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Recently, a technology was developed in Japan to accelerate the carbonation of alkaline construction sludge and reduce its alkalinity. Alkaline construction sludge is treated in advance using a paper sludge ash-based stabilizer (PSAS) so that it becomes granular and well aerated. Subsequently, CO2 gas is injected from the bottom to the top of the treated sludge layer in the underground pit. This technology can reduce the pH of alkaline sludge within short periods; however, the completion period of pH neutralization has often been predicted empirically. This may be due to the combined effects of density, water content, particle size, PSAS amount in the sludge, and CO2 concentration in the accelerated carbonation on the pH neutralization process. However, there have been few studies on how these factors affect the pH neutralization and CO2 capture of PSAS-treated alkaline sludges subjected to accelerated carbonation. Therefore, in this study, the effects of several accelerated carbonation factors on neutralization and CO2 capture from alkaline sludge were experimentally investigated. PSAS-treated alkaline sludges with different densities, water contents, particle sizes, and amounts of PSAS were cured in incubators with controlled CO2 concentrations. Based on the pH measurements, the pH neutralization completion period (tN) was evaluated for each alkaline sludge sample. The test results revealed that tN increased with increasing dry density and particle size and decreasing CO2 concentration. The results also suggest that tN increases with increasing amounts of PSAS. However, the water content had a more significant effect on tN than the PSAS amount. There may be an optimum water content for pH neutralization if conditions other than the water content are the same. From the results of the carbonate content evaluation, the amounts of CO2 captured in each specimen (mCO2) and mCO2 at tN were determined for each alkaline sludge sample. The results revealed that the density, water content, particle size of the alkaline sludge, and CO2 concentration in the incubators did not significantly affect the amount of CO2 captured by the sludge (mCO2) upon the completion of pH neutralization. However, the amount of PSAS significantly affects the captured CO2 content. A higher amount of PSAS caused mCO2 to increase at tN.

Lime mud, a kind of industrial waste that produced in paper mill, was proposed as CO2 sorbent in calcium looping process. The carbonation performance of the lime mud was investigated in a dual‐fixed bed reactor (DFR) and a thermogravimetric analyzer (TGA). The carbonation kinetics of the lime mud in the chemical reaction controlled stage was analyzed by a surface reaction‐controlled kinetic model. The results show that the lime mud presents much poorer carbonation performance during the chemical reaction controlled stage compared with the limestone, mainly due to the high content of chlorine in the lime mud. A prewash treatment process was used to decrease the chlorine content to mitigate the sintering of the lime mud when calcined at high temperature. After prewash treatment, the prewashed lime mud shows much higher CO2 capture capacity during the chemical reaction controlled stage compared with the lime mud. A prolonged carbonation process successfully further enhances the microstructure and improves the carbonation performance of the prewashed lime mud in the chemical reaction controlled stage. The lime mud can be effectively used as CO2 sorbent in calcium looping process after prewash treatment and the following prolonged carbonation treatment. [ABSTRACT FROM AUTHOR]

Abstract Lime mud, a kind of industrial waste that produced in paper mill, was proposed as CO2 sorbent in calcium looping process. The carbonation performance of the lime mud was investigated in a dual‐fixed bed reactor (DFR) and a thermogravimetric analyzer (TGA). The carbonation kinetics of the lime mud in the chemical reaction controlled stage was analyzed by a surface reaction‐controlled kinetic model. The results show that the lime mud presents much poorer carbonation performance during the chemical reaction controlled stage compared with the limestone, mainly due to the high content of chlorine in the lime mud. A prewash treatment process was used to decrease the chlorine content to mitigate the sintering of the lime mud when calcined at high temperature. After prewash treatment, the prewashed lime mud shows much higher CO2 capture capacity during the chemical reaction controlled stage compared with the lime mud. A prolonged carbonation process successfully further enhances the microstructure and improves the carbonation performance of the prewashed lime mud in the chemical reaction controlled stage. The lime mud can be effectively used as CO2 sorbent in calcium looping process after prewash treatment and the following prolonged carbonation treatment.

