Initial Adsorption Rate Research Articles

Mesoporous N-doped hierarchical porous materials derived from core-shell MOFs: A promising strategy for eliminating sulfamethoxazole using 1O2

Slfamethoxazole (SMX) has been considered as one kind of important micropollutants in water which need to be removed effectively. Developing one kind of material for effectively removing SMX in water is crucial in treatment process. In this study, core–shell structured metal–organic frameworks (MOFs) with increasing shell thickness (5, 10, and 20-ZIF-8@ZIF--67 s) were selected as an ideal platform to develop water-stable hierarchical porous carbons (HPCs) using one-step calcination, showing the dual functionals of both adsorption and catalysis by producing large amount of acitve species (1O2). These novel HPCs systematically optimized at increasing temperatures and ratios of two metals. The 10-Co-NHPC-900 at optimal conditions shows highest adsorption capacities and initial adsorption rates, which are 4.56 and 10.35 times higher than those of calcinated ZIF-67 s. The decomposition mechanisms based on PMS were systematically studied by analyzing oxidant consumption, reactive oxygen species and by-products of SMX. In addition, Co ions leached amount of 10-Co-NHPC-900 was 63.6 times lower than that of MOF precursor, indicating that the cobalt-based porous carbon have higher water stabilities. This study offers an efficient approach for reducing micropollutants risk using water-stable hierarchical porous carbons.

Enhanced phosphorus adsorption using modified drinking water treatment residues: A comparative analysis of powder and alginate bead forms

This study provides an analysis of the phosphorus adsorption efficacy of three modified drinking water treatment residues (MDWTRs): MDWTR-P (powdered form), MDWTR-D2, and MDWTR-D5 (alginate bead-entrapped forms with bead diameters of 2 mm and 5 mm, respectively). The preparation process involved washing and drying the drinking water treatment residue, followed by grinding and sieving to achieve particle sizes below 90 μm. The residue was then incinerated at 600 °C in oxygen-limited conditions. Subsequently, the MDWTR was formulated into alginate beads by mixing with sodium alginate and FeCl3 solutions, resulting in spherical particles of specified diameters. The evaluation of surface area, pore volume, pore size, and CHN concentration revealed that MDWTR-D5 possesses the largest surface area (284.7 m2 g−1) and highest micropore volume (0.04 cm3 g−1), indicating a greater capacity for adsorption. SEM-EDS analysis demonstrated significant compositional changes post-treatment, particularly elevated phosphorus levels, confirming effective adsorption. Metal content analysis indicated high aluminum levels in MDWTR-P and increased iron content in MDWTR-D5. Toxicity Characteristic Leaching Procedure (TCLP) and in vitro bioaccessibility (IVBA) tests confirmed the non-hazardous nature of all MDWTRs, ensuring their safety for environmental applications. Kinetic analyses using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models highlighted the superior performance of MDWTR-D5, with the highest equilibrium adsorption capacity and initial adsorption rate across all tested concentrations, suggesting both high efficiency and rapid adsorption potential. Further validation using Langmuir and Freundlich isotherms revealed MDWTR-D5's highest monolayer adsorption capacity (22.88 mg g−1) and Freundlich adsorption capacity parameter (6.97 mg g−1). Statistical analysis via one-way ANOVA confirmed significant differences in phosphorus concentrations among the MDWTRs samples (p-value <0.001), consistently underscoring MDWTR-D5's superior adsorption performance. These findings highlight MDWTR-D5's potential as an effective adsorbent for phosphorus removal in wastewater treatment, emphasizing its applicability in environmental remediation strategies.

