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International Journal of Molecular... Jan 2024Both cyclodextrin (CD) and porous silica possess interesting properties of adsorption and release. A silica-CD hybrid, therefore, could synergically merge the properties...
Both cyclodextrin (CD) and porous silica possess interesting properties of adsorption and release. A silica-CD hybrid, therefore, could synergically merge the properties of the two components, giving rise to a material with appealing properties for both environmental and pharmaceutical applications. With this aim, in the present study, a first hybrid is obtained through one-pot sol-gel synthesis starting from CD and tetramethyl orthosilicate (TMOS) as a silica precursor. In particular, methyl-β-cyclodextrin (bMCD) is selected for this purpose. The obtained bMCD-silica hybrid is a dense material containing a considerable amount of bMCD (45 wt.%) in amorphous form and therefore represents a promising support. However, since a high specific surface area is desirable to increase the release/adsorption properties, an attempt is made to produce the hybrid material in the form of an aerogel. Both the synthesis of the gel and its drying in supercritical CO are optimized in order to reach this goal. All the obtained samples are characterized in terms of their physico-chemical properties (infra-red spectroscopy, thermogravimetry) and structure (X-ray diffraction, electron microscopy) in order to investigate their composition and the interaction between the organic component (bMCD) and the inorganic one (silica).
Topics: Cyclodextrins; Adsorption; Desiccation; Physiological Phenomena; Silicon Dioxide
PubMed: 38256180
DOI: 10.3390/ijms25021108 -
Water Research Oct 2023The removal of micropollutants from wastewater by constructed wetlands (CWs) has been extensively studied and reviewed over the past years. However, most studies do not... (Review)
Review
The removal of micropollutants from wastewater by constructed wetlands (CWs) has been extensively studied and reviewed over the past years. However, most studies do not specifically focus on the removal of micropollutants from the effluent of conventional wastewater treatment plants (WWTP) that still contains micropollutants, but on the removal of micropollutants from raw wastewater. Raw wastewater has a significantly different composition compared to WWTP effluent, which positively or negatively affects micropollutant removal mechanisms. To determine the optimal CW design for post-treatment of WWTP effluent to achieve additional micropollutant removal, this review analyzes the removal of 16 Dutch indicator micropollutants for post-treatment technology evaluation from WWTP effluent by different types of CWs. It was concluded that CW systems with organic enhanced adsorption substrates reach the highest micropollutant removal efficiency as a result of adsorption, but that the longevity of the enhanced adsorption effect is not known in the systems studied until now. Aerobic biodegradation and photodegradation are other relevant removal mechanisms for the studied micropollutants. However, a current knowledge gap is whether active aeration to stimulate the aerobic micropollutant biodegradation results in an increased micropollutant removal from WWTP effluent. Further knowledge gaps that impede the wider application of CW systems for micropollutant removal from WWTP effluent and allow a fair comparison with other post-treatment technologies for enhanced micropollutant removal, such as ozonation and activated carbon adsorption, relate to i) saturation of enhanced adsorption substrate; ii) the analysis of transformation products and biological effects; iii) insights in the relationship between microbial community composition and micropollutant biodegradation; iv) plant uptake and in-plant degradation of micropollutants; v) establishing design rules for appropriate hydraulic loading rates and/or hydraulic retention times for CWs dedicated to micropollutant removal from WWTP effluent; and vi) the energy- and carbon footprint of different CW systems. This review finishes with detailed suggestions for future research directions that provide answers to these knowledge gaps.
Topics: Wastewater; Wetlands; Adsorption; Biodegradation, Environmental; Biological Transport
PubMed: 37659177
DOI: 10.1016/j.watres.2023.120534 -
Journal of Chemical Information and... Jan 2024Catalyst screening is a critical step in the discovery and development of heterogeneous catalysts, which are vital for a wide range of chemical processes. In recent...