Abstract: Carbon capture and storage (CCS) is one of a suite of technology options that might play a significant role in reducing greenhouse gas emissions. However, outside of traditional enhanced oil and gas recovery operations with a well established business model, CCS project deployments are struggling with adoption of a federal or international climate policy driver appearing unlikely for the foreseeable future. As part of a feasibility study for an industrial CCS project at the Boise White Paper mill in Washington State, a business model and CCS system design was developed that provided financial surety for the project developers while recognizing that uncertainty in revenue forecasts for CO2 storage would persist for the foreseeable future. Key to the business model was installation of a new 37MWe biomass-fueled power island at the plant that would replace antiquated boilers and that could still supply the necessary steam to run pulp and paper production operations when capturing CO2 emissions under favorable market conditions for monetizing CO2 storage credits. Under unfavorable market conditions, CO2 capture would be suspended and excess power generated from the plant would reduce external electrical energy purchases required for paper mill operations. The net CO2 reduction for the project versus current operations is 1.0MMT of CO2 per year with the CCS system online, and 139ktons per year with the CCS system offline due to reduced natural gas co-firing. So, both operational modes offered a significant net reduction in CO2 emissions. Based on assumptions regarding electricity and natural gas pricing, and CO2 storage revenue generated through an open market mechanism priced at $15 per metric ton CO2, the payback period for the project capturing 0.5MMT/yr (62% of total CO2 production) was estimated at 6.7 years versus 7.4 years with the CCS system offline. Geologic storage was evaluated in the deep flood basalt formations that dominate the storage capacity in Eastern Washington. Sub-basalt sediments were also examined at the site to provide alternative or supplemental storage capacity in the event that storage in the basalt sequences did not prove technically or economically feasible. [Copyright &y& Elsevier]

Abstract: Lime mud (LM), a solid waste that results from the causticization reaction in alkali recycling process of paper manufacture industry, was utilized as CO2 sorbent in calcium looping process in this study. The carbonation behavior of LM in the calcination/carbonation cycles was investigated in a dual fixed-bed reactor and a thermo-gravimetric analyzer. The results show that the carbonation conversions of LM are lower than those of limestone at the same reaction conditions. It attributes to the high chlorine content in LM which leads to more pronounced sintering and decreases the CO2 capture performance of LM. A pre-wash process was employed to decrease the chlorine content in LM. Based on an overall consideration of various factors, the pre-wash process is effective enough if the Cl/Ca molar ratio in LM is smaller than 1:100. Pre-washed lime mud (PLM) achieves higher carbonation rates and carbonation conversions, compared with LM. When calcined at 850°C and carbonated at 700°C, the carbonation conversion of PLM maintains at 36% after 100cycles, which is 1.8 and 4.8 times as high as LM and limestone after the same number of cycles, respectively. The pore volume and surface area of calcined PLM were greater than those of calcined LM after the same number of cycles, especially the volume of the pores in the range of 10–100nm in diameter. That is the reason why PLM exhibits higher CO2 capture capacity than LM in the multiple calcination/carbonation cycles. The carbonation conversions of LM and PLM are further enhanced by hydration of their calcines. [Copyright &y& Elsevier]