Development of two-dimensional amyloid fibril/carboxymethyl cellulose hybrid membranes for effective adsorption of hexavalent chromium

Amyloid fibrils (AFs) are protein aggregates with highly ordered fibrillar structures and can be formed via self-assembly of proteins under appropriate conditions. Owing to the unique properties of AFs, e.g., high surface-to-volume ratio and versatile functional groups, they offer abundant binding sites for the efficient adsorption of hexavalent chromium (Cr(VI)). This study was aimed at examining the performance of two-dimensional AF-based hybrid membranes for adsorbing Cr(VI). First, AF/carboxymethyl cellulose (AF/CMC) hybrid membranes were synthesized via chemical crosslinking coupled with phase inversion, followed by investigating the synthesis mechanism using Fourier transform infrared spectroscopy. Our results revealed that the surface microstructures and mechanical properties of the hybrid membranes could be affected by the AF:CMC mass ratio of the membrane. The porosity and ζ-potential of hybrid membranes were found to be dependent on both pH value and membrane composition. Analyses of the kinetics and thermodynamic behavior of Cr(VI) adsorption on the AF/CMC hybrid membranes revealed that the initial adsorption rate and maximum adsorption capacity were determined to be ∼149.20 mg g–1 h–1 and ∼311.11 mg g–1, respectively. The Cr(VI) removal percentage of hybrid membrane with high CMC content was found to remain at >75 % after five successive adsorption-desorption cycles. Finally, the mechanism and interactions involved in the adsorption of Cr(VI) on the hybrid membrane were further investigated via thermodynamic analysis and X-ray photoelectron spectroscopy. This study provides an excellent example of harnessing AF-based membranes in water remediation, highlighting the potential of AF-based hybrid materials for wastewater treatment applications.

Co-pyrolysis development of waste tire-sludge adsorbent by mixed of waste tires and oily sludge

To facilitate resource utilization of waste tires (WT) and oily sludge (OS), waste tire-sludge adsorbent (WTSA) was developed using co-pyrolysis technology, and its effectiveness in adsorbing crude oil was investigated. The study revealed that the optimal preparation conditions for WTSA included a 1.5:1 mass ratio of WT to OS, a co-pyrolysis temperature of 600 ℃, a co-pyrolysis holding time of 2 hours, and a co-pyrolysis heating rate of 15 ℃/min. The surface of WTSA exhibited numerous pores and cracks with varying shapes and sizes. The dominant pore structures were found to be mesopores and macropores. The carbon content of WTSA was measured to be 89.95%. Moreover, the BET specific surface area, pore volume, and average pore size were determined to be 686.81 m2/g, 0.74 cm3/g, and 5.91 nm, respectively. In the crude oil adsorption test, WTSA demonstrated a comparable adsorption capacity to activated carbon (AC), but with a more attractive initial adsorption rate. Furthermore, thermal regeneration treatment was found to significantly enhance the lipophilic properties of WTSA, leading to an increase in its initial adsorption rate. The adsorption capacity of regenerated WTSA was also found to be relatively stable, making it an ideal solution for emergency crude oil spill cleanups. Compared to AC, WTSA can be recycled and reused multiple times, making it a more sustainable and cost-effective option.

Preparation of micron-sized benzamidine-modified magnetic agarose beads for trypsin purification from fish viscera

The effective method for trypsin purification should be established because trypsin has important economic value. In this work, a novel and simple strategy was proposed for fabricating micron-sized magnetic Fe3O4@agarose-benzamidine beads (MABB) with benzamidine as a ligand, which can efficiently and selectively capture trypsin. The micro-sized MABB, with clear spherical core-shell structure and average particle size of 6.6 μm, showed excellent suspension ability and magnetic responsiveness in aqueous solution. The adsorption capacity and selectivity of MABB towards target trypsin were significantly better than those of non-target lysozyme. According to the Langmuir equation, the maximum adsorption capacity of MABB for trypsin was 1946 mg g−1 at 25 °C, and the adsorption should be a physical sorption process. Furthermore, the initial adsorption rate and half equilibrium time of MABB toward trypsin were 787.4 mg g−1 min−1 and 0.71 min, respectively. To prove the practicability, MABB-based magnetic solid-phase extraction (MSPE) was proposed, and the related parameters were optimized in detail to improve the purification efficiency. With Tris-HCl buffer (50 mM, 10 mM CaCl2, pH 8.0) as extraction buffer, Tris-HCl buffer (50 mM, 100 mM CaCl2, pH 8.0) as rinsing buffer, acidic eluent (0.01 M HCl, 0.5 M NaCl, pH 2.0) as eluent buffer and alkaline buffer (1 M Tris-HCl buffer, pH 10.0) as neutralization solution, the MABB-based MSPE was successfully used for trypsin purification from the viscera of grass carp (Ctenopharyngodon idella). The molecular weight of purified trypsin was determined as approximate 23 kDa through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The purified trypsin was highly active from 30 °C to 60 °C, with an optimum temperature of 50 °C, and was tolerant to pH variation, exhibiting 85 % of maximum enzyme activity from pH 7.0 to 10.0. The results demonstrated that the proposed MABB-based MSPE could effectively purify trypsin and ensure the biological activity of purified trypsin. Therefore, we believe that the novel MABB could be applicable for efficient purification of trypsin from complex biological systems.

