CO2 Absorption Rate Research Articles

Performance and pressure drop ofCO2absorption into task‐specific and halide‐free ionic liquids in a microchannel

AbstractThe gas–liquid two‐phase flow pattern, absorption rate and pressure drop of CO2absorbed into the aqueous solution of the task‐specific ionic liquids (1‐aminopropyl‐3‐methylimidazole tetrafluoroborate [Apmim][BF4] and 1‐hydroxyethyl‐3‐methylimidazole tetrafluoroborate [OHemim][BF4]) and halide‐free ionic liquid 1‐butyl‐3‐methylimidazolium methylsulfate [Bmim][CH3SO4] were investigated in a microreactor. The absorption mechanism of the three ionic liquids was analyzed employing the13C NMR spectroscopy. The [Apmim][BF4] was found to have the best ability of CO2capture compared with the other two ionic liquids, as chemical absorption occurred between [Apmim][BF4] and CO2, while only physical absorption took place between [OHemim][BF4]/[Bmim][CH3SO4] and CO2. The sequence of CO2absorption rate in three ionic liquids aqueous solutions is: [Apmim][BF4] > [Bmim][CH3SO4] > [OHemim][BF4]. Furthermore, the effects of gas–liquid flow rate and ionic liquids concentration on CO2absorption rate and pressure drop were studied, the pressure drop models based on various flow patterns were proposed.

CO2 absorption/desorption rates in aqueous DEEA/MDEA and sulfolane-contained hybrid solutions: effects of physical properties and reaction rate.

The rates of CO2 absorption into fresh and regenerated aqueous solutions of N,N-diethylethanolamine (DEEA), N-methyldiethanolamine (MDEA), and their mixture with sulfolane are investigated in a batch stirred cell reactor. The data are obtained in the temperature range of 293.15-313.15K, pressures up to 800kPa, and different concentrations of alkanolamines and sulfolane. The diffusion coefficients and Henry's law constants for all the solutions are obtained. The absorption rate of DEEA solutions increased by increasing component concentrations and pressure, but the effects of temperature on the absorption rates of hybrid and aqueous DEEA solutions are different. Comparison of absorption rates in aqueous and hybrid solutions under the same conditions can determine the role of sulfolane as the physical solvent. It has been found that sulfolane acts as an effective absorption activator in the hybrid DEEA solutions. However, in the MDEA solutions, in all experimental conditions except for high pressure ([Formula: see text] 400kPa) and certain MDEA concentration (20 wt%), sulfolane has a negative effect on the absorption rate. The absorption rates of regenerated aqueous DEEA solutions are in the range of 50.5-87.7% of fresh ones, while these values for the hybrid DEEA solution are in the range of 75-90.5%. These values for the aqueous and hybrid MDEA solutions are almost equal. Based on the values of Hatta number and enhancement factor, the CO2 absorption regime in the DEEA solutions is determined as the fast second-order reaction. The absorption rate can be interpreted considering the tradeoff between kinetics and thermodynamics of CO2 absorption in the aqueous and hybrid DEEA/MDEA solutions. The desorption rates in hybrid DEEA/MDEA solutions are higher than those in aqueous solutions.

A study of kinetics, equilibrium solubility, speciation and thermodynamics of CO2 absorption into benzylamine (BZA) solution

The kinetics between BZA and CO2 were investigated by the stopped-flow apparatus over the BZA concentration range from 0.05 to 0.1 mol/L (0.54–1.07 mass%), and over the temperature range from 293 to 313 K. The results also show that the predicted CO2 absorption rate exhibits good agreement with the experimental data with an absolute average deviation (AAD) of 5.15% and 4.15% with respect to the zwitterion and termolecular models, respectively. Furthermore, the NMR experiments confirmed the formation of carbamates. The VLE plots were made with speciation data obtained from NMR techniques applied to the CO2-BZA-H2O system with CO2 loading of 0–0.67 mol CO2/mol BZA at 298 K. A new VLE model was proposed, and the predicted results exhibit good agreement with the experimentaly measured results.

