Adsorption Properties Research Articles

Removal of Dyes from Waste Water Using Low‐Cost Adsorbents

AbstractThe principal objective of this article is a thorough analysis of the usage of inexpensive adsorbents to eliminate dyes from different aquatic environments. Dyes, commonly employed in industries—textiles, pharmaceuticals, and food, pose a significant environmental concern due to their persistence and potential toxicity. In response, researchers have explored the efficacy of low‐cost adsorbents (LCAs) as sustainable and economical alternatives for dye elimination. An overview of the environmental effects of dye contamination and the difficulties in using traditional dye removal techniques is given at the outset of the paper. It then delves into the diverse range of LCAs, including agricultural by‐products, waste materials, and natural substances, that have shown promise in adsorbing and eliminating dye contaminants. Examples of such adsorbents include activated carbon (AC) derived from agricultural residues, bio‐adsorbents from various plant materials, and industrial by‐products with inherent adsorption properties. Key mechanisms involved in the adsorption process, such as surface chemistry, pore structure, and electrostatic interactions, are elucidated to offer a fundamental understanding of the sorption capabilities of these materials. This comprehensive review consolidates the current knowledge on dye removal utilizing LCAs, offering insights into the challenges, advancements, and future directions in this environmentally significant field. The findings underscore the potential of harnessing readily available, sustainable materials as effective sorbents for mitigating the adverse impacts of dye pollutants in aqueous systems. The adsorption capacity is comparable to supplementary adsorbents suggested for the removal of dyes. The widely accessible adsorption properties of basic and acidic dyes do not significantly differ from one another.

Fabrication of surface functionalized QCM sensor for BTX detection at ambient conditions

Developing optimized gas sensors for detecting low concentrations of Benzene, Toluene, and Xylene (BTX) in ambient conditions is advantageous for health and environment monitoring applications. This study reports on the feasibility of using Quartz Crystals Microbalance (QCM) coated by Tungsten Oxide (WO3) to detect BTX compounds. A WO3 layer was deposited on the QCM surface using DC magnetron sputtering. Optical Profilometry (OP), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) were employed to analyze sensor surface morphology and structure. Adsorption properties were studied through the Langmuir adsorption isotherm. Thermal stability was evaluated by thermogravimetric analysis. The response to BTX vapours was investigated using a laboratory-designed gas-sensing setup in ambient conditions. The optimized film thickness was 200.81 ± 0.39 nm for 540 s of sputtering. XRD pattern confirms the amorphous nature, and SEM images of WO3 show the granular microstructure with 200 nm diameter. The developed sensor shows the highest sensitivity for xylene (5.10 ± 0.08 Hz/ppm), followed by toluene (5.69 ± 0.22 Hz/ppm) and benzene (3.36 ± 0.24 Hz/ppm). The limit of detection for BTX was 1.48 ppm, 0.79 ppm, and 0.33 ppm, respectively. The sensor exhibited faster response times of 30 s, 32 s, and 43 s for BTX, respectively. Repeatability of 99 % and reproducibility of 98 % were observed for BTX vapours. The fabricated WO3-coated QCM sensor can detect BTX vapour at room temperature with high sensitivity and response time. Thus, it can play a significant role in detecting BTX in the workplace for health and environment monitoring systems.

Waste biomass-based graphene oxide decorated with ternary metal oxide (MnO-NiO-ZnO) composite for adsorption of methylene blue dye

