Sorbent Utilization Research Articles

Unraveling the mechanism and the role of hydrogen bonds in CO2 capture by diluent-free amine sorbents through a combination of experimental and theoretical methods

The utilization of water-lean and non-aqueous amine sorbents is regarded as an appealing approach to reduce the energy costs of CO2 capture via liquid sorbents. However, significant research is still needed to achieve the technological maturity required for industrial-scale implementation. Here, we present a detailed experimental and computational analysis at the molecular level of CO2 capture by dipropylamine (DPA) as a case study to deepen our understanding of the mechanisms governing CO2 absorption by liquid secondary amines that can be used without any additional diluent. CO2 uptake with pure DPA was investigated, and the species produced over time were determined by NMR and FT-IR spectroscopy. In particular, the NMR analysis revealed the formation of carbamic acid at high CO2/DPA ratios. A detailed DFT investigation explained the mechanism of the reaction revealing a dynamic evolution in product distribution as CO2 loading increases. At low CO2 loadings, adducts with at least four DPA molecules are formed, ultimately leading to the carbamate/ammonium ionic pair stabilized through H-bonding interactions with DPA moieties. Conversely, at higher CO2 levels some stabilizing DPA molecules of ionic pair are required for the CO2 activation, resulting in the formation of carbamic acid. A reasonable mechanism for the evolution of product distribution is provided, and the main steps of the mechanistic picture are depicted and commented on. The dependence of carbamate and carbamic acid on the availability of hydrogen bond donors and acceptors in solution is also highlighted.

Pyrolysis solid product as a sorbent for flue gases mercury capture — Part II: Sorbent utilization

This study explores using solid pyrolysis products from six materials as sorbents to capture mercury from flue gas in an experimental fluidized bed combustor. It investigates the effects of activation methods, adsorption temperature, and Hg0/Hg2+ ratios on mercury removal efficiency. Physical and chemical activations are conducted using steam and NaOH, respectively. Tests are run at 100–160 °C with 5 g of sorbent. Results show 120 °C as optimal, with sorbents losing 0.34 % and 0.39 % efficiency with increasing temperature for lignite and black coal. Specific surface area (up to 641 m2∙g–1) significantly influences cumulative removal efficiency (CRE), reaching 80.8 % for lignite and 73.85 % for black coal. Mercury gas recovery averages 35.5 % and 53.7 % after physical and chemical activations. Lignite sorbents exhibit higher CRE than black coal, indicating greater mercury oxidation in black coal flue gas. This study offers a promising method for char recovery from pyrolysis, suggesting competitive sorbents for industrial use.

Investigation on desulfurization and ground granulated blast furnace slags reutilization for carbon dioxide sorption in a fluidized bed reactor

BackgroundThe atmospheric CO2 concentration is significantly increasing due to the utilization of fossil fuel in various activities. Implementation of steel slag is considered as a promising strategy for carbon capture MethodsIn this study, the slags from desulfurization (De-S) and ground granulated blast furnace (GGBS) processes in the steel company waste were applied as the sorbent in CO2 removal using a fluidized bed system. Various operating conditions were applied to determine the influence of operating parameters on sorbent performance. Moreover, examination on sorbent characteristic change and kinetics calculation were also carried out in this study. Significant findingOptimum operating temperature was reached by the application of 600 and 500 °C for De-S and GGBS slag, respectively. The higher CO2 concentration and 5 % water vapor improved the sorbent utilization. However, excessive water vapor and low fluidized velocity decreased the performance of sorbent. De-S slag performed better on overall CO2 capture process compared to GGBS slag. Therefore, upscaled study with 10 times greater size was further conducted with the 150–300 µm De-S slag for the CO2 capture from oxy-fuel and air combustion. The higher CO2 partial pressure in the flue gas of oxy-fuel combustion increased the capture process efficiency.

Effect of Mechanical Vibration on Kinetics of Solute Adsorption

Introduction: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device’s performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. Methods: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. Results: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. Conclusion: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed.