• Nanogel particles are deposited onto carbon paper by a spray coating method. • CO 2 adsorption-desorption experiments are performed in a milli-channel reactor. • The adsorbent exhibits fast CO 2 adsorption rate and desorption rate. • The adsorbent presents good stability under wet conditions. In this work, we report a proof-of-concept study on CO 2 adsorbents synthesized by a thermally initiated free-radical copolymerization and then coated onto carbon paper and poly tetra fluoroethylene via a spray coating approach. A milli-channel reactor was employed to support the obtained materials for efficient CO 2 capture with wet conditions, short cooling and heating cycles (303–348 K). CO 2 uptake and release performance of the materials were measured and compared with that of the polyamine-based materials prepared by other methods. CO 2 adsorption and desorption kinetics can be greatly enhanced when using the spray coating approach, especially for carbon paper as supporter. The CO 2 adsorption capacity of the spray-coated carbon paper reaches 80% of its maximum value in only 4.37 ± 0.7 min. Moreover, its adsorption rate (114.6 mg/(g∙min) at 303 K) and desorption rate (239.9 mg/(g∙min) at 348 K) were 81.2% and 81.5% higher than those of the polyamine-impregnated carbon paper, respectively (12% CO 2 at atmospheric pressure). Their largest increases of 71% and 67% were achieved by adjusting the concentration of polyamine nanogel particles deposited on the carbon paper surface. The prepared material also presents stable recyclability over 10 wet adsorption–desorption cycles and the aging experiments. The results obtained in this study indicate that the synthesized materials can serve as promising energy-efficient solid adsorbents for CO 2 capture. [ABSTRACT FROM AUTHOR]

Highlights: [•] 9–12h adsorption of CO2 in the 1st cycle increases cyclic CO2 adsorption of APMW. [•] Repeated prolonged adsorptions in cycles are feasible to capture CO2 using APMW. [•] Prolonged adsorption increases pores in 10–100nm of APMW after desorption of CO2. [Copyright &y& Elsevier]

Highlights • Synthetic CaO-based CO 2 sorbent was prepared using paper fibre as a biotemplate. • Synthetic sorbent is mainly composed of CaO and Ca 12 Al 14 O 33. • Synthetic sorbents possess microtube-like structure with superior CO 2 uptake. • Synthetic sorbent has improved sintering resistance in severe calcination condition. Abstract Calcium looping is regarded as an effective and viable way to address CO 2 emissions. To overcome the loss-in-capacity problems of calcium-based sorbents with the number of calcium looping cycles, a novel CaO/Ca 12 Al 14 O 33 sorbent with a microtube-like structure was prepared from carbide slag and Al(NO 3) 3 ·9H 2 O using paper fibre as a biotemplate. The CO 2 capture performance and microstructure of the novel synthetic sorbent under calcium looping conditions were investigated. The results show that the utilization of the biotemplate is good to retain the high cyclic CO 2 capture reactivity of the synthetic sorbent. Due to the unique hollow porous structure, the CO 2 capture capacity of the synthetic sorbent containing 7.5 wt% Al 2 O 3 retains 0.56 and 0.33 g/g after 30 cycles under mild and severe calcination conditions, respectively, which are 2.56 and 2.11 times higher than those of carbide slag under the same respective calcination conditions. With the presence of 10% steam in the carbonation atmosphere, the CO 2 capture capacity of the synthetic sorbent retains 0.55 g/g under the severe calcination conditions after 10 cycles. The native hierarchical biostructure of paper fibre is preserved in the synthetic sorbent. CaO and Ca 12 Al 14 O 33 are uniformly distributed in the synthetic sorbent, resulting in a high sintering resistance during multiple CO 2 capture cycles. CO 2 can penetrate through the microtube-like structure of the synthetic sorbent from two directions, i.e., from the outer surface and inner surface. This phenomenon effectively enlarges the contact area between CO 2 and CaO. The CaO/Ca 12 Al 14 O 33 sorbent with a hollow porous structure by means of a biotemplate appears promising in the calcium looping technology for CO 2 capture. [ABSTRACT FROM AUTHOR]

