Biomass-based materials for solar-powered seawater evaporation

Clean and safe water is crucial to maintaining human life on earth. Solar-powered seawater desalination (SSD) is a promising and feasible way to use solar energy resources to overcome water scarcity. Among all the candidate materials for solar seawater evaporators, biomass-based materials stand out thanks to their excellent inherent natural structure, ease of preparation, low cost, and abundant resources. In this article, we review biomass-based materials, from angiosperms, algae, and fungi to animal materials and other atypical biomass materials, proposed for solar-powered seawater evaporation in the shape of the nanofluid, membrane, gels, composite sponge structures, composites Janus structures and other composites. The approaches for improving biomass-based solar seawater evaporators (BSSE) performance are emphasized, including optical absorption regulation, system thermal management optimization, adequate water supply, salt resistance, and effective steam condensate recovery. In the end, the opportunities and challenges of biomass-based materials for SSD are illustrated.

Inorganic Salt Catalysed Hydrothermal Carbonisation (HTC) of Cellulose

The presence of inorganic salts either as part of the substrate or added to the reaction medium are known to significantly affect the reaction pathways during hydrothermal carbonisation (HTC) of biomass. This work aims to understand the influence of salts on hydrothermal carbonisation by processing cellulose in the presence of one or more inorganic salts with different valency. Batch experiments and Differential Scanning Calorimetry were used to investigate the change in reaction pathways during hydrothermal conversion. The effect of salts on the rate of HTC of cellulose can be correlated with the Lewis acidity of the cation and the basicity of the anion. The effect of the anion was more pH-dependent than the cation because it can protonate during the HTC process as organic acids are produced. The introduction of salts with Lewis acidity increases the concentration of low molecular weight compounds in the process water. The addition of a second salt can influence the catalytic effect of the first salt resulting in greater levulinic acid yields at the expense of hydrochar formation. Salts also play an important role in cellulose dissolution and can be used to modify the yield and composition of the hydrochars.