Hybrid enzymatic CO2 capture process in intensified flat sheet membrane contactors with immobilized carbonic anhydrase

A hybrid enzymatic CO2 absorption process in an intensified flat sheet membrane contactor with immobilized human carbonic anhydrase II (hCA II) enzyme was proposed. In addition to be immobilized on the membrane surface, extra carbonic anhydrase enzyme was immobilized on the surface of magnetic nanoparticles (MNPs) dispersed in the liquid phase to reduce the mass transfer limitations and enhance the absorption process. This hybrid enzymatic process is beneficial to attain high CO2 absorption rates, even if a component of the enzymatic system, either the biocatalytic membrane or biocatalytic MNPs, does not operate appropriately. The improvement CO2 hydration in the presence of biocatalytic MNPs was more significant at lower CA loadings on membrane surface. Reusability of the biocatalytic membranes and biocatalytic MNPs was demonstrated by 10 absorption cycles and the intensified membrane contactor displayed stable operation for several hours. A multiscale mathematical model (under gas-filled or partially liquid-filled membrane pores conditions) was proposed to explore the behaviour of the intensified membrane contactor. Model simulations showed that the resistance to mass transfer in membrane wetted zones is overcame by the CO2 enzymatic absorption in these zones (catalyzed by enzyme immobilized in membrane pores) and possible by the absorption of CO2 in the presence of biocatalytic MNPs.

A Combined Experimental and Computational Study on the Shuttle Mechanism of Piperazine for the Enhanced CO2 Absorption in Aqueous Piperazine Blends

Piperazine (PZ) blends containing PZ and monoethanolamine (MEA)/N-methyldiethanolamine (MDEA)/2-amino-2-methyl-propanol (AMP) were experimentally and computationally investigated to analyze their potential capabilities for CO2 capture, and the shuttle mechanism of PZ for enhanced CO2 absorption were verified. In experiments, the concentration of both PZ and MEA/MDEA/AMP were varied to show the effect of concentration ratio and the influence of amine components on the CO2 absorption rate and capacity. Experimental results showed that all the PZ blends possessed high absorption rates and large absorption capacities. To further understand the interaction behavior of amines/products and possible reaction pathways, both qualitative and quantitative 13C NMR analyses were conducted. The results indicated the conversion between absorption products, which can release free PZ to capture CO2 and consequently improve the absorption performance. Moreover, the static quantum mechanical calculations and ab initio molecular dynamics (AIMD) simulations combined with metadynamics sampling were conducted to evaluate the thermodynamic stability of absorption products and kinetically favorable key elementary reactions in PZ blends. This study highlights an accurate description of the shuttle effect of PZ for the enhanced CO2 capture by PZ blends.

Amine-Ionic Liquid Blends in CO2 Capture Process for Sustainable Energy and Environment

In the present work, an experiment for CO2 capture process were performed by absorption using various aqueous solvent blends of amine and ionic liquids. The solvent blends were prepared for various compositions by mixing TetraButylAmmonium Acetate [TBA][OAC] and TetraButylAmmonium Bromide [TBA][Br] ionic liquids with Monoethanolamine (MEA). The obtained results were compared with baseline MEA. It was observed that capture efficiency of CO2, absorption rate of CO2 and CO2 diffusion coefficient of MEA-[TBA][OAC] and MEA-[TBA][Br] solvent blends were comparatively higher than baseline 30%MEA. Moreover, the parameters such as density, viscosity, pH, carbon loading and surface tension of all the solvent blends were measured for before and after absorption process. The carbon loading of solvent blends MEA-[TBA][Br] (0.405 mole of CO2/mole of solvent) and MEA-[TBA][OAC](0.459 mole of CO2/mole of solvent) was slightly lower than baseline MEA (0.494 mole of CO2/mole of solvent). However, the viscosity of MEA-[TBA][Br] blends were remarkably lower than MEA-[TBA][OAC] blend and baseline MEA. This might be an important key factor in solvent recovery process with lesser energy demand for sustainable energy and environment.

CO2 absorption into primary and secondary amine aqueous solutions with and without copper ions in a bubble column.