Universal pathway towards metal sulfides decorated 3D porous Ti3C2Tx MXene aerogel for vapor-phase mercury removal

Utilization of monolithic mineral sulfide-based sorbent for the fix-bed elemental mercury (Hg0) removal is regarded as a predominant predicament in the field of Hg0 abatement. In this work, a general and facile route was exploited to establish CuS particles decorated 3D porous Ti3C2Tx MXene aerogel via divalent Cu2+ cations induced assembly combined with subsequent high-temperature sulfurization treatment, during which, uniform CuS particles were homogeneously anchored throughout the Ti3C2Tx substrate. The obtained 3D CuS/Ti3C2Tx MXene aerogel exhibited satisfactory textural property, hierarchical pore structure and strong interaction between Ti3C2Tx MXene and CuS. Meanwhile, the inherent restacking of Ti3C2Tx MXene nanosheet and serious agglomeration of CuS can also be effectively avoided in the formation of aerogel. Those structural advantages originating from this novel gelation process favorably contributes to satisfactory Hg0 mass transfer and sufficient utilization of CuS active ligands, which largely strengthens Hg0 removal performance and broadens the fix-bed application of mineral sulfides. Consequently, the Hg0 capture capacity and adsorption rate of CuS/Ti3C2Tx MXene aerogel reached 90596.4 g m−3 and 120.64 g m−3 min−1, respectively, far outbalancing those of the reported in-situ selenized copper foam with excellent Hg0 removal activity. The impressive Hg0 sequestration performance is attributed to its relatively large specific surface area, layered pore channel, and highly dispersed CuS particles, largely boosting Hg0 mass transfer and following sequestration. Moreover, other mineral sulfides/Ti3C2Tx MXene aerogels can also be constructed by just replacing divalent metal cations, which makes the initial effort towards the fix-bed utilization of mineral sulfides-based aerogel for vapor-phase Hg0 immobilization.

The utilization of cost-effective natural sorbents for the eradication of heavy metal contaminants from the real world-based adsorbate system

In India, Industrial growth has resulted towards the release of numerous contaminated heavy metals into the environment, Various industries directly discharged the effluents containing harmful pollutants such as toxic heavy metals into the aqueous medium. There are numbers of treatment methods available to remove toxic elements from effluents before disposal. Several research investigations have been conducted to determine the capacity of unconventional absorbents to remove various wastewater impurities. Bio-sorption technique uses agricultural and natural left-over materials as adsorbents since they remain considerably less expensive, supportable, and available than traditional effluent treatment technologies. This study concentrates removal efficiency of orange peels (OP), rice husk (RH) and sugarcane bagasse (SCB) from the industrial effluents. Adsorption studies have been conducted for OP, RH and SCB with differing dose, pH, and contact duration, determined to be appropriate and leading to the highest levels of removal effectiveness. At 1.00 gm dosage, the maximum % removal efficiency of Cu, Cr, Ni, Cd and Zn removal for OP, RH and SCB were 84.90%, 90.45%, 86.21%, 98.00% and 74.11% respectively by using OP, RH and SCB the max. percentage removal efficiency of Cu, Cr, Ni, Cd and Zn for OP, RH were 82.81%, 76.80%, 76.16%, 78.46%, 78.59% at a pH value of 5, 6, 5, 7 and 7 respectively. The max. percentage removal efficiency of Cu, Cr, Ni, Cd and Zn using OP, RH and SCB were 93.45%, 93.05%,77.66%, 94.62%, 85.10% at the contact time of 120, 60, 120, 60 and 80 minutes respectively.

Maize cob (Zea mays) as natural biomass sorbent for crude oil biosorptive removal from contaminated seawater: Taguchi process optimization and biosorptive removal mechanism.