In this study, a novel approach for the removal of methylene blue (MB) dye is effectively illustrated by using biomass based composite adsorbent. The investigation employed areca nut husk (AH) to produce graphene oxide (GO) by a single step calcination method. Thereafter, AH-GO was incorporated by using ternary metal oxide (TMO) via hydrothermal treatment. The developed AH-GO@MnO-NiO-ZnO composite was characterized by various analytical techniques, including FT-IR, XRD, FESEM, HRTEM, BET surface area and Raman spectroscopy which exhibited promising properties for dye adsorption. To study the adsorption efficiency of prepared composite, optimization experiments were performed for adsorbent dose, initial dye concentration and contact time. The optimized parameters during adsorption phenomenon were found to be 0.5g/L of dose, 20mg/L of initial concentration and 180min of time exhibiting removal efficacy of 93.05 ± 0.93%. Moreover, adsorption isotherm and kinetic models were analysed to explore the adsorption behaviour of AH-GO@MnO-NiO-ZnO towards MB dye. The adsorption isotherm and kinetic studies followed Langmuir isotherm model and pseudo-second-order (PSO) model respectively. AH-GO@MnO-NiO-ZnO has demonstrated a maximum adsorption capability of 127.06mg/g. These findings collectively underscore the potential of AH-based adsorbent as a viable, inexpensive, and environment friendly for the treatment of wastewater contaminated with MB dye.

Porous chitosan quaternary ammonium salt hydrogel embedded with Cu, Ni and Pd nanoparticles for efficient coupled adsorption-catalytic reduction of methylene blue and 4-nitrophenol

Anthropogenic wastewater generation and water pollution can have negative impacts on public health and ecosystems. However, most materials do not have both adsorptive and catalytic properties, so the design and development of sustainable and multifunctional materials is essential for wastewater treatment. Herein, composite hydrogel (PHG) containing [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA) and chitosan quaternary ammonium salts (HACC) were prepared for wastewater treatment. The adsorption capacities of the PHG hydrogels for nickel (NiII), copper (CuII), and palladium (PdII) ions were 158.68, 182.99, and 229.78 mg/g, respectively. The adsorption process is consistent with the Langmuir adsorption model and quasi-secondary kinetics. For further application of adsorbed metal ions, NaBH4 was selected for in situ reduction to prepare hydrogel-based catalysts cemented with metal nanoparticles (Ni-, Cu- and Pd-NPs), respectively. The PHG-Pd catalysts demonstrated significant catalytic efficiency in reducing 4-nitrophenol and methylene blue, and Kapp were 0.307 and 0.365 min−1, respectively. Among them, the activation parameters for the reduction of 4-NP over PHG-Pd catalyst were calculated as Ea = 36.27 kJ/mol, ΔH# = 33.72 kJ/mol and ΔS# = −259.68 J/(mol·K). This study is expected to provide insights into the design of multifunctional adsorption catalysts for the removal of dyes and nitro compounds from wastewater.

Insights into the relationship between Nitrilotri(methylphosphonic acid) (NTMP) adsorption and physicochemical properties of iron oxides

Non-reactive phosphorus (e.g., phosphonate) contributes to eutrophication, while little attention has been paid to its control. The iron-based materials are highly efficient in orthophosphate removal from water, while the correlation between their physicochemical properties and selective phosphonate (e.g. Nitrilotri(methylphosphonic acid) (NTMP)) adsorption is still unclear. In this study, Fe3O4 (magnetite), FeOOH (goethite) and Fe2O3 (hematite) with different crystal structures, particle sizes and surface area were synthesized for NTMP adsorption. The physicochemical properties of the three kinds of iron oxides were characterized. The batch experiments were applied to explore the NTMP adsorption and desorption performance. The maximum adsorption capacity of NTMP on Fe3O4, FeOOH and Fe2O3 were 4.14, 1.91 and 0.99 mg-P/g, respectively. Results implied the crystal structure and surface area of iron oxides determined the maximum NTMP adsorption capacity. The NTMP adsorption on the three iron oxides was spontaneous, endothermic and randomness increase. The iron oxides showed high selectivity towards NTMP adsorption in water containing anions, while the co-existing Ca2+ and Mg2+ remarkably increased the adsorption capacity. The successive adsorption-desorption cycles suggested a favorable reusability of the above iron oxides and a high NTMP desorption efficiency. The specific NTMP adsorption capacity followed the sequence of FeOOH > Fe2O3 > Fe3O4, and was highly dependent on surface OH− proportion. The NTMP adsorption mechanism was mainly attributed to inner-sphere complexation. This study provides insights into the iron-based adsorbents design for selective phosphonate adsorption in the future.