Chemical absorption of CO2 into aqueous amine solutions using a nonstirred bubble column was experimentally investigated. The performance of CO2 absorption of four different primary and secondary amines including monoethanolamine (MEA), piperazine (PZ), 2-piperidineethanol (2PE), and homopiperazine (HPZ) were compared. The effects of initial concentration of amine, the inlet mole fraction of CO2, and solution temperature on the rate of CO2 absorption and CO2 loading (mol CO2/mol amine) were studied in the range of 0.02-1 M, 0.10-0.15, and 25-40 °C, respectively. The effect of the presence of copper ions in the amine solution on CO2 loading was also studied. By comparison of the breakthrough curves of the amines at different operational conditions, it was revealed that the shortest and longest time for the appearance of the breakthrough point was observed for MEA and HPZ solutions, respectively. CO2 loading of MEA, 2PE, PZ, and HPZ aqueous solutions at 25 °C, 0.2 M of initial concentration of amine, and 0.15 of inlet mole fraction of CO2 were 1.06, 1.14, 1.13, and 1.18 mol CO2/mol amine, respectively. By decreasing the inlet mole fraction of CO2 from 0.15 to 0.10, CO2 loading slightly decreased. As the initial concentration of amine and temperature decreased, CO2 loading increased. Also, the presence of copper ions in the absorbent solution resulted in a decrease in the CO2 loading of MEA and HPZ aqueous solutions. In case of PZ and 2PE amines, adding copper ions led to precipitation even at low copper ion concentrations.

CO₂ Absorption Rate of a 2-Amino-2-Methyl-1-Propanol/Piperazine Solution Containing Degradation Compounds during Post-combustion CO₂ Capture

CO₂ Absorption Rate of a 2-Amino-2-Methyl-1-Propanol/Piperazine Solution Containing Degradation Compounds during Post-combustion CO₂ Capture

A review on the selection criteria for slow and medium kinetic solvents used in CO2 absorption for natural gas purification

This review paper evaluates the critical selection criteria for slow and medium kinetic chemical solvents used in the CO2 absorption process during natural gas purification. The chemical absorbents’ reaction mechanism, capacities, chemical structure, and operating parameters on the CO2 absorption performance was discussed. Other solvent properties such as vapor pressure, corrosively, viscosity, forming tendency, regeneration energy, thermal stability, and toxicity was investigated to portray their overall potentials industrial applications. Generally, the absorbents absorption rate is the superior determinant factor for their industrial applications. Thus, desirable solvent performance breakthrough will depend on CO2 absorption rate enhancement research via chemical/mechanical methods.

Enhancing Absorption Performance of CO2 by Amine Solution through the Spiral Wired Channel in Concentric Circular Membrane Contactors.

The CO2 absorption rate by using a Monoethanolamide (MEA) solution through the spiral wired channel in concentric circular membrane contactors under both concurrent-flow and countercurrent-flow operations was investigated experimentally and theoretically. The one-dimensional mathematical modeling equation developed for predicting the absorption rate and concentration distributions was solved numerically using the fourth Runge–Kutta method under various absorbent flow rate, CO2 feed flow rate and inlet CO2 concentration in the gas feed. An economical viewpoint of the spiral wired module was examined by assessing both absorption flux improvement and power consumption increment. Meanwhile, the correlated average Sherwood number to predict the mass-transfer coefficient of the CO2 absorption mechanisms in a concentric circular membrane contactor with the spiral wired annulus channel is also obtained in a generalized and simplified expression. The theoretical predictions of absorption flux improvement were validated by experimental results in good agreements. The amine solution flowing through the annulus of a concentric circular tube, which was inserted in a tight-fitting spiral wire in a small annular spacing, could enhance the CO2 absorption flux improvement due to reduction of the concentration polarization effect. A larger concentration polarization coefficient (CPC) was achieved in the countercurrent-flow operations than that in concurrent-flow operations for various operations conditions and spiral-wire pitches. The absorption flux improvement for inserting spiral wire in the concentric circular module could provide the maximum relative increment up to 46.45%.

Kinetic modeling of Polyamine-based Water-Lean solvents for CO2 capture: Reverse temperature dependence of the overall mass transfer coefficient

Amine-based water-lean solvents (WLS) are promising energy-saving alternatives to the aqueous amine solutions for CO2 capture. Herein, we determined the apparent kinetic parameters of WLS containing 3,3′-iminobis(N,N-dimethylpropylamine) (60 wt%), water (10–20 wt%), and a non-amine chemical (balance). For CO2 absorption rate modeling, the termolecular reaction model and reaction rate model of tertiary amines were incorporated into the equilibrium model proposed by previous work, and the absorption rate of CO2 was estimated using a wetted wall column-based apparatus. The average CO2 absorption rates of the studied 10 wt%–H2O WLS at 313 and 333 K were approximately 5.0e-03 and 4.0e-03 mol/m2∙kPa∙s, respectively, which were much higher than that of a conventional aqueous amine solvent for CO2 capture. In addition, we observed that the overall mass transfer coefficient decreased with increasing temperature in low content water of WLS. This is due to the change of physical properties (Henry's law constant and diffusion coefficient) of WLS with decreasing water concentration. In this work, the cause of the reverse temperature dependence of WLS was investigated and verified through experiments and modeling.

