Innovative solid bio-desiccants for sustainable dehumidification applications preparation, characterisation and performance evaluation -a critical review

This review critically examines bio-desiccants and hybrid desiccants for sustainable dehumidification, analysing preparation methods, characterisation techniques, and performance metrics. Bio-desiccants demonstrate adsorption capacities of 0.8−2.16 g/g at 90% RH, with a hybrid formulation achieving 28−45% higher performance. Regeneration occurs at 40−60 °C versus 120−200 °C for synthetic desiccants, representing 50−70% energy reduction. Critical limitations include cyclic degeneration (15−30% capacity loss after 20 cycles), slower saturation kinetics (2−5 × longer than silica gel), and microbial susceptibility (60% of untreated samples). Despite the sustainability advantages of agricultural waste valorisation, biodegradability, and reduced carbon footprint supporting SDG 12 and 13, comprehensive life cycle assessments and techno-economic analysis are lacking. Claims of environmental superiority remain unsubstantiated without rigorous quantitative validation. Future research requires standardised testing protocols, stability optimisation, and pilot-scale validation for commercial viability.