Two composite materials were synthesized based on sodium alginate and biochar derived from licorice processing waste functionalized with silicon dioxide nanoparticles (SiO2) and iron oxide (Fe2O3), respectively, enabling the valorization of industrial waste. The adsorptive capacities of the two materials (Alg-SiO2 and BCLFe2O3) toward CO2 in the gaseous stream with nitrogen were evaluated by acid titration of carbonates present in a trap for CO2 consisting of a KOH solution placed downstream of the adsorption column. The aim of the present work is to evaluate the CO2 adsorption capacity of material functionalized by nanoparticles. Adams–Bohart, Thomas models, and % removal efficiency curves for the adsorption were examined to investigate the dynamic behavior of the column. From the tests performed in CO2 and N2 flow, the BCL-Fe2O3 material was demonstrated to have an adsorbent higher capacity than Alg-SiO2, respectively CO2 adsorbed 25 and 6 mg/g

Di Palma Luca

Rosa Domenico

Segneri Valentina

Vilardi Giorgio

English

Archivio della ricerca- Università di Roma La Sapienza

                                                                                                                                                                          DOI: 10.3303/CET23101022                                                                       Paper Received: 18 December 2022; Revised: 11 April 2023; Accepted: 13 May 2023 Please cite this article as: Rosa D., Segneri V., Di Palma L., Vilardi G., 2023, Synthesis and CO2 adsorption capacity of biomass waste functionalized by nanoparticles , Chemical Engineering Transactions, 101, 127-132  DOI:10.3303/CET23101022      CHEMICAL ENGINEERING TRANSACTIONS   VOL. 101, 2023 A publication of  The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Paolo Ciambelli, Luca Di Palma Copyright © 2023, AIDIC Servizi S.r.l. ISBN 979-12-81206-00-7; ISSN 2283-9216 Synthesis and CO2 Adsorption Capacity of Biomass Waste Functionalized by Nanoparticles Domenico Rosa, Valentina Segneri*, Luca Di Palma, Giorgio Vilardi Department of Chemical Engineering Materials Environment & UdR INSTM, Sapienza-Università di Roma, Via Eudossiana 18, 00184 Roma, Italy valentina.segneri@uniroma1.it Two composite materials were synthesized based on sodium alginate and biochar derived from licorice processing waste functionalized with silicon dioxide nanoparticles (SiO2) and iron oxide (Fe2O3), respectively, enabling the valorization of industrial waste. The adsorptive capacities of the two materials (Alg-SiO2 and BCL-Fe2O3) toward CO2 in the gaseous stream with nitrogen were evaluated by acid titration of carbonates present in a trap for CO2 consisting of a KOH solution placed downstream of the adsorption column. The aim of the present work is to evaluate the CO2 adsorption capacity of material functionalized by nanoparticles. Adams–Bohart, Thomas models, and % removal efficiency curves for the adsorption were examined to investigate the dynamic behavior of the column. From the tests performed in CO2 and N2 flow, the BCL-Fe2O3 material was demonstrated to have an adsorbent higher capacity than Alg-SiO2, respectively CO2 adsorbed 25 and 6 mg/g. 1. Introduction Global warming effects from excessive greenhouse gas emissions, such as CO2, are now becoming a serious environmental problem (Trinca et al., 2022).  Many strategies have been developed to solve this, with the advancement of nanoscience and nanotechnology, direct CO2 becomes an effective strategy to capture CO2 and transform it directly into compounds valuable chemicals in delicate environments. (Lu et al., 2021). Among the many sorbents, char made from the carbonization of biomass waste has been found to have exceptional CO2 adsorption capabilities. Carbon-based adsorbents, due to their large surface area, ability to pore size modification and ease of turnover, low cost of preparation, and low impact are considered to be one of the best materials for CO2 sequestration (Goel et al., 2021).  