Bioconversion of chemically captured carbon dioxide into microalgal lipids, a potential source of biodiesel: An integrated technique

The rise of atmospheric carbon dioxide (CO2) concentration due to extensive anthropogenic activity besides rapid exhaustion of non-renewable energy sources demands evolution of clean and ecofriendly alternative fuel source. Recently, lipid rich microalgal biomass is being considerably researched for generation of biodiesel conversely, the expenses incurred on production of microalgal biomass is a substantial obstacle. Almost 80 % of the production cost is generated from the cultivation medium which majorly consists of carbon, nitrogen and phosphate. CO2 absorption by means of aqueous amine solvents is known to be a mature technology and could be integrated with microalgal cultivation unit for efficient utilization of the captured CO2. In this current investigation, piperazine (PZ) promoted aqueous blend of methyldiethanolamine (MDEA) having mass percentage ratio of (8/22 wt%) was used a CO2 capturing agent and then the captured CO2 was utilized as an inorganic carbon source for growing Chlorella sorokiniana BTA 9031 for biodiesel production. The CO2 absorption rate was governed by series of process variables namely, absorption temperature, initial CO2 concentration, solvent flow rate, gas flow rate and the optimal conditions were 315 K, 15 kPa, 3.6 × 10−4 m3 min−1 and 4 × 10−3 m3 min−1 respectively. The highest biomass strength of Chlorella sorokiniana BTA 9031 was observed to be 1.20 ± 0.028 g L−1. The fatty acid methyl esters (FAME) profile was determined after acid transesterification of the extracted microalgal lipids. It was observed to contain fatty acids suitable for biodiesel production.

Concurrent H2 Generation and Formate Production Assisted by CO2 Absorption in One Electrolyzer.

Electrolyzers coupling electrocatalytic hydrogen evolution with oxidation reactions of small organic molecules have the merits of reducing cell voltage and generating high-value products. Herein, an electrolyzer is designed and optimized that can simultaneously achieve efficient hydrogen generation at the cathode, CO2 absorption by the catholyte, and methanol upgrading to formate at the anode. For these purposes, transition metal phosphides are used as the low-cost catalysts. The unique electrolyzer exhibits a low working voltage of 1.1V at 10mA cm-2 . Under optimal conditions, the Faraday efficiencies of hydrogen evolution and formic acid conversion reactions, which are the reaction products at the cathode and anode, respectively, are nearly 100% at various current densities from 10 to 400mA cm-2 . Meanwhile, the CO2 absorption rate is about twice that of the hydrogen generation rate, which is close to the theoretical value. An innovative and energy-efficient strategy is presented in this work to realize simultaneous hydrogen production and CO2 capture based on low-cost catalyst materials.

Amine infused hydrogel-based CO2 gas storage technology for CO2 hydrate-based cold thermal energy storage

Carbon dioxide (CO2) hydrate-based cold thermal energy storage (CTES) is a promising method for load shifting and demand management of cooling systems and for CO2 utilisation. A challenge of CO2 hydrate-based CTES is to find a compatible CO2 gas storage, the CO2 regeneration and absorption conditions of which can be coupled with the charging and discharging conditions of the CTES, respectively. Amine diethanolamine infused hydrogels (DEAIHs) can be an effective CO2 absorber as the gas–DEA surface contact area is greatly enlarged by infusing the solution into a hydrogel. However, the influencing factors of the CO2 absorption and regeneration performance of DEAIHs are unknown. This paper investigates the performance of DEAIHs and explores the possibility of applying them in cyclic CO2 gas storage for CTES. The effects of pressure, temperature, DEAIH sample mass and amine diethanolamine (DEA) mass fraction on CO2 absorption and absorption rate are investigated. It was found that a higher pressure prompted CO2 absorption while a temperature of 12℃ resulted in the highest CO2 absorption rate. The average CO2 absorption rates in the first 100 min were 0.250, 0.228, 0.155 and 0.033 mmol min–1 for 20-g DEAIH sample with 30-wt% DEA and 60-g DEAIH sample with 30, 47 and 89-wt% DEA, respectively. CO2 regeneration from DEAIH under zero and non-zero gauge pressures are studied. Under non-zero gauge pressures, a pressure rise followed by a pressure drop caused by CO2 re-absorption appeared in the CO2 regeneration from DEAIH. It was found for the first time that the system passed through a meta-equilibrium state before it reached an equilibrium pressure. Cyclic absorption and regeneration at 110℃ under zero gauge pressure showed that the CO2 absorption decreased dramatically after the third cycle due to the volatility of amine. Operating a coupled CO2 hydrate-based CTES and CO2 gas storage system demonstrated the possibility of DEAIH material for CO2 gas storage in CTES systems.