Crude oil pollution poses a serious threat to the aquatic environment. Hence, there is an increasing interest in developing an efficient cleaner process technique for oil spill cleanup via agricultural biomass waste-organic sorbent utilization. This work evaluated the effects of independent biosorptive removal at three varying levels (initial concentration of crude oil (Z1, 7.8-15.6 g/L), seawater-oil temperature (Z2, 25-45 °C), sorbent dose (Z3, 1-3 g), and sorbent particle size diameter (Z4, 1.18-4.72 mm)) on the biosorptive removal efficiency and biosorptive capacity performance of maize cob sorbent for crude oil biosorptive removal from seawater. Experiments were designed based on Taguchi orthogonal array experimental design (L9(34)) to study the effects and process optimization. The results revealed that the maize cob sorbent's crude oil biosorptive removal efficiency is related to Z1, Z3, and Z4, while the biosorptive capacity is related to Z1 and Z3. The optimum biosorptive removal efficiency and the biosorptive capacity values were 96.53% and 12.64 g/g, respectively, achieved at optimum factors of Z1 (7.8 g/L), Z3 (3 g), and Z4 (1.18 mm), as well as at Z1 (15.6 g) and Z3 (1 g). The isotherm and kinetic data, respectively, followed the Langmuir isotherms and the pseudo-second-order kinetics with a maximum monolayer biosorptive capacity of 23.31 g g-1. The mechanism of biosorptive crude oil removal was by physical sorption and film diffusion control. Therefore, the maize cob represents an inexpensive and effective natural sorbent for oil spill removal from water bodies.

Application of Biodegradable Materials in Oil‐Spill Cleanup: Recent Advances and Future Perspectives

During the transportation of oil, various oil‐spill incidents are reported. The utilization of oil sorbents for the treatment of oil spills is a promising approach among the all‐existing solutions. Nonbiodegradability and non‐renewability are the two major issues in the case of synthetic oil sorbents. In this review, the use of biodegradable polymers for oil‐spill cleanup is highlighted. In each section, the biodegradable materials and modifiers used, the method applied for a modification, the contact angle after modification, sorption capacities, and the reusability of developed biodegradable sorbents are extensively discussed. Mechanisms of biodegradation of biopolymers are also discussed. The manuscript also incorporates the recent developments in the fabrications of advanced sorbents with sustainable approaches along with challenges associated with current sorbents and future prospects.

The adsorption mechanism of arsenic in flue gas over the P-doped carbonaceous adsorbent: Experimental and theoretical study

The utilization of carbon-based sorbent has gained extensive attention for arsenic removal from flue gas due to their high specific surface area, sufficient active sites and abundant sources. This study proposes that the addition of phosphorous could be used as an effective promoter for the activation and modification of carbonaceous sorbent to enhance their arsenic fixation capacity. Both experimental and density functional theory (DFT) methods were employed to systematically investigate the adsorption characteristics of arsenic over different carbon based sorbents. The results reveal that the modification of H3PO4 generated C-O-P, C-P-O, and C3-P-O functional groups on the surface of activated carbon, and the adsorption ability of H3PO4-modified activated carbon for gaseous arsenic was significantly improved compared with the untreated activated carbon. DFT calculations indicate that unsaturated C atoms on carbonaceous surface served as active sites during arsenic adsorption, the electronegativity of which could be enhanced by phosphorous functional group, thereby facilitating the adsorption of gaseous arsenic species. Additionally, the positive effect of the phosphorous functional group on arsenic adsorption is more pronounced on zigzag carbonaceous surface than on armchair carbonaceous surface. This work provides a theoretical basis of the development of high-performance biochar preparation for arsenic adsorption by explaining the promoting effect of phosphorous functional group on gaseous arsenic adsorption on carbonaceous surface.

