Langmuir Monolayers Research Articles

Insights into the adsorption of emerging organic contaminant by low-cost readily separable modified jute fiber.

A high-efficiency biosorbent based on the low-priced jute fiber was developed, characterized, and applied to remove the emerging organic contaminant diclofenac from aqueous solutions. Jute fiber was treated by NaOH (named AJF) followed by graftingdifferent amounts of trimethyl[3-(trimethoxysilyl) propyl] ammonium chloride (named AJF-TTSAC). The composition, morphology, porosity, and adsorption features of the neat and modified jute fiber were evaluated and compared. The surface of neat JF was smooth, nonporous, and free of cracks. NaOH treatment increased the fibrillation, created cracks and grooves, and increased the oxygen content, total pore volume, and surface area. In comparison to AJF, grafting TTSAC filled in the crevices, grooves, and spaces between fibrillates, and decreased the total pore volume and surface area. The adsorption of diclofenac by the neat and modified JF occurred at highly acidic pHo and peaked at pHo 3. Among the neat and modified JF, AJF-TTSAC5 was the most efficient followed by AJF. The efficiency of AJF and AJF-TTSAC5 was highest using 1.00 g/L, at 35 °C and was not affected by the presence of NaCl. The Elovich, pseudo-first-order, and pseudo-second-order models described the adsorption kinetic satisfactorily with the marginal advantage of Elovich for AJF and pseudo-second-order for AJF-TTSAC5. The isotherm study exposed the multilayer and physisorption nature of the adsorption of diclofenac onto AJF and AJF-TTSAC5. The Langmuir monolayer saturation capacity of AJF-TTSAC5 was 37.43 mg/g which revealed its great potential relative to other adsorbents in the literature. The AJF and AJF-TTSAC5 were easily regenerated using distilled water and kept good performance for 5 repetitive cycles.

Optical anisotropy and surface phases of cholesterol derivative monolayer at air–water interface

Cholesterol and its derivatives play crucial roles in regulating processes of biological membranes. Langmuir monolayer can mimic a bio-membrane which can be used to investigate the molecular interaction governing the important physical phenomena. The cholesterol derivative exhibiting mesophases (CHLC molecules) was synthesized and spread at the air–water (A/W) interface to investigate the surface behavior. The monolayer exhibited a variety of surface phases such as gas, liquid expanded (LE), low density liquid like (L1) and liquid condensed (L2) phases. Treating the CHLC molecules to be rod-like, the average tilt of the molecules with respect to the surface normal in these phases are found to be different. The tilt angle decreases systematically from LE to L2 phase. The optical anisotropy of the ultrathin Langmuir-Blodgett (LB) films of CHLC molecules in these phases was measured using the surface plasmon resonance (SPR) spectroscopy. The high tilted molecules in the ultrathin LB film displayed a high value of optical anisotropy. The ultrathin film of CHLC molecules at different interfaces was investigated using Brewster angle microscopy, X-ray reflectivity (XRR), SPR spectroscopy and atomic force microscopy. This study is useful for the systems where the physical phenomena are governed by tilt of the molecules.

Molecular characteristics of dissolved organic matter regulate the binding and migration of tungsten in porous media

Tungsten (W) is an emerging contaminant that poses potential risks to both the environment and human health. While dissolved organic matter (DOM) can significantly influence the W's environmental behavior in natural aquifers, the mechanisms by which DOM's molecular structure and functional group diversity impact W binding and migration remain unclear. Using molecular weight-fractionated soil and sediment DOM (<1 kDa, 1–100 kDa, and 100 kDa–0.45 μm), this study systematically investigated the relationship between DOM molecular characteristics and tungstate (WO42−) binding properties using multiple spectroscopic methods, including FTIR, fluorescence spectroscopy and XPS. The migration behavior of WO42− in porous media was also investigated through quartz sand column experiments. Results revealed that approximately 75 % of W was controlled by DOM, with over 50 % binding to low molecular weight DOM (<1 kDa). Tungsten bound to medium-high molecular weight DOM (1–100 kDa, >100 kDa) showed a greater propensity for retention, with the >100 kDa fractions demonstrating stronger selective binding to W, exhibiting distribution coefficients (Kmd) of 6.11 L/g and 10.69 L/g, respectively. Further analysis indicated that W primarily binds with aromatic rings, phenolic hydroxyls, polysaccharides, and carboxyl groups in DOM, potentially affecting DOM structural stability and consequently influencing W migration characteristics. Free W migration in quartz sand was primarily controlled by Langmuir monolayer adsorption, leading to local enrichment (Da = 6.83, Rd = 86.98). When bound to DOM, W's migration ability significantly increased (Rd = 8–10), with adsorption shifting to a Freundlich multilayer model, primarily controlled by convective transport (Npe = 27–62> > 1.96), while adsorption effects weakened (Da ≈ 1). This study, for the first time, systematically reveals the regulatory mechanisms of DOM molecular characteristics on tungsten's environmental behavior. It offers crucial parameter support for constructing tungsten migration models and provides important guidance for tungsten pollution risk assessment and remediation strategies.