Microfluidic analysis of seawater-based CO2 capture in an amine solution with nickel nanoparticle catalysts

Post-combustion CO2 capture methods like amine scrubbing are currently being utilized to reduce CO2 emissions from fossil fuel power plants. Aqueous monoethanolamine (MEA) solutions are typically used in these processes due to their high CO2 absorption capacity and rapid reaction rate, but these solutions also produce environmentally harmful toxic wastewater and consume large amounts of freshwater. This research analyzes the effectiveness of seawater-based MEA solutions containing nickel nanoparticles (NiNPs) as catalysts, with the goal to minimize the amount of MEA required in the amine scrubbing process and eliminate the use of freshwater. This study is the first to use natural seawater solutions as an alternative to freshwater solutions for CO2 capture. In a microfluidic environment, CO2 microbubbles were generated and their change in size with respect to time was observed to determine the CO2 absorption capacity and rate of the test solutions. Pure seawater demonstrated comparable CO2 absorption to deionized (DI) water. Seawater-based amine solutions absorbed merely 1.79 % less CO2 than DI water-based amine solutions. Seawater-based amine solutions demonstrated faster CO2 absorption rates than their freshwater counterparts. Lastly, to further optimize CO2 absorption, NiNPs were added to each test solution. Seawater with MEA and NiNPs absorbed only 1.15 % less than its DI water counterpart, confirming seawater’s potential as amine-based solvent for industrial CO2 capture applications.

Effects of Light Condition on Growth and Physiological Characteristics of the Endangered Species Sedirea japonica under RCP 6.0 Climate Change Scenarios.

This study was conducted to evaluate the physiological and growth responses of Sedirea japonica cultured in chambers under RCP 6.0 and different light conditions. S. japonica was grown in a soil–plant daylight system chamber under two treatments, a control (CO2 = 400 ppm) and a climate change treatment (CCT) (CO2 = 650 ppm, temperature = control + 3 °C), and three different shading treatments (60%, 90%, and no-shading). S. japonica showed the characteristics of typical Crassulacean acid metabolism (CAM) plants. As the shading rate increased, it increased chlorophyll content, leaf area, and leaf dry weight to efficiently absorb and use light. The CCT had a lower CO2 absorption rate, stomatal conductance, and growth rate and slightly higher water utilization efficiency than the control. This was because stomatal closure occurred in the CCT to reduce water loss due to a relatively higher temperature. As CO2 fixation decreased and consumption increased due to respiration, the overall growth was inhibited. The CCT without shading revealed a dynamic photoinhibition phenomenon showing a significant increase in ABS/RC, TRo/RC, ETo/RC, and DIo/RC and a decrease in PI ABS and DF ABS. In this group, leaf, root, and total dry weight, chlorophyll content, and carotenoid content were the worst growth indices.

Conjugated Mass Transfer of CO2 Absorption through Concentric Circular Gas–Liquid Membrane Contactors

A new design of gas absorption that winds the permeable membrane onto an inner concentric tube to conduct a concentric circular gas–liquid membrane module has been studied theoretically in the fully developed region. An analytical formulation, referred to as conjugated Graetz problems, is developed to predict the concentration distribution and Sherwood numbers for the absorbent fluid flowing in the shell side and CO2/N2 gas mixture flowing in the tube side under various designs and operating parameters. The analytical solutions to the CO2 absorption efficiency were developed by using a two-dimensional mathematical modeling, and the resultant conjugated partial differential equations were solved analytically using the method of separation variables and eigen-function expansion in terms of power series. The predictions of CO2 absorption rate by using Monoethanolamide (MEA) solution in concentric circular membrane contactors under both concurrent- and countercurrent-flow operations are developed theoretically and confirmed with the experimental results. Consistency in both a good qualitative and quantitative sense is achieved between the theoretical predictions and experimental results. The advantage of the present mathematical treatment provides a concise expression for the chemical absorption of CO2 by MEA solution to calculate the absorption rate, absorption efficiency, and average Sherwood number. The concentration profiles with the mass-transfer Graetz number, inlet CO2 concentration, and both gas feed and absorbent flow rates are also emphasized. Both theoretical predictions and experimental results show that the device performance of the countercurrent-flow operation is better than that of the concurrent-flow device operation. The availability of such simplified expressions of the absorption rate and averaged Sherwood as developed directly from the analytical solutions is the value of the present study.

