Utilization of cocoa activated carbon for trimethylamine and hydrogen sulfide gas removals in a confined space and its techno-economic analysis and life-cycle analysis

In this study, a removal technique of porous activated carbon filter was developed using copper impregnated on commercially available cocoa activated carbon (Cu/AC) for the removal of toxic pollutant gases (trimethylamine [TMA] and hydrogen sulfide [H2S]). Cu/AC (filter) was characterized with Scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDS), Thermogravimetric analysis (TGA)/Differential thermal analysis, proximate analysis, Carbon, hydrogen, nitrogen, sulfur (CHNS)/O, and Brunauer-Emmett-Teller, the results indicated the Cu/AC possesses good physical and chemical characteristics and is suitable for adsorption of air pollutants. The Cu/AC filter exhibited excellent adsorption capacity for the removal of TMA (q(e) = 654.8 mg/g) and H2S (q(e) = 220.37 mg/g). The isotherm and kinetic models were applied to analyze the adsorption properties and adsorption mechanism. Langmuir isotherm showed best fit for the adsorption of TMA and H2S, whereas the pseudo-first- and second-order kinetic models best fitted in describing the adsorption of H2S and TMA, respectively. Also, the adsorption process for the removal of TMA and H2S was controlled by the intraparticle diffusion model. The H2S-adsorbed Cu/AC filter can be regenerated but not lasting too many cycles. Techno-economic analysis and life-cycle analysis (LCA) were performed at a plant scale. Production costs were 1.37 for cocoa AC filter and 10.13 for activated rice husk (ARH) filter. Also, the LCA result for during the filter production was estimated to be 2.52 kg CO2-eq for cocoa AC filter and 4.47 kg CO2-eq for ARH filter. This study proves the competitiveness compared to ARH filter of the previous study in the adsorption performance and the filter production cost.