Adsorption Performance Research Articles

Adsorption performance of harmful gas molecules over copper decorated aluminene: a DFT study

Adsorption performance of harmful gas molecules over copper decorated aluminene: a DFT study

Fabrication of Highly Efficient ZIF-8@PEI Monoliths for CO2 Capture Using Phosphorylated Cellulose Nanofiber as a Binder.

This study involves the synthesis and comparison of zeolitic imidazolate frameworks (ZIFs), specifically ZIF-8 and ZIF-67 pristine with a commercial zeolite, emphasizing their CO2 affinity and sorption capability. To overcome challenges persisting in the handling and integration of these materials into industrial adsorption processes, particularly when limited to microcrystalline fine powders, we present herein an innovative manufacturing method to produce standalone monolithic supports. This process involves pseudoplastic paste formulations utilizing polyethylenimine (PEI) as a coagulant and locally fabricated phosphorylated cellulose nanofiber (PCNF) as a binding agent. Rheological investigation was conducted to anticipate the required shaping and design by means of paste flowability, consistency, and stiffness. XRD and FTIR results confirm the preservation of crystalline structure and the occurrence of amine functionalization associated with the presence of PEI, respectively. The proposed method significantly enhances the CO2 adsorption performance of the produced ZIF-8 monolith in comparison with that reached when using the pristine material, achieving a capacity of 1.25-2 mmol·g-1 at 30 °C under dry conditions in a pressure range of 1-13 bar, respectively. In other words, this work clearly highlights an effective applicability of the ZIF-8 monolith as an innovative sorbent for further designing CO2 capture industrial setups.

Oxygen-Assisted Supercapacitive Swing Adsorption of Carbon Dioxide.

We report on the supercapacitive swing adsorption (SSA) of carbon dioxide at different voltage windows in the presence of oxygen using activated carbon electrodes, and deliquescent, aqueous electrolytes. The presence of O2 in the CO2/N2 gas mixture results in an up to 11 times higher CO2 adsorption capacity with 3M MgBr2 (at 0.6V) and up to 4-5 times higher adsorption capacity with 3M MgCl2 (at 1V). A tradeoff between high CO2 adsorption capacities and lower coulombic efficiencies was observed at voltages above 0.6V. The energetic and adsorptive performance of the electrodes in the presence of oxygen below 0.5V was similar to the performance with a CO2/N2 mixture without oxygen at 1V. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of the electrodes demonstrate that the specific capacitance increases while the diffusion resistance decreases in the presence of oxygen. Oxygen concentrations ranging between 5-20% give similar energetic and adsorptive performance. The electrodes exhibit stable performance for up to 100 cycles of operation.

Oxygen‐Assisted Supercapacitive Swing Adsorption of Carbon Dioxide

We report on the supercapacitive swing adsorption (SSA) of carbon dioxide at different voltage windows in the presence of oxygen using activated carbon electrodes, and deliquescent, aqueous electrolytes. The presence of O2 in the CO2/N2 gas mixture results in an up to 11 times higher CO2 adsorption capacity with 3M MgBr2 (at 0.6V) and up to 4‐5 times higher adsorption capacity with 3M MgCl2 (at 1V). A tradeoff between high CO2 adsorption capacities and lower coulombic efficiencies was observed at voltages above 0.6V. The energetic and adsorptive performance of the electrodes in the presence of oxygen below 0.5V was similar to the performance with a CO2/N2 mixture without oxygen at 1V. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of the electrodes demonstrate that the specific capacitance increases while the diffusion resistance decreases in the presence of oxygen. Oxygen concentrations ranging between 5‐20% give similar energetic and adsorptive performance. The electrodes exhibit stable performance for up to 100 cycles of operation.

P-d Orbital Hybridization in Ag-based Electrocatalysts for Enhanced Nitrate-to-Ammonia Conversion.

