Adsorption Rate Research Articles

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.

Recovering ammonium from real treated wastewater by zeolite packed columns: The effect of flow rate and particle diameter

Nitrogen (N) recovery from wastewater is a desirable way to create a (N) neutral society in view of a circular economy approach. Nitrogen recovery from wastewater by employing adsorption columns filled with zeolite can be a very attractive solution. This study assessed the effect of influent flow rates (namely, 1.6 and 2.3 L h−1) and particle diameters (namely, 0.5–1.0 and 2.0–5.0 mm) of zeolite packed in columns on recovering NH4+ from real domestic treated wastewater (RDTWW). Findings revealed that maximum NH4+ recovery can be achieved by using zeolite with the smallest particle diameter (0.5–1.0 mm) and the highest influent flow rate (2.3 L h-1). The maximum NH4+ adsorption rate was 1.2, 21 and 9.8 mg NH4+ kg-1 h-1 after 205, 32 and 35 h of operation. NH4+ adsorption data were analysed by fitting them to both pseudo-first and pseudo-second order kinetic models. The former model best approximated NH4+ adsorption data. Such a result suggested that the amount of NH4+ adsorbed depended solely on the amount of NH4+ in contact with the zeolite surface. Results successfully established the application of zeolite-packed columns in removing NH4+ from real domestic treated wastewater and the effects of process parameters.

Simple Model to Predict the Adsorption Rate of Polymer Melts

Simple Model to Predict the Adsorption Rate of Polymer Melts

Purified Clinoptilolite-Tuff as an Efficient Sorbent for Food-Derived Peanut Allergens.

The avoidance of allergen intake is crucial for persons affected by peanut allergy; however, the cross-contamination of food is common and leads to unpredictable consequences after the consumption of supposedly "safe" food. The aim of the present study was to eliminate harmful traces of peanut allergens from food using purified clinoptilolite-tuff (PCT)-a specially processed zeolite material. Analyses were performed using a peanut ELISA and a Coomassie blue (Bradford) assay. Mimicking conditions of the human gastrointestinal tract demonstrated a higher efficacy of PCT in the intestine (pH 6.8) than in the stomach (pH 1.5). Adsorption rates were fast (<2 min) and indicated high capacities (23 µg and 40 µg per 1 mg of PCT at pH 1.5 and pH 6.8, respectively). Allergenically relevant peanut protein concentrations were sorbed in artificial fluids (32 µg/mL by 4 mg/mL of PCT at pH 1.5 and 80.8 µg/mL by 0.25 mg/mL of PCT at pH 6.8) when imitating a daily dose of 2 g of PCT in an average stomach volume of 500 mL. Experiments focusing on the bioavailability of peanut protein attached to PCT revealed sustained sorption at pH 1.5 and only minor desorption at pH 6.8. Accompanied by gluten, peanut proteins showed competing binding characteristics with PCT. This study therefore demonstrates the potential of PCT in binding relevant quantities of peanut allergens during the digestion of peanut-contaminated food.

Organic–Inorganic Composite Antifouling Coatings with Complementary Bioactive Effects

Traditional antifouling coatings are toxic to marine life, which makes developing new environmentally friendly marine antifouling coatings imperative. Antifouling coatings that are nonadhesive and antimicrobial may provide an effective approach to achieving this goal. In this study, an organic–inorganic composite coating consisting of fluorinated polyurethane (FPU) and carboxymethyl chitosan–zinc oxide (CMC–ZnO) was prepared to achieve antifouling. The coating took advantage of the complementary bioactive effects of the low surface energy of FPU and the antimicrobial properties of CMC–ZnO. The coating showed good antifouling performance, with a survival rate for Escherichia coli of 3.15% and that for Staphylococcus aureus of 3.97% and an anti-protein adsorption rate of more than 90%. This study provides a simple method for preparing antifouling coatings using nonpolluting raw materials with minimal adverse effects on marine environments.