In a search of the single-atom electrocatalysts for hydrogen production: the first sulfur-free mono- and diphenanthrenyl-terminated iron and cobalt(II) clathrochelates versus their thioanalogs

This paper reports on green chemistry approaches to the molecular design and synthesis of cheap, efficient and eco-friendly electrocatalysts of the hydrogen evolution reaction (HER). The title clathrochelates (including first those do not containing sulfur derivatives as “catalytic poisons”) were prepared using nucleophilic substitution of their chloroclathrochelate precursors and characterized by analytical, spectral and XRD methods. These complexes showed the HER 2H+/H2 electrocatalytic activity in the solutions. They form the Langmuir monolayers and possess a high physisorption on activated carbon (AC, up to 0.55mmol·g–1) and reduced graphene oxide (RGO, up to 0.33mmol·g–1). Contrary that on carbon paper (CP) is very low. Therefore, AC- or RGO-containing clathrochelate-immobilized components are suitable for preparation of hybrid CP-based cathodes, allowing to substantially increase a surface concentration of electrocatalytically active centers up to 0.5 μmol·m–2. Cyclic voltammetry data suggest that the electrochemically generated cobalt(I) complexes, as the catalytically active intermediates, are stable and most prospective candidates for electrocatalytic hydrogen production. Clathrochelate-based single-atom catalysts were prepared in accordance with basic principles of green chemistry. They are derivatives of abundant and cheap 3d-biometals and low-toxic α-dioximes and possess an extremely high atomic utilization efficiency matching the “economy of atoms” principle. Nowadays, the carbon-supported metallic platinum is used as HER catalyst. The reserves of this noble and expensive metal on the Earth are limited and its replacement by such cheap and abundant HER materials will accelerate the development and implementation of green hydrogen-producing technologies. The recommendations on chemical structures of optimal molecular electrocatalysts were evaluated.

Fabrication of mango-leaf biowaste mediated green magnetite (Fe3O4@MBE NPs) and modified EDTA/Fe3O4@MBE NCs for enhanced heavy metals sequestration: Characterisation, simulation modelling, mechanism, cost-effectiveness and electroplating wastewater performance

