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International Journal of Molecular... Jul 2023Over the past two decades, there has been increasing interest in the use of low-cost and effective sorbents in water treatment. Hybrid chitosan sorbents are potential... (Review)
Review
Over the past two decades, there has been increasing interest in the use of low-cost and effective sorbents in water treatment. Hybrid chitosan sorbents are potential materials for the adsorptive removal of phosphorus, which occurs in natural waters mainly in the form of orthophosphate(V). Even though there are numerous publications on this topic, the use of such sorbents in industrial water treatment and purification is limited and controversial. However, due to the explosive human population growth, the ever-increasing global demand for food has contributed to the consumption of phosphorus compounds and other biogenic elements (such as nitrogen, potassium, or sodium) in plant cultivation and animal husbandry. Therefore, the recovery and reuse of phosphorus compounds is an important issue to investigate for the development and maintenance of a circular economy. This paper characterizes the problem of the presence of excess phosphorus in water reservoirs and presents methods for the adsorptive removal of phosphate(V) from water matrices using chitosan composites. Additionally, we compare the impact of modifications, structure, and form of chitosan composites on the efficiency of phosphate ion removal and adsorption capacity. The state of knowledge regarding the mechanism of adsorption is detailed, and the results of research on the desorption of phosphates are described.
Topics: Humans; Phosphates; Chitosan; Wastewater; Phosphorus; Adsorption; Water Purification; Water Pollutants, Chemical; Hydrogen-Ion Concentration; Kinetics
PubMed: 37569435
DOI: 10.3390/ijms241512060 -
Journal of the Air & Waste Management... Oct 2023To explore the characteristic of competitive adsorption of formaldehyde (HCHO) and benzene(CH) on activated carbon, the slit models of activated carbon with different...
To explore the characteristic of competitive adsorption of formaldehyde (HCHO) and benzene(CH) on activated carbon, the slit models of activated carbon with different pore sizes of 1 nm, 2 nm and 4 nm were constructed by using the Visualizer module of Materials Studio molecular simulation software. The adsorption of single-component CH and HCHO at three different temperatures of 288.15K,293.15K and 323.15K were conducted by the method of grand canonical Monte Carlo. Experiments were carried out to verify the accuracy of simulation results. For the single-compound adsorption, the adsorption amount of CH varied little at different temperature conditions, while the pore size had a significant effect on the adsorption amount of CH, and the adsorption capability increased as the pore size goes up. The adsorption capacity of HCHO decreased as the temperature goes up, and the adsorption capacity of both 1 nm and 4 nm pore size activated carbon was less than that of 2 nm pore size. As for the competitive adsorption, HCHO has a better adsorption effect by activated carbon when the pore is in small size like 1 nm, while the competitive adsorption ability of CH is much better than HCHO as the pore size goes up to 2 nm or 4 nm.: (1) Understanding the equilibrium process of activated carbon adsorption at the molecular level based on the co-existence of multi-component VOCs. (2) The effects of concentration, temperature and humidity factors on the coupling of the dynamic equilibrium of competing adsorption of benzene and formaldehyde were analyzed. (3) The accuracy of the molecular simulations was verified using an experimental approach.
Topics: Charcoal; Adsorption; Benzene; Computer Simulation; Formaldehyde
PubMed: 37610379
DOI: 10.1080/10962247.2023.2249204 -
Journal of Molecular Graphics &... Dec 2023N-Nitrosodimethylamine (NDMA, ONN(CH)) is a highly potent carcinogenic investigated by health authorities in some countries. In this manuscript, density functional...
N-Nitrosodimethylamine (NDMA, ONN(CH)) is a highly potent carcinogenic investigated by health authorities in some countries. In this manuscript, density functional theory (DFT) is applied to study the NDMA molecular and dissociative adsorption on a Ni nanocluster. Molecular adsorption is two times stronger than the NDMA adsorption on the Ni{111} surface. NDMA dissociative adsorption is found more stable than molecular adsorption by ≈1 eV. To dissociate the NDMA molecule into O and NN(CH) fragments, an activation energy is calculated in 0.954 and 0.810 eV from the two most stable molecular configurations. However, to dissociate the NDMA molecule into ON and N(CH) fragments, a smaller activation energy of 0.654 eV is calculated. With the inclusion of the London dispersion forces (optB88-vdW functional), NDMA molecular interactions are a bit stronger. However, the activation energies are slightly smaller. Meta-GGA functional SCAN has also, been applied. The inclusion of the implicit solvation model displays a NDMA weaker interaction with the Ni nanocluster. Dissociative adsorption is more stable than molecular adsorption, but the energy difference is a bit smaller, ≈0.850 eV. Present results show that the Ni nanoclusters are promising catalysts to NDMA elimination from water.
