20 Jun Natural regeneration as a model of circular economy

We are used to thinking that the only ways through which the circular economy can reduce emissions of climate-altering substances and/or greenhouse gases are:

1) eliminating waste and reducing pollution along the entire production chain;

2) fostering circularity of products/materials through reuse and/or recycling.

In addition to these two ways, there is a third that can have very positive effects on the environment: natural regeneration!

Regenerating nature means “sequestering” carbon to put it into the soil and products, preventing it from being released into the atmosphere in its polluting forms (CO2, CO, etc…).

One example is the use of biomass, which can be converted into new chemicals or even energy.

What are biomasses?
Biomasses are biological materials of an organic nature, originating naturally through the processes of photosynthesis, from both animal (e.g., sludge from intensive livestock farming) and plant sources (lignocellulosic residues recovered from agriculture and/or forestry activities).

Biomasses can be excellent raw materials from which to obtain chemicals and energy because they are cheap, abundant and easy to obtain.

How can biomass be exploited?

At the industrial level, biomass processing can take place through biochemical and thermochemical treatments.

Biochemical treatments such as bio-digestion and fermentation can yield biologically active substances of pharmaceutical, cosmetic, and nutraceutical interest.

On the other hand, thermochemical treatments (combustion, gasification, pyrolysis), based on breaking the chemical bonds of the organic macromolecules constituting biomass, are of interest to both the agricultural and energy sectors. In fact, thermochemical splitting is capable of transforming biomass into three main products:

1) bio-oil, a liquid mainly used to produce hydrogen and electricity;

2) syngas, a gaseous compound that can be harnessed to generate thermal energy and/or electricity;

3) biochar, a solid material rich in carbon and minerals that has potential as an agricultural fertilizer.

In line with EU goals for the realization of the European Green Deal, the conversion of biomass into bioproducts and bioenergy can represent a circular and sustainable resource management system that can restore nature by fostering biodiversity.

Anna Sagnella

References.

1) https://ellenmacarthurfoundation.org/topics/climate/overview.

2) Saidur et al. A review of biomass as a boiler fuel. Renew. Sustain. Energy Rev. 2011, 15, 2262-2289.

3) Saxena et al. Biomass-based energy fuel through biochemical pathways: A review. Renew. Sustain. Energy Rev. 2009, 13, 167-178.

4) Das et al. CO hydrogenation of syngas into fuel using silica-supported Fe-Cu-K catalysts: Effects of active components. Fuel Process. Technol. 2014, 118, 82-89

5) Persson et al. Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment. Energy 2018, 154, 346-351.

6) Qambrani et al. Biochar properties and ecological applications for climate change mitigation, waste management, and wastewater treatment: A review. Renew. Sustain. Energy Rev. 2017, 79, 255-273.

7) Zeng et al. Hydrogen Generation from Wood Chip and Biochar by Combined Continuous Pyrolysis and Hydrothermal Gasification. Energies 2021, 14, 3793.