Study On Emergency Adsorption Material For Removal Of Heavy Metal Cr⁶⁺ From Water

Nowadays heavy metal ions pollution of water has become a major problem about thesurvival and development of human beings. Development of low cost and good heavy metalions absorbent was imminent. This article used diatomite and reed straw as raw materials.Through physical and chemical modifying, created two new heavy metal ions adsorbents andstudied the adsorptivity of Cr6+in water. The experiment investigated the preparationinfluence factors, adsorption influence factors, other ions interferences, adsorption kineticsand adsorption isotherm of the two new adsorbents. Also discussed the recycling and revivingfunctions.During the effects of diatomite preparation influence factors, acid concentration,calcinations temperature, lye concentration, corrosion temperature, Mn2+concentration werediscussed. The manganese oxide diatomite had strong adsorption when the acid concentration10%, calcinations temperature700℃, lye concentration20%, corrosion temperature80℃,MnCl2concentration2.5mol/L. Meanwhile the effects of reed straw discussed about theadsorbent size, lye concentration, and modification temperature. When the adsorbent meshnumber80, lye concentration30%, modification temperature80℃and modificationtemperature50℃the reed straw has good effects. The effects of pH value, adsorbent dosage,adsorption time and initial concentration of Cr6+and other ions interference were discussed tothe test of two kinds of new adsorbent. In the condition of25℃temperature, the resultsshowed that the removal efficiency has been improved with adsorbent dosage, but weakenwith increase of pH value and initial concentration of Cr6+. When the pH=1, absorption time120min and the Cr6+concentration10mg/L, the removal rate of Cr6+reached more than96.5%and99.6%. The experiment showed that other ions had interference. The adsorption kineticprocess was consistent with the pseudo-second order kinetic model. The reed straw adsorptionisotherm agreed well with the Langmuir formula. The manganese oxide diatomite adsorptionisotherm agreed well with the Freundlich formula. Both of new adsorbents had goodadsorption effect to Cr6+water and had an important application value.