STUDY ON HEAVY METAL ADSORPTION TO COASTAL SEDIMENT OF THE YELLOW RIVER ESTUARY

The surface sediments of the Yellow River estuary are selected as the research objects to study the adsorption characteristics of Cu and Pb in the coastal sediments. The sediments are screened out into four gradational granularities to discuss the effects of granularity, pH, adsorption time and initial concentration of sorbents. The results indicate that:the smaller the granularity is, the bigger the saturated adsorption capacity is.The adsorption equilibrium time of Cu²⁺and Pb²⁺ is different, but all can achieve adsorption equilibrium in 1.5 h.The adsorption capacity increases gradually along with pH, that of Cu²⁺ in sediments increases rapidly, but that of Pb²⁺ increases slowly. The adsorption capacity of Cu²⁺ assumes a linear relation with initial concentration of absorbent basically, that of Pb²⁺ increases rapidly under lower initial concentration of absorbent, but then becomes lower along with initial concentration. The adsorption capacity of Cu²⁺and Pb²⁺ increases along with the equilibrium concentration, that of Cu²⁺ increases rapidly, but that of Pb²⁺ increases rapidly when the equilibrium concentration is relatively lower, then it tends to slow down along with the concentration. The adsorption isotherms of Cu²⁺ in sediments conform to Langmuir type relatively while those of Pb²⁺ conform to Freundlich type,and the adsorption types are different. The regularity of heavy metal adsorption in coastal sediment provides the basis for investigation and management of marine pollution in the Yellow River estuary.