Novel aerogel of aminated MXene composite orange peel biomass for ultra-high capacity of V(V) adsorption

Efficient and selective adsorption of V(V), pentavalent vanadium, from strategic polymetallic shale leaching solutions is crucial for resource utilization. However, the lack of a high-capacity adsorbent poses a significant challenge. Herein, we have successfully developed a novel composite adsorbent material by cross-linking orange peel biomass with aminated MXene, referred to as OPM. The incorporation of aminated MXene enhanced the availability of reactive groups within the material. The unique aerogel structure avoids the accumulation of MXene, thus improving the exposure of active sites. Furthermore, the positively charged surface of OPM enabled efficient adsorption of pentavalent vanadium ions. Experimental results showed that the adsorption of V(V) fitted well with the Langmuir adsorption isotherm model, and its adsorption rate was controlled by the pseudo-second-order kinetic mechanism. Remarkably, OPM exhibited a remarkable maximum adsorption capacity of 748.42 mg/g at pH=4. Even in the presence of interfering anions and cations, OPM maintains a high adsorption capacity for V(V).In the simulated wastewater adsorption experiment, the removal rate of V by the adsorbent exceeded 80 % After five cycles of adsorption, the material retains an adsorption capacity of more than 78 %. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy revealed that the adsorption mechanism of OPM on V(V) is attributed to the fact that OPM is protonated under acidic conditions and has strong electrostatic interactions with pentavalent vanadium anion, in which abundant hydroxyl and carboxyl groups can undergo ion-exchange reactions with vanadium anion. Meanwhile, the amino group reduces V(V) to V(IV) and forms a complex with the oxygen/nitrogen functional group. This study provides theoretical understanding and practical application for the synergistic adsorption of V(V) on aerogels prepared from MXene composite orange peel biomass.

Solar‐Driven Lithium Extraction by a Floating Felt

AbstractOceans/brine offers a massive supply of lithium sources that can support the renewable energy storage system. However, the current lithium extraction processes from seawater are complicated for scalable production. Here, a high‐performance solar‐driven, direct lithium‐extraction felt (DEF) is developed. DEF consists of a reasonable addition of Li1.6Mn1.6O4 particles on polypropylene/polyethylene core‐sheath fibers, which are dark‐colored and can float on top of bodies of water. Compared with the conventional method, DEF shows improved Li‐ion adsorption rate and capacity by solar‐driven. Meanwhile, the fibers’ hydrophilicity promotes spontaneous upward transport of water/ions, avoiding concentration polarization. Even for the test using simulated seawater (≈100 kg) with low Li‐ion concentration outdoors, DEF demonstrates high efficiency under natural sunlight. DEF shows good salt‐rejection performance in outdoor real‐time evaporation experiments to ensure working stability. In addition, this method saves the steps of liquid storage, liquid transportation, and pump drive. This work provides an easy, highly efficient, and low‐cost strategy to extract lithium directly from seawater/brine with the assistance of solar energy.

Adsorption Behavior of Co2+, Ni2+, Sr2+, Cs+, and I- by Corrosion Products α-FeOOH from Typical Metal Tanks.

Throughout the nuclear power production process, the disposal of radioactive waste has consistently raised concerns about environmental safety. When the metal tanks used for waste disposal are corroded, radionuclides seep into the groundwater environment and eventually into the biosphere, causing significant damage to the environment. Hence, investigating the adsorption behavior of radionuclides on the corrosion products of metal tanks used for waste disposal is an essential component of safety and evaluation protocols at disposal sites. In order to understand the adsorption behavior of important radionuclides 60Co, 59Ni, 90Sr, 135Cs and 129I on α-FeOOH, the influences of different pH values, contact time, temperature and ion concentration on the adsorption rate were studied. The adsorption mechanism was also discussed. It was revealed that the adsorption of key nuclides onto α-FeOOH is significantly influenced by both pH and temperature. This change in surface charge corresponds to alterations in the morphology of nuclide ions within the system, subsequently impacting the adsorption efficiency. Sodium ions (Na+) and chlorate ions (ClO3-) compete for coordination with nuclide ions, thereby exerting an additional influence on the adsorption process. The XPS analysis results demonstrate the formation of an internal coordination bond (Ni-O bond) between Ni2+ and iron oxide, which is adsorbed onto α-FeOOH.