Considering the substantial role of ammonia, developing highly efficient electrocatalysts for nitrate-to-ammonia conversion has attracted increasing interest. Herein, we proposed a feasible strategy of p-d orbital hybridization via doping p-block metals in an Ag host, which drastically promotes the performance of nitrate adsorption and disassociation. Typically, a Sn-doped Ag catalyst (SnAg) delivers a maximum Faradaic efficiency (FE) of 95.5 ± 1.85 % for NH3 at -0.4 V vs. RHE and reaches the highest NH3 yield rate to 482.3 ± 14.1 mg h-1 mgcat.-1. In a flow cell, the SnAg catalyst achieves a FE of 90.2 % at an ampere-level current density of 1.1 A cm-2 with an NH3 yield of 78.6 mg h-1 cm-2, during which NH3 can be further extracted to prepare struvite as high-quality fertilizer. A mechanistic study reveals that a strong p-d orbital hybridization effect in SnAg is beneficial for nitrite deoxygenation, a rate-determining step for NH3 synthesis, which as a general principle, can be further extended to Bi- and In-doped Ag catalysts. Moreover, when integrated into a Zn-nitrate battery, such a SnAg cathode contributes to a superior energy density of 639 Wh L-1, high power density of 18.1 mW cm-2, and continuous NH3 production.

P‐d Orbital Hybridization in Ag‐based Electrocatalysts for Enhanced Nitrate‐to‐Ammonia Conversion

Considering the substantial role of ammonia, developing highly efficient electrocatalysts for nitrate‐to‐ammonia conversion has attracted increasing interest. Herein, we proposed a feasible strategy of p‐d orbital hybridization via doping p‐block metals in an Ag host, which drastically promotes the performance of nitrate adsorption and disassociation. Typically, a Sn‐doped Ag catalyst (SnAg) delivers a maximum Faradaic efficiency (FE) of 95.5 ± 1.85 % for NH3 at ‐0.4 V vs. RHE and reaches the highest NH3 yield rate to 482.3 ± 14.1 mg h‐1 mgcat.‐1. In a flow cell, the SnAg catalyst achieves a FE of 90.2 % at an ampere‐level current density of 1.1 A cm‐2 with an NH3 yield of 78.6 mg h‐1 cm‐2, during which NH3 can be further extracted to prepare struvite as high‐quality fertilizer. A mechanistic study reveals that a strong p‐d orbital hybridization effect in SnAg is beneficial for nitrite deoxygenation, a rate‐determining step for NH3 synthesis, which as a general principle, can be further extended to Bi‐ and In‐doped Ag catalysts. Moreover, when integrated into a Zn‐nitrate battery, such a SnAg cathode contributes to a superior energy density of 639 Wh L‐1, high power density of 18.1 mW cm‐2, and continuous NH3 production.

Fabrication and characterization of graphene oxide and reduced graphene oxide decorated diatomite composite materials and their adsorption performance for uranium ions

Fabrication and characterization of graphene oxide and reduced graphene oxide decorated diatomite composite materials and their adsorption performance for uranium ions

Adsorption Performance of Chitosan and Glutaraldehyde Modified Biochars for Trivalent Antimony in Acidic Wastewater

Adsorption Performance of Chitosan and Glutaraldehyde Modified Biochars for Trivalent Antimony in Acidic Wastewater

Unexpected Molecular Sieving of Xylene Isomer Using Tethered Ligand in Polymer-Metal-Organic Frameworks (polyMOFs).

Promising advances in adsorption technology can lead to energy-efficient solutions in industrial sectors. This work presents precise molecular sieving of xylene isomers in the polymer-metal-oragnic framework (polyMOF), a hybrid porous material derived from the parent isoreticular MOF-1 (IRMOF-1). PolyMOFs are synthesized by polymeric ligands bridged by evenly spaced alkyl chains, showing reduced pore sizes and enhanced stabilities compared to its parent material due to tethered polymer bridge within the pores while maintaining the original rigid crystal lattice. However, the exact configuration of the ligands within the crystals remain unclear, posing hurdles to predicting the adsorption performances of the polyMOFs. This work reveals that the unique pore structure of polyIRMOF-1-7a can discriminate xylene isomers with sub-angstrom size differences, leading to highly selective adsorption of p-xylene over other isomers and alkylbenzenes in complex liquid mixtures (αpX/OM = 15 and αpX/OME = 9). The structural details of the polyIRMOF-1-7a are elucidated through computational studies, suggesting a plausible configuration of alkyl chains within the polyMOF crystal, which enable a record-high p-xylene selectivity and stability in liquid hydrocarbon. With this unprecedented molecular selectivity in MOFs, "polymer-MOF" hybridization is expected to meet rigorous requirements for high-standard molecular sieving through precisely tunable and highly stable pores.