Utilization of dragon fruit (Hylocereus undatus) peel-derived biochar for the adsorptive removal of tetracycline from aqueous solution

The peel of Hylocereus undatus was employed in the preparation of biochar and firstly applied for tetracycline removal from aqueous solution. Based on different characterization techniques, the material was found to possess a variety of surface functional groups on a porous structure and a pH point of zero charge (pHpzc) of 9.3. Adsorption of tetracycline (TC) was conducted under varying conditions, revealing significant effects of carbonization temperature, solution pH, adsorbent dose, ionic strength, contact time and initial concentration of TC on the biochar adsorption capacity. Kinetic data on TC adsorption were best described using the Elovich kinetic model, with an initial adsorption rate of 167.3 mg g−1 min−1. Isotherm data on adsorption of the desired biochar showed the best fit with the Temkin isotherm model, followed by the Langmuir model, displaying maximum adsorption capacity at 12.4 mg g−1. The electrostatic interactions between the charged biochar surfaces and certain fractions of TC were proposed as the major mechanism, together with H-bonding, pore-filling effect and π–π interaction. This study demonstrates great potential of H. undatus peel as a starting material to prepare an effective and reusable adsorbent in the removal of TC.

Study on CaO-based materials derived from steel slag for solar-driven thermochemical energy storage

The calcium looping (CaL) technique, renowned for its exceptional ability to withstand high temperatures and remarkable heat storage capacity, perfectly complements 3rd generation concentrated solar power (CSP) plants. However, the poor cycling stability and low spectrum absorption rate of CaO obstruct system efficiency. In order to tackle these problems, we impregnated steel slag with acetic acid and doped Mn to create a novel CaO-based energy storage material. Thermogravimetric analysis (TGA) and fixed-bed cycling of the material revealed that the material has outstanding cyclic heat storage properties. Compared to CaO, the material has an 85 % higher initial adsorption rate, 73 % higher 30-cycle energy storage density, and 9.5 times higher average light absorption. Spherical pellets were prepared for industrial applications through the extrusion-spheronization method. The energy storage density for 30 cycles was reduced by 10.26 % for the pellets compared to the powder material, but the average light absorption rate was improved. The compressive strength of the composite pellets was 8.4 times higher than the dolomite pellets. It was found that the light absorption capacity of the material increased with the number of cycles, which was attributed to the migration of Mn and Mg from the interior to the surface. Finally, the excellent photothermal conversion capability of the new composite material was verified by the photothermal conversion test. Therefore, Mn-doped CaO-based composite material derived from steel slag is promising for application in the next-generation CaL-CSP system.

Heterocyclic-based Schiff base material designed as optochemical sensor for the sensitive detection of chlorinated solvent vapours