Experimental and thermodynamic modeling of CO2 absorption into aqueous DEA and DEA+Pz blended solutions

The important environmental concern of the carbon dioxide (CO2) capture by the absorption process with amine solutions is studied in the current study. The experiments are performed at operating conditions of a temperature range of 25 65 °C, a pressure range of 1.5 6.5 bar, diethanolamine (DEA) concentration of 0 1.5 M, PZ concentration of 0 0.5 M, and stirrer speed of 0 300 rpm. The effects of operating conditions on CO2 loading, absorption rate, and mass transfer flux are investigated into two solutions of DEA and DEA+piperazine (Pz) blend in a stirred reactor. In the DEA+CO2+H2O system, by increasing stirrer speed from 0 to 300 rpm, the maximum values of CO2 loading and mass transfer flux at the same DEA concentration are increased 65% and 137%, respectively. The CO2 loading and mass transfer flux have higher values at higher initial pressures. The predicted values for species concentrations into the DEA+CO2+H2O system are also evaluated based on the Pitzer model, mass, and charge balance equations. The results showed that by increasing stirrer speed, the concentration of DEA molecule is decreased 40% but the concentrations of other ions and molecules are increased. In the DEA+Pz+CO2+H2O system, the results indicated that adding Pz to the absorbent solution was more efficient in CO2 capture relative to only the DEA solution. The equilibrium CO2 loading is increased by 20% and 16% for blend solutions with 4:6 and 6:4 molar ratios of DEA and Pz, respectively, but using only Pz solution is increased it up to 29%.

Carbon Dioxide Flux at the Water\u2013Air Boundary at the Continental Slope in the Kara Sea

The values and direction of carbon dioxide flux in the area of the continental slope in the north of the Kara Sea (St. Anna Trough) are calculated based on field studies in 2020 within the Siberian Arctic Sea Ecosystems program. The existence of a stable frontal zone in this area has been confirmed, which is formed by an alongslope current and limits the northward spread of surface waters freshened by the continental runoff. The simultaneous analysis of the carbonate system in the upper sea layer and the CO2 concentration in the surface air layer shows the CO2 flux with a rate of 0.2 to 22 mmol/m2 day to be directed from the atmosphere into the water in the area of the outer shelf, which is affected by the river runoff, and in the area of the continental slope, which is beyond this effect. The highest rates of CO2 absorption by the sea surface layer are localized above the continental slope. Local processes in the area of the slope frontal zone determine the CO2 emission into the atmosphere with a rate of 0.34 mmol/m2 day.

Performance evaluation and environment risk assessment of steel slag enhancement for seawater to capture CO2

Major CO2 emitters are concentrated in coastal areas of China. The seawater with potential to capture CO2 was used as an absorbent and the addition of steel slag (SS) enhanced CO2 absorption by seawater. CO2 solubility in steel-slag-enhanced seawater was measured by an on-line chromatography apparatus, and the characterization analysis, thermodynamics, and kinetics were researched. CO2 solubility in seawater with a steel slag of 1.00 wt% increases by 64.27% relative to that in seawater, but is smaller than that in simulated-steel-slag-seawater (increasing by 29.86% relative to that in seawater with real steel slag). The results of XRD, TGA, IR and SEM-EDS show that Ca(OH)2 in the steel slag reacts with CO2 to form CaCO3. More quantity of CaO in simulated steel slag reacted with CO2 compared to real steel slag from XRF analysis. Increasing the concentration of steel slag and decreasing particle size of steel slag can also improve CO2 solubility and CO2 absorption rate. The steel slag and products after capturing CO2 are not hazardous waste and the steel slag can operate the solidification/stabilization of toxic metals. Steel slag can enhance CO2 absorption by seawater and perennially segregate CO2, providing CO2 capture and storage for coastal zones.