Preparation of Al-doped carbon materials derived from artificial potassium humate prepared from waste cotton cloth and their excellent Cr(VI) adsorption performance

Millions of tons of cotton textile waste are generated annually worldwide, and most of it enters the municipal solid waste (MSW) stream for landfill or incineration disposal, resulting in a significant waste of resources and environmental pollution. This article developed an innovative low-temperature pyrolysis process for producing artificial humic acid (HA) from waste cotton textiles. Subsequently, Al3+ was introduced for a secondary pyrolysis to prepare an Al-doped biochar (Al/BC) with superior adsorption properties. The experimental results show that the presence of Al3+ has an important influence on the pyrolysis process of cotton fabric and the formation and structure of Al/BC. This is the first time to synthesize low-cost adsorbent by pyrolysis and aluminum mixing process of waste cotton cloth and explains the mechanism. This increased in defects (ID/IG = 0.76 to ID/IG = 0.92), a larger specific surface area (6.47 m2/g to 566.94 m2/g), and an increase in oxygen-containing functional groups (from none to C-O-C, OC-O, etc.) when compared to the undoped Al3+ biochar. The optimum Al3+-doped biochar (Al/BC-15) prepared with HA as a precursor exhibited a superior adsorption capacity for Cr(VI) of up to 176.23 mg/g, surpassing the results reported for similar materials in the literature. The adsorption mechanism of Cr(VI) is primarily based on physical adsorption, with some chemical adsorption. At a lower pH, the Al/BC-15 surface exhibits a high positive charge (46 mV). The Al3+-O-Cr(VI) association group is formed through rapid electrostatic attraction between C-Al and Cr(VI). Due to the strong positive electronegativity of Al3+ and the negative electronegativity of C in the vicinity of Al, Cr(VI) is further reduced to Cr(III) by C-Al. Therefore, the method proposed in this paper for preparing Al-doped carbon materials from waste cotton fabric offers a new approach and potential application for the production of high-performance adsorbent materials from waste cotton fabric.

Utilizing triethylenetetramine-functionalized MIP-206 for highly efficient removal of Pb(II) from wastewater

The global concern over heavy metal pollution necessitates urgent measures to safeguard human health and the environment. This study focuses on employing triethylenetetramine (TETA)-functionalized MIP-206-OH (TMIP-206) as an effective adsorbent for removing Pb(II) from wastewater. TMIP-206 was synthesized via a hydrothermal method followed by functionalization with TETA. Kinetic studies demonstrate that lead removal on TMIP-206 conforms to the pseudo-second-order model, indicating an efficient removal process. Experimental results reveal that TMIP-206 aligns with the Langmuir isotherm, exhibiting a maximum removal capacity of 267.15 mg/g for lead ions. The sorption efficiency of TMIP-206 for Pb ions remains stable across six cycles, with a reduction of less than 15%. Optimal adsorption performance is observed at a pH of 6. These findings underscore the potential of TMIP-206 as an alternative for adsorbing Pb(II) from aqueous environments, addressing the global challenge of heavy metal pollution. Future research should explore the scalability and long-term stability of TMIP-206-based adsorbents to enhance their practical applicability in diverse environmental contexts and contribute to broader strategies for mitigating heavy metal contamination.

The Tribological and Adsorption Performance of Chlorophenyl Silicone Oil Using Different Ceramic Materials under High Temperature

With the development of technical requirements, the current challenges faced by bearing materials mainly revolve around high-temperature conditions and the trend towards material lightweighting. Full ceramic bearings are the new candidate due to their excellent properties. This article details the tribological and adsorption performance of chlorophenyl silicone oil (CPSO) as a high-temperature lubricant in ceramic tribological systems (ZrO2, Al2O3, and Si3N4). Among the three ceramic tribological systems, the lubrication performance can be ordered as Si3N4 > Al2O3 > ZrO2, as the wear rates of the ZrO2 and Al2O3 tribo-systems are almost 1135.67 and 283.33 times larger than that of the Si3N4 tribo-system, respectively. The observed results can be explained by the superior adsorption performance of CPSO on a Si3N4 ceramic surface, which was calculated by molecular dynamic simulation. The molecular dynamic simulation results show the adsorption energy of CPSO/Si3N4 is almost 54.09 and 61.18 times higher compared to that on ZrO2 and Al2O3 ceramics. These findings provide experimental and theoretical insights for understanding the lubrication performance of CPSO in a full ceramic tribo-system.

