Efficient preparation of porous biopolymer-based functional nanocomposite microspheres and their conversion to porous carbon materials

Efficient preparation of porous biopolymer-based functional nanocomposite microspheres and their conversion to porous carbon materials

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The continuous increase of world population and of the industrialization has led to an increased demand for fresh clean water. Of very high interest is the development of new and efficient adsorbers, based on renewable and biodegradable biopolymers, for the removal of different pollutants such as toxic heavy metals, dyes, fertilizers, phenolic compounds, or viruses and bacteria from water. The materials or processing aids used in the project should be mainly based on renewable biopolymers (cellulose, chitosan), well-established functional nanoparticles (Fe3O4, TiO2) and environmentally friendly solvents (ionic liquids, water).

In the first part of the project, research is focused on establishing a platform for the direct processing of the biopolymers from their solutions in ionic liquids (optionally containing a fraction of another solvent, without or with dispersed nanoparticles) towards porous particles of spherical shape with defined size (between 10 µm and 1 mm) along with adjustable pore size distribution and high specific surface area. The functionality of the porous spheres will be provided by blending cellulose with chitosan (adsorber groups) and by doping with functional nanoparticles (magnetic or photocatalytic properties). One key innovation of the project is the development of an ink-jet cum phase separation process for shaping biopolymers from their solutions into well-defined porous spheres with diameters below 100 µm and high specific surface area. The second part of the project is focused on the carbonization of the biopolymer-based spheres obtained in the first part. It will be aimed at establishing efficient pre-treatment and carbonization processes (temperature, atmospheres, duration, optionally use of N-delivering substances) for the preparation of functional carbon-based porous materials with defined particle sizes, high porosity (> 100 m2/g) and integrated functionalities (e.g. N doping of carbon or TiO2, recovery by magnetic separation). The adsorber and photocatalytic properties of the resulting biopolymer- and carbon-based porous nanocomposites will be studied for selected cases in order to obtain feed-back for improving processing steps and to evaluate the potential of such materials for water purification.

 

References

  1. A. Wittmar, H. Thierfeld, S. Köcher, M. Ulbricht, RSC Adv. 2015, 5, 35886
  2. A. S. M. Wittmar, M. Ulbricht, Ind. Eng. Chem. Res. 2017, 56, 296
  3. A. S. M. Wittmar, Q. Fu, M. Ulbricht, ACS Sust. Chem. Eng. 2017, 5 9858

Contact:
Dr. Alexandra Wittmar