Ϊ�о� OH^-���ͼ���Ǧ������Ⱦ����ˮ�޸��Ŀ����ԣ�ͨ������ʵ���Ʊ�����������þ��������ȥ������ˮ�� Pb �� Cd �����ܽ����о���ʵ�����������ؽ������ȶ���������ҪΪ����Ӧ����ȥ����һ�ؽ��� (Pb �� Cd) ʵ���У�Pb �� Cd ��ȥ���ʶ��ɴﵽ 99%���ϣ���Ӧ����һ����Ӧ����ѧ����Ӧ���ʳ����ֱ�Ϊ 0. 173 7 min^-1 �� 0. 003 7 min^-1 ������������þ�ڴ��� Pb �� Cd �ĸ�����Ⱦʱ Pb ������ Cd ��Ӧ��Pb �Ĵ��ڻ�� Cd �ij������������á�

To investigate the feasibility of OH^- slow-releasing agent used to remedy lead and cadmium pollu- ted groundwater��modified magnesium hydroxide was prepared in lab��and its feasibility to remedy the lead and cadmium polluted groundwater was studied in this work�� The experimental results showed that precipitation was the predominant mechanism of the heavy metals removal�� In the experiments for Pb or Cd removal alone��both of their removal efficiencies were over 99%�� The reaction followed first- order reaction kinetics; and the observed Pb and Cd reaction rate constant was 0. 173 7 and 0. 003 7�� respectively�� In the combination system of Pb and Cd�� precipitation of lead was prior to cadmium; while the presence of Pb would pose an inhibitive effect on the precipitation of cadmium