A Multifunctional Magnetic Fluorescent Nanoprobe for Copper(II) Using ZnS-DL-Mercaptosuccinic Acid-Modified Fe3O4 Nanocomposites

Cu2+ has increasingly become a great threat to the natural environment and human health due to its abundant content and wide application in various industries. DL-Mercaptosuccinic acid and ZnS-modified Fe3O4 nanocomposites were designed, synthesized, and applied in the determination of Cu2+. The prepared nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and thermogravimetric analyzer (TG). The magnetic fluorescent nanoprobe exhibited highly selective and sensitive fluorescence-quenching characteristics with Cu2+ ions. The fluorescence detection linear range was 0–400 μM, with the detection limit being 0.489 μM. In addition, the magnetic fluorescent nanoprobe exhibited a high adsorption and removal rate for Cu2+. It had been successfully applied to detect Cu2+ in real water samples with a satisfactory recovery rate. The magnetic fluorescent nanoprobe could simultaneously realize the functions of enrichment, quantitative detection, and separation, reduce the pollution of copper ions and probes, and establish an environment-friendly detection method. Consequently, the magnetic fluorescent nanoprobe offered a new pathway for the removal and detection of not only Cu2+ but also other heavy metal ions in water.

Colloidal and interfacial properties of spray dried pulse protein-blueberry polyphenol particles in model dispersion systems

The phytochemical composition and physicochemical attributes of polyphenol-enriched protein particle ingredients produced with pulse proteins (e.g. chickpea protein, pea protein, and a chickpea-pea protein blend) and polyphenols recovered from wild blueberry pomace were investigated for colloidal and interfacial properties. Anthocyanins were the major polyphenol fraction (27.74–36.47 mg C3G/g) of these polyphenol-rich particles (44.95–62.08 mg GAE/g). Dispersions of pea protein-polyphenol particles showed a superior phase stability before and after heat treatment compared to the chickpea pea protein-polyphenol system. This observation was independent of the added amount of NaCl in the dispersion. In general, at quasi equilibrium state, pulse protein-polyphenol particles and parental pulse protein ingredients showed similar oil-water interfacial tension. However, pea protein-polyphenol particles demonstrated a reduced diffusion-driven oil-water interfacial adsorption rate constant compared to the parental pea protein ingredient. Overall, the obtained results suggest application potential of pea protein-polyphenol particles as a functional food/beverage ingredient.

The galactomannan-EGCG physical complex: Effect of branching degree and molecular weight on structural and physiological properties

The galactomannan-EGCG physical complex: Effect of branching degree and molecular weight on structural and physiological properties

Adsorption behavior of triazine pesticides on polystyrene microplastics aging with different processes in natural environment

The presence of microplastics in the ecological environment, serving as carriers for other organic pollutants, has garnered widespread attention. These microplastics exposed in the environment may undergo various aging processes. However, there is still a lack of information regarding how these aged microplastics impact the environmental behavior and ecological toxicity of pollutants. In this study, we modified polystyrene microplastics by simulating the aging behavior that may occur under environmental exposure, and then explored the adsorption behavior and adsorption mechanism of microplastics before and after aging for typical triazine herbicides. It was shown that all aging treatments of polystyrene increased the adsorption of herbicides, the composite aged microplastics had the strongest adsorption capacity and the fastest adsorption rate, and of the three herbicides, metribuzin was adsorbed the most by microplastics. The interactions between microplastics and herbicides involved mechanisms such as hydrophobic interactions, surface adsorption, the effect of π-π interactions, and the formation of hydrogen bonds. Further studies confirmed that microplastics adsorbed with herbicides cause greater biotoxicity to E. coli. These findings elucidate the interactions between microplastics before and after aging and triazine herbicides. Acting as carriers, they alter the environmental behavior and ecological toxicity of organic pollutants, providing theoretical support for assessing the ecological risk of microplastics in water environments.