Herein, a newly synthesized intermediate, piperazine-based Schiff base (PBSB) gas sensor was fabricated by the Schiff base condensation of amino functionalized methylpiperazine with aromatic aldehyde containing nitro substituent. This organic sensor material was structurally identified with spectroscopic techniques such as FTIR, HRMS, 1H- and 13C-NMR. The designed sensor candidate was explored for its optical response to chlorinated volatile organic compounds, namely trichloroethylene, dichloromethane and chloroform in the light of structure–property relationship investigation by using surface plasmon resonance (SPR) technique. The results showed that Schiff bases could be candidates for chlorinated vapour sensing materials with their good response and reversibility. Concordantly, compound PBSB exhibited good response against chlorinated solvent vapours aided by the electron-withdrawing group on benzene ring that promoted better intermolecular interactions and opened up a new strategy to create a novel set of responsive materials for gas sensing applications. In addition, the adsorption kinetics of SPR data obtained from PBSB spun film on exposure to these chlorinated vapours at different concentrations was also evaluated using the Elovich Model. The values of the initial adsorption rate, a and Elovich constant, b were analysed depending on the concentration values and the highest values were obtained for dichloromethane between 372.92 and 4377.53 ppm/mm2.Graphical abstract

Grafting of Polyethyleneimines on Porous Silica Beads and Their Use for Adsorptive Removal of Cr(VI) from Aqueous Medium

Porous silica-based adsorbents for hexavalent chromium (Cr(VI)) ion removal were prepared by the combined use of functionalization with (3-glycidyloxypropyl)trimethoxysilane and the grafting of branched and linear polyethyleneimine (BPEI and LPEI). LPEI was prepared from polyethyloxazolin by hydrolysis with HCl. The preparation of LPEI was identified by NMR measurements and the grafting of BPEI and LPEI on the silica beads was confirmed by an XPS analysis. The Cr(VI) ion adsorption of the obtained BPEI-grafted silica beads (BPEI–silica beads) was investigated as a function of the pH value, the content of amino groups, the temperature, the Cr(VI) ion concentration, and the molecular mass of the grafted BPEI chains. The Cr(VI) ion adsorption at pH 3.0 increased with an increase in the content of amino groups, and the maximum adsorption capacity of 1.06 mmol/g was obtained when the content of amino groups was at 2.17 mmol/g. This value corresponds to 589 mg/g−1.8KPEI, and the adsorption ratio of about 0.5 is a noteworthy result. The data fit to the pseudo-second-order kinetic model, and the suitability of this fitting was supported by the results that the adsorption capacity and initial rate of adsorption increased with the temperature. In addition, the equilibrium data followed the Langmuir isotherm model. These results clearly demonstrate that the Cr(VI) adsorption occurred chemically, or through the electrostatic interaction of protonated amino groups on the grafted BPEI chains with hydrochromate (HCrO4−) ions. A higher adsorption capacity was obtained for the silica beads grafted with shorter BPEI chains, and the adsorption capacity of BPEI–silica beads is a little higher than that of linear PEI-grafted silica beads, suggesting that the Cr(VI) ion adsorption is affected by the chain isomerism of PEI (linear and branched) as well as the molecular mass of the grafted PEI chains, in addition to the content of amino groups. The experimental and analytical results derived from this study emphasize that the BPEI–silica beads can be used as an adsorbent for the removal of Cr(VI) ions from an aqueous medium.

Enhanced removal of selected ionizable micro-pollutants from drinking water by adsorption on activated carbon fiber filters under electrochemical assistance

Micro-pollutants have raised serious concerns for drinking water safety because of their great harm to the ecological environment and public health. Traditional water purification technologies, including coagulation and sand filtration, are commonly insufficient to treat micro-pollutants. Adsorption process through carbon-based material has the potential to remove micro-pollutants from aqueous solution. However, the adsorption efficiency is restrained by insufficient adsorption capacity of the adsorbent. Ionization is a common character of most micro-pollutants in aquatic environment, which enables the possibility to improve adsorption capacity by enhance the electrostatic interaction through electrochemical ways. In this work, the activated carbon fiber (ACF) filter possessing high inherent adsorption capacity was prepared and the electrochemical assistance was adopted to improve the adsorption capacity by enhancing the electrostatic attraction between ionizable micro-pollutant and the adsorbent. The adsorption behavior under electrochemical assistance was well fitted by the pseudo-second-order kinetic model. The initial adsorption rates v0 for dichloroacetic acid (DCAA), levofloxacin (LVFX) and ciprofloxacin (CIP) reached 10.8 mg·g−1·h−1 (2.0 V), 48.3 mg·g−1·h−1 (−2.0 V) and 39.4 mg·g−1·h−1 (−2.0 V), respectively, which were 1.1–2.0 times higher than those without electrochemical assistance. The Langmuir model well fitted the adsorption isotherms of the three pollutants under electrochemical assistance. The calculated adsorption capacities (qm) of DCAA, LVFX and CIP under electrochemical assistance were 1.9, 1.3 and 1.1 times higher than those without electrochemical assistance. Furthermore, the adsorption of DCAA of 100 μg·L−1 by ACF filters under continuous flow-through mode was further investigated. The DCAA concentration in effluent maintained lower than the World Health Organization (WHO) limitation of 50 μg·L−1 for 3150 bed volumes under electrochemical assistance, which was 2.4 times higher than that without electrochemical assistance. This work provided a new approach for the efficient removal of ionizable micro-pollutants during drinking water treatment.