• Waste tissue paper was successfully utilized for the preparation of WTP-PVA CAs. • The WTP-PVA CAs displayed low density and superior mechanical properties with specific Young's modulus 1246.8 MPa cm3 g−1. • The WTP-PVA CAs showed good electrical and thermal properties. • The average EMI shielding effectiveness of WTP-PVA is ~40.8 dB with an absorption-dominant shielding feature. • WTP-PVA CAs showed considerable capacity to CO 2 adsorption with excellent selectivity and recyclability. Carbon aerogels (CAs) have always shown great potential for multifunctional applications. However, simultaneous improvement of mechanical, electrical and thermal properties of CAs with low density is still a big challenge due to their structural defects, disordered microstructure, and colossal oxygen containing functional groups. Herein, a subtle approach is developed to prepare CAs from waste tissue paper (WTP) and poly(vinyl alcohol) (PVA) as the basic ingredients. The WTP-PVA CAs possessed a highly interconnected three-dimensional porous structure with low density (0.057 g cm−3), high porosity (~97%) and specific surface area (1384 m2 g−1). Albeit with low density, the resultant CA displayed superior mechanical properties (specific Young's modulus up to 1246.8 MPa cm3 g−1) and thermal stability. Besides, they also featured high electrical conductivity (1.35 S cm−1) and low thermal conductivity (0.087 W m−1 K−1). These properties provided an opportunity for some advanced applications such as electromagnetic interference (EMI) shielding and CO 2 gas capture. The highest shielding effectiveness (SE), specific SE and thickness-averaged specific SE of WTP-PVA in the X-band are 40 dB, 700 dB cm3 g−1 and 1818 dB cm2 g−1 respectively, with an absorption-dominant shielding mechanism. More importantly, the WTP-PVA CA with abundant ultramicropores showed great potential for CO 2 adsorption (5.14 mmol g−1 at 0 °C) with good selectivity and regeneration capability even without the aid of any chemical activation, functionalization or heteroatom doping. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of combining CO2 capture and storage with alternative systems for biomass-based combined heat and power production (CHP) in Kraft pulp and paper mills. We compare heat, power, and CO2 balances of systems with alternative configurations of the CHP and CO2-capture systems. Because the captured CO2 comes from renewable biomass, the studied systems yield negative CO2 emissions. It is shown that pulp mills and integrated pulp and paper mills have the potential to become net exporters of biomass-based electricity while at the same time removing CO2 from the atmosphere on a net basis. The study shows that that the overall best CO2 abatement is achieved when CO2 capture is carried out within a biomass integrated gasifier with combined cycle where the syngas undergoes a CO-shift reaction. This configuration combines efficient energy conversion with a high CO2 capture efficiency. Furthermore, cost curves are constructed, which show how the cost of CO2 capture and storage in pulp and paper mills depends on system configuration and the CO2 transportation distance. [Copyright &y& Elsevier]

Based on KAMa pulp and paper mill, a polygeneration system integrated with a black liquor gasifier is proposed. The effects of CO2 captured by oxygen-fuel combustion and Selexol absorption on the performance of the polygeneration system are studied in terms of both thermodynamic performance and cost assessment. Using the Aspen Plus simulator, the performance of the studied polygeneration systems are analyzed from the perspectives of the first and second laws of thermodynamics. Compared with the reference system, the first law efficiency of the polygeneration system increased from 15.7% to 29.3%, with an investment increment of 17.9%. The investment incremental rates for CO2 capture by oxyfuel combustion and Selexol absorption are 15.1% and 16.7%, respectively. Energy penalty due to CO2 capture and compression is 0.61 MJ electricity/kg CO2, avoided in the oxygen-fuel method at a cost of $29.6/tonne CO2. However, energy penalty can reach 1.03 MJ product (electricity and methanol) per kg CO2, avoided in the Selexol absorption CO2 capture process at a cost of $46.0/tonne CO2. [ABSTRACT FROM AUTHOR]

