Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions.However,the lower heavy metal adsorption capacity of kaolin limits its practical application.A novel environmental friendly material,calcium alginate immobilized kaolin (kaolin/CA),was prepared using a sol-gel method.The effects of contact time,pH,adsorbent dose,and temperature on Cu 2+ adsorption by kaolin/CA were investigated.The Langmuir isotherm was used to describe the experimental adsorption,the maximum Cu 2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g.The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.