Topics: Dimethylnitrosamine; Adsorption; Water; Water Pollutants, Chemical
PubMed: 37552910
DOI: 10.1016/j.jmgm.2023.108578 -
Food Chemistry Jul 2023Native starches have low water solubility at room temperature and poor stability, which demand modifications to overcome. Porous starch as a modified one shows enhanced... (Review)
Review
Native starches have low water solubility at room temperature and poor stability, which demand modifications to overcome. Porous starch as a modified one shows enhanced adsorptive efficiency and solubility compared with its native starch. In contrast, some inherent disadvantages exist, such as weak mechanical strength and low thermal resistance. Fortunately, modified porous starches have been developed to perform well in adsorption capacity and stability. Modified porous starch can be prepared by esterification, crosslinking, oxidation and multiple modifications to the porous starch. The characterization of modified porous starch can be achieved through various analytical techniques. Modified porous starch can be utilized as highly efficient adsorbents and encapsulants for various compounds and applied in various fields. This review dealt with the progress in the preparation, structural characterization and application of modified porous starch. The objective is to provide a reference for its development, utilization, and future research directions.
Topics: Starch; Porosity; Solubility; Adsorption; Oxidation-Reduction
PubMed: 36854239
DOI: 10.1016/j.foodchem.2023.135765 -
Environmental Monitoring and Assessment Oct 2023Calix[4]arene/polyurethane (C4PU) has been synthesized and characterized as an alternative adsorbent for the adsorption of methylene blue (MB) and malachite green (MG)...
Calix[4]arene/polyurethane (C4PU) has been synthesized and characterized as an alternative adsorbent for the adsorption of methylene blue (MB) and malachite green (MG) dyes from the aqueous solution. C4PU was synthesized by reacting p-tert-butyl calix[4]arene with hexamethylene diisocyanate (HMDI) as the cross-linking agent. Different polymer ratios were synthesized, and C4PU-4 shows better adsorption than other ratios. The polymer was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) analysis, and point of zero charges (pH). The isotherms and kinetics of the adsorption of MB and MG were studied under a range of experimental conditions, including pH, adsorbent dosage, initial dye concentration, and contact time. The adsorption was determined by the adsorption percentage of MB and MG dyes from the solution. The Langmuir isotherm model best describes the adsorption process for both dyes, and it follows a pseudo-second-order kinetic model, with the maximum adsorption capacity (q) of MB and MG, respectively, was found to be 1.991 mg·g and 2.240 mg·g.
Topics: Coloring Agents; Polyurethanes; Adsorption; Environmental Monitoring; Methylene Blue; Kinetics; Hydrogen-Ion Concentration; Water Pollutants, Chemical; Spectroscopy, Fourier Transform Infrared
PubMed: 37828347
DOI: 10.1007/s10661-023-11909-z -
Environmental Research Sep 2023This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The...
This paper investigated the uptake of CIP and OFL in single and multicomponent adsorptive systems using modified carbon nanotubes (CNTs) as adsorbent material. The characterization analyses of the pre- and post-process material by XPS, TG/DTG, FT-IR, SEM/EDS, and XRD helped in the elucidation of the mechanisms, indicating greater involvement of n-n and π -π interactions. In the kinetic studies, the simple systems with CIP and OFL were similar, both showed equilibrium time around 20/30 min and increased adsorptive capacity with increasing initial drug concentration. In the multicomponent system, different fractions of CIP and OFL were tested and the time to reach equilibrium also varied between 20 and 30 min. In general, the adsorption capacity of CIP is slightly lower than that of OFL under the conditions tested. The selectivity analysis of the system showed that the selectivity's of the two drugs are identical in equimolar fractions. The mathematical modeling of the kinetic data indicated that in monocomponent systems, the model of pseudo-second order (PSO) adequately described both CIP and OFL kinetics. Furthermore, with the implementation of Artificial Neural Networks (ANN), it was possible to obtain a more assertive prediction of the behavior of single and binary systems.
Topics: Ofloxacin; Ciprofloxacin; Nanotubes, Carbon; Kinetics; Adsorption; Spectroscopy, Fourier Transform Infrared; Water Pollutants, Chemical
PubMed: 37356533
DOI: 10.1016/j.envres.2023.116503 -
Chemosphere Nov 2023In order to solve the problem of efficient desorption of per- and polyfluoroalkyl substances (PFAS) and regeneration of adsorbents, a novel biochar composite was...
