Adsorption of Cd and Pb metal ions onto chelating resin and their application in removal of lead from battery factory wastewaters

Abstract

Lead is one of the most used metals in various factory activities. The contamination of soil and water with the metal has become a real or major environmental and public health problem or concern. Therefore, removal this toxic metal from wastewaters is a great challenge to protect environment and people. This study aims to assess adsorbing properties by batch procedure of a chelating ion exchange functionalized by iminodiacetic acid group toward Pb and Cd by varying the concentration of these metals at different contact times and at a given pH. In the second step, this adsorbent support is used in dynamic condition in a column for the removal of Pb particularly from effluents from an industrial unit. Finally, the exchange material, packed in bed, is regenerated in order to establish its reusability and efficiency in removing process. The adsorption rate of Pb and Cd onto the chelating adsorbent increases as the initial content and time contact increase and the maximum adsorption capacity is found to be 137.40 and 90.40 mg/g at the plateau of saturation, respectively. In a column, the adsorbing support or material reduce totally the concentration of loaded Pb in effluents during the two first cycles. During the third cycle, the removal power is still good and the content of Pb in the washing is reduced from 22 mg/L to 0.014 mg/L which is lower than the law's discharge levels. The regeneration of the support is achieved by 10 volume bed of 1 M HCl during thirty minutes at least. These results demonstrate clearly the effectiveness of the chelating adsorbent in removing  lead from the effluents of the factory and its reusability in numerous cycles after a regeneration stage.