摘要
The removal of cadmium（Cd） from synthetic solutions by batch adsorption process was performed using eggshell powder, which is mainly composed of calcite（CaCO3）. In order to optimize the adsorption process, a re- sponse surface methodology（RSM） based on Central Composite Design（CCD） was applied. Developed model for Cd removal yields（R, %） response was statistically validated by variance analysis（ANOVA） which showed a high de- termination coefficient value（R2=0.9889）. According to Minitab software, the optimal conditions were found at tem- perature of 44℃, eggshell adsorbent dose of 2.98 g, initial Cd concentration of 36.74 mg/L and initial pH of 7. Under these conditions, the Cd removal yield was 98.76%. The deviation value of 1.24% confirms the validity of the model for the adsorption process optimization. The adsorption isotherm has been described by a Freundlich model. In addition, the predominant sorption mechanisms are the chemisorptions or precipitation（non-reversible） and ion ex- change（reversible）.
The removal of cadmium（Cd） from synthetic solutions by batch adsorption process was performed using eggshell powder, which is mainly composed of calcite（CaCO3）. In order to optimize the adsorption process, a re- sponse surface methodology（RSM） based on Central Composite Design（CCD） was applied. Developed model for Cd removal yields（R, %） response was statistically validated by variance analysis（ANOVA） which showed a high de- termination coefficient value（R2=0.9889）. According to Minitab software, the optimal conditions were found at tem- perature of 44℃, eggshell adsorbent dose of 2.98 g, initial Cd concentration of 36.74 mg/L and initial pH of 7. Under these conditions, the Cd removal yield was 98.76%. The deviation value of 1.24% confirms the validity of the model for the adsorption process optimization. The adsorption isotherm has been described by a Freundlich model. In addition, the predominant sorption mechanisms are the chemisorptions or precipitation（non-reversible） and ion ex- change（reversible）.