Commonly, converting biomass into porous carbons for CO2 capture includes carbonization, activation through exposure to high temperature and CO2 and steam environments (physical activation) or using potassium hydroxide KOH (chemical activation), and surface modification by addition of additives like metal oxides, that can potentially improve the surface chemistry and adsorption chemistry by improving the interaction between the adsorbent surface and the CO2 molecule (Akeeb et al., 2022). In this work, two composite materials functionalized with nanoparticles have been synthesized: the first based on sodium alginate functionalized with silicon dioxide nanoparticles (SiO2), while the second formed by iron oxide nanoparticles supported on a lignocellulosic matrix (biochar derived from licorice), thus allowing the valorization of an industrial waste. Silica-based nanoparticles have attracted considerable interest from researchers due to their high surface area, large pore volume, narrow pore size distribution, and excellent regeneration stability of silica. On the other hand, adsorbents based on iron oxides are efficient reversible sorbents for CO2 capture. The technique for CO2 adsorption made from biomass might be proven to be one of the most affordable and environmentally beneficial ways to combat climate change.  1272. Materials and methods 2.1 Chemicals In this work, the following reagents are employed: silicon dioxide (Carlo Erba), hexahydrated ferric chloride (FeCl3*6H2O, Honeywell), sodium alginate (Special Ingredients), sodium hydroxide (NaOH, Honeywell), potassium hydroxide (KOH, Honeywell), phenolphthalein (Carlo Erba), sulfuric acid (H2SO4 98 %, Honeywell), nitric acid (HNO3 64 % Honeywell) acetic acid (CH3COOH glacial, Carlo Erba), hydrochloric acid (HCl 37 %, Honeywell), licorice roots waste (Amarelli). All the chemicals were used without any further purification. Demineralized water was used as a solvent for both solutions. 2.2 Composite materials synthesis Synthesis of SiO2 nanoparticles supported on alginate (Alg-SiO2) was performed by preparing a 1 wt% aqueous solution of alginate by dissolving sodium alginate (1.2 g) in a 1 wt% aqueous solution of acetic acid (1.2 ml in 120 ml of water) under constant magnetic stirring until achieving a homogeneous solution (400 rpm for 2 h). The alginate solution was then immersed in the suspension of SiO2 nanoparticles (6.1 g in 1000 ml) and placed in an ultrasonic bath for 20 minutes. Then the mixture was maintained at 60 °C for 4 h under constant stirring at 400 rpm and subsequently placed in an ice water bath for 1 h. The sample was centrifuged at 10000 rpm for 10 min, the solid was separated from the liquid and placed in an oven at 60 °C overnight. The sample Alg-SiO2 was obtained (Figure 1). Synthesis of Fe2O3 nanoparticles supported on BCL (BCL-Fe2O3) was performed in two steps. First, BCL was prepared from licorice processing waste by washing the licorice roots with plenty of water to remove soil and other impurities. The roots were then placed in an oven at 60 °C overnight. Then they were ground and sieved through a 1 mm sieve and placed in an autoclave and pressed to make the environment as anoxic as possible. The sample was placed in a muffle furnace at 700 °C for 2 h thus obtaining BCL. 10 g of BCL were then functionalized by holding it at 60 °C for 4 h under constant magnetic stirring at 400 rpm in 200 ml of an acid solution made of 10 ml HNO3 (64 %) and 30 ml H2SO4 (98 %) to form carboxylic groups on the BC surface. After the solid was washed with demineralized water until neutral pH and dried in an oven at 60 °C overnight. Then 10 g of functionalized BCL were dispersed in 200 ml of an aqueous solution containing 0.6 mol of FeCl3 and magnetically stirred for 2h at 60 °C. After that, 100 ml of NaOH 2 M solution was added to the mixture dropwise and magnetically stirred for 2h at 60 °C. After the solid was filtered and washed with demineralized water until neutral pH and dried in an oven at 60 °C overnight. Finally, the solid was calcined in muffle at 600 °C for 1 h obtaining BCL-Fe2O3 sample (Figure 1).    Figure 1: Synthesized materials: at left SiO2-based sample supported on alginate (Alg-SiO2) and at right Fe2O3-based sample supported on licorice biochar (BCL-Fe2O3). 