Abstract: Earlier work has shown that capturing the CO2 from flue gases in the recovery boiler at a pulp mill can be a cost-effective way of reducing mill CO2 emissions. However, the CO2 capture cost is very dependent on the fuel price. In this paper, the potential for reducing the need for external fuel and thereby the possibility to reduce the cost for capturing the CO2 are investigated. The reduction is achieved by using thermal process integration. In alternative 1, the mill processes are integrated and a steam surplus made available for CO2 capture, but still there is a need for external fuel. In alternative 2, the integration is taken one step further, the reboiler is fed with MP steam, and the heat of absorption from the absorption unit is used for generation of LP steam needed at the mill. The avoidance costs are in both cases lower than before the process integration. The avoidance cost in alternative 1 varies between 25.4 and 30.7EUR/tonne CO2 depending on the energy market parameters. For alternative 2, the cost varies between 22.5 and 27.2EUR/tonne CO2. With tough CO2 reduction targets and correspondingly high CO2 emission costs, the annual earnings can be substantial, 18.6MEUR with alternative 1 and 21.2MEUR with alternative 2. [Copyright &y& Elsevier]

This paper investigates overall CO2 balances of combined heat and power (CHP) plants with CO2 capture and storage (CCS) in Kraft pulp and paper mills. The CHP plants use biomass-based fuels and feature advanced gasification and combined cycle technology. Results from simple process simulations of the considered CHP plants are presented. Based on those results and taking into account the major direct and indirect changes in CO2 emissions, the study shows that implementing CCS leads to steep emission reductions. Furthermore, a preliminary cost assessment is carried out to analyse the CO2 mitigation cost and its dependence on the distance that the CO2 must be transported to injection sites. [ABSTRACT FROM AUTHOR]

Earlier work has shown that capturing the CO2 from flue gases in the recovery boiler at a market pulp mill can be a cost-effective way of reducing mill CO2 emissions. In this paper, it is investigated whether the same is valid for an integrated pulp and paper mill. Five configurations are compared, supplying the extra energy needed by a biofuel boiler, an NGCC, a heat pump or by reducing the steam demand at the mill in combination with a biofuel boiler or an NGCC. The configurations have been evaluated with energy market scenarios and the avoidance cost has been calculated. The NGCC configurations have the lowest avoidance costs in all scenarios and they also have the advantage of liberating biofuel for use in other parts of society. [ABSTRACT FROM AUTHOR]

In the last few decades of industrial growth, the amount of carbon dioxide has augmented rapidly in to the environment. CO2 rising level in the environment is enormously contributing to increase in surface temperature of earth. The paramount domineering issue is the worrying speed at which the CO2 amount is increasing in the atmosphere. The available CO2-reducing technologies have the potential to reduce emission cost of carbon dioxide. Numerous recommended techniques can be amended to existing plants based on nonrenewable type fuel source. To date, considerable work has been done for CO2 capturing using a variety of adsorbent either commercially available or synthesized by suitable activation technique. In this review paper, CO2 capture by adsorption using a variety of adsorbents such as carbonaceous, non-carbonaceous and modified adsorbents has been studied. Various methods of physical and chemical activation to produce activated carbon for enhanced CO2 capture from different class of biomass have been investigated. All the information in CO2 capture and related issues have been described, summarized and thoroughly presented in the review article with emphasis on date pits-derived activated carbons. The reported adsorption capacity for various class of adsorbent has been discussed in detail and presented in the review article. [ABSTRACT FROM AUTHOR]

Addressing the environmental challenges posed by CO2 emissions is crucial for mitigating global warming and achieving net-zero emissions by 2050. This study compares CO2 storage (CCS) and utilization (CCU) technologies, highlighting the benefits of integrating captured CO2 into fuel production. This paper focuses on various carbon utilization routes such as Power-to-Gas via the Sabatier reaction, indirect production of DME, and Power-to-Fuel technologies. The maturity of these technologies is evaluated using the Technology Readiness Level (TRL) method, identifying the advancements needed for future implementation. Additionally, global regulations and policies surrounding carbon capture and storage are reviewed to provide context for their current status. The study emphasizes the potential of CCU technologies to reduce future CO2 emissions by converting captured CO2 into valuable fuels and chemicals, thus supporting the transition to a sustainable energy system. The findings indicate that while CCS technologies are more mature, promising CCU technologies can significantly contribute to reducing greenhouse gas emissions if green hydrogen becomes more affordable. This research underscores the importance of further technological development and economic evaluation to enhance the feasibility and adoption of CCU technologies in the pursuit of long-term environmental sustainability. [ABSTRACT FROM AUTHOR]