Catalyst screening is a critical step in the discovery and development of heterogeneous catalysts, which are vital for a wide range of chemical processes. In recent years, computational catalyst screening, primarily through density functional theory (DFT), has gained significant attention as a method for identifying promising catalysts. However, the computation of adsorption energies for all likely chemical intermediates present in complex surface chemistries is computationally intensive and costly due to the expensive nature of these calculations and the intrinsic idiosyncrasies of the methods or data sets used. This study introduces a novel machine learning (ML) method to learn adsorption energies from multiple DFT functionals by using invariant molecular representations (IMRs). To do this, we first extract molecular fingerprints for the reaction intermediates and later use a Siamese-neural-network-based training strategy to learn invariant molecular representations or the IMR across all available functionals. Our Siamese network-based representations demonstrate superior performance in predicting adsorption energies compared with other molecular representations. Notably, when considering mean absolute values of adsorption energies as 0.43 eV (PBE-D3), 0.46 eV (BEEF-vdW), 0.81 eV (RPBE), and 0.37 eV (scan+rVV10), our IMR method has achieved the lowest mean absolute errors (MAEs) of 0.18 0.10, 0.16, and 0.18 eV, respectively. These results emphasize the superior predictive capacity of our Siamese network-based representations. The empirical findings in this study illuminate the efficacy, robustness, and dependability of our proposed ML paradigm in predicting adsorption energies, specifically for propane dehydrogenation on a platinum catalyst surface.
Topics: Cattle; Animals; Catalysis; Adsorption; Machine Learning; Neural Networks, Computer
PubMed: 38197612
DOI: 10.1021/acs.jcim.3c00594 -
Journal of the Mechanical Behavior of... Oct 2023Biological composites incorporate structural arrays of rigid-elastic reinforcements made of minerals or crystalline biopolymers, which are connected by thin, compliant,...
Biological composites incorporate structural arrays of rigid-elastic reinforcements made of minerals or crystalline biopolymers, which are connected by thin, compliant, and viscoelastic macromolecular matrix material. The near-interface regions of these biological composites grant them energy dissipation capabilities against dynamic mechanical loadings, which promote various biomechanical functions such as impact adsorption, fracture toughness, and mechanical signal filtering. Here, we employ theoretical modeling and finite-element simulations to analyze the mechanical response of the near-interface in biological composites to nanoscale dynamic mechanical analysis (DMA). We identified the dominating load-bearing mechanisms of the near-interface region and employed these insights to introduce simple semi-empirical formulations for approaching the mechanical properties (storage and loss moduli) of the biological composite from the nanoscale DMA results. Our analysis paves the way for the nanomechanical characterization of biological composites in diverse natural materials systems, which can also be employed for bioinspired and biomedical configurations.
Topics: Humans; Adsorption; Fractures, Bone; Weight-Bearing
PubMed: 37672957
DOI: 10.1016/j.jmbbm.2023.106091 -
Waste Management (New York, N.Y.) Apr 2024In line with the objectives of the circular economy, the conversion of waste streams to useful and valuable side streams is a central goal. Ash represents one of the... (Review)
Review
In line with the objectives of the circular economy, the conversion of waste streams to useful and valuable side streams is a central goal. Ash represents one of the main industrial side-products, and using ashes in other than the present landfilling applications is, therefore, a high priority. This paper reviews the properties and utilization of ashes of different biomass power plants and waste incinerations, with a focus on the past decade. Possibilities for ash utilization are of uttermost importance in terms of circular economy and disposal of landfills. However, considering its applicability, ash originating from the heat treatment of chemically complex fuels, such as biomass and waste poses several challenges such as high heavy metal content and the presence of toxic and/or corrosive species. Furthermore, the physical properties of the ash might limit its usability. Nevertheless, numerous studies addressing the utilization possibilities of challenging ash in various applications have been carried out over the past decade. This review, with over 300 references, surveys the field of research, focusing on the utilization of biomass and municipal solid waste (MSW) ashes. Also, metal and phosphorus recovery from different ashes is addressed. It can be concluded that the key beneficial properties of the ash types addressed in this review are based on their i) alkaline nature suitable for neutralization reactions, ii) high adsorption capabilities to be used in CO capture and waste treatment, and iii) large surface area and appropriate chemical composition for the catalyst industry. Especially, ashes rich in AlO and SiO have proven to be promising alternative catalysts in various industrial processes and as precursors for synthetic zeolites.