Revealing the mechanism of hydration on the CO2 kinetic adsorption of CaO surface via ReaxFF MD simulations with experiments

Hydration has been regarded as an effective method to improve the cyclic activity of CaO during the Calcium looping CO2 capture process, but its mechanism remains unclear. In this work, the hydration reaction of CaO surface and its underlying mechanism was studied by ReaxFF molecular dynamics simulation combing with TGA experiments. The effect of hydration on the initial CO2 adsorption rate showed a trend of promoting at low H2O degree and inhibiting at high H2O concentration. The CaO surface was easily passivated, and it can maintain its crystal structure and begin to distort at about 1.0 H2O monolayer contents. Hydration failed to promote the CO2 adsorption rate, inversely the CO2 adsorption process accelerated the diffusion of H ions inward the CaO lattice·H2O dissociation produced two hydroxyl groups: direct OwH and indirect OsH. Atomic density profiles showed that the direct hydroxyl pairs were always, and indirect OsH groups can consume surface oxygen active sites, reducing the initial rapid CO2 adsorption activity. On the pre-hydrated CaO surface, CO2 molecules were more likely to bind to solid oxygen active sites than OH groups. The H free radical diffused inside the lattice in the form of transition HO2 state, promoting the slow CO2 adsorption amount.

Synthesis and Characterization of Silver-Modified Nanoporous Silica Materials for Enhanced Iodine Removal.

In aquatic environments, the presence of iodine species, including radioactive isotopes like 129I and I2, poses significant environmental and health concerns. Iodine can enter water resources from various sources, including nuclear accidents, medical procedures, and natural occurrences. To address this issue, the use of natural occurring nanoporous minerals, such as zeolitic materials, for iodine removal will be explored. This study focuses on the adsorption of iodine by silver-modified zeolites (13X-Ag, 5A-Ag, Chabazite-Ag, and Clinoptilolite-Ag) and evaluates their performance under different conditions. All materials were characterized using scanning electron microscopey (SEM), energy-dispersive X-ray spectroscopy (EDS), powdered X-ray diffraction (P-XRD), Fourier-transform infrared spectrometry (FTIR), and nitrogen adsorption studies. The results indicate that Chabazite-Ag exhibited the highest iodine adsorption capacity, with an impressive 769 mg/g, making it a viable option for iodine removal applications. 13X-Ag and 5A-Ag also demonstrated substantial adsorption capacities of 714 mg/g and 556 mg/g, respectively, though their behavior varied according to different models. In contrast, Clinoptilolite-Ag exhibited strong pH-dependent behavior, rendering it less suitable for neutral to slightly acidic conditions. Furthermore, this study explored the impact of ionic strength on iodine adsorption, revealing that Chabazite-Ag is efficient in low-salinity environments with an iodine adsorption capacity of 51.80 mg/g but less effective in saline conditions. 5A-Ag proved to be a versatile option for various water treatments, maintaining its iodine adsorption capacity across different salinity levels. In contrast, Clinoptilolite-Ag exhibited high sensitivity to ionic competition, virtually losing its iodine adsorption ability at a NaCl concentration of 0.1 M. Kinetic studies indicated that the pseudo-second-order model best describes the adsorption process, suggesting chemisorption mechanisms dominate iodine removal. Chabazite-Ag exhibited the highest initial adsorption rate with a k2 value of 0.002 mg g-1 h-1, emphasizing its superior adsorption capabilities. Chabazite and Clinoptilolite, naturally occurring minerals, provide eco-friendly solutions for iodine adsorption. Chabazite superior iodine removal highlights its value in critical applications and its potential for addressing pressing environmental challenges.