Design and preparation of a novel Mg-Al LDH@EDTA-Melamine nanocomposite for effective adsorptive removal of methylene blue and rhodamine B dyes from water

This paper deals with the preparation of a novel nanocomposite consisted of magnesium-aluminum layered double hydroxide (Mg-Al LDH) and ethylenediaminetetraacetic acid (EDTA) as well as melamine (MA) as an adsorbent. This nanocomposite was utilized to adsorb different dyes such as rhodamine B (RhB) and methylene blue (MB) from water. The prepared adsorbent was characterized using FT-IR, EDS, XRD, TGA, and FE-SEM analyses. The effects of various parameters such as concentration, time, adsorbent dosage, temperature, and pH were tested to investigate their influence on adsorption conditions. Both methylene blue and rhodamine B dyes showed pseudo-second-order adsorption kinetics, and their adsorption followed the Langmuir isotherm. Moreover, the maximum adsorption capacities for methylene blue and rhodamine B were found to be 1111.103 mg/g at 45 °C and 232.558 mg/g at 60 °C, respectively. Additionally, the adsorption processes were found to be spontaneous (ΔG°< 0, for both dyes) and exothermic (ΔH°= -12.42 KJ/mol for methylene blue and ΔH°= -25.84 KJ/mol for rhodamine B) for both dyes. Hydrogen bonding and electrostatic forces are responsible for the interactions occur between the nanocomposite and the functional groups in the dyes. The experimental findings demonstrated a greater adsorption rate of MB than RhB, suggesting the adsorbent's stronger affinity for MB. This preference is likely due to MB's size, specific functional groups, and smaller molecule size, enabling stronger interactions and more efficient access to adsorption sites compared to RhB. Even after recycling 4 times, the dye adsorption percentages of the adsorbent for MB and RhB dyes were 90% and 87%, but the desorption percentages of the adsorbate dyes were 85% and 80%, respectively. The prepared adsorbent boasts several unique properties, such as the swift and effortless adsorption of MB and RhB dyes, straightforward synthesis, mild adsorption conditions, remarkable efficiency, and the ability to be recycled up to 4 times without a significant decrease in activity.

Water-bearing properties of high rank coal reservoir and the effect on multiphase methane

Coal reservoirs commonly exhibit the coexistence of gas and water, wherein the distribution of water plays a crucial role in influencing methane storage and transportation. The presence of water affects methane adsorption, and models predicting adsorbed methane that do not account for water conditions can introduce errors, posing challenges in meeting practical production needs. In this study, through a series of centrifugation experiments and nuclear magnetic resonance (NMR) adsorption experiments, the distribution characteristics of bound water and movable water in reservoirs and their influence on multiphase methane were assessed. The results indicate that under water-bearing conditions, there exists specific methane in the adsorption space, exhibiting properties similar to free methane. In terms of the relaxation characteristics, the presence of water affects both the peak area and morphology of the T2 spectra of multiphase methane. Based on the NMR response characteristics of adsorbed methane at different water saturations, we proposed and established a theoretical model for predicting the content and density of adsorbed methane under varying water saturations. Additionally, utilizing two-dimensional NMR technology, a simple identification spectrum for multiphase methane was established. The study suggests that the presence of water delays the time of adsorption equilibrium for methane. At low water saturations, water primarily inhibits the adsorption rate of methane. However, with increasing pressure and water saturation, water predominantly suppresses the adsorption capacity of methane. At low water saturations, the bound water has a significant effect on adsorbed methane. Conversely, as water saturations increase, movable water gradually occupies adsorption sites with weaker adsorption potential. It is worth noting that with an increase in water saturation, the content of adsorbed methane decreases, but the adsorption phase density may not necessarily decrease. These research findings provide new insights into the interaction mechanisms between water and methane in water-bearing coal reservoirs.

