Control Of As And Heavy Metals In Water Body Using Clay Mineral Material

In recent years, with the development of industry and agriculture, soil, rivers and lakes in our country exist arsenic and heavy metal pollution in different degrees.arsenic poisoning and heavy metal pollution events attracted much attention, at the same time also stressed the urgency of arsenic and heavy metal pollution control,This paper utilizes the adsorbability of environmental mineral materials to deal with this kind of pollution.Research on arsenic contamination is the result of sepiolite and attapulgite adsorbing As3+、-As5+ in water,and through appropriate modification to improve the adsorption performance of this two kinds of material.operate simulation experinent in laboratory to confirm saturated adsorption、reaction equilibrium time and the influence of pH、particle size、anion (sulfuric acid root, carbonic acid, phosphoric acid root.through dynamic collection device to simulate the dynamic adsorption.Research of heavy metals includes adsorption of Pb2+、Cd2+ in water and fixation of Pb、Cd in sediment.Adsorption of water study the saturated adsorption amount、adsorption equilibrium time and the influence of pH. Fixation of sediment study the effect of two material on the BCR of Pb、Cd in sediment.Experimental results show that original sepiolite and attapulgite absorb As3+、As5+ poorly, But 800℃ hot modified sepiolite and 700℃ hot modified attapulgite have a good performance.Saturated adsorption amount of As3+、As5+ on sepiolite is 27.9 mg/g,33.6 mg/g respectively,adsorption equilibrium time is 4 hours and 1 hour respectively;Saturated adsorption amount of As3+、As5+ on attapulgite is 68.26mg/g、31.84mg/g,equilibrium time is 24 hours�'�4 hours respectively.Sepiolite and attapulgite show a better adsorption effect at higher pH,Particle size have little effect,anion as sulfuric acid root, carbonic acid root have negative effcet,phosphoric acid root show little effect.Saturated adsorption amount of Pb2+、 Cd2+on sepiolite is 27.12mg/g、25.93mg/g respectively,adsorption equilibrium time is a little long,all is 24 hours;Saturated adsorption amount of Pb2+、Cd2+on attapulgite is 26.75mg/g、 24.55mg/g,equilibrium time all are above 24 hours.Import sepiolite and attapulgite decrease the pH value of sediment.sepiolite reduce Pb、Cd in weak acid extraction condition and increase Pb、Cd in oxidation state; The influence of attapulgite on sediment is similar to sepiolite.