Biocrusts Critical Regulation of Soil Water Vapor Transport (Diffusion, Sorption, and Late‐Stage Evaporation) in Drylands

AbstractSoil surface cover is one of the most critical factors affecting soil water vapor transport, especially in drylands where water is limited, and the water movement occurs predominantly in the form of vapor instead of liquid. Biocrusts are an important living ground cover of dryland soils and play a vital role in modifying near‐surface soil properties and maintaining soil structure. The role of biocrusts in mediating soil water vapor transport during daytime water evaporation and nighttime condensation remains unclear. We investigated the differences in vapor diffusion properties, vapor adsorption capacity, and water evaporation between bare soil and three types of biocrusts (cyanobacterial, cyanobacterial‐moss mixed, and moss crusts) in the Chinese Loess Plateau. Our results showed that the three types of biocrusts had 5%–39% higher vapor diffusivity than bare soil. At the same level of ambient relative humidity and temperature, the initial vapor adsorption rates and cumulative adsorption amounts of the biocrusts were 10%–70% and 11%–85% higher than those of bare soil, respectively. Additionally, the late‐stage evaporation rate of cyanobacterial‐, cyanobacterial‐moss mixed‐, and moss‐biocrusts were 31%–217%, 79%–492%, and 146%–775% higher than that of bare soil, respectively. The effect of biocrusts on increasing vapor transport properties was attributed to the higher soil porosity, clay content, and specific surface area induced by the biocrust layer. All of these modifications caused by biocrusts on surface soil vapor transport properties suggest that biocrusts play a vital role in reshaping surface soil water and energy balance in drylands.

Исследование адсорбционного разделения газовых смесей в условиях нестационарности

The influence of the initial concentration, rate and temperature of adsorption on the adsorption separation of gas mixtures (CO2, CH4, N2, H2S) is investigated. Components: N2 – 5%, H2S – 5%, CO2 – 5% and CH4 – 85%. And as an adsorbent granule of clinoptilolite of irregular shape were used. Isothermal adsorption of CO2 was obtained at different temperatures (293, 313, and 323 K). The obtained isotherms of CO2 adsorption showed that with an increase in temperature, the adsorption of CO2 decreased. The type of isotherms corresponds to Langmuir. The output curves of gas mixture adsorption depending on the gas flow rate and various main components of CO2 were also experimentally studied. The output curves of the adsorption of the CO2 component were studied at various gas flow rates of 20, 50, and 80 mL/min. Equilibrium time increases with a decrease in the gas flow rate. Output curves were also obtained depending on the initial CO2 concentrations of 5%, 10% and 20%. It was determined that with a decrease in the initial concentration of CO2, the equilibrium time also increases. Gas mixture components sorbed downwards: H2S→CO2→CH4→N2. The resulting system of model equations describing the adsorption separation of gas mixtures in a fixed adsorbent layer represents a complete mathematical model of the process under unsteady conditions. The obtained regularities of the process of adsorption of gas mixtures testify to the fact that the process takes place under non-stationary conditions. The proposed models for the optimal design of industrial absorbers can be used for adsorption separation of gas mixtures in the conditions of their unsteady flow.