Design and Preparation of Magnetically-Oriented Poly(styr-co-MMA)-3MPS Capped Fe(ZnO) Hybrid Microspheres for Ion Exchange Removal of Toxic Pollutants from Wastewater

In this work, polymeric microspheres derived from polystyrene-co-methyl methacrylate embedded with magnetic ZnO nanoparticles (poly(styrene-co-MMA)-3MPS-Fe (ZnO)) were synthesized using the suspension polymerization method. The surfaces of polymeric Fe(ZnO) microspheres were improved by functionalization with amino and sulphonate groups. The physicochemical analysis indicated a large number of positively charged (anion exchange) groups (91 mmol/g) on the amine-modified polymeric microsphere (MFZPI) and a large number of negatively charged (cation exchange) groups (90 mmol/g) on the sulphonate-modified polymeric microsphere (SMFZPI)—revealing ambivalent character of obtained sorbent. The characterization of the synthesized compounds using various analytical techniques such as TGA, FTIR, XRD, SEM/EDX, UV-VIS and VSM indicated that synthesized microspheres were thermally stable, semi-crystalline in structure with hollow irregular morphology, optically active in UV region and slightly magnetic in nature. Due to the introduction of groups having ion exchange properties, these modified poly(styrene-co-MMA)-3MPS-Fe(ZnO) microspheres were used for the ion exchange sorptive removal of Cr(III) and fluorescein from aqueous matrix. The equilibrium sorption capacity of Cr(III) was 16.79 mg/g whereas of fluorescein was 12.03 mg/g under optimized conditions. Therefore, SMFZPI was found to be a promising sorbent for both cationic heavy metals and anionic dyes due to the presence of both acidic and basic groups. The mathematical modelling revealed that the sorption phenomenon followed pseudo-second-order kinetics with Freundlich equilibrium isotherm, indicating multilayer chemisorption of the pollutants on the synthesized ion exchange sorbents. This work establishes the utilization of polymeric magnetic ZnO-based ion exchange sorbents to effectively remove harmful toxins from wastewater.

Copolymerized Natural Deep Eutectic Solvent Encapsulated in Calcium Alginate Beads: Application as a Green Sorbent for Analysis of Multiclass Pesticides in Nonalcoholic Malt Beverages by GC–MS/SIM

A novel sorbent material consisting of a copolymeric deep eutectic solvent (DES) gel doped in calcium alginate (CA) hydrogel beads was synthesized and used in a green micro-solid phase extraction of 24 pesticides in 8 nonalcoholic malt beverages. The analyses were performed by gas chromatography–mass spectrometry/selective-ion monitoring. The DES was prepared by combining thymol (Thy, thyme oil) and methacrylic acid (MAA, can be obtained from Roman chamomile oil) in a 1:1 molar ratio via the heating-stirring method. Then, it was copolymerized using ammonium persulfate as a polymerization initiator and ethylene glycol dimethacrylate (EGDMA) as a crosslinking monomer through thermally induced free-radical reaction and finally was encapsulated in CA beads. The DES was characterized by Fourier transform infrared, Fourier transform nuclear magnetic resonance, and scanning electron microscopy techniques. A comparison study indicated that t extractionhe efficiency of the modified CA with polymeric DES (CA/[poly(MAA-co-EGDMA)]:[Thy]) was 1.5–3.4-fold higher than unmodified CA hydrogel beads. The influence of significant parameters affecting extraction efficiency was optimized. The method was validated by the matrix effect, specificity, precision, limits of quantifications (0.010–0.230 μg L–1), matrix-matched calibration linearity (0.010–300 μg L–1), and determination coefficients (r2 = 0.990–0.998). The method was successfully utilized for the detection of pesticide residues in nonalcoholic malt beverage samples, and the obtained relative recoveries were 68.2–115.6% (relative standard deviation < 10.2%). The procedure’s greenness was evaluated by the Complex Green Analytical Procedure Index and the Analytical Eco-Scale protocols. This paper is the first report on the preparation and utilization of this novel sorbent for the analysis of pesticides in nonalcoholic malt drinks.