2.3 Experimental setup The experimental set-up consisted of two gas cylinders of CO2 and N2. The flow rate used for the tests was 40 ml/min for CO2 and 60 ml/min for N2 and was controlled by flowmeters placed before a Y-valve that would allow the mixing of the two gases before reaching the adsorbent column, which consisted of a tubular polyethylene reactor of volume 10 ml and diameter 0.5 cm inside of which the adsorbent material was placed until full; 12.02 g of Alg-SiO2 and 3.98 g of BCL-Fe2O3 were employes, this different amount is due to the huge difference in density of the two solids. Paper filters were placed to support the adsorbent material both at the head and tail, and the column was placed horizontally to the work surface. The gas stream leaving the column was directed into a cylinder containing a 1 L 2M KOH solution to convert CO2 to carbonate ion according to the following equation (Eq. 1): Alg-SiO2 BCL-Fe2O3 128𝐶𝑂2 +𝐾𝑂𝐻 = 𝐶𝑂32− + 𝐻+ +𝐾+                                                                                                                                                         (1) The experimental set-up is illustrated below (Figure 2):    Figure 2: Experimental set-up used to carry out adsorption CO2 employing based nanoparticles composite materials (Alg-SiO2 and BCL-Fe2O3). 2.4 Evaluation of CO2 adsorption capacity As soon as the gas flowed, at room temperature, 10 mL samples each were taken at different times (0-180 min) of CO2 trapping solution (no additional solution was added to compensate for the decrease in volume due to withdrawals but was considered in the calculation of carbonate moles) employing both columns containing the two different materials and without any column as a checking test. All samples taken were titrated using a known titer solution of HCl and drops of saturated phenolphthalein solution with a characteristic fuchsia color. Phenolphthalein is the ideal indicator for titration of carbonates because the color change (from fuchsia to transparent) occurs at pH 8.3, which corresponds to the pH below which the carbonate ions protons into the bicarbonate ions. Knowing the moles of acid needed for titration, it was possible to derive the moles of carbonate. Having calculated the concentration of carbonate ions in the samples, it was possible to derive the adsorptive capacity of the materials toward CO2 (defined as mg of CO2 adsorbed per g of material) by the difference between checking and adsorbent column tests and normalizing by the weight of the solid employed.  As further verification, the samples were acidified with drops of HCl to lower the pH to about 6 and analyzed for inorganic carbon by Shimadzu TOC-L analyzer. 2.5 Breakthrough curve modeling An exceptional overview of the column adsorption process primarily requires prediction of the break-through curve for effluent. Several simplistic models of packed bed dynamics to describe and analyze lab-scale studies are mainly used in industrial applications. In order to predict column dynamics, the Adams–Bohart, Thomas, Yoon and Wang models were used to fit adsorption breakthrough data (Subbaiah et al., 2011). These fixed bed models are popular because their model equations can be linearized, allowing their unknown parameters to be estimated by linear regression analysis (Chu, 2020). In this work, to evaluate the performance, Adams–Bohart model was used. To analyze the Adams–Bohart model parameter the value of rate constant decreases with increase of influent concentration. The century-old Bohart-Adams model is arguably the best known one which also serves as the foundation of the bed depth-service time equation. Bohart and Adams (S Bohart and Adams, 2023) described the relationship between 𝐶𝑡/𝐶0 and 𝑡 in a continuous system, which is used for describing the initial part of the breakthrough curve. The expression is as follows: 𝐶0𝐶𝑡 ={      exp( 𝑘𝐴𝐵𝐶0 (𝑡 −𝜀𝑍𝑈0))exp(𝑘𝐴𝐵𝑁0(𝑍/𝑈0)) + exp( 𝑘𝐴𝐵𝐶0 (𝑡 −𝜀𝑍𝑈0)) − 1, 𝑡 >𝜀𝑍𝑈00, 0 < 𝑡 <𝜀𝑍𝑈0                                                                       (2) 129where 𝐶0 and 𝐶𝑡 are the influent and effluent concentration (g/L), 𝑘𝐴𝐵 is the Bohart Adams kinetic constant (L/gmin), 𝑁0 is the adsorption capacity of the adsorbent per unit volume of the bed (g/L), 𝜀 is the bed voidage, 