In order to solve the problem of efficient desorption of per- and polyfluoroalkyl substances (PFAS) and regeneration of adsorbents, a novel biochar composite was prepared based on the quaternary ammonium groups and hydrophobicity of sulfobetaine polymer, which can be used for the efficient removal of various PFASs and has great regeneration ability. Through adsorption, regeneration and degradation experiment, the comprehensive effect of the novel biochar composite on the whole process of removal of PFAS was systematically investigated. The results showed that the maximum adsorption capacity of PFOS, PFOA, PFBS, and PFBA reached 634 mg/g, 536 mg/g, 301 mg/g and 264 mg/g, respectively. The adsorption process involved hydrophobicity, electrostatic, pore diffusion and complexation. The NaI + NaOH solution was used at 50 °C to achieve efficient regeneration of the adsorbent, which can be recycled more than 4 times. When the vacuum-ultraviolet (VUV)/sulfite reduction system was used for deep degradation of the regenerated solution, the effect of hydrated electrons on PFAS was enhanced due to the inclusion of NaI and NaOH in the regeneration reagent, resulting in an increase in the degradation efficiency (89.1%-99.9%) and defluorination efficiency (63.3%-84.1%). Based on the performance of BC-P(SB-co-AM) and the treatment efficiency of PFAS, the design idea of the whole process treatment technology of PFAS proposed in this work is expected to hold great promise in environmental applications. This work provides a novel idea and system for the efficient adsorption removal and desorption of PFAS, and subsequent deep degradation.
Topics: Adsorption; Sodium Hydroxide; Diffusion; Fluorocarbons
PubMed: 37660789
DOI: 10.1016/j.chemosphere.2023.140051 -
Environmental Science and Pollution... Nov 2023Palladium (Pd) is widely used in catalyst, aerospace, and medical applications, but only 1% of its reserves are found in nature. So, the recovery of Pd(II) is very...
Palladium (Pd) is widely used in catalyst, aerospace, and medical applications, but only 1% of its reserves are found in nature. So, the recovery of Pd(II) is very important. Natural fibers are a good adsorption material, and the abundant functional groups in bamboo shoot shell (BSS) fibers can form interactions with metal particles. However, few studies on Pd(II) adsorption using BSS fibers exist. In the present work, waste bamboo shoot shells were doped with titanium dioxide (TiO) particles, and the surface activation of BSS-TiO@CA by citric acid (CA) was carried out to prepare an efficient and recyclable adsorbent BSS-TiO@CA for the adsorption of Pd(II). The adsorption performance, adsorption mechanism, and regeneration performance of BSS-TiO@CA on Pd(II) were systematically analyzed by continuous adsorption experiments, characterization, and response surface method. It was found that the surface-activated waste bamboo shoot shells had an outstanding adsorption capacity of Pd(II), and the maximum adsorption rate of BSS-TiO@CA reached 85% with a maximum adsorption capacity (Q) of 175.74 mg/g. The functionalized use of waste bamboo shoot shells provides a new idea for the development of sustainable, cost-effective, and environmentally friendly adsorbents.
Topics: Palladium; Adsorption; Biomass; Titanium; Water Pollutants, Chemical
PubMed: 37848798
DOI: 10.1007/s11356-023-30377-z -
International Journal of Nanomedicine 2023Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields... (Review)
Review
Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe/Fe exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.
Topics: Iron; Metal-Organic Frameworks; Polymers; Adsorption; Anti-Bacterial Agents
PubMed: 37675409
DOI: 10.2147/IJN.S417543 -
The Science of the Total Environment Sep 2023Due to their high specific surface area (SSA), numerous active sites, and customizable pore structure, metal-organic frameworks (MOFs) have emerged as a popular topic in... (Review)
Review
Due to their high specific surface area (SSA), numerous active sites, and customizable pore structure, metal-organic frameworks (MOFs) have emerged as a popular topic in wastewater treatment research. Unfortunately, MOFs exist in the form of powder, which poses significant challenges such as difficult recycling and powder contamination in practical applications. Accordingly, for solid-liquid separation, the strategies of endowing magnetism and constructing appropriate device architectures are important. This review offers a detailed overview of the preparation strategies for recyclable MOFs-based magnetism and device materials and introduces the characteristics of these preparation methods through relevant instances. Besides, these two recyclable materials' applications and working mechanisms for removing pollutants from water through adsorption, advanced oxidation, and membrane separation technologies are introduced. The findings presented in this review will provide a valuable reference for the preparation of MOFs-based materials with excellent recyclability.
Topics: Metal-Organic Frameworks; Powders; Water Purification; Adsorption; Drug Contamination
PubMed: 37244622
DOI: 10.1016/j.scitotenv.2023.164345