Abstract: <SPAN lang=EN-US>Carbonate hydroxylapatite(CHAP) sorbent has been synthesized by hydrothermal method with abandoned eggshell as raw material,which was used to eliminate hexavalent chrome in wastewater.Factors,such as pH,adsorption time,and initial concentration of hexavalent chrome in wastewater that might influence the adsorption performance,were investigated.Results showed that the removal rate of hexavalent chrome by CHAP sorbent was increased to 98.3% and the maximum adsorption capacity was up to 29.85 mg/g when pH was 3.0,adsorption time was 30 min,dosage of CHAP was </SPAN><?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:chmetcnv w:st="on" UnitName="g" SourceValue="5" HasSpace="True" Negative="False" NumberType="1" TCSC="0"><SPAN lang=EN-US>5 g</SPAN></st1:chmetcnv><SPAN lang=EN-US>/L</SPAN><SPAN lang=EN-US> and the initial concentration of hexavalent chrome in wastewater was 100 mL 50 mg/L at room temperature.Basically,it was 30 min to reach adsorption equilibrium.The adsorption isotherms for hexavalent chrome could be well fitted by both Langmuir and Freundlich equations,which could be used to describe the adsorption behavior.Their correlation coefficients were 0.998 4 and 0.922 6,respectively.After adsorption,CAHP could be regenerated quantificationally with NaOH or H</SPAN><SPAN lang=EN-US><SUB>2</SUB>SO</SPAN><SPAN lang=EN-US><SUB>4</SUB> and regeneration ratio could reach 94.3% and 94.8% respectively under microwave heating.<BR></SPAN>