BIObased MAcroporous MAterials for Heavy Metal Adsorption

Due to massive and, still, rapidly evolving anthropogenic activities, heavy metals easily enter fresh water resources, travel along with water cycles and, eventually, enter and harm animal and human bodies. Therefore, removing heavy metals from running waters, e.g. by adsorbents, is urgently needed. Conventional adsorbents are made either from petroleum based synthetic polymers or inorganic materials, with their manufacture involving many industrial processes with polluted side streams. Furthermore, along their service in water, small particles could leach from these conventional adsorbents, causing a re-contamination of the water body. Prof. Alexander Bismarck from University of Vienna and Dr Youssef Habibi from Luxemburg Institute of Science and Technology propose a joint project to research, develop and produce biobased, renewable porous adsorbents for heavy metal removal from running waters. Prof. Bismarcks group will produce the materials by using a technology called foam/emulsion templating. The beauty of this technology is to being able to control the pore diameters and porosity of the porous materials and adjust the performance of the adsorbents for their applications in running waters. In Dr Habibis research group, natural materials such as lignin and nanocellulose will be modified, so that they can be used as feedstocks in the foam/emulsion templating technology. In the final porous adsorbents, the natural materials will not only contribute to the mechanical integrity but also function to enhance the stability and heavy metal removal capacity of the adsorbents. In summary, the project is targeting the production of renewable porous adsorbents, which have identical efficiency, but lower environmental impact compared to conventional synthetic polymeric and inorganic adsorbents. Furthermore, thanks to the abundance, renewability and, therefore, low cost, of the natural materials, the biobased based porous adsorbents are expected to eventually being produced in a large scale and to find wide-spread application thus relieving water pollution by heavy metals.

The BioMaMa project focused on developing sustainable, biobased macroporous materials for the adsorption of heavy metals and other pollutants from water. Utilizing renewable resources such as lignin and cellulose, the project successfully created functional materials with high adsorption capacity and permeability, offering an eco-friendly alternative to conventional adsorbents that are based on polymers produced from oil (or in other words: fossil carbon). The results of the project demonstrate significant potential for industrial applications in water purification, the use of lignin to produce functional materials in general, and lignin-cellulose composites, contributing to environmental sustainability and advancing the field of lignin-chemistry. We showed specifically, that lignin-based foams can be used for water purification (both from heavy metals and organic pollutants), and that industrially, non-treated lignin in the form of black liquor (as it is produced domestically in Austria) can be directly deployed for the production of lignocellulosic polymeric materials and composites based on such bio-derived polymers. Beyond the demonstrated use as water purification platform of lignin-based materials the interaction of lignin-based epoxy resins (and resins in general) with cellulosic foams/cellulosic preforms was investigated. The impact of wetting of resins on fibrous composite preforms was investigated and novel theories have been published about this field. These findings enable future research involved in the production of bio-composites based on cellulose or lignin to tailor specific properties, as they might be needed in the context of water purification. Possible applications of the general findings of the project are: i) the production highly effective heavy metal adsorbents based on biogenic resources, ii) the production of polymeric materials based on lignin, iii) the production of a new family of porous lignin-cellulose-composites, and iv) the tailoring of specific mechanical and morphological properties of the latter. Such possibilities are economically especially appealing for the Austrian industry, given the highly developed domestic pulp and paper industry. Especially appealing in this context is the possibility to close the loop on carbon. A polymeric material is often incinerated at the end of a life cycle. By producing it from plant-based materials (like lignin or cellulose) carbon that was sequestered from the atmosphere (in the form of CO2) can be used to manufacture polymers. Based on research carried out over the course of the project BioMaMa methods have been established to produce porous and non-porous materials that are partially of fully based on atmospheric carbon derived from plant mass that has been produced in Austria.