Topics: Silicon Dioxide; Adsorption; Biomass; Incineration; Industry
PubMed: 38342059
DOI: 10.1016/j.wasman.2024.01.051 -
Environmental Research Sep 2023Seaweed, one of the most abundant biomaterials, can be used as a biosorbent to remove organic micropollutants. In order to effectively use seaweed to remove a variety of...
Seaweed, one of the most abundant biomaterials, can be used as a biosorbent to remove organic micropollutants. In order to effectively use seaweed to remove a variety of micropollutants, it is vital to rapidly estimate the adsorption affinity according to the types of micropollutants. Thus, the isothermal adsorption affinities of 31 organic micropollutants in neutral or ionic form on seaweed were measured, and a predictive model using quantitative structure-adsorption relationship (QSAR) modeling was developed. As a result, it was found that the types of micropollutants had a significant effect on the adsorption of seaweed, as expected, and QSAR modeling with a predictability (R) of 0.854 and a standard error (SE) of 0.27 log units using a training set could be developed. The model's predictability was internally and externally validated using leave-one-out cross validation and a test set. Its predictability for the external validation set was R = 0.864, SE = 0.171 log units. Using the developed model, we identified the most important driving forces of the adsorption at the molecular level: Coulomb interaction of the anion, molecular volume, and H-bond acceptor and donor, which significantly affect the basic momentum of molecules on the surface of seaweed. Moreover, in silico calculated descriptors were applied to the prediction, and the results revealed reasonable predictability (R of 0.944 and SE of 0.17 log units). Our approach provides an understanding of the adsorption process of seaweed for organic micropollutants and an efficient prediction method to estimate the adsorption affinities of seaweed and micropollutants in neutral and ionic forms.
Topics: Adsorption; Quantitative Structure-Activity Relationship; Seaweed; Water Pollutants, Chemical; Anions
PubMed: 37290627
DOI: 10.1016/j.envres.2023.116349 -
Environmental Technology Aug 2023HighlightsVictorian lignites were assessed for their retention capacity using adsorption isotherms and N tracing. adsorption capacity of lignites increased (up to...
HighlightsVictorian lignites were assessed for their retention capacity using adsorption isotherms and N tracing. adsorption capacity of lignites increased (up to 3-fold) with pH, especially from pH 5 to 7.Biological immobilisation did not play a substantial role in the retention capacity of the lignites.pH-dependent adsorption was the dominant means by which lignite retained .
Topics: Ammonium Compounds; Coal; Nitrogen; Manure; Adsorption
PubMed: 35225754
DOI: 10.1080/09593330.2022.2048315 -
International Journal of Biological... Jan 2024Combining adsorption with other technologies holds great potential in fast and deep arsenic ion removal. Herein, chitosan‑zirconium composite adsorptive membranes...
