Valorisation of Plant Waste for Use as a Construction Material

Development and validation of different strategies for valorising waste generated during the cultivation and management of various crops, including grapevines, rice, palm trees, mulberry, cotton, almonds, hemp, olives, sorghum, citrus fruits and common reed, to produce a range of new materials with low embodied energy. Manufacture of particleboards and panels that comply with the relevant European EN standards and can be used in furniture, packaging, partitions and building envelopes. These materials aim to improve energy efficiency, reduce pollution and emissions to the air, water and soil through increased carbon sequestration, and use raw materials and energy more efficiently. Particleboards have already been manufactured using various types of plant waste as raw materials.

The particleboards being developed require less energy to manufacture than conventional industrial boards. Commercial particleboards manufactured using conventional dry processes typically require the raw material to be air-dried, crushed and then dried in industrial dryers. These processes generally use temperatures of 180–200°C and pressures of around 3.5 MPa. They also commonly use urea-formaldehyde adhesives, which may pose carcinogenic risks and are subject to increasingly strict restrictions.

• The particleboards manufactured by our research team have the following characteristics:
• Crushing requires the same or less energy, as plant waste is easier to crush than the trunks of tree species.
• Pressing takes place at temperatures of 110–150°C and pressures of 2.1–2.6 MPa.
• Natural binders such as lignin, starch and citric acid are used to bind the particles, producing a fully biodegradable material.

Using plant waste to manufacture particleboards therefore offers two key advantages: significant environmental benefits and lower energy consumption during production compared with conventional industrial processes.

Laboratory prototypes of particleboards measuring 40 × 60 cm have been developed using waste from grapevines, rice, palm trees, mulberry, cotton, almonds, hemp, olives, sorghum, citrus fruits and common reed. These prototypes have demonstrated promising physical, mechanical, thermal, acoustic and fire-resistance properties. Moving towards an industrial-scale prototype would require suitable equipment to manufacture boards ranging in size from 205 × 122 cm to 488 × 250 cm.

• Construction Industry and Sustainable Architecture.
• Furniture Industry and Interior Design.
• Agricultural Waste Management Companies.
• Insulation Material Manufacturers.
• Packaging Industry and Eco-Friendly Packaging Solutions.

Manuel Ferrández-Villena García – University Institute for Research and Innovation in Agri-Food and Environmental Sciences (CIAGRO)