Biosorption Studies of Cyanide Ion from Wastes by Spent Black Tea Leaves

The present study is concerned with the adsorption of cyanide ion (CN-) from aqueous solutions using the wastes of spent black tea leaves (SBTL) as an adsorbent Batch adsorption experiments were carried out at equilibrium conditions for concentrations of cyanide ion between 50 and 300mgL-1 .The parameters examined in this study were the effect of contact time ,solution pH , temperature and amount of adsorbent .The results showed that significant amounts about 90% of 50 mgL-1 cyanide ion was removed at 37°C and solution pH= 8.The equilibrium adsorption isotherms have been analyzed by the Freundlich and Langmuir equations using Linearized correlation coefficient at different temperatures. The Freundlich is found the best represent the equilibrium data for cyanide-SBTL system. Thermodynamic parameters were calculated at three different temperatures and the obtained values support the conclusion that the cyanide ion adsorbs by spontaneous and endothermic process. To examine the kinetic of the adsorption process, models of pseudo-first-order and pseudo-second-order were applied. The data showed that the pseudo –second-order model was best-fit model. Key Words: cyanide ion , Adsorption ,isotherm, spent black tea leave