Efficient PFAS removal from contaminated soils through combined washing and adsorption in soil effluents

This study investigates soil washing as a viable strategy to remove poly- and perfluoroalkyl substances (PFAS) from contaminated soils using various washing agents including water, methanol, ethanol, and cyclodextrin ((2-Hydroxypropyl)-β-cyclodextrin HPCD)). Water was less effective (removing only 30 % of PFAS), especially for long-chain hydrophobic PFAS. Methanol (50 % v/v) or HPCD (10 mg g–1 soil) achieved > 95 % PFAS removal regardless of PFAS type, soil size fraction (0–400 µm or 400–800 µm), or experimental setups (batch or column, at liquid/solid (L/S) = 1). Column optimization studies revealed improved efficiency at L/S = 10 with diluted washing solutions, where HPCD exhibited rapid PFAS mobilization even at lower concentrations (1 mg mL–1). We then applied a first-order decay model to effectively predict PFAS breakthrough curves and mobilization within soil columns. Subsequent treatment of wash effluents by activated carbon and biochar effectively reduced PFAS concentrations below detection limits. The performance of both soil washing and subsequent adsorption was found to depend strongly on the specific characteristics of PFAS compounds. These findings highlight the significant potential of methanol and HPCD in soil washing and the effectiveness of integrated soil washing and adsorption for optimizing PFAS removal.

Study on the adsorption performance of modified high silica fly ash for methylene blue.

Presently, there are several issues associated with solid waste fly ash, such as its accumulation and storage, low comprehensive utilization rate, lack of high-value utilization technology, environmental risk and ecological impact. Thus, based on the high silica content and adsorption characteristics of fly ash, two novel adsorbents, namely mesoporous silica-based material (MSM) and sodium dodecyl sulfate-modified fly ash (SDS-FA), were prepared using an ultrasound-assisted alkali fusion-hydrothermal method and surface modification method. Furthermore, effects of adsorbent dosage, initial pH, contact time, and initial concentration of the solution on the adsorption of the organic pollutant methylene blue (MB) by fly ash, MSM, and SDS-FA were investigated to select the optimal modified high silica fly ash adsorbent. Based on the adsorption isotherms and adsorption kinetics, together with SEM, XRD, FTIR and BET analyses, the adsorption mechanism of MSM for MB was revealed. The results showed that under the conditions of an adsorbent dosage of 2 g L-1, initial pH of 9, contact time of 150 min, and initial concentration of 100 mg L-1, MSM and SDS-FA exhibited removal efficiencies of 92.69% and 84.64% for MB, respectively, which were significantly higher than that of fly ash alone. The adsorption of MB by MSM and SDS-FA followed the Langmuir model and pseudo-second-order kinetics, indicating monolayer adsorption with chemical adsorption as the dominant mechanism. The mechanism of the adsorption of MB by MSM is mainly the result of the synergistic effect among its increased specific surface area, hydrogen bonding, ion exchange, and electrostatic interactions. After five cycles of adsorption-desorption process, the removal efficiency of MSM for MB consistently remained above 80%. Therefore, MSM can serve as a valuable reference for the resource utilization of fly ash and remediation of dye-polluted wastewater.