This work reports biogenic green fabricated novel magnetite nanoparticles (Fe3O4@MBE NPs) coated with mango-leaf biowaste extract and modified disodium ethylenediamine tetra-acetate (EDTA) functionalised nanocomposite (EDTA/Fe3O4@MBE NCs). Several approaches were used to characterise them, and their applicability as nanoadsorbents was exhaustively investigated in batch mode sequestration of Cd(II), Ni(II), and Zn(II) from synthetic solutions. The Brunauer Emmett and Teller’s surface areas of Fe3O4@MBE and EDTA/Fe3O4@MBE was determined to be 47.73 and 43.95 m2/g, respectively, with average porous diameters of 10.36 and 7.44 nm, revealing mesoporosity. EDTA/Fe3O4@MBE NCs exhibit soft ferromagnetism with a saturation magnetisation of 40.67 emu/g. Further, EDTA modification creates carboxyl and amino sites, improving adsorption performance. Adsorption was pH dependent, with optimal sequestration at 40 mg/L divalent metal ions, 0.5 g/L nanoadsorbent dosage, and 75 min of reaction duration at 27 °C. Among the simulation models employed, the Langmuir isotherm, pseudo second order kinetic, and Elovich kinetic were the best fitted and offered the highest capability to explain the adsorption process. The Langmuir monolayer adsorption capacity (qmax) of 147.06, 129.87, and 117.65 mg/g for Cd(II), Ni(II), and Zn(II) by EDTA/Fe3O4@MBE, respectively, were significantly higher than Fe3O4@MBE (120.48, 102.04, and 95.24 mg/g). The best-suited kinetics precisely describe chemisorption as the primary rate-limiting phase in divalent metal ions adsorption. Thermodynamics approved the endothermic nature and feasibility of divalent metals adsorption, with modest improvement in efficacy at higher temperatures. The ability of EDTA/Fe3O4@MBE to form stable surface complexes with divalent metals enhances adsorption even in the presence of other co-existing ionic species. EDTA/Fe3O4@MBE NCs magnetic separability, improved sequestration upto five recycles, and regenerability of ≥89.07 % demonstrate its cost-effectiveness in heavy metals sequestration. Finally, practicality study confirmed that EDTA/Fe3O4@MBE nanoadsorbent provides a practical and economically efficient option for heavy metals sequestration from electroplating wastewater; thus, it contributed towards UN-2030, SDG No-6.

Sequestration of Ni2+ and Zn2+ utilising agricultural biowaste-based amorphous M−SiO2 and modified green M−SiO2/Fe3O4 nano-adsorbents: Modelling and electroplating wastewater performance

This work reports the synthesis of novel amorphous mesoporous silicon dioxide (M−SiO2) nanoparticles and modified hybrid green mesoporous silicon dioxide embedded magnetite (M−SiO2/Fe3O4) nanocomposite by one-pot co-precipitation green approach. The nano-adsorbents’ ability to sequester Ni2+ and Zn2+ ions was investigated in batch experiments using synthetic solutions. The M−SiO2/Fe3O4, having specific surface area of 171.71 m2/g and mesoporous diameters of 6.281 nm, exhibits soft ferromagnetism with a saturation magnetisation of 35.45 emu/g. Specific surface areas and mesoporous diameters of 909 m2/g and 2.288 nm were recorded for M−SiO2. The Langmuir isotherm, pseudo second order kinetic, and Elovich kinetic were found to be best fitted to explain the highest capability of adsorption. The Langmuir monolayer coverage (qmax) of 108.70 and 96.15 mg/g for Ni2+ and Zn2+ by M−SiO2/Fe3O4, respectively, was notably higher than M−SiO2 (80.65 and 72.46 mg/g). The best-fitted kinetics imply that chemisorption predominates on M−SiO2 and M−SiO2/Fe3O4 heterogeneous adsorption surfaces. Thermodynamic parameters confirm endothermic adsorption of cationic metals, and sequestration improved marginally at elevated temperatures. The lab scale cost estimation, magnetic separability and superior metal ions sequestration efficacy of M−SiO2/Fe3O4 nanocomposite up to five ad-desorption cycles with > 90 % regenerability render it an economically feasible and recyclable nano-adsorbent. The feasibility of cationic metals sequestration from electroplating effluent confirms an effective and cost-efficient environmentally friendly nano-adsorbent (M−SiO2/Fe3O4) for treatment of wastewater contaminated with potentially toxic metals.

Cm-p5, a molluscan-derived antifungal peptide exerts its activity by a membrane surface covering in a non-penetrating mode