With the advantages of low raw material cost and 100% atom utilization, the synthesis of high value-added chemical product cyclic carbonates by the cycloaddition of CO2 to epoxides has become one of the most prospective approaches to achieve the industrial utilization of CO2. In the reported catalytic systems, the complexity of the catalyst synthesis process, high cost, separation difficulties, and low CO2 capture limit the catalytic efficiency and its large-scale application. In this paper, Ag nanoparticles loaded on polyethyleneimine (PEI)-modified UiO-66-NH2 (Ag/PEI@UiO-66-NH2) are successfully synthesized by in situ immersion reduction. The Ag nanoparticles and the amino groups on the surfaces of PEI@UiO-66-NH2 contribute to the adsorption of CO2 and polarization of C–O bonds in epoxides, thereby boosting the conversion capability for the CO2 cycloaddition reaction. At the amount of propylene oxide of 0.25 mol and the catalyst dosage of 1% of the substrate, the yield and selectivity of propylene carbonate are up to 99%. In addition, the stability and recyclability of Ag/PEI@UiO-66-NH2 catalyst are attained. The Ag/PEI@UiO-66-NH2 catalyst also demonstrates a wide range of activity and distinctive selectivity toward cyclo-carbonates in the cycloaddition of CO2 to epoxides. This work provides a guide to designing a highly efficient catalyst for in situ capture and high-value utilization of CO2 in industrial applications. [ABSTRACT FROM AUTHOR]

Microalgae are used to produce renewable biofuels and high-value components and in bioremediation and CO2 sequestration tasks. These increasing applications, in conjunction with a desirable constant large-scale productivity, motivate the development and application of practical controllers. This paper addresses the application of robust control schemes for microalgae cultivation in continuous photobioreactors. Due to the model uncertainties and external perturbations, robust control designs are required to guarantee the desired microalgae productivity. Furthermore, simple controller designs are desirable for practical implementation purposes. Therefore, two robust control designs are applied and evaluated in this paper for two relevant case studies of microalgae cultivation in photobioreactors. The first control design is based on an enhanced simple-input output model with uncertain estimation. The second control design is the robust nonlinear model predictive control considering different uncertain scenarios. Numerical simulations of two case studies aimed at lipid production and CO2 capture under different conditions are presented to evaluate the robust closed-loop performance. [ABSTRACT FROM AUTHOR]

Hydrogen from natural gas reforming can be produced efficiently with a high CO2 capture rate. This can be achieved through oxygen-blown autothermal reforming as the core technology, combined with pressure-swing adsorption for hydrogen purification and refrigeration-based tail gas separation for CO2 capture and recirculation of residual hydrogen, carbon monoxide, and methane. The low-temperature tail gas separation section is presented in detail. The main objective of the paper is to study and quantify the exergy efficiency of this separation process in detail. To achieve this, a detailed exergy analysis is conducted. The irreversibilities in 42 different process components are quantified. In order to provide transparent verification of the consistency of exergy calculations, the total irreversibility rate is calculated by two independent approaches: Through the bottom-up approach, all individual irreversibilities are added to obtain the total irreversibility rate. Through the top-down approach, the total irreversibility rate is calculated solely by the exergy flows crossing the control volume boundaries. The consistency is verified as the comparison of results obtained by the two methods shows a relative deviation of 4 · 10 − 7 . The exergy efficiency of the CO2 capture process is calculated, based on two different definitions. Both methods give a baseline exergy efficiency of 58.38%, which indicates a high degree of exergy utilisation in the process. [ABSTRACT FROM AUTHOR]