Experimental evaluation of lime spray drying for SO&lt;sub&gt;2&lt;/sub&gt; absorption

&lt;abstract&gt; &lt;p&gt;This paper presents the findings of an experimental investigation on the performance of a laboratory-scale spray dryer involving flue gas desulfurization. Using commercial hydrated lime as a sorbent, a systematic set of experiments were performed to evaluate SO&lt;sub&gt;2&lt;/sub&gt; absorption capacity of the spray dryer. The experimentation involved accurate measurement of the spray drying characteristics, such as temperature and SO&lt;sub&gt;2&lt;/sub&gt; concentration along the spray chamber, by varying the input and output variables. Tests were done to investigate the effects of spray characteristics, i.e., inlet gas phase temperature (120–180 ℃) and calcium-to-sulfur ratio (1–2.5), on SO&lt;sub&gt;2&lt;/sub&gt; removal efficiency. The performance of the spray dryer was further evaluated based on the degree of conversion of calcium (sorbent utilization) after SO&lt;sub&gt;2&lt;/sub&gt; absorption. Results indicated an increase in SO&lt;sub&gt;2&lt;/sub&gt; removal efficiency by increasing the stoichiometric ratio and decreasing the temperature. Absorption efficiency of SO&lt;sub&gt;2&lt;/sub&gt; beyond 90% was achieved at a stoichiometric ratio of 2.5. A high degree of conversion of calcium was realized at low stoichiometric ratios, with a maximum utilization of 94% obtained at a stoichiometric ratio of 1.5. The analysis of the final desulfurization product revealed the presence of sulfite with better conversion achieved at a stoichiometric molar ratio of 1.5. A significant amount of unreacted sorbent (63.43%) was observed at a stoichiometric ratio of 2, while samples collected at a stoichiometric ratio of 1.5 had the lowest concentration of unreacted Ca[OH]&lt;sub&gt;2&lt;/sub&gt; (41.23%).&lt;/p&gt; &lt;/abstract&gt;

Polyaniline and Polyaniline-Based Materials as Sorbents in Solid-Phase Extraction Techniques.

Polyaniline (PANI) is one of the best known and widely studied conducting polymers with multiple applications and unique physicochemical properties. Due to its porous structure and relatively high surface area as well as the affinity toward many analytes related to the ability to establish different types of interactions, PANI has a great potential as a sorbent in sample pretreatment before instrumental analyses. This study provides an overview of the applications of polyaniline and polyaniline composites as sorbents in sample preparation techniques based on solid-phase extraction, including conventional solid-phase extraction (SPE) and its modifications, solid-phase microextraction (SPME), dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (MSPE) and stir-bar sorptive extraction (SBSE). The utility of PANI-based sorbents in chromatography was also summarized. It has been shown that polyaniline is willingly combined with other components and PANI-based materials may be formed in a variety of shapes. Polyaniline alone and PANI-based composites were successfully applied for sample preparation before determination of various analytes, both metal ions and organic compounds, in different matrices such as environmental samples, food, human plasma, urine, and blood.

Utilization of Spent Sorbent in the Production of Ceramic Bricks

The composition and technology for the production of semi-dry ceramic bricks using a nanostructured complex sorbent based on bentonite clay of the 11th horizon of the Tagan deposit of the Republic of Kazakhstan and basalt fiber (gabbro-diabase) of the Karauzek deposit of East Kazakhstan have been developed. The characteristics, chemical composition, and structure of the spent sorbent are given based on electron microscopic and X-ray phase analyses. A number of physical and mechanical parameters have been studied to evaluate the spent sorbent as a raw material for the production of ceramic products. The microstructures of fired ceramic samples with loam and spent sorbent have been studied, and the features of their structure have been revealed. The environmental safety of waste sorbents utilization by extraction in acidic, alkaline, and neutral media with the determination of the content of chromium, zinc, and iron ions has been studied. Experimentally obtained data indicate an insignificant concentration of chromium and zinc ions, not exceeding 3.5 µg/L. Relatively high concentrations of iron ions in ceramic bricks are associated with their high content in the feedstock and in the spent sorbent. It has been established that the introduction of the spent sorbent in the amount of 25% of the total mass increases the strength of the final product from 10.8 to 15.8 MPa, which corresponds to the M125 ceramic brick grade.

