A novel synthetic method for the preparation of different sorbent-polymer composite beads has been developed under simple laboratory conditions. Copper hexacyanoferrate was synthesized, and its composite beads of required size were synthesized by phase-inversion technique, using polyethersulfone as the polymer matrix. Suitable size and mechanical stability, along with their spherical shape, make these composite beads most appropriate for column operation. The efficiency of these composite beads was tested for the removal of cesium, using radioanalytical techniques, in batch conditions. The effect of pH, the initial metal ion concentration, and contact time was also investigated. The synthesized beads perform best in the pH range 5-9. Different sorption isotherm models were applied to the experimental data. Equilibrium data are represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 1.56 mg g À1 for the swollen beads. Kinetic modeling analysis, by fitting the data in the pseudo firstorder, pseudo second-order, and intraparticle diffusion equations, shows that the pseudo second-order equation is the most appropriate model for the description of sorption of cesium ions onto the composite beads. The process mechanism is found to be complex, consisting of both intraparticle diffusion and film diffusion.

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Printed Circuit Board (PCB) is an essential co mponent of almost all electrical and electron ic equip ments. The rapid growth of the use of such equipments has contributed enormously to the generation of large quantity of waste PCBs. The WPCBs not only contain valuable metals but also a large variety of hazardous materials. Conventional treat ments of such WPCBs have their o wn limitations. By pyrolysis of WPCBs, it is not only possible to obtain the organic part o f it as a fuel or useful chemical but can make further processing to recover metals much easier and efficient. In the present work, a kinetic study on the low temperature pyrolysis of WPCBs using a thermogravimet ric analyser has been attempted. The TG analysis was conducted in nitrogen and air at mospheres in the temperature range of 200-600℃ at a heating rate of 40℃ /min. The kinetic expressions for both the environments were determined and the activation energies were found to be 110.7 and 90.2 kJ/ mo l for n itrogen and air, respectively. The effect of thermal pre-t reatment on the subsequent copper leaching in nitric acid for untreated, pyrolysed and air-burned PCB was also studied. Copper recoveries fro m these samples were 30.4%, 92.5% and 96.2%, respectively indicating the importance of thermal pre-treat ment in leaching of the metal content.

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A novel synthetic method was developed to synthesize resorcinol-formaldehyde (RF) resin in spherical form, of required mesh size, using XAD-4 as template beads. The synthesized RF-coated XAD (RF-XAD) beads were characterized, using different techniques. Suitable size and mechanical stability, along with their spherical shape, make these beads most appropriate for column operation. The efficiency of these beads was evaluated for removal of cesium from alkaline medium, in batch conditions, using a radioanalytical technique. The effect of sodium ion concentration, the initial cesium ion concentration and the contact time were also investigated. It was observed that the K d value for Cs + ions decreases with increase in Na + ion concentration. The equilibrium data were fitted into different isotherm models, and were found to be represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 287 mg g 21 . Kinetic modeling analysis, using pseudo first-order, pseudo second-order and intraparticle diffusion equations, shows that the pseudo secondorder equation is the most appropriate model for the description of the sorption of cesium ions onto the RF-XAD beads. The rate constants were determined at different initial concentrations. The process mechanism was found to be complex, consisting of both surface sorption and pore diffusion.