𝑍 is the bed depth of the fix-bed column (cm) and 𝑈0 is the superficial velocity (cm/min) defined as the ratio of the volumetric flow rate Q (cm3/min) to the cross-sectional area of the bed A (cm2), 𝑘𝐴𝐵 and 𝑁0 can be calculated from the linear plot of ln(Ct/C0) against time. Their model assumes that the adsorbate is adsorbed irreversibly and at a local rate of removal that is proportional to both the residual capacity of the adsorbent and the gas phase concentration of the adsorbate. A key feature of the 100-year-old model of Bohart and Adams (Chu, 2020) is that it predicts a linear relationship between bed depth and the time taken for breakthrough to occur. This linear relationship simplifies the tasks of adsorber design and analysis and provides a simple approach to running pilot tests. Since the exponential term 𝑒𝑥𝑝 (𝑘𝐴𝐵𝑁0𝑍𝑈0) is expected to be much larger than unity and 𝑡 is usually much greater than 𝜀𝑍/𝑈0 . 𝑙𝑛 (𝐶0𝐶𝑡− 1) = 𝑘𝐴𝐵𝑁0 (𝑍𝑈0)  − 𝑘𝐴𝐵𝐶0(𝑡)                                                                                                                                       (3) 3. Results and discussions 3.1 Adsorption performances Figure 3 shows the capture kinetic curve for each of the composite materials.   Figure 3: CO2 adsorption kinetics of two different materials BCL-Fe2O3 and Alg-SiO2 using respectively 3.98 and 12.02 g, gas flow 40 ml/min for CO2 and 60 ml/min for N2 at room temperature.  From the data shown in Figure 3 the significant difference in the adsorption capacity of the two materials was evident, in fact Alg-SiO2 showed an adsorptive capacity of 6 mg/g while BCL-Fe2O3 of 25 mg/g under the conditions employed (room temperature and flow of CO2 40 ml/min and N2 60 ml/min) in agreement with other authors (KIRBIYIK, 2019; Rafigh and Heydarinasab, 2017). This result could be justified by the different properties of the materials, primarily to the surface area and porosity but also other factors such as interactions with functional groups on the surface could play an important role in CO2 adsorption. It is known that there are nitrogen groups present on the surface of biochars that are weakly basic and polar (combination of physical and chemical adsorption) and could increase the adsorption capacity of CO2. (Zhang et al., 2013). Another important difference is due to the nature of iron oxide, which has weakly basic properties which is advantageous in terms of capturing CO2 that is acidic, whereas sicile is known to be an oxide with acidic characteristics (Schott et al., 2017). 3.2 Breakthrough curve modeling The following figures show the comparison between the experimental values of the C/C0 ratio, and the breakthrough curve determined using the Adams Bohart model. 0510152025300 50 100 150CO2 adsorbed (mg/g)Time (min)BCL-…Alg-SiO2130 Figure 4: Breakthrough curve of Alg-SiO2 using Adams - Bohart Model, where KAB = 0.081 L/(gmin) and N0 = 562 g/L (with R2 = 99.81%).   Figure 5: Breakthrough curve of BCL-Fe2O3 using Adams - Bohart Model, where 𝐾𝐴𝐵 = 0.23 L/gmin and 𝑁0 = 299 g/L (with 𝑅2 = 99.63%). The data points in the initial part of the failure curve indicate that failure of the tested materials occurred almost immediately. A large increase in the dimensionless effluent concentration to approximately 70% was followed by a relatively slow approach to saturation, a characteristic of tailing that has been attributed to a variety of factors, including non-specific adsorption or flow non-uniformity. Accounting for these possible stalking causes mechanistically requires the use of complex models. The following Table shows the values of the parameters determined using the Adams - Bohart model. As can be seen, the iron oxide particles supported on a lignocellulosic matrix have a higher kinetic constant than Alg-SiO2 ones, managing to adsorb CO2 faster. Table 1: Adams Bohart Model Parameter Adams - Bohart 𝐴𝑙𝑔 − 𝑆𝑖𝑂2  N0 [g/l] KAB [l/gmin] R2 562 0.081 99.81% 𝐵𝐶𝐿 − 𝐹𝑒2𝑂3 N0 [g/l] KAB [l/gmin] R2 299 0.23 99.63% 00.20.40.60.810 2 4 6 8 10 12C/C0Time [min]Experimental DataBreakthrough curveTangent lineBreakthrough Point00.20.40.60.810 2 4 6 8 10 12C/C0Time [min]Experimental DataBreakthrough curveTangent lineBreakthrough