Synergistic enhancement of NC-GCN/Ag2O photocatalytic reduction of uranium by D-A and p-n junction structures

Recently, how to improve the photocatalytic uranium removal performance of Graphite-phase carbon nitride (GCN) has always been a hot research topic. In this paper, a new strategy based on p-n junction and D-A structure is proposed to improve the photocatalytic performance. And as a result, a novel cyano modified photocatalytic material NC-GCN/Ag2O was designed and prepared for the reduction of U(VI). Interestingly, the material shows better adsorption performance for U(VI) in the dark treatment stage, and its removal of U(VI) is close to 70 % under the initial U(VI) concentration of 20 ppm and the solid–liquid ratio of 0.2 g/L. And the adsorption is in accordance with the Langmuir model and Pseudo second order model. After 30 min of illumination, the removal rate of U(VI) can reach 93.2 %, significantly higher than that of GCN (13.6 %) and NC-GCN10(37.7 %). It’s worth mentioning that photocatalytic reduction dominated the adsorption-reduction process for U(VI) removal after light exposure. In addition, after four cycles, the removal of U(VI) from the composite material decreased by only 5 % with no change in the crystal structure, i.e., it has good reusability and stability. Meanwhile, there was no significant interference with other ions except for Cu2+ and V5+, which had a weak interference. Finally, a new mechanism for U(Ⅵ) reduction was proposed.

Natural Products of Licorice for Uranium Decorporation with Low Toxicity and High Efficiency.

The development and exploration of uranium decorporation agents with straightforward synthesis, high removal ability, and low toxicity are crucial guarantees for the safety of workers in the nuclear industry and the public. Herein, we report the use of traditional Chinese medicine licorice for uranium decorporation. Licorice has good adsorption performance and excellent selectivity for uranium in the simulated human environment. Glycyrrhizic acid (GL) has a high affinity for uranium (p(UO2) = 13.67) and will complex with uranium at the carbonyl site. Both licorice and GL exhibit lower cytotoxicity compared to the commercial clinical decorporation agent diethylenetriamine pentaacetate sodium salts (CaNa3-DTPA). Notably, at the cellular level, the uranium removal efficiency of GL is eight times higher than that of CaNa3-DTPA. Administration of GL by prophylactic intraperitoneal injection demonstrates that its uranium removal efficiency from kidneys and bones is 55.2 and 23.9%, while CaNa3-DTPA shows an insignificant effect. The density functional theory calculation of the bonding energy between GL and uranium demonstrates that GL exhibits a higher binding affinity (-2.01 vs -1.15 eV) to uranium compared to DTPA. These findings support the potential of licorice and its active ingredient, GL, as promising candidates for uranium decorporation agents.

Porous β-cyclodextrin polymers for rapid and efficient removal of organic micropollutants from water: The role of sulfonation and porosity on adsorption performance

Removal of organic micropollutants (OMPs) from water, especially hydrophilic and ionized ones, is challenging for water remediation. Herein, porous β-cyclodextrin polymers (PCPs) with tailored functionalization were prepared based on molecular expansion strategy and sulfonation. Partially benzylated β-cyclodextrin was knotted by external crosslinker to form PCP1, and knotting PCP1 by expansion molecule generated PCP2. PCP1 and PCP2 were sulfonated to achieve PCP1-SO3H and PCP2-SO3H. Based on systematical adsorption evaluation toward multiple categories of OMPs, it was found that the introduced strong polar -SO3H group could bring strong hydrogen bonding and electrostatic interactions. PCP2 showed the highest surface (998.97 m2/g) displayed more excellent adsorption performance toward neutral and anionic OMPs, and the adsorption mechanism for this property of PCP2 was dominated by hydrophobic interactions. In addition, the PCP1-SO3H with the lowest surface area (39.75 m2/g) rather than PCP2-SO3H with higher surface (519.28 m2/g) exhibited more superior adsorption towards hydrophilic and cationic OMPs, benefiting by hydrogen bonding and electrostatic interactions as well as appropriate porosity. These results not only confirmed the performance enhancement of PCPs through the integration of novel preparation strategy, but also provided fundamental guidance for PCPs design for water remediation.