ZIF-8-CdS photonic crystal beads for slow photon effect induced enhanced photocatalysts

The unique periodic structure of photonic crystals demonstrates an effective slow photon effect that enhances the interaction between light and matter. This study designed and prepared MOF photonic crystal beads, and significantly improved the photocatalytic efficiency by utilizing the slow light effect. Utilizing microfluidic technology, ZIF-8 was self-assembled to form photonic crystal beads (PCB-Z) to enhance adsorption properties and light absorption. The surface of PCB-Z is modified with CdS to form a heterostructure (PCB-ZC), which widens the absorption spectrum, reduces the carrier recombination rate, and increases the specific surface area, while the photocurrent intensity of PCB-ZC is about 1.8 and 29 times that of CdS and PCB-Z. Under the combined effect of photonic crystal structure, ZIF-8/CdS heterojunction and slow photon effect, the degradation rate of Rhodamine B by PCB-ZC was 15.22 times higher than the disordered ZIF-8 powder, and the photocatalytic performance was significantly improved. The dominant role of holes in Rhodamine B degradation was confirmed by free radical trapping experiments and EPR tests. This research confirms that MOF-based photonic crystals can be assembled into periodic structures to enhance adsorption properties and light absorption, which provides a new paradigm for the development of MOF-based photocatalysts.

Preparation of porous carbon from hydrothermal treatment products of modified antibiotic mycelial residues and its use in CO2 capture

Antibiotic mycorrhizal residues (AMR) are valuable organic wastes but have become a significant environmental and economic challenge due to their potentially hazardous nature and high treatment costs. In this study, an environmentally friendly and low-cost in situ nitrogen-doped porous carbon material was successfully prepared by hydrothermal carbonisation combined with KOH activation for efficient CO2 capture. The obtained material was systematically characterized and tested, and its physical and chemical properties were analyzed. By adjusting the activation temperature from 600 to 800 °C, the prepared porous carbon materials exhibited different specific surface areas (648.41–1712.72 m²/g), pore volumes (0.310–0.879 cm³/g), and the nitrogen was uniformly distributed in the carbon skeleton. The optimal N-doped porous carbon demonstrated the adsorption capacities of 3.99 mmol g−1 at 25 ℃ and 5.35 mmol g−1 at 0 ℃ under 1 bar. In addition, the prepared adsorbents exhibited excellent CO2/N2 selectivity, high isosteric heat, and good cyclic stability. These excellent CO2 adsorption properties were attributed to the highly developed microporous structure of the materials and the uniformly distributed nitrogen functional groups in the carbon skeleton. Overall, the results highlight the great potential of this class of heteroatom-doped novel carbon materials as selective CO2 adsorbents, providing a practical way to seek efficient CO2 abatement solutions.

A DFT study of gas molecules adsorption on TM-doped PtS2 gas nanosensors

In this study, we examined the adsorption and sensing capabilities of transition metal doped PtS2 monolayers (TM = Co, Cu, Fe, Ni) towards three industrially relevant toxic and hazardous gases: CO, NO, and H2S, using density functional theory (DFT) calculations. The interaction between the gases and the TM-doped PtS2 monolayer substrates was thoroughly investigated, taking into account various adsorption configurations, charge transfer phenomena, band structures, and state densities. Results indicate that the TM dopants markedly enhances the conductivity and gas adsorption capacity of PtS2 monolayer. Specifically, the TM-doped PtS2 monolayers exhibit strong adsorption properties towards CO, NO, and H2S, with the adsorption process identified as chemisorption. By analyzing the alterations in conductivity subsequent to gas adsorption, we discerned that Ni-PtS2 could potentially serve as an effective sensor for CO, NO, and H2S. Consequently, our results furnish a solid theoretical foundation for the development of PtS2-based sensors aimed at detecting these gases. Furthermore, the findings of this research offer valuable insights into the design of gas nanosensors.

