Investigation into the influencing factors and adsorption characteristics in the effective capture of carbon dioxide in flue gas by chitosan grafted Leca biocomposite

ABSTRACT

The main goal of this research was to evaluate the capability of chitosan (CS)-lightweight expanded clay aggregate (Leca) composite as a green adsorbent for efficient capture of carbon dioxide (CO₂). The adsorption process was modelled by response surface methodology (RSM). The composite was recognised by BET, SEM, EDX, XRF, XRD, TGA, XPS and FTIR analysis. It was evidenced the CS-Leca properties attributing to its adsorption ability were eminently improved as compared to pristine Leca. Maximum removal efficiency of CO₂ (91.59%) was achieved at 40°C, 40 mL/min gas flow rate and 5% moisture content. Under aforementioned provisions, the actual CO₂ removal percentage was found to be 90.4%. According to uptake isotherm studies, the Toth model indicated good affinity between the sorbent and sorbate. This model declares adsorption of CO₂ onto CS-Leca involves a heterogeneous and uneven adsorption behaviour. The monolayer adsorption capacity (q_m) was determined to be 351.24 mg/g. The outcomes of thermodynamic studies displayed that the adsorption was physical and exothermic in nature. The exothermic isosteric heat of adsorption (IHA) was found as 37.1–48.3 kJ/mol which represented weak chemical interactions between CS-Leca and CO₂ molecules. Adsorption mechanism studies revealed that multiple mechanisms are involved in the adsorption reaction of CO₂. Regeneration tests of CS-Leca exhibited multiple potential applications. All these results enlightened that the CS-Leca, due to its grafting polymer, can be applied as a potential sorbent to the recycle of CO₂ and other acidic gases.

KEYWORDS:

• Adsorption
• carbon dioxide
• chitosan composite
• optimisation
• regeneration

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author statement

Hassan Rasoulzadeh: Experiments, analysis and interpretation of data, writing - original draft; Saeed Motesaddi Zarandi: writing, supervision; Mohamadreza Massoudinejad: Methodology, interpretation of data; Mostafa Amini: Characterization study, Critical revision; Amir Sheikhmohammadi: Experiments, analysis, interpretation of data.

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Additional information

Funding

This work was related to a Ph.D. thesis and was funded by the project number of 20120 (Ethical code: IR.SBMU. PHNS.REC.1398.099) from the school of health, Shahid Beheshti University of Medical Sciences, Tehran, Iran. The authors thank the Environmental Health Engineering Department, School of Public Health & safety of Shahid Beheshti University of Medical Science, Tehran, Iran for financial support and providing instrumentation facilities.