Utilizing silica fume and synthetically produced mesoporous silicas for simulated flue gas CO2 adsorption

ABSTRACT Carbon capture and storage (CCS) is crucial in mitigating greenhouse gas emissions. Solid adsorbents, notable for their reusability and corrosion resistance, are gaining attention in CO2 gas separation. This study uses Silica fume as an adsorbent and silica source for SiO2 and MCM-41 silica-based adsorbents. Silica was extracted via an alkaline dissolution method, and adsorbents were synthesized using a CO2-induced precipitation method, chosen for its shorter synthesis time and CO2 utilization. The effects of pore volume, average pore diameter, and specific surface area on amine loading and CO2 adsorption capacity were investigated using CTAB surfactant in SiO2 synthesis, resulting in MCM-41. The synthesized adsorbents were modified with TEPA and DEA amines due to their high affinity for CO2. After determining optimal amine loading, the impact of combining TEPA with DEA was examined. The highest CO2 adsorption capacity under simulated flue gas conditions (15% volume CO2 and 85% volume N2) was 198 milligrams per gram of adsorbent for the SiO2 adsorbent functionalized with 50% by weight amine (28% TEPA and 22% DEA). Variations in CO2 adsorption over time, the influence of adsorbent quantity on adsorption capacity, the affinity of the adsorbent for N2 adsorption, and the adsorption–desorption cycle were investigated. The 28%TEPA-22%DEA-SiO2 adsorbent emerged as the optimal choice due to its large total volume and average pore diameter, absence of a template in its structure, excellent performance in CO2 adsorption, lack of affinity for N2, and robust adsorption–desorption stability.

High efficiency of treated-phengite clay by sodium hydroxide for the Congo red dye adsorption: optimization, cost estimation, and mechanism study.

Wastewater textile dye treatment is a challenge that requires the development of eco-friendly technology to avoid the alarming problems associated with water scarcity and health-environment. This study investigated the potential of phengite clay as naturally low-cost abundant clay from Tamgroute, Morocco (TMG) that was activated with a 0.1M NaOH base (TMGB) after calcination at 850°C for 3 hours (TMGC) before its application in the Congo red (CR) anionic dye from the aqueous solution. The effect of various key operational parameters: adsorbent dose, contact time, dye concentration, pH, temperature, and the effect of salts, was studied by a series of adsorption experiments in a batch system, which affected the adsorption performance of TMG, TMGC, and TMGB for CR dye removal. In addition, the properties of adsorption kinetics, isotherms, and thermodynamics were also studied. Experimental results showed that optimal adsorption occurred at an acidic pH. At a CR concentration of 100 mg L-1, equilibrium elimination rates were 68%, 38%, and 92% for TMG, TMGC, and TMGB, respectively. The adsorption process is rapid, follows pseudo-second-order kinetics, and is best described by a Temkin and Langmuir isotherm. The thermodynamic parameters indicated that the adsorption of CR onto TMGB is endothermic and spontaneous. The experimental values of CR adsorption on TMGB are consistent with the predictions of the response surface methodology. These led to a maximum removal rate of 99.97% under the following conditions: pH =2, TMGB dose of 7g L-1, and CR concentration of 50 mg L-1. The adsorbent TMGB's relatively low preparation cost of around $2.629 g-1 and its ability to regenerate in more than 6 thermal calcination cycles with a CR removal rate of around 56.98%, stimulate its use for textile effluent treatment on a pilot industrial scale.

Nanoarchitectonics of hydrothermal carbonized sugarcane juice-derived biochar for high supercapacitance and dye adsorption performance

Here, we report the exfoliation of micron-sphere biochar to a few layers using the conventional KOH activation process. Micron-sphere biochar is obtained from hydrothermal carbonization (HTC) of sugarcane juice (Saccharum officinarum). HR-TEM and Raman spectroscopy studies revealed the conversion of micron-sphere biochar (MSB) to a few layers of biochar (FLB) in the activation process. BET characterization revealed FLB with a high surface area of 681.21 m2/g having mesopores. Consequently, an electrochemical study demonstrated excellent supercapacitor performance with a specific capacitance of 964.5 F/g and an energy density of 33.11 Wh/kg at a maximum power density of 936 W/kg. Batch adsorption studies showed rapid Methylene blue (MB) dye adsorption in 10 min. The equilibrium data analysis indicated the Langmuir adsorption isotherm with a correlation coefficient of 0.99. Evaluation of the kinetic models suggests that pseudo-second-order kinetics is the most appropriate model, implying that the adsorption of MB dye is primarily due to chemisorption. These findings suggest a Nanoarchitectonics of biochar into a few layers using traditional KOH activation, suitable for various applications.