Adsorption最新文献

The escalating demand for energy across various sectors has led to a significant increase in greenhouse gas emissions, primarily due to the extensive use of fossil fuels. This study addresses the critical need for effective carbon capture adsorbents to mitigate environmental impacts. Bio-based activated carbons, known for their high surface area and pore volume, were synthesized from poplar and spruce sawdust through hydrothermal carbonization (HTC) followed by simultaneous carbonization and activation. HTC, aimed at enriching precursors with oxygen-rich surface functional groups, was conducted at temperatures of 180, 200, and 220 °C for 90 min. This process produced hydrochars that were subsequently activated at 800 °C in the presence of KOH under a nitrogen atmosphere. Remarkably, the activated carbons derived from poplar sawdust hydrochar (at a HTC temperature of 200 °C) and spruce sawdust hydrochar (at a HTC temperature of 220 °C) demonstrate superior specific surface areas of 1680.59 and 1231.57 m²/g, along with total pore volumes of 0.87 and 0.62 cm³/g, respectively. Moreover, both poplar and spruce hydrochar-based activated carbons exhibit high CO₂ adsorption capacities of 3.75 and 3.43 mmol/g, respectively, at 24.85 °C and 1 atm. Their CH₄ adsorption capacities are 1.52 and 1.42 mmol/g, respectively, under the same conditions. This work highlights the potential of bio-based activated hydrochars in applications such as indoor air quality improvement and industrial flue gas treatment, emphasizing the importance of pretreatment and activation conditions in optimizing adsorbent performance.

This study evaluated Brazilian natural clays for copper sorption from water. Clays were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and sorption tests. Affinity tests showed that brasgel (B, 69%), chocobofe (Cb, 46%), and chocolate (Ch, 41%) had higher Cu²⁺ capture potential than zeolite (Z, 26%), palygorskite (P, 18%), treated palygorskite (TP, 11%), and cloisite 20A (C20A, 4%). The capture of Cu²⁺ by clays and zeolite occurs with the release of light metal ions, especially Na⁺, Mg²⁺ and Ca²⁺, which were initially present in the nanomaterials structure. The organomodification of clays possibly altered specific surface area, affecting Cu²⁺ removal. Besides, the lamellae morphology of B, Cb, and Ch and their crystalline structure of smectites facilitated the metal ion removal. Next, B, Cb, and Ch clays were selected based on their affinity with Cu²⁺ to investigate these systems’ sorption kinetics and equilibrium isothermal. The sorption kinetics showed that the equilibration time was reached within 120 min for all clays. The Pseudo-second order (PSOR) and External mass transfer resistance (EMTR) models effectively represented the kinetics data. The isothermal equilibrium revealed that the maximum uptake capacity for clays by Cu²⁺ increased in the following order: B (0.264 mmol g⁻¹) > Cb (0.223 mmol g⁻¹) > Ch (0.177 mmol g⁻¹). The isothermal curves better fit the Freundlich (B nanoclay) and Langmuir (Cb and Ch clays) models. The findings suggest that Brazilian clay nanostructures, particularly B, Cb, and Ch, are promising nanoadsorbents for removing bivalent copper ions from aqueous solutions.

There has been substantial research focused on developing environmentally friendly materials to remove pollutants from wastewater. In this regard, a key study area is focused on green materials derived from plants and agricultural wastes. These materials have shown promising results in removing pollutants from water, providing a sustainable solution for wastewater treatment. Additionally, using plant-based materials has helped reduce reliance on traditional chemical-based methods, contributing to a more environmentally friendly approach. The current study investigated the efficacy of utilizing pomegranate skin (PG) and date pedicels (DPd) as potential green adsorbents for the elimination of synthetic dye Yellow Bemacid (YB) from aqueous solutions. The investigation involved adsorption tests conducted under various experimental conditions, such as contact time, solution pH, initial dye concentration, and temperature. The obtained findings manifested that both PG and PdD exhibited considerable adsorption capacities for YB, quantified at 20.75 mg/g and 12 mg/g, respectively. The Langmuir model exceptionally fit the experimental data, and the adsorption kinetics closely followed the pseudo-second-order model for both materials studied. The thermodynamic parameters unveiled that the adsorption of YB was a feasible, spontaneous, and endothermic process, with enthalpy (ΔH) values of 2.330 and 4.165 kJ/mol for PG and PdD, respectively. Furthermore, the favourable affinity between the materials PG, PdD, and the YB molecules was indicated by the positive values (0.010 and 0.014 kJ/mol.K ) of entropy (∆S⁰). Lastly, the negative values of the free enthalpies (∆G⁰ < 0) for the studied systems signified the spontaneity of the adsorption process.