This paper presents a literature review on the effects of accelerated carbonation on alkali-activated materials. It attempts to provide a greater understanding of the influence of CO2 curing on the chemical and physical properties of various types of alkali-activated binders used in pastes, mortars, and concrete. Several aspects related to changes in chemistry and mineralogy have been carefully identified and discussed, including depth of CO2 interaction, sequestration, reactions with calcium-based phases (e.g., calcium hydroxide and calcium silicate hydrates and calcium aluminosilicate hydrates), as well as other aspects related to the chemical composition of alkali-activated materials. Emphasis has also been given to physical alterations such as volumetric changes, density, porosity, and other microstructural properties caused by induced carbonation. Moreover, this paper reviews the influence of the accelerated carbonation curing method on the strength development of alkali-activated materials, which has been awarded little attention considering its potential. This curing technique was found to contribute to the strength development mainly through decalcification of the Ca phases existing in the alkali-activated precursor, leading to the formation of CaCO3, which leads to microstructural densification. Interestingly, this curing method seems to have much to offer in terms of mechanical performance, making it an attractive curing solution that can compensate for the loss in performance caused by less efficient alkali-activated binders replacing Portland cement. Optimising the application of such CO2-based curing methods for each of the potential alkali-activated binders is recommended for future studies for maximum microstructural improvement, and thus mechanical enhancement, to make some of the "low-performing binders" adequate Portland cement substitutes. [ABSTRACT FROM AUTHOR]

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To mitigate the effect of CO2 on climate change, significant efforts have been made in the past few decades to capture CO2, which can then be further sequestered or converted into value-added compounds, such as methanol and hydrocarbons, by using thermochemical or electrocatalytic processes. However, CO2 capture and conversion have primarily been studied independently, resulting in individual processes that are highly energy-intensive and less economically viable due to high capital and operation costs. To enhance the overall process efficiency, integrating CO2 capture and conversion into a single system offers an opportunity for a more streamlined process that can reduce energy and capital costs. This strategy can be achieved by employing dual function materials (DFMs), which possess the unique capability to simultaneously adsorb and convert CO2. These materials combine basic metal oxides with active metal catalytic sites that enable both sorption and conversion functions. In this review paper, we focus on the recent strategies that utilize mixed metal oxides as DFMs. Their material design and characteristics, reaction mechanisms, as well as performance and limitations will be discussed. We will also address the challenges associated with this integrated system and attempt to provide insights for future research endeavors. [ABSTRACT FROM AUTHOR]

This paper consists of a deep analysis and data comparison of the main strategies undertaken for achieving truly reversible capture of carbon dioxide involving optimized gas uptakes while affording weakest retention strength. So far, most strategies failed because the estimated amount of CO2 produced by equivalent energy was higher than that captured. A more viable and sustainable approach in the present context of a persistent fossil fuel-dependent economy should be based on a judicious compromise between effective CO2 capture with lowest energy for adsorbent regeneration. The most relevant example is that of so-called promising technologies based on amino adsorbents which unavoidably require thermal regeneration. In contrast, OH-functionalized adsorbents barely reach satisfactory CO2 uptakes but act as breathing surfaces affording easy gas release even under ambient conditions or in CO2-free atmospheres. Between these two opposite approaches, there should exist smart approaches to tailor CO2 retention strength even at the expense of the gas uptake. Among these, incorporation of zero-valent metal and/or OH-enriched amines or amine-enriched polyol species are probably the most promising. The main findings provided by the literature are herein deeply and systematically analysed for highlighting the main criteria that allow for designing ideal CO2 adsorbent properties. [ABSTRACT FROM AUTHOR]

