In order to investigate the adsorption characteristics for Sr ion using the Na-X zeolite synthesized from coal fly ash, batch tests and response surface analyses were carried out. The adsorption kinetic data for Sr ions, using Na-X zeolite, fitted well with the pseudo-second-order model. The uptake of Sr ions followed the Langmuir isotherm model, with a maximum adsorption capacity of 196.46 mg/g. Thermodynamic studies were conducted at different reaction temperatures, with the results indicating that Sr ion adsorption by Na-X zeolite was an endothermic (ΔHo>0) and spontaneous (ΔGo<0) process. Using the response surface methodology of the Box-Behnken method, initial Sr ion concentration (X1), initial temperature (X2), and initial pH (X3) were selected as the independent variables, while the adsorption of Sr ions by Na-X zeolite was selected as the dependent variable. The experimental data fitted well with a second-order polynomial equation by multiple regression analysis. The value of the determination coefficient (R2=0.9937) and the adjusted determination coefficient (adjusted R2=0.9823) was close to 1, indicating high significance of the model. Statistical results showed the order of Sr removal based on experimental factors to be initial pH > initial concentration > temperature.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 실험재료
  2.2. 실험방법
  2.3. 실험계획법
 3. 결과 및 고찰
  3.1. 흡착제의 제조
  3.2. 흡착 속도 해석
  3.3. 등온흡착 해석
  3.4. 열역학적 해석
  3.5. 반응표면분석에 의한 반응표면모형 추정
 4. 결 론
 REFERENCES

• 이창한(부산가톨릭대학교 환경행정학과) | Chang-Han Lee (Department of Environmental Adminstration, Catholic University of Pusan)
• 감상규(제주대학교 환경공학과) | Sang-Kyu Kam (Department of Environmental Engineering, Jeju National University)
• 이민규(부경대학교 화학공학과) | Min-Gyu Lee (Department of Chemical Engineering, Pukyong National University) Corresponding author