Aquatic environments have faced significant and severe impacts in recent years due to oil spills and chemical leaks in oceanic and river ecosystems. Because of this, several studies have aimed to develop sustainable adsorbents with hydrophobic characteristics. This research focuses on creating eco-friendly sorbents using macadamia nutshell waste (MW) incorporated into castor oil-based polyurethane foam at different proportions (5, 10, 15, and 20 wt%). The study also evaluates the absorption efficiency of these sorbents for different oil types, including crude oils (crude oil CB, crude oil SB, diesel S10, and diesel S500). The eco-friendly sorbents (biocomposites) were characterized by optical microscopy, scanning electron microscopy, density, and contact angle analyses. Results revealed that the pore morphology of sorbents changed to a partial closed-cell structure with a smaller pore size. Additionally, the biocomposites exhibited a higher contact angle (119.1º ± 0.4) compared to pure polyurethane (PU). The oil absorption efficiency by biocomposites showed maximum sorption of 7.3, 7.1, 5.1, and 3.9 g.g⁻¹ for crude oils (SB and CB), S10, and S500 diesel, respectively. The absorption results showed that the biocomposites showed good removal of heavy oils (crude oil) compared to light oils (diesel S10 and S500). Among the isotherm models used, the Langmuir model demonstrated the most accurate fit and estimated a maximum adsorption capacity of 5.39, 4.23, 3.24, and 2.69 g.g⁻¹ for crude oil CB, crude oil SB, S10, and S500 diesel respectively, using PU + 20% MW. Additionally, PU + 20% MW showed excellent reusability during 30, 30, 30, and 10 cycles of sorption–desorption for crude oil CB, crude oil SB, S10, and S500 diesel, respectively.

Nanotechnology is offering solutions to water contamination issues, as new techniques are needed to improve the removal of harmful compounds from water bodies. Despite previous reviews on this topic, nanotechnology is paving the way for more effective water treatment methods. Understanding the substitute influence of divalent Co²⁺ and rare earth elements Sm³⁺ on the structure, magnetic, and removal efficiency of hexagonal ferrites requires an understanding of a sequence of SrFe₁₂O₁₉, SrFe_11.5Co_0.5O₁₉, Sr_0.95Sm_0.05Fe₁₂O₁₉, and Sr_0.95Sm_0.05Fe_11.5Co_0.5O₁₉ M-type hexagonal ferrites were prepared using the flash technique. The XRD examination revealed that the crystallized material formed a single M-type hexagonal phase. The characteristics of M-type hexagonal ferrites include absorption bands with low wavenumbers in the FTIR curves between 400 to 1000 cm⁻¹. There was a variation in magnetic characteristics with the replacement of Sm³⁺ and Co²⁺ doping, possibly due to the spin canting impact created by rare earth Sm³⁺ and Co²⁺ ions. The goal of the research is to explore the potential of doping magnetic hexaferrites and its influence in wastewater treatment. Various parameters, such as pH and contact duration, that influence the adsorption of lead ions from aqueous solutions were also examined. At pH 7 and 25 °C after 70min, the maximal removal efficiency of the Sr_0.95Sm_0.05Fe_11.5Co_0.5O₁₉ was found to be 99%. Magnetic separation was carried out by applying an external magnetic field using a permanent magnet. The strong magnetization of the ferrites (51–58 emu/g) enabled the rapid separation of the magnetic particles from the solution, with over 95% of the ferrite particles being recovered within 10 to 70 min. The Freundlich isotherm model fitted all the isotherm data. Adsorption kinetics were explained by the pseudo-first-order, pseudo-second order, and intraparticle diffusion models. The investigated samples’ adsorption capacity remained efficient till 5 cycles.

Nitrogen oxides (NOx) are posing significant environmental risks. A nonmetallic 9-cyano quinacridone-porphyrin-based sensor is designed for their detection. This sensor demonstrates commendable sensitivity towards all forms of NOx. Nudged elastic band (Bouzineb et al. (2023) J Mol Model 29:365) method Transit/ Quadratic Synchronous Transit (QST) method / Linear Synchronous Transit QST method (LST) is applied to study the activation energy barrier for sensor to sense NOx. Optimal distances between NOx molecules and the porphyrin sensor are determined. Assessment of activation energy and adsorption energy values provide crucial insights into the sensor’s aptitude for sensitivity. Remarkably, adsorption energy (E_ad) values for NO, NO₂, N₂O₃, N₂O₄, N₂O₅ are found to be − 0.01, − 0.78, − 7.29, − 2.75, − 3.02 eV, respectively. Non-covalent interactions (NCI) analysis presents weak attraction in the blue region and van der Waals interaction in the green region. The sensor’s swift recovery time (τ) within the range of 10⁻¹² further underscores its potential for prompt response. An exploration of the sensor’s energy gap, recovery time, and adsorption energy values elucidates its sensitivity towards different NOx species. These are crucial factors in environmental monitoring. Furthermore, a detailed exploration of the sensing mechanism enhances comprehension of molecular interactions, showcasing the sensor’s potential as an effective tool for environmental monitoring and remediation. It will be used in wrist watches, and automobiles to sense nitrogen oxides (NOx).

