Bacterial Cellulose as a Template for Preparation of Hydrotalcite-Like Compounds

Gustavo F Perotti,Sidney J L Ribeiro,Vera R L Constantino,Hernane S Barud

doi:10.5935/0103-5053.20140153

Abstract

Bacterial cellulose (BC) was used as a template for preparation of Hydrotalcite-type compounds or layered double hydroxides (LDHs) by co-precipitation method, and submitted to three aging times. Isolated composites containing LDH supported on BC (BC-LDH) were calcined to remove the organic matrix. Mixed metal oxides formed after thermal decomposition underwent reconstruction reaction in Na2CO3 solution producing again hydrotalcite-like materials (RBC-LDH). To evaluate the influence of BC on the LDH formation, it was also analyzed LDH fractions not attached to the BC fibers and LDH synthesized in absence of the polymeric membrane. XRD pattern of BC-LDH composites show broadened peaks related to the organic semi-crystalline matrix, indicating a deep level of interaction between organic and inorganic phases. Interaction is also evidenced by changes in the composites thermal decomposition profiles compared to pristine polymer. SEM images revealed formation of submicrometrical round-shaped LDH particles after removal of membrane (RBC-LDH), differently from the plate-habit exhibited by pristine LDH. Aging plays a key role in growth of all LDHs samples, leading to the formation of larger inorganic particles as time is increased. RBC-LDH aging for three days shows significant improvement in the surface area (more than three times) if contrasted to LDH prepared in BC absence.

Highlights

The search for nanostructured materials has become a challenge during the last decades due to some unique properties that can be achieved once such particles are obtained
A slightly change is observed in the relative intensity of the peaks at (2θ) 14.5 and 22.7° for the BC-layered double hydroxide (LDH) membranes aged for longer periods, which could be caused be an increase in the signal of the amorphous region
Composite materials comprised of bacterial cellulose and layered double hydroxides containing Mg2+ and Al3+ intercalated with CO32− were successfully prepared using co-precipitation method

Summary

Introduction

The search for nanostructured materials has become a challenge during the last decades due to some unique properties that can be achieved once such particles are obtained. These drastic changes are mainly caused by an increase in the ratio of the surface in comparison to the volume of particle which means a highest availability of reactive sites.[1] This is an especially important feature in heterogeneous catalysis field, where a large exposed surface of catalyst is beneficial to the promoted reaction, resulting in a substantial decrease in the amount of catalyst to be introduced in the system.[2]. Notwithstanding, considerable expenses of energy and time are required in “top-down” processes such as milling and laser ablation, usually leading to particles presenting unwanted broad size dispersion.[4]

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