Absorption studies on hydrophilic membranes based on Carboxy methyl cellulose/PEG Hydrogel filled with TiO2

Introduction: In recent years conventional mass separation techniques such as distillation, crystallization solvent extraction, etc., have been supplemented by a class of processes that utilize semipermeable membranes as the essential element for the separation of molecular or particulate mixtures (1,2). Membrane processes can be very different in their application, in the structures used as the separating barrier, and in the driving forces used for the transport of different chemical components. Separations with synthetic membranes have become increasingly important processes in the chemical industry, in food and wastewater processing, and in medical treatment. Synthetic membranes made from a variety of polymers are used in processes such as microfiltration, ultrafiltration, reverse osmosis, electrodialysis, and gas separations. Membrane separation processes are very different in their mode of operations and their application, several common features make them particularly attractive (4,5) In many cases membrane processes are faster, more efficient and economical than conventional separation techniques (6). Current work proposes the preparation of CMC/ PEG blend hydrogel membrane crosslinked and modified by TiO₂ for water separation process.

Methods: CMC solution was taken, and PEG solution was added to it, cross linking agent citric acid (CA) were added as per the formulations and mixed well. The solutions were casted and allowed to dry in an oven to remove the water in the sequence. Different concentrations of PEG were prepared as in the above and CA added to each of the solutions and casted. Same formulations were made with TiO2, each of the solutions casted and dried in an oven. Membrane preparation: The preparation of membranes was carried out at various compositions. Membranes were obtained by casting prescribed amounts of solutions on to petridishes followed by drying at 70^oC for 6 hours. The films were peeled off. All films were white in color and free of air bubbles and the yield was determined.

Results & Discussions: Tensile properties of CMC / PEG blend membrane prepared and the Tensile properties of membranes with Various ratios of TiO₂ added when PEG is added the tensile properties decreased and on TiO₂ addition, strength increase upto 4% loading and then decreases. This will be due to the dilution effect of the fillers in the matrices. The thermal transitions without TiO₂ and with TiO₂ respectively and it is clear that not much change it the transitions occur when TiO₂ is added to the system. Therefore, can be worked in the similar manner with respect to temperature.

Conclusions:  In CMC/PEG (CA) with TIO₂ membranes alkali resistance decreases with increasing concentration of both PEG and TIO₂. In the case of CMC/PEG (CA) without TIO₂ alkali resistance increases with increasing concentration of PEG. In both cases acid resistance decreases with increasing concentration of PEG. Heat resistance decreases with increasing concentration of PEG. CMC/PEG (CA) with TIO₂ water absorption decreases with increasing concentration of both PEG and TIO₂ because they are hydrophobic in nature. CMC/PEG (CA) without TIO₂ water absorption increases with increasing concentration of PEG because they are hydrophilic in nature.

Keywords: Carboxymethyl cellulose, hydrogels, Membranes

References

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