by X-ray diffraction(XRD), Brunauer-Emmet-Teller(BET) and Total content analysis, the mechanism of phosphorus adsorption was analyzed and studyed.The saturated phosphorus adsorption quantity of the four original mineral material is:Bentonite:0.513mg/g, Zeolite:0.415mg/g, Kaolin:0.996mg/g, Attapulgite:0.748mg/g respectively.The four mineral material were modified by Hydrochloric acid. The result shows that phosphorus adsorption capacity can be improved by these minerals after being modified by acid. The optium sample modied by aicd of each mineral material and its saturated phosphorus adsorption quantity are:Bentonite modified by Hydrochloric acid(9%):1.623mg/g, Zeolite modified by Hydrochloric acid(9%):1.370mg/g, Kaolin modified by Hydrochloric acid(9%):2.096mg/g, Attapulgite modified by Hydrochloric acid(3%):0.816mg/g respectively.The four mineral material were modified by heating at different temperature. The adsorption capacity of phosphorus by these samples were investigated, The optium sample modied by heating of each minral material and its saturated phosphorus adsorption quantity are:Bentonite modified by heating at 500℃:0.611mg/g, Zeolite modified by heating at 400℃:0.470mg/g, Kaolin modified by heating at 500℃:3.584mg/g, Attapulgite modified by heating at 400℃:0.776mg/g.Kaolin modified by heating at 500℃was modified by AlCl3 and MgCl2 respectively. The saturated phosphorus adsorption quantity of the two samples is: 3.425mg/g,3.247mg/g respectively.Kaolin modified by heating at 500℃is ascertained as the optimum sample which has the best adsorption propertey of phosphorus. Use Kaolin modified by heating at 500℃to reacted with practical wasterwater under the condition of pH=4.03, T=10℃. The result shows that removal rate of phosphorus is 63.5%.The adsorption of phosphorus by these mineral material have a nice linear relationship with Langmuir isotherm, and it means single adsorption is the main form of adsorption.