Cellulose acetate/chitosan composite film loaded with ground cinnamon for active packaging: water vapor sorption kinetic, compounds release, and antimicrobial effect

This study evaluated structural, physical, and water sorption properties of cellulose acetate/chitosan composite film incorporated with ground cinnamon as an antimicrobial. The controlled release of antimicrobial compounds and antimicrobial effects on Escherichia coli and Staphylococcus aureus were also monitored. The composite film formed highly porous and fibrous materials with higher thermal resistance. A higher ratio of chitosan in the film improved the swelling degree and water-vapor absorption capacity but reduced adsorption rates. Consequently, antimicrobial compounds, including eucalyptol, naphthalene, and β-caryophyllene, were more quickly released from the composite film with a larger chitosan ratio, affecting stronger antimicrobial effects. The inclusion of ground cinnamon with residual fat content in the film contributed to an extended inhibition of microbial growth in an indirect packaging system. Understanding the chitosan/cellulose acetate ratio in the film composite formation and the incorporation of ground cinnamon is important to control the compounds' release and generate long-term antimicrobial effects of active packaging materials on fresh food products.

Preparation of composites with MgAl-LDH-modified commercial activated carbon for the quick removal of Cr(VI) from aqueous solutions.

The problem of soil and water contamination caused by Cr(VI) discharged from the dyeing, electroplating, and metallurgical industries is becoming increasingly serious, posing a potentially great threat to the environment and public health. Therefore, it is crucial to develop a fast, efficient, and cost-effective adsorbent for remediating Cr-contaminated wastewater. In this work, MgAl-LDH/commercial-activated carbon nanocomposites (LDH-CACs) are prepared with hydrothermal. The effects of preparation and reaction conditions on the composite properties are first investigated, and then its adsorption behavior is thoroughly explored. Finally, a potential adsorption mechanism is proposed by several characterizations like SEM-EDS, XRD, FTIR, and XPS. The removal of Cr(VI) reaches 72.47% at optimal conditions, and the adsorption study demonstrates that LDH-CAC@1 has an extremely rapid adsorption rate and a maximum adsorption capacity of 116.7 mg/g. The primary removal mechanisms include adsorption-coupled reduction, ion exchange, surface precipitation, and electrostatic attraction. The reusability experiment illustrates that LDH-CAC@1 exhibits promising reusability. This study provides an effective adsorbent with a remarkably fast reaction, which has positive environmental significance for the treatment of Cr(VI) wastewater.

Effects of straw management and N levels on gross nitrogen transformations in fluvo-aquic soil of the North China Plain

Straw incorporation with nitrogen (N) fertilization is crucial for enhancing soil fertility and minimizing negative environmental impacts by altering the magnitude and direction of soil N transformation processes. However, the response of soil N transformations to long-term carbon (C) and N inputs, and their primary driving factors, remain poorly understood. Thus, a 15N tracing study was conducted to investigate the effects of straw incorporation (AS) and straw removal (NS) with N levels of 0, 150 and 250 kg N ha−1 per season (N0, N150 and N250) on gross N transformation rates in the North China Plain after 6-year trial. Results indicated that at N0, AS significantly increased soil microbial immobilization of nitrate (NO3−-N, INO3) and autotrophic nitrification rates (ONH4) compared to NS. With N fertilization, AS increased gross N immobilization (Itotal), ammonium-N immobilization (NH4+-N, INH4), net NH4+-N immobilization (InetNH4) and net NH4+-N absorption rates (AnetNH4). Specifically, at N150, AS significantly increased recalcitrant organic N mineralization rate (MNrec), while significantly reducing ONH4, labile organic N mineralization (MNlab), and gross N mineralization rates (Mtotal). At N250, AnetNH4, MNlab, MNrec and ONH4 under AS were significantly higher than under NS. Nitrogen application significantly increased ONH4, Itotal and INO3 under two straw management practices, and enhanced INH4 and InetNH4 under AS. Compared to N250, N150 significantly increased INH4 and InetNH4 under AS, while decreasing Mtotal. Opposite results were observed under NS. Meanwhile, NO3−-N and dissolved organic carbon (DOC) were master factors controlling immobilization, total nitrogen (TN), hydrolysable NH4+-N (HNN) and stable organic N significantly affected AnetNH4, while labile organic N were the key environmental factors affecting MNrec, all of which positively influenced the rates of assimilation, mineralization and clay mineral adsorption. Overall, this study provides new insights into reducing N fertilization under straw incorporation by quantifying soil N transformation processes.