Investigation of the hydrogen adsorption properties on titanium metal under vacuum conditions

Investigation of the hydrogen adsorption properties on titanium metal under vacuum conditions

Preparation of ZnAlLa-LDHs by one-step hydrothermal method and its adsorption properties for phosphate

Abstract Phosphate is one of the main limiting factors of water eutrophication, and the effective removal of phosphate is essential to control the eutrophication of the aquatic environment and meet the increasingly stringent phosphate discharge regulations. This study successfully prepared ZnAlLa-LDHs materials using a simple hydrothermal method using triethanolamine as a soft template, which SEM, XRD, and FT-IR characterized. The results show that ZnAlLa-LDHs is a kind of two-dimensional porous structure material; the adsorption isotherm of ZnAlLa-LDHs on phosphate conforms to the Langmuir model, and the maximum adsorption capacity is 83.333 mg g−1; the adsorption kinetics conforms to the pseudo-second-order kinetic model, and the adsorption rate is mainly controlled by chemical adsorption; the adsorption mechanism of ZnAlLa-LDHs on phosphate is mainly ion exchange and electrostatic adsorption. ZnAlLa-LDHs have an excellent effect on phosphorus in wastewater from sewage treatment plants.

A multi-layer antimicrobial cellulose filter with electrostatic adsorption properties prepared by coating cellulose with chitosan and CuO

The health impacts of air pollution such as particulate matter (PM) and bioaerosols have prompted a focus on the utilization of personal protective filters. Traditional filters pose environmental concerns due to their non-biodegradable composition, while cellulose presents a promising alternative for biodegradable air filtration applications. This research involved the development of cellulose filter substrates with a customizable pore structure by adjusting the nanofiber content in cellulose filters and employing a simultaneous freeze-drying method. By integrating chitosan and CuO nanoparticles, the filters gained electrostatic adsorption capabilities, leading to a substantial enhancement in filtration efficiency, as well as imparting moisture resistance and durable antimicrobial properties to the filter. Subsequently, a three-layer cellulose filter integrated with chitosan and CuO (abbreviated as Int-Cs&CuO) was constructed based on the generalized Murray’s law to enable multi-stage PM filtration. The Int-Cs&CuO cellulose filter demonstrated filtration efficiencies of 99.2 % for non-oily PM0.3 and 99.5 % for oily PM0.3, with a low pressure drop of 49.5 Pa. Under humid conditions, the filtration efficiency of the Int-Cs&CuO cellulose filter against PM0.3 particles was minimally impacted, showcasing a decrease of only 1.3 %. Notably, the filter exhibited complete biodegradation in composted soil within approximately 2 months.

Functionalized agro-waste for the sustainable remediation of malachite green from wastewater

Herein, a novel eco-friendly spent coffee grounds (SCG) impregnated guar gum adsorbents (SGH-x) were fabricated by using borax as the cross-linking agent. Several influences as borax dosage, initial dye concentration, pH, contact time, and temperature on the adsorption properties of SGH-x for Malachite Green (MG) were investigated. At a borax dosage of 0.9 wt%, the SGH-x possess maximum adsorption capacity of 921.84 mg/g towards MG and water swelling ratio of 2075 % owing to the presence of three-dimensional network structure and abundant hydroxyl groups. At pH= 10, the removal of MG by SGH-x is nearly 100 %. An increase of adsorption capacities with the molecular weight of cationic dyes followed the sequence as: Rhodamine B (RhB, 479.0 Da), Crystal violet (CV, 407.98 Da), and Basic red 9 (BR9, 323.82 Da) can be explained as the synergy between the pore filling and charge effect. Kinetic and isothermal studies revealed that the adsorption process of MG adhered to pseudo-second-order kinetic model and Freundlich isothermal model, suggesting a chemical adsorption on heterogeneous surfaces. Additionally, regeneration experiments showed SGH-x maintain high adsorption capacity (above 80 mg/g) of MG after three cycles. This study provided a feasible route to prepare biogradable and cost-effective adsorbents for water purification.