Carbon Capture and Storage (CCS) technology has attracted increasing attention as global climate change accelerates. Carbon dioxide removal processes under development include pressure swing adsorption (PSA) and chemical absorption using amine solvents. In this paper, an ammonia solvent, which is relatively inexpensive and has good material properties, was used instead of amines in the carbon dioxide removal process simulation as a chemical absorption method. This simulation used the eNRTL thermodynamics model which has the advantage of predicting ions in the liquid phase in Aspen Plus. A case study (Case Study 1) was conducted to verify the validity of the thermodynamic model. The purpose of this research was to find the operating conditions to eliminate more than 90% of the carbon dioxide contained in the flue gas from coal-fired power stations, and to lower heat duty and operating cost conditions. A second case study (Case Study 2) was conducted to find the operating conditions by comparing various process operating conditions. Additionally, this paper determined lower operating cost conditions by manipulating the amount of steam and cooling water. The results showed that the heater's outlet temperature should be set at under 80 ℃ to lower the operating costs. As a result of changing the flow rate of the side stream of the split flow process, energy consumption was reduced when compared to the conventional flow process. It was shown that the split flow is a superior process with 10.24% less energy use than the conventional flow. In this study, the split flow process achieved an energy saving advantage when compared to the conventional flow process, and a carbon dioxide removal rate of 95% was achieved. [ABSTRACT FROM AUTHOR]

The emission of carbon dioxide (CO2) into the atmosphere is considered the main cause of global warming. CO2 is mostly viewed as the principal product associated with the combustion of fossil fuels. One of the emerging studies at the moment is the use polymeric ionic liquids (PILs) for capturing CO2 from flue gas streams. The objective of this paper is to provide an overview of the various PILs for CO2 capture. PILs can be used in different processes, including absorption, membrane, and adsorption. In this paper, preparation and synthesis of PILs for various processes are discussed. The paper includes elaboration on using composite, grafted, and blended PILs to achieve a powerful and effective capture mode. The effects of different parameters such as temperature and pressure on CO2 sorption are also discussed. [ABSTRACT FROM AUTHOR]

The objective of this paper is to explore the utilisation of plastic waste via the gasification process to produce electricity with low carbon dioxide emissions. Worldwide, plastic production has increased, reaching 390 million tons in 2021, compared to 1.5 million tons in 1950. It is known that plastic incineration generates approximately 400 million tons of CO2 annually, and consequently, new solutions for more efficient plastic reuse in terms of emissions generated are still expected. One method is to use plastic waste in a gasifier unit and the syngas generated in a gas turbine for electricity production. The co-gasification process (plastic waste with biomass) was analysed in different ratios. Gasification was carried out with air for an equivalent ratio (ER) between 0.10 and 0.45. The volume concentration of CO2 in syngas ranged from 2 to 12%, with the highest value obtained when the poplar content in the mix was 95%. In this study, the option of pre- and post-combustion integration of the chemical absorption process (CAP) was investigated. As a result, CO2 emissions decreased by 90% compared to the case without CO2 capture. The integration of the capture process reduced global efficiency by 5.5–6.1 percentage points in a post-combustion case, depending on the plastic content in the mix. [ABSTRACT FROM AUTHOR]

Biocementation is an emerging nature-inspired method of producing eco-friendly cement for soil stabilization. This paper used the bovine-derived carbonic anhydrase (CA) enzyme to catalyse the bioprecipitation of CaCO3 in a fine-grained soil and thus to biocement the soil. To increase the efficiency of the CA, an innovative copper–carbonic anhydrase (CA) hybrid was fabricated. This study is a proof-of-concept of the potential application of these enzyme carriers for soil biocementation. The hybrid carriers are aimed to enhance the stability, recovery and reusability of the enzyme used in the biocementation process. The results showed that the fabricated copper phosphate-based inorganic hybrid was stable throughout the duration of the tests (2 months) and under a wide range of pH and temperatures. Its enzymatic activity was enhanced compared to the free CA enzyme and it was proved suitable for soil biocementation. This was further confirmed by the SEM analysis. Additionally, the treated soil with the formulated hybrid carrier showed improved unconfined compressive strength, especially when the carriers were implemented into the soil by mixing. The material analysis by Raman spectroscopy confirmed calcium carbonate as the primary precipitate, consistent with soil biocementation. Overall, this innovative method of delivery of enzymes with enhanced stability and activity shows promise that, upon further development, it can be successfully used to increase the efficiency and sustainability of the biocementation process. [ABSTRACT FROM AUTHOR]