Simultaneously enhancing toluene adsorption and regeneration process by hierarchical pore in activated coke: a combined experimental and adsorption kinetic modeling study.

Activated coke is a type of commonly used adsorbent for benzene series VOCs such as toluene, but traditional microporous activated coke usually faces the challenge of poor regeneration performance. Herein, based on self-made activated cokes with typical pore configuration, we found that adsorption and regeneration of toluene can be simultaneously enhanced by constructing hierarchical pore in activated coke. Correlations of pore configuration with toluene adsorption capacity and regeneration efficiency reveal that micropore contributes for strong toluene adsorption; meso-macropore provides mass transfer channel for toluene desorption and regeneration process. Hierarchical porous activated coke prepared from Zhundong subbituminous coal not only achieves the highest toluene adsorption capacity of 340.92mg·g-1, but also can retain more than 90% of initial adsorption capacity after five adsorption-regeneration cycles. By contrast, micropore-dominant activated cokes can only retain 70% of initial adsorption capacity. Adsorption kinetic modelling on adsorption breakthrough curves shows that hierarchical porous activated coke prepared from Zhundong subbituminous coal exhibits high adsorption and diffusion rate constants of 14.39 and 33.45min-1, respectively, much higher than those of micropore-dominant activated cokes. Due to the accelerated surface adsorption and diffusion processes induced by meso-macropore, toluene adsorption and regeneration behavior can be simultaneously improved. Results from this work validated the role of pore hierarchy in toluene adsorption-regeneration process, providing guidance for designing high-performance activated coke with synergistically improved toluene adsorption capacity and regeneration performance.

Effects of the Indirect Correlations of Interacting Particles on the Mono- and Bimolecular Adsorption and Desorption Rates during Chemisorption

Effects of the Indirect Correlations of Interacting Particles on the Mono- and Bimolecular Adsorption and Desorption Rates during Chemisorption

Achieving Molecular Sieving of CO2 from CH4 by Controlled Dynamical Movement and Host-Guest Interactions in Ultramicroporous VOFFIVE-1-Ni by Pillar Substitution.

Engineering the building blocks in metal-organic materials is an effective strategy for tuning their dynamical properties and can affect their response to external guest molecules. Tailoring the interaction and diffusion of molecules into these structures is highly important, particularly for applications related to gas separation. Herein, we report a vanadium-based hybrid ultramicroporous material, VOFFIVE-1-Ni, with temperature-dependent dynamical properties and a strong affinity to effectively capture and separate carbon dioxide (CO2) from methane (CH4). VOFFIVE-1-Ni exhibits a CO2 uptake of 12.08 wt % (2.75 mmol g-1), a negligible CH4 uptake at 293 K (0.5 bar), and an excellent CO2-over-CH4 uptake ratio of 2280, far exceeding that of similar materials. The material also exhibits a favorable CO2 enthalpy of adsorption below -50 kJ mol-1, as well as fast CO2 adsorption rates (90% uptake reached within 20 s) that render the hydrolytically stable VOFFIVE-1-Ni a promising sorbent for applications such as biogas upgrading.