Amidst the health crisis caused by the rise of multi-resistant pathogenic microorganisms, Antimicrobial Peptides (AMPs) have emerged as a potential alternative to traditional antibiotics. In this sense, Cm-p5 is an AMP with fungistatic activity against the yeast Candida albicans. Its antimicrobial activity and selectivity have been well characterized; however, the mechanism of action is still unknown. This study used biophysical approaches to gain insight into how this peptide exerts its activity. Stability and fluidity of lipid membrane were explored by liposome leakage and Laurdan generalized polarization (GP) respectively, suggesting that Cm-p5 does not perturb lipid membranes even at very high concentrations (≥100µm.L-1). Likewise, no depolarizing action was observed using 3,3'-propil-2,2'-thyodicarbocianine, a potential membrane fluorescent reporter, with C. albicans cells or the corresponding liposome models. Changes in liposome size were analyzed by Dynamic Light Scattering (DLS) data, indicating that Cm-p5 covers the vesicular surface slightly increasing liposome hydrodynamic size, without liposome rupture. These results were further corroborated with Langmuir monolayer isotherms, where no significant changes in lateral pressure or area per lipid were detected, indicating little or no insertion. Finally, data obtained from molecular dynamics simulations aligned with in vitro observations, whereby Cm-p5 slightly interacted with the fungal membrane model surface without causing significant perturbation. These results suggest Cm-p5 is not a pore-forming anti-fungal peptide and that other mechanisms of action on the membrane as some limitation of fungal nutrition or receptor-dependent transduction for depressing growth development should be explored.

A crude, cold-pressed oil from elderberry (Sambucus nigra L.) seeds: Comprehensive approach to properties and characterization using HPLC, DSC, and multispectroscopic methods

The physicochemical characterization of fresh, undiluted, cold-pressed oil from elderberry seeds (EO) is presented. The results showed EO's uniqueness for the 93 % presence of essential fatty acids, including linoleic n-6 (41 %), α-linolenic n-3 (38 %), and oleic n-9 (13 %) acids with favorable ratios for human nutrition, n-3/n-6 = 0.93. A γ-tocopherol is the dominant tocopherol (96 %), with a concentration of 20.62 mg/100 g, indicating low oil oxidative stability. DSC heating and cooling traces determined the thermal properties. These results also revealed the presence of metastable triacylglycerol (TAG) structures composed of polyunsaturated fatty acids. The presence of characteristic groups for fatty acids and TAGs in EO was confirmed by FTIR-ATR spectra. For the first time, Langmuir monolayer studies on EO revealed its low compressibility, indicating its low emulsifiability, and the presence of minor components of EO, including tocopherols, phenolic acids, polyphenols, flavonoids, and carotenoids, was determined using UV–Vis absorption and fluorescence excitation-emission matrix (EEM) along with the chemometric method.

Langmuir adsorption model to assess the impact of silane coupling on nano-dispersion of silica in SBR

Surface active agents are often used to improve dispersion of nanoparticles. Quantitative correlation between these surface-active molecules and nanoscale dispersion is absent from the literature partly because a quantitative measure of nanoscale dispersion does not exist. Recently, we have developed the Virial-van der Waals method to quantify dispersion in nanocomposites using virial coefficients. In this paper, the Langmuir adsorption model is used to quantify the influence of surface-active agents on nano-scale dispersion in terms of the effective second virial coefficient B2∗. The impact of silane coupling agent on the nano-dispersion and silica aggregate structure in precipitated silica/SBR nanocomposites is demonstrated. It is shown that the higher viscosity SBR matrix led to a greater silica aggregate structural breakup, while lower viscosity matrix improved surface silanization. The isomeric content of the SBR, which impacts the dielectric behavior, impacted whether the system could be modeled through a mean-field or specific interactions. We earlier showed that larger aggregates improve dispersion, and this is reaffirmed in these results. After account is made for aggregate size, nano-scale dispersion improves with the addition of silane coupling agent. The behavior is well modeled using Langmuir monolayer adsorption.

Thin-film polydiacetylenes of a stable blue phase based on symmetrical and unsymmetrical diacetylene &lt;i&gt;N&lt;/i&gt;-arylcarbamates

The conditions and features of the formation of Langmuir monolayers of symmetrical and asymmetrical diacetylene N-arylcarbamates and the structural organization of Langmuir-Schaefer films based on them were studied. Photopolymerization of monolayer solid films of two types of molecules was monitored using absorption spectroscopy and showed the transition of diyne molecules to the blue phase polydiacetylene state. The efficiency of the solid-phase topochemical polymerization reaction in a film of symmetrical diynes turned out to be 5 times higher than in a film of asymmetrical diyne molecules. The morphology of monolayer surfaces before and after UV irradiation was studied using scanning electron microscopy.