Multifunctional Loblolly Pine-Derived Superactivated Hydrochar: Effect of Hydrothermal Carbonization on Hydrogen and Electron Storage with Carbon Dioxide and Dye Removal.

Pore modulation via hydrothermal carbonization (HTC) needs investigation due to its crucial effect on surface that influences its multirole utilization of such ultraporous sorbents in applications of energy storage- hydrogen and capacitive- as well as for pollutant abatement- carbon capture and dye removal. Hence, loblolly pine was hydrothermally carbonized followed by KOH activation to synthesize superactivated hydrochars (SAH). The resulting SAHs had specific surface area (SSA) 1462–1703 m2/g, total pore (TPV) and micropore volume (MPV) of 0.62–0.78 cm3/g and 0.33–0.49 cm3/g, respectively. The SAHs exhibit excellent multifunctional performance with remarkably high atmospheric CO2 capture of 145.2 mg/g and high pressure cryogenic H2 storage of 54.9 mg/g. The fabricated supercapacitor displayed substantial specific capacitance value of maximum 47.2 Fg−1 at 1 A g−1 in 6 M KOH and highest MB dye removal of 719.4 mg/g. Higher HTC temperature resulted in increased surface porosity as higher SSA, TPV benefitted H2 storage and MB dye removal while superior MPV favored CO2 capture. Moderate HTC temperature ensured higher mesopore-to-macropore volume ratio favoring electrochemical performance. Isotherm modelling of the adsorbates was compared using models: Langmuir, Freundlich, Langmuir- Freundlich and Temkin.

Development and assessment of magnetic Fe2O3@MOF-74 composite sorbents for ethylene/ethane separation

Development of smart sorbents that can be regenerated when triggered by external stimuli such as magnetic field can overcome the poor energy utilization of the current sorbents investigated for light olefins/paraffins separation. In this work, we report the development of novel magnetic sorbents comprising of MOF-74 crystals and superparamagnetic Fe2O3 particles in a core–shell structure, and assessment of their C2H4/C2H6 separation performance. The electromagnetic properties of the materials were tuned by varying the Fe2O3 (Fex) loading (x = 1–20 wt%), and their effects on adsorption capacity, selectivity, and desorption rates were systematically investigated. The surface area, microporosity, and the C2H4/C2H6 selectivity of composites were reduced as the Fex content increased, while the specific heat absorption rate (SAR) was increased from 60 to 80 % upon varying the magnetic field intensity from 12.6 to 31.4 mT. On the basis of the SAR enhancement upon increasing the Fex loading, the C2H4 desorption rates were gradually increased with Fex up to 10 wt%, however beyond this composition a decline in the desorption rates was noted. Moreover, the cooling rate was found to be ∼76 % higher in induction heating compared to the conventional thermal heating method, which is expected to significantly shorten the cycle time, thereby reducing the column size and improving the throughput of the system. Our results highlight the importance of assessing the trade-offs between capture capacity and extent of responsiveness to magnetic field (i.e., temperature rise during regeneration) when developing smart sorbents. This work builds on previous studies that demonstrate the suitability of novel stimuli-responsive sorbents for next generation of olefin/paraffin separation systems.

Chiral separation of dipeptides on Cinchona-based zwitterionic chiral stationary phases under buffer-free reversed-phase conditions.

