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The conventional synthesis of the Metal–Organic Framework (MOF) MIL-101(Cr)-SO3H employs hydrofluoric acid as the modulator, posing handling challenges due to its irritating, corrosive, and toxic nature, as well as its reactivity with glass and metals. This study aims to find a new hydrofluoric acid-free synthesis route for MIL-101(Cr)-SO3H, proposing acetic acid and nitric acid as modulator alternatives. Four MIL-101(Cr)-SO3H samples were prepared: one without any modulator and the other three using a similar volume of either hydrofluoric acid, acetic acid, or nitric acid as the modulator. The so-obtained mass yield ranked as follows: without any modulator (32.6%) > acetic acid (29.6%) > nitric acid (25.2%) >> hydrofluoric acid (2.2%), whereas the total pore volume and BET surface area followed the order: hydrofluoric acid (0.87 cm3 g−1, 1862 m2 g−1) > nitric acid (0.81 cm3 g−1, 1554 m2 g−1) > acetic acid (0.72 cm3 g−1, 1374 m2 g−1) > without any modulator (0.69 cm3 g−1, 1342 m2 g−1). Despite the superior texture parameters obtained using hydrofluoric acid, the low synthesis yield and associated risks make this route non-viable. Acetic or nitric acid-based synthesis offers a promising alternative with a drastically higher yield, safer handling, and reduced environmental impact. In an attempt to improve the textural properties of the hydrofluoric acid-free MOFs, a series of samples were produced with increasing amounts of acetic acid, achieving BET surface areas of up to 1504 m2 g−1 and pore volumes of up to 0.81 cm3 g−1. [ABSTRACT FROM AUTHOR]

Traditional methods to develop biomass-based carbon adsorbents generally involve carbonization followed by chemical or physical activation. However, routes involving the hydrothermal treatment of biomass are receiving growing interest. In this work, two different strategies for the synthesis of sustainable CO2 adsorbents are compared, i.e., in situ ionic activation and hydrothermal treatment followed by activation with CO2. The latter is a green and simple procedure that does not require the addition of chemicals or acid-washing stages, and which leads to carbon adsorbents with relatively high CO2 adsorption capacity at low pressures, up to 0.64 mmol g−1 at 15 kPa and 50 °C, conditions relevant for postcombustion CO2 capture applications. On the other hand, in situ ionic activation can lead to carbon adsorbents with superior CO2 adsorption capacity in the aforementioned conditions, 0.78 mmol g−1, and with reduced cost and environmental impact compared to conventional chemical activation. [ABSTRACT FROM AUTHOR]

The performance of the CNS adsorbent for biogas upgrading was assessed with high-pressure CO SB 2 sb and CH SB 4 sb adsorption isotherms in a high-pressure magnetic suspension balance, at three temperatures (30, 50 and 70 °C) and pressures up to 10 bars. The single adsorption isotherms showed greater values of CO SB 2 sb adsorption compared to CH SB 4 sb . Alvarez-Gutierrez et al. [[11]] studied the performance of phenol-formaldehyde (PF) resin-based activated carbons to separate CO SB 2 sb from several mixtures (CO SB 2 sb /CH SB 4 sb ; CO SB 2 sb /N SB 2 sb , CO SB 2 sb /H SB 2 sb ). Multicomponent adsorption from binary CO SB 2 sb /CH SB 4 sb mixtures was predicted from the fitting of the single component adsorption data to the Sips model. [Extracted from the article]

The Spanish CO SB 2 sb Technology Platform Association (PTECO2) was founded in 2006 by Spain's industrial sector, research and technology centres, and universities. Acknowledging the opportunity given by I Greenhouse Gases: Science and Technology i , this special issue gathers nine interesting papers featuring the activities of some of the members of PTECO2. Acknowledging the opportunity given by I Greenhouse Gases: Science and Technology i , this special issue gathers nine interesting papers featuring the activities of some of the members of PTECO2. [Extracted from the article]

Abstract: Activated carbons for adsorption of CO2 under flue gas conditions were prepared by means of hydrothermal carbonization (HTC) and subsequent CO2 activation of spent coffee grounds. The HTC of the samples consisted of their heating at moderate temperature with a high water content in autoclave. A preliminary screening concluded that 1:2 biomass/water ratio (spent coffee grounds as received) and no chemicals added during HTC with further activation in CO2 at 800°C for 1 h are suitable conditions to produce the CO2 adsorbents. In addition, the response surface methodology (RSM) successfully evaluated the combined effect of HTC temperature and dwell time, to maximize the CO2 capture capacity within the experimental region. Both the lowest temperature and dwell time (120°C, 3 h) resulted in the maximum CO2 capture capacity (2.95 wt.%). Two activated carbons (ACs) were then produced: one via hydrothermal carbonization optimized by means of response surface methodology (RSM) followed by CO2 activation (HC‐Co) and the other one by single‐step CO2 activation as described in the Group's patent ES2526259 (AC‐Co). Analysis of the features and performances of the two ACs revealed superior chemical and textural characteristics on HC‐Co for CO2 adsorption under post‐combustion capture conditions; HTC process is the sole responsible of this enhancement. Moreover, the proposed methodology to produce CO2 adsorbents from spent coffee grounds represents a more energy‐efficient approach. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The selective separation of CO2 from gas mixtures representative of flue gas generated in waste incineration systems is studied on two activated carbons obtained from pine sawdust and compared to a commercial activated carbon. Dynamic adsorption experiments were conducted in a fixed-bed adsorption column using a binary mixture (N2/CO2) with a composition representative of incineration streams at temperatures from 30 to 70 °C. The adsorption behavior of humid mixtures (N2/CO2/H2O) was also evaluated in order to assess the influence of water vapor in CO2 adsorption at different relative humidity in the feed gas: 22% and 60%. Moreover, CO2 adsorption was studied in less favorable conditions, i.e., departing from a bed initially saturated with H2O. In addition, the effect of CO2 on H2O adsorption was examined. Experimental results showed that the CO2 adsorption capacity can be reduced significantly by the adsorption of H2O (up to 60% at high relative humidity conditions). On the other hand, the breakthrough tests over the adsorbent initially saturated with water vapor indicated that H2O is little affected by CO2 adsorption. The experimental results pointed out the biomass based carbons as best candidates for CO2 separation under incineration flue gas conditions. [ABSTRACT FROM AUTHOR]