The burning of fossil fuels is the major cause of the surge in atmospheric CO₂ concentration. The unique properties of Metal–organic frameworks (MOFs) have made them a highly promising and efficient class of materials for gas adsorption projects. In this piece of research, white-box machine learning algorithms, including gene expression programming (GEP), group method of data handling (GMDH), and genetic programming (GP), are implemented to generate reliable and efficient explicit correlations for estimating CO₂ uptake capacity of MOFs based on the most extensive databank gathered up-to-date containing 6530 data points from 88 different MOFs. The CO₂ uptake capacity is considered a strong function of pressure, temperature, surface area, and pore volume. The results indicated that the GMDH correlation could provide more reliable results by showing total root mean square error (RMSE) and correlation coefficient (R²) of 2.77 mmol/g and 0.8496, respectively. Also, the trend analysis reflected that this correlation could precisely detect the physical trend of CO₂ uptake capacity with pressure variations. Moreover, the sensitivity analysis showed the high impact of pressure on the estimated CO₂ uptake capacity values. Based on the sensitivity analysis of the GMDH correlation’s estimations, it can be expected that the CO₂ adsorption capacity of MOFs increases by raising MOFs’ surface area and pore volume and designing the adsorption process at elevated pressures and lower temperatures. The proposed correlation can be simply employed to estimate MOFs’ CO₂ uptake capacity with an acceptable level of confidence using a simple calculator.

Millions of tons of dyes are released into water bodies each year, most of which are azo dyes and pose a threat to soil and water ecosystems. This article introduces a simple sol–gel technique for producing a composite of Cellulose-Graphene oxide (CGO) beads as an adsorbent with outstanding adsorption efficiency for a commercial textile dye, Doracryl Red MD (DRMD). The crystal phases, functional groups, thermal stability, and morphology of GO, Cellulose, and CGO beads were extensively studied using various characterization methods, including XRD, FTIR, FESEM, and TGA. The adsorption process was optimized for different pH levels, dosages, initial dye concentrations, and contact times. The adsorption process followed Freundlich adsorption isotherm and Pseudo-second-order kinetics. CGO adsorbent demonstrated a maximum adsorption capacity of 577.874 mg/g, indicating its potential for eliminating organic contaminants from wastewater.

Currently, there is a significant interest among researchers in elemental monolayer materials owing to their exceptional sensitivity, selectivity, and stability in detecting air pollutants. In the proposed study, the structural stability of bare arsenaluminane is validated through cohesive energy analysis. It is used to adsorb the sewer gas contaminants, which are butyric acid and butyl acetate. Subsequently, the electronic properties of arsenaluminane are examined using band structure analysis and projected density of states spectra. The calculated band gap of arsenaluminane is 1.408 eV (predicted using hybrid-GGA/B3LYP), indicating its semiconducting state. Notably, the adsorption characteristics of butyric acid and butyl acetate molecules on arsenaluminane were investigated by analysing adsorption energy, relative band gap changes, and Mulliken charge transfer. Specifically, the calculated adsorption energies fall within the physisorption regime and the Mulliken charge transfer ranges from 0.084 e to 0.598 e, suggesting that arsenaluminane behaves as a promising chemical sensor for detecting sewer gas molecules.

We perform molecular simulations to explore methane adsorption on carbon and boron nitride (BN) nanoscrolls, highlighting the impact of radius, pressure, and temperature on adsorption performance. Surprisingly, increasing nanoscroll layers, particularly in BN nanoscrolls, does not enhance methane adsorption but rather reduces release capacity. Our molecular simulations reveal a linear relationship between methane release and structural parameters of both carbon and BN nanoscrolls, with carbon nanoscrolls showing higher release independent of structure, while BN nanoscrolls’ release varies with porosity, pore volume, and material density. The stability of this relationship is evident despite limited variability in structural parameters, pointing to elemental composition and molecular force fields as the key determinants of methane release behavior. At 30 MPa, BN nanoscrolls’ volume adsorption marginally meets the DOE target, while carbon nanoscrolls show significant, yet insufficient, progress toward the same goal. Temperature studies indicate that lower temperatures benefit carbon nanoscrolls’ adsorption and release but negatively impact BN nanoscrolls’ release. Our results indicate that while both types of nanoscrolls can meet the DOE’s targets for methane adsorption at low temperatures of 208 K and high pressures of 30 MPa, and have release capacities close to the targets, BN nanoscrolls, unlike carbon nanoscrolls, exhibit higher methane adsorption at low pressures of 0.1 MPa. This leads to more complex release phenomena for BN nanoscrolls. These findings provide critical insights, guiding the design and optimization of nanoscroll materials for enhanced methane adsorption and release in gas storage applications.