Study on adsorption character of marine sediment on heavy metal

The surface sediments of the north Bohai Bay were selected as the research objects to study the adsorption characteristics of the coastal sediments on Cu2+,Pb2+.The sediments are screened out to four gradational granularities to discuss the effects,pH value,adsorption time and initial concentration of the adsorbents.The results showed that the smaller granularity is the bigger saturated adsorption capacity.The adsorption equilibrium time of Cu2+,Pb2+ is different,but all can reach the adsorption equilibrium in 1.5h.The adsorption capacity is increased gradually with pH value.The adsorption capacity for Cu2+ is increased rapidly,but for Pb2+ slowly.The adsorption capacity of Cu2+ assumes a linear relation with initial concentration of absorbent basically;that of Pb2+ rapidly under lower initial concentration of absorbent,but then becomes lower along with initial concentration adding.The adsorption capacity of Cu2+,Pb2+ is increased with the equilibrium concentration elevating,that of Cu2+ rapidly,but of Pb2+ rapidly when the equilibrium concentration is relatively lower,then it tends to slow down with the concentration adding.The adsorption isotherms of Cu2+ in sediments conform to Freundlich type relatively while those of Pb2+ conform to Langmuir type,the adsorption types are different.