Recycling and breakdown photodegradation processes cost of BEN-TiQD via different photodegradation processes of Brilliant Green S dye and industrial effluents

The development of efficient photocatalytic materials for environmental remediation is of paramount importance. This study reports the synthesis and characterization of novel bentonite-titanium dioxide quantum dot (BEN-TiQD) nanocomposites for the photodegradation of Brilliant Green S, a prominent industrial pollutant. The nanocomposites were prepared via a co-precipitation method, ensuring uniform dispersion of TiO2 nanoparticles on the bentonite (BEN) surface, followed by heat treatment to achieve optimal crystallinity and surface properties. Comprehensive characterization techniques, including FTIR, XRD, SEM, BET surface area analysis, and optical spectroscopy, were employed to elucidate the structural, morphological, and photophysical characteristics of the composites. The BEN-TiQD nanocomposites exhibited an augmented surface area of 277.75 m2/g, surpassing BEN alone by more than threefold, and an intermediate bandgap of 3.17 eV, rendering them suitable for visible light absorption and photocatalytic applications. The photocatalytic efficacy of BEN-TiQD was evaluated by monitoring the degradation of Brilliant Green S under various operational parameters. The nanocomposites demonstrated superior photocatalytic performance, with a rate constant of 22.24 × 10−3 s−1, significantly only lower than TiQD (28.32 × 10−3 s−1) by nearly about 21.5 %. The enhanced activity was attributed to the quantum size effect of the incorporated TiO2 quantum dots, optimizing light absorption and charge separation. Mechanistic studies revealed the generation of reactive oxygen species, particularly hydroxyl radicals, as the primary drivers of dye degradation. The reusability of BEN-TiQD was evaluated through multiple photocatalytic cycles, exhibiting remarkable stability for up to six consecutive cycles. However, a gradual decline in photodegradation efficiency was observed after prolonged sunlight exposure, likely due to particle agglomeration and reduced surface area. This research contributes to the field of environmental remediation by developing a novel composite material that synergistically combines the adsorptive properties of BEN with the photocatalytic capabilities of titanium dioxide quantum dots. The findings pave the way for further exploration and optimization of these composites for sustainable and efficient treatment of industrial dyes and effluents, addressing critical environmental challenges.

Gas sensing performance regulating of ZIF-8 encapsulated WO3 nanosheets

Reasonably regulating the adsorption properties on the surface of metal oxide semiconductors (MOS) to enhance sensor selectivity remains a challenge, limiting their application in detecting diseases biomarkers in human exhaled gas. To address this, we proposed a metal-organic frameworks (MOFs) encapsulated strategy to provide a gas-selective permeable nano-filtration layer for MOS gas sensors. By adjusting the coating thickness of ZIF-8, we successfully modulate the sensing properties of WO₃ to different potential biomarkers. The optimized WO₃/ZIF-8 composite shows improved selectivity and response to various disease biomarkers compared to WO₃ alone. The unique porous structure of ZIF-8 and the heterojunction of WO3/ZIF-8 synergistically promote the gas adsorption performance. QCM test results confirm that ZIF-8 modification effectively regulates gas adsorption on the WO₃ surface. This study provides a valuable reference for designing exhaled gas sensor arrays for detecting serious diseases.

Comparative study of silica-based porous materials in the purification of radioactive wastewater

A significant challenge in the treatment of low-level radioactive wastewater is the effective purification of low-concentration radionuclides. Silica-based adsorbents are advantageous for the deep-purification of low-concentration metal ions. This study investigates three primary types of silica-based adsorbents: functionalized mesoporous silica, various modified zeolites, and mesoporous calcium silicate hydrate (C-S-H). These adsorbents were synthesized and their deep-purification effects on heavy metals and radionuclides were compared. The results indicated that mesoporous silica showed relatively poor adsorption for most metal ions. Zeolites outperformed mesoporous silica, with Zn framework-modified zeolites showing enhanced adsorption for several metal ions. Notably, C-S-H displayed superior adsorption performance, achieving high adsorption capacities for various metal ions and radionuclides. Specifically, at a dose of 0.5 g/L, the adsorption efficiency of C-S-H for numerous radionuclides in nuclear power plant wastewater exceeded 92–99 %, highlighting its potential for practical applications. An in-depth analysis of the physical and chemical structure and the adsorption mechanisms of C-S-H revealed its large mesoporous structure and electrostatic attraction to cations across a wide pH range. Multivalent cations were removed through exchange with Ca2+ in C-S-H, whereas monovalent cations were removed through exchange with Na+ in C-S-H. The cyclic structure of silica-oxygen tetrahedra in C-S-H, which promotes large pore formation and provides abundant ion exchange sites, underpins its excellent adsorption properties. This study offers valuable insights for the selection and application of silica-based materials in radioactive wastewater treatment.