Point1314. Conclusions  This study presents a novel method to capture CO2 from two nanoparticle-functionalized matrix-based composite materials. The experimental phase was carried out using 40 ml/min for CO2 and 60 ml/min for N2 conveyed in an adsorbent column, consisting of a tubular polyethylene reactor with a volume of 10 ml. From tests performed in CO2 and N2 flow (40 and 60 ml/min), it was demonstrated that the BCL-Fe2O3 material has a higher adsorbing capacity than Alg-SiO2, CO2 adsorbed 25 and 6 m/g respectively due to the different nature of the materials and also to the different synthesis strategy. From the analysis of the results and mediated modeling of the Adams Bohart model, the BCL-Fe2O3 material has been shown to have a higher kinetic constant than Alg-SiO2, showing good CO2 adsorption capacity. These results confirm what was reported in previous studies concerning iron oxide-based adsorbents, which are prospective and efficient adsorbents for CO2 capture. Acknowledgement The authors acknowledge Sapienza and EU for the project funded under the National Recovery and Resilience Plan (NRRP), of Italian Ministry of Research funded by the European Union – NextGenerationEU: Partnerships extended to Universities, Research Centres, Companies for Funding Basic Research Projects  The authors also recognize the financial support by “Sapienza” University of Rome for grant no. RM120172A298917B. References Akeeb, O., Wang, L., Xie, W., Davis, R., Alkasrawi, M., Toan, S., 2022. Post-combustion CO2 capture via a variety of temperature ranges and material adsorption process: A review. J Environ Manage 313, 115026. https://doi.org/10.1016/j.jenvman.2022.115026 Chu, K.H., 2020. Breakthrough curve analysis by simplistic models of fixed bed adsorption: In defense of the century-old Bohart-Adams model. Chemical Engineering Journal 380. https://doi.org/10.1016/j.cej.2019.122513 Goel, C., Mohan, S., Dinesha, P., 2021. CO2 capture by adsorption on biomass-derived activated char: A review. Science of the Total Environment 798, 149296. https://doi.org/10.1016/j.scitotenv.2021.149296 KIRBIYIK, Ç., 2019. Modification of biomass-derived activated carbon with magnetic-Fe2O3nanoparticles for CO2and CH4adsorption. Turk J Chem 43, 687–704. https://doi.org/10.3906/kim-1810-32 Lu, C., Shi, X., Liu, Y., Xiao, H., Li, J., Chen, X., 2021. Nanomaterials for adsorption and conversion of CO2 under gentle conditions. Materials Today 50, 385–399. https://doi.org/10.1016/j.mattod.2021.03.016 Rafigh, S.M., Heydarinasab, A., 2017. Mesoporous Chitosan-SiO2 Nanoparticles: Synthesis, Characterization, and CO2 Adsorption Capacity. ACS Sustain Chem Eng 5, 10379–10386. https://doi.org/10.1021/acssuschemeng.7b02388 S Bohart, B.G., Adams, E.Q., 2023. SOME ASPECTS OF THE BEHAVIOR OF CHARCOAL WITH RESPECT TO CHLORINE.1. UTC. Schott, J.A., Wu, Z., Dai, S., Li, M., Huang, K., Schott, J.A., 2017. Effect of metal oxides modification on CO2 adsorption performance over mesoporous carbon. Microporous and Mesoporous Materials 249, 34–41. https://doi.org/10.1016/j.micromeso.2017.04.033 Subbaiah, M.V., Yuvaraja, G., Vijaya, Y., Krishnaiah, A., 2011. Equilibrium, kinetic and thermodynamic studies on biosorption of Pb(II) and Cd(II) from aqueous solution by fungus (Trametes versicolor) biomass. J Taiwan Inst Chem Eng 42, 965–971. https://doi.org/10.1016/j.jtice.2011.04.007 Trinca, A., Segneri, V., Mpouras, T., Libardi, N., Vilardi, G., 2022. Recovery of Solid Waste in Industrial and Environmental Processes. Energies (Basel). https://doi.org/10.3390/en15197418 Zhang, C., Song, W., Sun, G., Xie, L., Wang, J., Li, K., Sun, C., Liu, H., Snape, C.E., Drage, T., 2013. CO2 capture with activated carbon grafted by nitrogenous functional groups, in: Energy and Fuels. pp. 4818–4823. https://doi.org/10.1021/ef400499k    132

Synthesis and CO2 adsorption capacity of biomass waste functionalized by nanoparticles

https://iris.uniroma1.it/bitstream/11573/1686536/1/Rosa_Synthesis-CO2-adsorption_2023.pdf

Synthesis and CO2 adsorption capacity of biomass waste functionalized by nanoparticles

Abstract

Similar works

Full text

Available Versions

Archivio della ricerca- Università di Roma La Sapienza