Adsorption of Cu2+ from aqueous solutions by Si-substituted carbonate hydroxyapatite prepared from egg-shell: kinetics, isotherms and mechanism studies

作者：Zeng, Rongying; Tang, Wenqing^*; Liu, Xing; Ding, Chunxia; Gong, Daoxin^*

来源：Desalination and Water Treatment, 2018, 116: 137-147.

DOI：10.5004/dwt.2018.22587

• Adsorption
• Si-substituted carbonate hydroxyapatite
• Cu
• Mechanism
• Kinetics
• Isotherms

Si-substituted carbonate hydroxyapatite (Si-CHAP) was obtained by embedding silicate and carbonate into hydroxyapatite prepared from eggshell via sonochemistry coprecipitation. Batch experiments were performed to investigate the effect of contact time, solution pH and temperature on the adsorption of Cu2+ by Si-CHAP. Our results showed that the maximal adsorption capacity, Q(m) of Cu2+ reached to 246.80 mg g(-1) at pH 5.7, and at 90 min contact time under 313 K. Adsorption kinetics followed pseudosecond order. The equilibrium process fit the Langmuir isotherm model and the maximum adsorption capacity of Si-CHAP for Cu2+ was found to be 273.51 mg g(-1). The thermodynamic studies showed that the adsorption of Si-CHAP on Cu2+ was a spontaneously endothermic process. Si-CHAP was characterized by using FTIR, XRD and SEMEDS. The mechanism of Cu2+ adsorption by Si-CHAP may include ion exchange, precipitation and electrostatic interactions. Furthermore, the well stability properties of the Si-CHAP adsorbent were confirmed through desorption assays. These results showed that Si-CHAP has the potential to become a cheap and efficient adsorbent to remove Cu2+ from aqueous solutions.

• 单位
  衡阳师范学院; 湖南农业大学