Combining adsorption with other technologies holds great potential in fast and deep arsenic ion removal. Herein, chitosan‑zirconium composite adsorptive membranes (CS-Zr CM) were successfully prepared using simple casting and sodium hydroxide coagulation strategies, which was demonstrated the use in arsenic ion-capture electrodialysis based on their good adsorption performance. In the batch adsorption tests, the maximum adsorption capacities of CS-Zr CM for As(III) and As(V) were 134.2 mg/g and 119.5 mg/g, respectively. CS-Zr CM also exhibited satisfying adsorption selectivity and good reusability toward As(III) and As(V). However, the adsorption kinetics showed that they needed 48 h to reach the adsorption equilibrium and the adsorption ability toward trace arsenic ion was ineffective. Furthermore, CS-Zr CM was applied as the adsorptive membrane in the electrodialysis process. Under the influence of electric field, the As(III) and As(V) removal equilibrium time was shortened to 12 h and the concentrations of As(III) and As(V) ions could be efficiently reduced to below the WHO limit in drinking water (10 μg/L), which far surpassed the physicochemical adsorption method. Such good arsenic ion removal ability of CS-Zr CM together with the ease scalable fabrication, low cost, and biodegradable properties shows its huge prospects in arsenic-containing wastewater treatment.
Topics: Arsenic; Zirconium; Chitosan; Adsorption; Water Pollutants, Chemical; Hydrogen-Ion Concentration; Water Purification; Kinetics
PubMed: 37995789
DOI: 10.1016/j.ijbiomac.2023.128356 -
The Science of the Total Environment Mar 2024Global water quality has deteriorated, leaving over 844 million individuals without access to clean drinking water. While sand filters (SF) offer a solution, their... (Review)
Review
Global water quality has deteriorated, leaving over 844 million individuals without access to clean drinking water. While sand filters (SF) offer a solution, their limited surface area and adsorption capacity for emerging contaminants remain a challenge. This has prompted the development of new materials such as graphene-coated sand (GCS) to enhance the sand's adsorptive properties. Notably, GCS also possesses inherent anti-bacterial properties and can function as a photocatalyst when exposed to UV and visible light, offering enhanced water purification. This manuscript 1) reviews the synthesis of GCS, detailing the characterization techniques employed to understand its structure, composition, and multifunctional properties and 2) highlights the superior efficacy of GCS in removing contaminants, including metals (>95 % removal of Cd, Pb, Zn, and Cu in low pH environment), sulfides (full removal compared to 26 % removal by raw sand), antibiotics (98 % removal of tetracycline), and bacteria (complete cell membrane destruction), compared to traditional SF. Due to its enhanced performance and multifaceted purification capabilities, GCS presents a promising alternative to SFs, especially in developing countries, aiming to improve water quality and ensure safe drinking water access. To the best of our knowledge, no other work groups the available research on GCS. Furthermore, future research directions should focus on reducing the overall production cost of GCS, exploring surface modification techniques, and expanding the range of contaminants tested by GCS, to fully realize its potential in water purification.
Topics: Humans; Graphite; Drinking Water; Metals; Water Purification; Adsorption; Water Pollutants, Chemical
PubMed: 38232845
DOI: 10.1016/j.scitotenv.2024.170107 -
Environmental Science & Technology Oct 2023Nitrate-to-ammonia electrochemical conversion is important for decreasing water pollution and increasing the production of valuable ammonia. However, achieving high...
Nitrate-to-ammonia electrochemical conversion is important for decreasing water pollution and increasing the production of valuable ammonia. However, achieving high ammonium production without undesirable byproducts is difficult. Cu-doped MIL-88-derived bimetallic oxide catalysts with electrocatalytically active Fe-O-Cu bridges, which have high NO adsorption energy and facilitate N-intermediate hydrogenation, are developed for NH production. Cu doping promotes hybridization between the O 2p of NO and Fe-Cu 3d, facilitating the adsorption and reduction of NO with a low Tafel slope (62.1 mV dec) and high ammonia yield (1698.8 μg·h·cm). The cathode efficiency is stable for seven cycles. Cu adjacent to Fe sites inhibits hydrogen evolution, promotes NO adsorption, and decreases the intermediate adsorption energy barrier. This study provides new opportunities for fabricating diverse binary metal oxides with new interfaces as efficient cathode materials for selective electroreduction.
Topics: Nitrates; Ammonia; Catalytic Domain; Adsorption; Oxides
PubMed: 37865968
DOI: 10.1021/acs.est.3c05606