Imidacloprid removal by modified graphitic biochar with Fe/Zn bimetallic oxides

Coping with the critical challenge of imidacloprid (IMI) contamination in sewage treatment and farmland drainage purification, this study presents a pioneering development of an advanced modified graphitic white melon seed shells biochar (Fe/Zn@WBC). The Fe/Zn@WBC demonstrates a substantial enhancement in adsorption efficiency for IMI, achieving a remarkable removal rate of 87.69% within 30 min and a significantly higher initial adsorption rate parameter h = 4.176 mg g−1·min−1. This significant improvement outperforms WBC (12.22%, h = 0.115 mg g−1·min−1) and highlights the influence of optimized adsorption conditions at 900 °C and the graphitization degree resulting from Fe/Zn bimetallic oxide modification. Characterization analysis and batch sorption experiments including kinetics, isotherms, thermodynamics and pH factors illustrate that chemical adsorption is the main type of adsorption mechanism responsible for this superior ability to remove IMI through pore filling, hydrogen bonding, hydrophobic interaction, electrostatics interaction, π-π interactions as well as complexation processes. Furthermore, we demonstrate exceptional stability of Fe/Zn@WBC across a broad pH range (pH = 3–11), co-existing ions presence along with humic acid under various real water conditions while maintaining high removal efficiency. This study presents an advanced biochar adsorbent, Fe/Zn@WBC, with efficient adsorption capacity and easy preparation. Through three regeneration cycles via pyrolysis method, it demonstrates excellent pyrolysis regeneration capabilities with an average removal efficiency of 92.02%. The magnetic properties enable rapid separation facilitated by magnetic analysis. By elucidating the efficacy and mechanistic foundations of Fe/Zn@WBC, this research significantly contributes to the field of environmental remediation by providing a scalable solution for IMI removal and enhancing scientific understanding of bimetallic oxides-hydrophilic organic pollutant interactions.

Unconventional extraction of uranium from seawater through microenvironment-specific conjugated microporous poly(aniline)s

The sustainability of uranium-based nuclear energy relies on the development of quick and effective uranium adsorbents. Herein, we propose a facile post-synthetic technique by grafting amino-functional groups onto the fluorenone-functionalized conjugated microporous poly(aniline)s (CMPs) network to acquire a novel class of N decorated polymers for uranium capture. By leveraging the abundant N sites and microenvironment-containing molecular structure, CMPA-F-BDA showcases excellent UO22+ adsorption performance with fast adsorption kinetic with initial adsorption rate up to 43.78 mg g−1 min−1, Langmuir adsorption capacity of 443 mg g−1 and exceptional adsorption selectivity of Kd = 1.3 × 107 mL g−1 even in the serious presence of competitive cations. Additionally, CMPA-F-BDA could treat up to 18.5 L g−1 of low-concentration uranium solution (1 mg L−1) and actual seawater, removing 87.9% of uranium from 10 L of seawater, and has excellent reusability. This study demonstrates the bright future of CMPs for the extraction of low-concentration uranium.

Polyaniline-Based Cationic Porous Organic Polymers for Fast and Efficient Anion-Exchange-Driven Capture of Cr2O7 2.

Efficient treatment of wastewater contaminated with carcinogenic Cr(VI) has been a long-term challenge for both academic and industrial research efforts. Removal of Cr(VI) species by ion exchange is a relatively simple and efficient method, and its combination with highly tailorable nanomaterials is promising for the treatment of such wastewater. Here, we report a type of cationic porous organic polymer (POP), namely, PTPA-PIP, which can be prepared simply by converting the corresponding aromatic polyamine PTPA to its protonated form, thereby significantly increasing its hydrophilicity and ability to disperse homogeneously in water, crucial for application in water treatment. In addition to detailed characterization of the physicochemical properties of PTPA-PIP (including using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), and solid-state NMR techniques), adsorption experiments demonstrate that PTPA-PIP removes low-concentration dichromate anions with very high performance, including excellent exchange capacity (maximum capacity of 230 mg Cr2O7 2-/g PTPA-PIP), ultrafast removal (initial adsorption rate of 83 mg g-1 min-1), excellent selectivity (∼10% loss of adsorption capacity in the presence of 40-fold concentration of competing anions), as well as superior reusability (reusable for at least 5 cycles without compromised performance). These results demonstrate that PTPA-PIP is an outstanding candidate for application in industrial settings for the effective removal of harmful Cr(VI) pollutants in wastewater.

