Study on biomass derived activated carbons for adsorptive heat pump application

[Display omitted] •Highly porous activated carbons have been synthesized from biomass (waste palm trunk and mangrove).•Porous properties and surface morphology of synthesized ACs have been studied.•A remarkably high ethanol uptake has been observed for prepared ACs.•Two well-known isotherm models are used to fit experimental data.•Isosteric heats of adsorption have been derived from isotherms. Biomasses are renewable resources and suitable precursors for synthesis of activated carbons (ACs). Two biomass sources: (i) Waste Palm Trunk (WPT) and (ii) Mangrove (M) are employed to synthesis activated carbons with huge surface area by chemical activation with potassium hydroxide (KOH). Thermophysical characteristics of the derived activated carbons namely thermal conductivity, particle size distribution, pore size distribution, surface area and pore volume are assessed. The total surface area of WPT-derived AC and mangrove-derived AC are found to be as high as 2927m2g−1 and 2924m2g−1, respectively. The adsorption capacities of the synthesized biomass-derived ACs for ethanol are evaluated for assorted temperature and pressure conditions. It is observed that WPT-AC shows an ethanol uptake of 1.90kgkg−1 whilst the M-AC can adsorb up to 1.65kgkg−1. The isosteric heat of adsorption associated with the present adsorbents/adsorbate (ACs/ethanol) calculated at different coverages showed only marginal difference. For a typical operating condition of adsorption heat pump, both biomass derived ACs showed similar net ethanol uptake which is significantly higher than the net uptake of commercially prevalent Maxsorb III AC.