Functionalization of Ti3C2 MXene with Diethylenetriamine for a Column-Based Solid-Phase Extraction of Heavy Metals.

Transition metal carbides, nitrides, and carbonitrides, known as MXenes, are attracting attention for their potential application in trace detection of heavy metals. This study presents diethylenetriamine-functionalized Ti3C2 MXene for trace detection of cadmium and lead ions. Functionalization of Ti3C2 significantly improves the adsorption properties of MXenes by replacing native functional groups with silane moieties that contain three amine groups, offering higher affinity for heavy metals. We demonstrate the efficacy of this material as a solid-phase extractor in column-based solid-phase extraction for heavy metal analysis in various food samples. Diethylenetriamine-functionalized Ti3C2 coupled with the flame atomic absorption spectrometer exhibits exceptional analytical performance. While maintaining a robust stability for 15 adsorption-desorption cycles, the proposed method shows detection limits of 0.09 ng mL-1 for cadmium and 1.7 ng mL-1 for lead, with a linear dynamic range of 0.3-50 ng mL-1 for cadmium and 5-90 ng mL-1 for lead, and relative recoveries of 97.50-101.05 and 98.65-100.80% for cadmium and lead ions, respectively. Additionally, relative standard deviations and enrichment factors were calculated as 0.60-4.70% and 42.3 for cadmium ions and 0.65-1.24% and 44.2 for lead ions.

The adsorption of p-hydroxybenzoic acid on graphene oxide under different pH and in-situ desorption in direct current electric field

The development and ongoing optimization of measures to reduce and eliminate p-hydroxybenzoic acid (p-HBA) in industrial wastewater are significant due to its potential carcinogenic effect and bio-recalcitrant. Graphene oxide (GO) is an ideal adsorbent for removing aromatic acids and achieving adsorbent recovery and resource conservation. In this study, the adsorption properties of p-HBA onto GO at different pH values and the regeneration mechanism of adsorbent under varying electric field intensities were analyzed using molecular dynamics (MD) simulation. The simulation results demonstrate that GO exhibits preferable adsorption capabilities for p-HBA at low pH, and van der Waals (vdW) interaction plays a leading role. However, the adsorption stability decreases at high pH (particularly pH > 9.3) with most p-HBA desorption from the GO surface. When an electric field of 1.0 V/nm is applied to the acidic system (HGO_HBA_HBA−), the total adsorption interaction energy between GO and p-HBA decreases but remains high (−1836.93 kJ/mol). When a 0.6 V/nm electric field is added to the alkaline system (GO2−_HBA2−), the vdW and electrostatic interaction energies are recorded as −35.34 kJ/mol and 3546.97 kJ/mol. The vdW interaction is weak, and electrostatic repulsion increases, facilitating the desorption of p-HBA from the GO surface. This work aims to share insights into the microscopic removal mechanism of p-HBA on the GO surface under different pH values and provide a theoretical perspective on the regeneration mechanism of GO.

Exploring the adsorption characteristics of quinoline derivatives on iron via ab initio DFT simulations and COSMO-RS profiles