In situ self-activation strategy for the synthesis of double-layered S/Cl co-doped sorbents for elemental mercury removal from oxy-fuel combustion flue gas

Mercury capture from oxy-fuel combustion flue gas remains an enormous challenge for carbon capture and storage because of the lack of cost-effective, sulfur-resistant and water-resistant sorbent. In this work, double-layered S/Cl co-doped sorbents (CDSs) were synthesized through an in situ self-activation method i.e. co-pyrolysis of waste tire and PVC plastic, which were adopted for elemental mercury (Hg0) immobilization from oxy-fuel combustion flue gas. A synergistic effect between waste tire and PVC plastic was observed during co-pyrolysis. For this reason, chlorine was successfully doped into the CDSs in the form of covalent chlorine and ionic chlorine. The CDSs showed high Hg0 removal efficiency (>80 %) over a wide temperature range (20–140 °C) and excellent sulfur and water resistance. Both the initial Hg0 adsorption rate and adsorption capacity of CDSs were far higher compared with raw tire char. The Hg0 removal mechanisms were further proposed, where Hg0 preferentially reacted with covalent chlorine instead of active sulfur species. Density functional theory calculations revealed that the Hg0 adsorption over CDSs was chemisorption with an adsorption energy of −249.85 kJ/mol. The synergistic effect between sulfur and chlorine was beneficial for the formation of HgCl2 whereas it had negligible effect on the formation of HgCl.

Performance enhanced Ti-based thin film getter with porous nickel as scaffold

n order to meet the requirement of high vacuum in MEMS devices, an improved Ti-based thin film getter with porous nickel scaffold was prepared by using dynamic hydrogen bubble template (DHBT) method, which finally effectively increased the specific surface area (SSA) and improved the adsorption performance. The microstructure and adsorption performance of the getter were studied by scanning electron microscope, BET, thermogravimetric analysis (TGA) and hydrogen adsorption test. The results show that the SSA of the prepared porous nickel scaffold can reach up to 11.622 m2/g. The aspect ratio of mesopores is around 2. The Ti film deposited on the scaffold have a good coating effect on the porous structure and have little effect on the aspect ratio. When the deposition thickness is 300 nm, the adsorption capacity (3.51374 mg) and adsorption rate (6.507 × 10−4mg/(s∙g)) can reach the highest. Hydrogen adsorption tests also show that the Ti-based thin film getter with porous nickel scaffold has a good repeatability, and its average initial adsorption rate reaches 8.195ml/(s∙cm2), which is nearly an order of magnitude higher than that of the two-dimensional planar getter.

Comparison of the Adsorption and Desorption Dynamics of Biological Molecules on Alginate Hydrogel Microcapsules-The Case of Sugars, Polyphenols, and Proteins.

The aim of this work was to analyze and compare the adsorption and desorption processes of carbohydrates (glucose as a model molecule), polyphenols (gallic acid as a model molecule), and proteins (bovine serum albumin, BSA as a model molecule) on alginate microcapsules. The adsorption and desorption processes were described by mathematical models (pseudo-first-order, pseudo-second-order, and Weber-Morris intraparticle diffusion model for adsorption, and first-order, Korsmeyer-Peppas, and the Higuchi model for desorption) in order to determine the dominant mechanisms responsible for both processes. By comparing the values of adsorption rate (k2) and initial adsorption rate (h0) based on the pseudo-first-order model, the lowest values were recorded for BSA (k1 = 0.124 ± 0.030 min-1), followed by glucose (k1 = 0.203 ± 0.041 min-1), while the model-obtained values for gallic acid were not considered significant at p < 0.05. For glucose and gallic acid, the limiting step of the adsorption process is the chemical sorption of substances, and the rate of adsorption does not depend on the adsorbate concentration, but depends on the capacity of the hydrogel adsorbent. Based on the desorption rates determined by the Korsmeyer-Peppas model (k), the highest values were recorded for gallic acid (k = 3.66236 ± 0.20776 g beads/mg gallic acid per min), followed by glucose (k = 2.55760 ± 0.16960 g beads/mg glucose per min) and BSA (k = 0.78881 ± 0.11872 g beads/mg BSA per min). The desorption process from alginate hydrogel microcapsules is characterized by the pseudo Fickian diffusion mechanism.