Browsing by Author "Ozmen, Serap"
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Item Open Access Activated carbon derived from biomass combustion bottom ash as solid sorbent for CO2 adsorption(Elsevier, 2023-05-05) Gorbounov, Mikhail; Petrovic, Ben; Ozmen, Serap; Clough, Peter T.Climate change and global warming, caused mainly by the anthropogenic CO2 emissions, has been recognised to be the biggest threat to global ecosystems. Replacing fossil fuels with sustainable biomass for heat and power generation is a key tool in our fight against climate change. Such combustion, however, generates large quantities of ash which, unlike the coal counterparts, are yet to find major applications in industry. This leads to challenging waste management and thus, necessitating urgent measures to valorise this increasing waste stream. However, producing activated carbon from biomass combustion ash allows for not only effective waste valorisation into value-added products, but also to prepare a sorbent for post-combustion carbon capture from an abundant and cheap source that is readily available for in-situ application (hence, minimising overall costs). This work has focused on preparation and activation of industrial-grade biomass ash-derived porous carbon via an economical direct method, followed by an extensive characterisation of its textural properties as well as an evaluation of the CO2 uptake of both the virgin and the activated carbonaceous sorbents. The final sample was selected based on an extensive optimisation campaign aiming towards maximisation of yield and CO2 uptake. The optimum activated sample adsorbed 0.69 mmol/g, thus, nearly doubling the adsorption capacity of the virgin biomass combustion bottom ash-derived carbon.Item Open Access Highly robust ZrO2-stabilized CaO nanoadsorbent prepared via a facile one-pot MWCNT-template method for CO2 capture under realistic calcium looping conditions(Elsevier, 2022-12-27) Mousavi, Seyed Borhan; Heidari, Mohammad; Rahmani, Farhad; Sene, Rojiar Akbari; Clough, Peter T.; Ozmen, SerapThis research assessed the textural and structural characterizations and CO2 capture activity of novel and highly thermal-resistance ZrO2-stabilized adsorbents templated with MWCNT, prepared via a facile one-pot preparation approach. Various MWCNT contents, 2.5, 5, and 10 wt%, were incorporated into the CaO adsorbent containing 12.8 wt% ZrO2 species. The conducted structural properties revealed that the CaO grain size, surface area, and pore volume of untemplated ZrO2-supported CaO improved by 33.25%, 185%, and 141% through merging with 10 wt% MWCNT, conformed with FESEM images that showed the highly porous structure. Moreover, the TGA analyses under the severe calcium looping conditions, carbonation under 15 vol% CO2 balanced with N2 at 650 °C for 10 min, and calcination under 100 vol% CO2 at 930 °C for 10 min, demonstrated the incorporation of 10 wt% MWCNT into the ZrO2-stabilized CaO adsorbent increased cyclic durability and the ultimate CO2 capture capacity from 29.5% and 0.03 g CO2/g adsorbent to 61.12% and 0.1 g CO2/g adsorbent, indicating 107% and 233.3% enhancement, respectively. In addition to the significant reduction in CaO grain size and the formation of more high-volume pores, the influence of the MWCNT on calcium zirconate distribution into the CaO structure, mitigating CaO sintering and the agglomeration of CaO grains is another potential reason for the discussed multicyclic and textural improvements. The acquired findings indicated the effectiveness of MWCNT-template preparation method on textural, structural, and multicyclic properties of nano-scale ZrO2-promoted CaO adsorbents.Item Open Access The novel Carbon Nanotube-assisted development of highly porous CaZrO3-CaO xerogel with boosted sorption activity towards high-temperature cyclic CO2 capture(Elsevier, 2022-11-14) Heidari, Mohammad; Mousavi, Seyed Borhan; Rahmani, Farhad; Clough, Peter T.; Ozmen, SerapHerein, for the first time, we employed three minor concentrations of Carbon Nanotubes (CNT), 2.5, 5, and 10 wt.%, as an auxiliary additive to boost the textural and structural features and CO2 capture potential of sol–gel-derived CaZrO3-CaO adsorbents. The corresponding xerogels were developed with 15/1 and 30/1 Ca/Zr molar ratios to minimize the required amount of prohibitive Zr-based precursor. For both types of CaZrO3-CaO adsorbents, 5 wt.% of CNT was recognized as the most efficient amount. In addition to 15.84 and 33.1% reduction in CaO crystallite sizes, 50.57 and 90.55% increments in pore volume values were reported for CaO adsorbents developed with 15/1 and 30/1 Ca/Zr molar ratios, respectively. Over 15 cycles under harsh CO2 capture conditions, the total amount of captured CO2 for both abovementioned types of Zr-promoted adsorbents raised from 2.01 and 1.96 to 2.92 and 3.01 g CO2/g adsorbent, sequentially. Zr-promoted CaO nanoadsorbents merged with 5 wt.% CNT showed the ultimate CO2 capture capacity of 0.164 and 0.149 g CO2/g adsorbent for xerogel prepared with 15/1 and 30/1 M ratios of Ca/Zr, respectively. Even though the xerogel containing a Ca/Zr molar ratio of 15/1 showed the best sorption durability and ultimate capture capacity, CNT more significantly affects the CaO xerogel developed with a Ca/Zr molar ratio of 30/1. It can be deduced that the low content of multi-walled CNT notably contributes to developing highly efficient and fluffy-like Zr-promoted xerogels containing minor concentrations of Zr-based species.