Study On The Preparation Of Chemically Modified Orange Peel Cellulose Containing Cyanex272 Adsorbents And Biosorption Of Pb(Ⅱ) And Cd(Ⅱ)

In this paper, resourceful orange peel in our country, whose effective element is cellulose, has been used as the material.After modifying with acid or alkali, Cyanex272 has been immobilizing on the orange peel. Therefore, six types of adsorbents were prepared and use to examined the adsorption capacity to Pb(Ⅱ) and Cd(Ⅱ).The biosorption of Pb(Ⅱ) and Cd(Ⅱ) on modified orange peel have been investigated. Effects of solution pH, contact time, initial concentration and solid-quid ratio were also investigated. From these we can find the best conditions for adsorption and desorption. Therefore, we get fully recognize about the adsorption capacity of the adsorbent which were immobilized Cyanex272 on orange peel.The conclusions as follow:1.Cyanex272 is successfully immobilized on orange peel biosorbents with macroporous network structure and high specific surface area. Adsorption capacities of cadmium and lead onto orange peel were enhanced and equilibrium time has been reduced. Biosorption mechanism is regarded as a combination of the ion exchange and surface complexation.2. Adsorption of Pb(Ⅱ) strictly depends on pH, the optimum pH for the Pb(Ⅱ) adsorption process is in the range of 5.0-6.0 for all adsorbents and the order of adsorption capacity is: 272SCO>SCO>272OP>272CO>OP, the removal rate of Pb(Ⅱ) by 272SCO could be up to 100% at pH=5.8.The optimum pH for the Cd(Ⅱ) adsorption process is in the range of 5.5-6.0 for all adsorbents and the order of adsorption capacity is:272SCO>SCO>272OP >272CO>CO>OP, the removal rate of Cd(Ⅱ) by 272SCO could be up to 100% at pH 5.5-6.0.3. Biosorption equilibrium on adsorption of Pb(Ⅱ) was obtained after 60 min on CO and SCO when the concentration of metal solution was 0.001 mol·l-1.equilibrium time has been reduced to 40 min on 272OP,272CO and 272SCO. Biosorption equilibrium on adsorption of Cd(Ⅱ) was established quickly in 6 min and 1 min on SCO and 272SCO, respectively. Besides, equilibrium time has been reduced from 40 min (CO) to 25 min (272CO). Biosorption process of all adsorbents followed the pseudo-second-order mode4. A comparison of different isotherm models revealed:Langmuir and Freundlich (L-F) isotherm model fitted experimental data of Pb (Ⅱ) best, the order of maximum capacities is: 272SCO(1.30 mol·kg-1)>SCO(1.26 mol·kg-1)>272CO(1.20 mol·kg-1)>272OP(1.02 mol·kg-1)>CO (0.62 mol·kg-1).Langmuir isotherm fits the experimental data of Cd(Ⅱ) best, the order of maximum adsorption capacities is:272SCO (0.8663 mol·kg-1)>SCO (0.6909 mol·kg-1)>272CO(0.6873 mol·kg-1)>272OP (0.6853 mol·kg-1).5.The optimum s/1 ratio of Pb(Ⅱ) was 3.7 g·l-1 with 272SCO, that of Cd(Ⅱ) was 3.67 g·l-1 in 0.002 mol·l-1 solution.6. For the study of regeneration,272SCO was used to remove Pb(Ⅱ) and Cd(Ⅱ).0.1 mol·l-1 HCl is regarded as the optimum desorption agent, and the percentage of desorption is almost 100%.