Self-regenerating hybrid alginate-carbon bioactive beads for gas-phase toluene removal under ambient conditions
摘要
Adsorptive materials capable of controlling gaseous VOCs at room temperature without external regeneration face significant challenges. In this study, hybrid alginate-carbon beads were prepared by co-immobilizing powdered activated carbon and Pseudomonas putida F1 within a calcium-alginate matrix. The beads were designed to capture toluene through carbon-based adsorption and to restore adsorption capacity through microbial oxidation occurring inside the material. Batch adsorption experiments showed that the powered-carbon control followed typical Langmuir and Freundlich isotherms, while the bioactive beads exhibited non-equilibrium behaviors consistent with simultaneous microbial degradation described by Michaelis–Menten kinetics. In a continuous-flow gas-phase column (33 ppmv inlet, 80% relative humidity, 28 °C) operated under 8 h flow/16 h idle cycles, toluene removal efficiency increased from 65% to over 99% within several days and remained stable during prolonged cyclic operation. Daily carbon balance and CO2 production confirmed that adsorbed toluene was oxidized during the idle period, regenerating adsorption sites without external heating or chemical treatment. Microscopic observations further indicated that the hybrid matrix maintained its structural integrity while supporting viable microbial clusters over long-term use. These results demonstrate that the hybrid beads act as a self-regenerating bioactive adsorbent capable of stable gas-phase VOCs control under ambient conditions. The coupled adsorption–biodegradation cycle offers a practical low-energy route to reduce sorbent consumption and waste generation in VOCs abatement systems.