Quinoline derivatives have been the subject of extensive research due to their excellent electronic properties and wide range of applications. This study conducts a comprehensive computational examination of the adsorption properties of substituted quinoline derivatives on Fe(110) surfaces. Four specific compounds, namely 2-amino-7-hydroxy-4-phenyl-1,4-dihydroquinoline-3-carbonitrile (QN1), 2-amino-7-hydroxy-4-(p-tolyl)-1,4-dihydroquinoline-3-carbonitrile (QN2), 2-amino-7-hydroxy-4-(4-methoxyphenyl)-1,4-dihydroquinoline-3-carbonitrile (QN3), and 2-amino-4-(4-(dimethylamino)phenyl)-7-hydroxy-1,4-dihydroquinoline-3-carbonitrile (QN4) were investigated using first-principles density functional theory (DFT) calculations along with COSMO-RS analysis for solvation properties. Our results revealed that the presence of functional groups significantly influence the adsorption strength on Fe(110) surfaces. Quinoline molecules have adsorbed on the iron surface through complex mechanisms involving physical interactions and charge transfer. Specifically, QN1 and QN4 showed strong physical interactions with iron atoms while QN2 and QN3 exhibited high affinity to coordinate with Fe atoms. The stability of coordinated quinolines was enhanced by a notable charge redistribution and bond formation as observed via projected density of states (PDOS). On the other hand, electron density difference (EDD) and electron localization function (ELF) iso-surfaces highlighted the critical role of van der Waals interactions, predominantly influenced by nitrogen atoms, in stabilizing the adsorbed molecules. The COSMO-RS analysis elucidated the solvation characteristics, emphasizing the importance of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) in the interaction of quinolines with water molecules. Overall, this study provides crucial insights into the molecular mechanisms underlying the corrosion inhibition properties of quinoline derivatives, emphasizing the influence of functional groups and solvation effects on adsorption behavior and stability.

Mechanism of selective uranium adsorption using polyvinyl alcohol /Cyphos IL-101 / reduced graphene oxide composites

A novel composite material for uranium extraction from seawater, APGO, was prepared by crosslinking reduced graphene oxide (rGO) loaded with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101) with polyvinyl alcohol. The experimental results indicate that the surface of APGO contains functional groups, such as carboxyl, hydroxyl, and phosphate, that have adsorption properties for uranium. APGO exhibits excellent hydrophilicity and stability while preserving the intact two-dimensional network structure of rGO. The specific surface area of APGO was 9.23 m2/g with an average pore size of 27.50 nm. Furthermore, the optimal pH range for APGO to adsorb uranium is 6–8, making it more suitable for extracting uranium from seawater. Notably, the selective adsorption capacity of APGO for uranium is significantly enhanced compared to that of AGO, with a Kd value approximately 4.6 times higher than that of AGO. The theoretical adsorption capacity is 467mg/g at 318 K (pH = 6). The process of uranium adsorption by APGO is a spontaneous endothermic reaction. The adsorption performance of APGO is noteworthy because it exhibits only a 2 % decrease after five adsorption–desorption cycles. Furthermore, APGO demonstrates commendable recyclability. Overall, APGO demonstrates a remarkable affinity for uranium and promising potential for efficiently extracting uranium from seawater.

Preparation of dandelion flower extract-based polyvinyl alcohol-chitosan-dandelion-CuNPs composite gel for efficient bacteriostatic and dye adsorption

A multifunctional composite gel with efficient bacteriostatic and dye adsorption properties was prepared using polyvinyl alcohol, chitosan, and soybean isolate protein as carriers, CuNPs prepared by green reduction of dandelion extract as bacteriostatic agent, and glutaraldehyde as cross-linking agent. The composite gel showed good inhibition capacity of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa with the diameter of inhibition zone of 27.0–28.3 mm by agar diffusion method. The composite gel antibacterial rate remained above 90 % after 14 days of preparation. After 6 times reuse of composite gel in water, the antibacterial rate remained above 90 %, proving its good stability and reusability. Adding dandelion extract and CuNPs greatly improved the gel antioxidant property, acquiring free radical scavenging rate at 95.6 %. This composite gel had good biocompatibility and adsorption performance, and the maximum adsorption amount of methylene blue and methyl orange was 40.36 mg/g and 41.81 mg/g, respectively. To sum up, the green composition of composite gel has good antimicrobial performance and high dye adsorption, which holds significant promising for treating the water body pollution and protecting the environment. To build cost-effective antibacterial and dye adsorption process on a large-scale, in-depth exploration about this topic is still needed to develop.