Optimization of Activated Carbon Monolith Co₃O₄-Based Catalyst for Simultaneous SO₂/NO_x Removal from Flue Gas Using Response Surface Methodology

Abstract

Coal combustion is a primary source of acid gases such as sulfur dioxide (SO2) and nitrogen dioxide (NOx); meanwhile, their effects are detrimental to man and the environment. In this work, three different adsorbents were developed by loading Co3O4 on monolith using pore volume impregnation, deposition precipitation, and hydrothermal methods (HMs) of synthesis.The breakthrough study in the simultaneous SO2 and NOx removal from flue gas revealed that the performance of the adsorbent developed by HM was better than the adsorbents developed by the other methods. Therefore, the characterization analysis and optimization of the variables that affect the adsorption capacity on the best performed adsorbent by response surface methodology were carried out. The model prediction and the experimental results for the adsorption capacity of SO2 are 134.5 and 132.9 mg/g while 152.1 and 151.6 mg/g were obtained for NOx. Furthermore, the optimized independent variables comprising amount of adsorbents, airflow rate, and temperature are 1 mg, 400 mL/min, and 100°C. The regression coefficient of 0.9934 for SO2 and 0.9991 for NOx was obtained which indicates that the interaction between the independent variables and the adsorption capacity of SO2 and NOx is very significant. These results confirmed the suitability of the model for the prediction of the process behavior and the performance of the adsorbent at low temperature with high adsorption capacity emerged as a new finding.

Eco-Friendly Sustainable Fluorescent Carbon Dots for the Adsorption of Heavy Metal Ions in Aqueous Environment

“…The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites [70]. The adsorption process as explored by both Langmuir The values of the Langmuir constant K L and the monolayer capacity q max can be evaluated from the three forms of Langmuir adsorption models.…”

“…Since the processes followed the pseudo second-order equation, it literally suggests that the adsorption is mainly by simple chemisorption reaction occurring between the lead ions and the surface functional groups of CDs [49,50]. The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites [70]. The adsorption process as explored by both Langmuir and Freundlich isotherms have proven favorability of the adsorption process.…”

Demineralization and Characterization of Coal Deposit Found in Maiganga, Akko Local Government, Gombe State, Nigeria

“…The peaks at 1072 and 1383, cm -1 assigned to Si-O stretching vibrations indicates the presence of quartz and cerrusite, the absorption at at 1320-1210 cm −1 is stretching vibration (C-O) of phenol and ether (Bora et al, 2021;Rawat and Yadav, 2020;Silas et al, 2019), the stretching band of aromatic compounds can be observed at 1615 cm -1 peak (Boral et al, 2021), 2800-3000 cm -1 is due to the stretching vibration aliphatic and alicyclic (-CH 3 , -CH 2 and -CH) groups carbon where different aliphatic -CH bonds is associated to sub-bituminous coal (Manoj and Elcey, 2013;Rodrigues et al, 2020). According to (Nyakuma et al, 2021), sub-bituminous coals have the potential to be liquefied and used to make synthetic crude oil and tar.…”

Adsorbents for Noxious Gas Sequestration: State of the Art

“…AC has been investigated for SO x and NO x [99,100], H 2 S [101], and CO 2 [100] sequestration at different process conditions. To optimize capture and selectivity of AC for specific gases, modification of the structure to increase its affinity for specific gases have been reported [102][103][104][105][106][107][108].…”