Chiral zwitterion ion exchangers represent efficient chiral stationary phases for stereoselective resolution of various analytes including chiral acids, bases, and zwitterions. In this contribution, we have focused on utilization of chiral zwitterionic sorbents, denoted as ZWIX (+A) and ZWIX (-A). These are analogical chiral systems to commercially available columns, Chiralpak ZWIX (+) and Chiralpak ZWIX (-), which are usually operated with buffered mobile phases. In this contribution, we have studied the enantiorecognition power of the ZWIX (+A) and ZWIX (-A) columns on a series of dipeptides operated under buffer-free reversed-phase conditions. Retention characteristics of zwitterionic dipeptides are discussed using an electrostatically driven adsorption model, which provides a good fit with both monotonous and U-shaped curves.

Multifunctional Ni-based oxygen carrier for H2 production by sorption enhanced chemical looping reforming of ethanol

The sorption enhanced chemical looping reforming is a prospective technology for high-quality hydrogen production. In this technology, the full benefits of catalysis, oxygen transfer, and CO2 adsorption are achieved by the utilization of oxygen carriers and sorbents. However, most sorbents that are mixed physically into the reforming bed are liable to encountering ash fouling and porosity reduction, preventing CO2 adsorption and sorbent regeneration. In this work, we develop a multifunctional composite oxygen carrier, which combines the NiO/NiAl2O4 catalyst with the CaO sorbent into a one-body composite pellet. Compared with the conventional physically mixed oxygen carrier, the composite oxygen carrier shows uniform element distribution, superior reducibility, and shortened dead time, resulting in enhanced CO2 adsorption capacity, high H2 production efficiency, and excellent ethanol conversion. Furthermore, during 20 cycle tests, the stable CO2 adsorption capacity and H2 concentration of composite oxygen carrier were maintained, while the H2 concentration of mixed oxygen carrier sharply decreased because of deteriorated adsorption performance. The results confirm that the multifunctional composite oxygen carrier is more suitable than the mixed oxygen carrier for CO2 adsorption and high purity hydrogen production. This work opens a new avenue toward the performance improvement of oxygen carriers.

Utilization of Waste-Based Sorbents for Removal of Pharmaceuticals from Water: A Review

Abstract Nowadays, the water contamination which is due to pharmaceuticals is increasing and alarming. The pharmaceuticals in water are very hazardous and toxic not only for the human life but also for environment. One of the promising methods of removing pharmaceuticals from the contaminated water is adsorption. Agricultural and industrial wastes or by-products can be used as low-cost adsorbents for pharmaceuticals removal. Low-cost adsorbents provide particular economic and environmental advantages. This paper presents an overview of utilizing of the waste-based adsorbents (mainly spent coffee grounds) for the removal of pharmaceuticals from water.

Effective removal of hydrogen sulfide using Mn-based recovered oxides from recycled batteries

The use of clean and environmentally friendly renewable energy as well as the minimization of waste disposal are fundamental aspects to be considered nowadays in a circular economy approach. In this way, the development of efficient systems for sulfur removal in biomass and waste gasification is of key relevance and the use of recycled materials will provide an opportunity to combine the reduction of waste‘s production and the application of circular economy principles.Sorbents from waste powder of recycled batteries have been prepared at laboratory scale. Subsequently, their potential application to syngas cleaning is evaluated specifically for H2S removal. Lab-scale tests at 400°C, 10 bar and space velocity of 3500 h−1 were carried out using first a simplified gas mixture of 0.9% H2S in N2 and then a more complex one consisting of 20% H2, 40% CO and 0.45% H2S/N2 to investigate the effect of reducing components, CO and H2 co-existing with H2S in any syngas. Sorbent utilization values as high as 80% (w/w, %) were obtained when tested under realistic syngas composition. XRF, XRD, XPS, TEM and textural characterization results of fresh and sulfided samples showed that those materials with higher Mn contents showed higher H2S removal capacity although the Mn/Zn ratio demonstrated to play a crucial role in their selectivity to form sulfides. Additionally, plausible mechanisms for H2S removal are discussed where the influence of composition, structure and morphology of the recovered binary metal oxides on sulfur removal efficiency is analysed.