Study on adsorption of potassium ions in lithium chloride solution
Lithium chloride products,as primary raw materials,have been affected in their application,as well as in the de-velopment of metal lithium and series products prepared due to the high content of potassium,sodium and calcium.The ad-sorption of potassium ions in lithium chloride solution containing sodium was studied by static adsorption experiments using hydrothermal synthesis of silicoaluminate molecular sieves.The effects of contact time,temperature,initial potassium con-centration,pH and ionic strength on adsorption of potassium ions by molecular sieves were investigated.The adsorption ki-netics and thermodynamics of potassium ions by molecular sieves were studied and analyzed.The results showed that mo-lecular sieves had selective adsorption for potassium ions with fast rate,the adsorption capacity reached to 56 mg/g after 30 min at the conditions of initial potassium concentration 0.005 mol/L and 25 ℃,which was close to adsorption equilib-rium capacity.Initial potassium concentration and ionic strength had a great impact on adsorption equilibrium capacity of po-tassium ions by molecular sieves.Based on the analysis of thermodynamics and kinetics,the adsorption of potassium ions by molecular sieves was exothermic reaction and conformed to the Freundlich adsorption isotherm model.Low temperature was benefical for adsorption.The adsorption process followed a quasi second order kinetic model and adsorption arte was deter-mined by multiple control steps together.In addition,molecular sieves showed better desorption efficiency and re-adsorption capacity for potassium ions.
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