Clémence Queffelec

Advances in the development of alternative binders from biomass for the production of biosourced road binders

This chapter will focus on recent advances for the production of biosourced road binders as an alternative to bitumen. Indeed, in recent years, tensions have appeared on the asphalt supply for road construction. Thus, valorization of different types of biomass for the production of alternative binders might be attractive. The more developed alternative binder is based on the high molecular weight material, generally from the wood industry, mixed with mineral or vegetable viscous oil. The resulting binder has characteristics similar to bitumen and has been used on several experimental road work sites. In some cases, aging issues of the binder occurred, with a brittle behavior at service temperature. Other promising biomasses have been studied, such as microalgae and swine manure, using hydrothermal liquefaction. The resulting binders appear to have the same rheological properties as asphalts. Vegetable resources are also used to produce fluxes, whose main advantage is the reduction of emissions of dangerous organic volatile compounds. Finally, research on new biomasses shows a credible alternative for future full or partial replacement of bitumen.

Wilkinson‐type immobilized catalyst on diamond nanoparticles for alkene reduction

The immobilization of heterogeneous catalysts on solid support materials is an important task of current catalytic and materials science research. We report here the development of a diamond nanoparticles‐based Wilkinsons type catalyst for the reduction of olefins to saturated hydrocarbons. The strategy is based on the formation of rhodium(I)‐modified nanodiamonds (NDs–Rh) using a surface‐immobilized catechol phosphane ligand, to which rhodium metal centers can be coordinated. The resulting material was characterized by solid‐state NMR spectroscopy, X‐ray photoelectron spectroscopy, thermogravimetry, and TEM before testing the catalytic efficiency of the catalyst. Excellent hydrogenation efficiency with yields in the range of 85–99 % could be obtained with these new NDs–Rh catalysts, which showed in addition good recyclability without loss of activity.

Biosourced analogs of elastomer-containing bitumen through hydrothermal liquefaction of Spirulina sp. microalgae residues

The hydrothermal liquefaction of Spirulina sp. microalgae (i.e. cyanobacteria) byproducts was investigated for the production of road binders from renewable sources. In the 220–300 °C temperature range, a water-insoluble viscous material was obtained in a ca. 50% yield, which consisted of an oily fatty acid-based fraction mixed with organic and inorganic solid residues (ca. 20%). More interestingly, this material exhibited viscoelastic properties similar to elastomer-containing bitumen, when operating the hydrothermal liquefaction between 240 and 260 °C. This is the first example of a bio-sourced product showing such properties. At higher temperature, fragmentation of species of high molecular weight occurred, resulting in less viscous materials that were no more thermorheologically simple. The reactor filling ratio was also allowed to vary (i.e. 30% versus 60%), showing very little influence in terms of yield and viscoelastic properties of the resulting bio-binders.