Reversible in Situ Control over Monolayer Organization.

Cr2+ and Cr3+ ions are shown to mediate the formation, morphology, and organization of arachidic acid (AA) Langmuir-Blodgett (LB) monolayers. This finding, based on cyclic voltammetry (CV), linear sweep voltammetry (LSV) and fluorescence recovery after photobleaching (FRAP) measurements, show that Langmuir monolayer formation depends on subphase pH and metal ion concentration. Following monolayer deposition on ITO, the LB monolayer organization can be modified reversibly through control of the Cr oxidation state, which has not been shown before by other monolayers formed with other divalent metal ions. The dynamics and the mobility of a chromophore (perylene) incorporated into the monolayer sense changes in Cr oxidation state-dependent organization of the LB monolayer. Demonstrating reversible changes in monolayer organization provides an opportunity to control chemical and electron access to the interface support.

Exploring the influence of acetylenic acetogenin unsaturation patterns on lipid interface interactions: Insights from surface chemistry, rheology, and spectroscopy

This study explores how the unsaturation patterns of three acetogenins from Porcelia macrocarpa (2S,3R,4R)-3-hydroxy-4-methyl-2-(eicos-11′-yn-19′-enyl)-butanolide (1), (2S,3R,4R)-3-hydroxy-4-methyl-2-(eicos-11′-ynyl)-butanolide (2), and (2S,3R,4R)-3-hydroxy-4-methyl-2-eicosyl-butanolide (3)—affect their interactions with lipid interfaces, using Langmuir monolayers of dipalmitoyl-phosphoethanolamine (DPPE) as a model for protozoal membranes. The hypothesis posits that unsaturated acetogenins (1 and 2) will exhibit distinct behaviors compared to the saturated acetogenin (3) due to structural differences. Experiments incorporated each acetogenin into DPPE monolayers, employing techniques like tensiometry, dilatational rheology, infrared spectroscopy, and Brewster angle microscopy (BAM) to assess interactions and changes in film properties. Results showed that unsaturated acetogenin 1, active against Leishmania infantum and Trypanosoma cruzi, destabilized the film and induced rapid molecular reorganization, while acetogenin 2, inactive against these parasites, uniquely increased the viscous contribution to viscoelasticity. Saturated acetogenin 3 did not integrate into the film. All acetogenins enhanced fluidity, reducing elasticity and viscosity, with BAM revealing phase separation only in acetogenin 2. Infrared spectroscopy underscored the impact of drug-lipid interactions, leading to the conclusion that unsaturated acetogenins 1 and 2 have a more significant influence on thermodynamic and structural properties than acetogenin 3, offering insights into their potential therapeutic mechanisms.

Thermodynamic Study on Biomimetic Legionella gormanii Bacterial Membranes.

The presented studies were aimed at determining the interactions in model membranes (Langmuir monolayers) created of phospholipids (PL) isolated from Legionella gormanii bacteria cultured with (PL + choline) or without (PL - choline) choline and to describe the impact of an antimicrobial peptide, human cathelicidin LL-37, on PL's monolayer behavior. The addition of choline to the growth medium influenced the mutual proportions of phospholipids extracted from L. gormanii. Four classes of phospholipids-phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), cardiolipin (CL), and their mixtures-were used to register compression isotherms with or without the LL-37 peptide in the subphase. Based on them the excess area (Ae), excess (ΔGe), and total (ΔGm) Gibbs energy of mixing were determined. The thermodynamic analyses revealed that the PL - choline monolayer showed greater repulsive forces between molecules in comparison to the ideal system, while the PL + choline monolayer was characterized by greater attraction. The LL-37 peptide affected the strength of interactions between phospholipids' molecules and reduced the monolayers stability. Accordingly, the changes in interactions in the model membranes allowed us to determine the difference in their susceptibility to the LL-37 peptide depending on the choline supplementation of bacterial culture.

Fabrication of novel metal oxide nanosheets-decorated carbon nanofibers for highly efficient removal of ultra-small nanoplastics

The extensive use of plastic products leads to white pollution and the formation of nanoplastics (NPs) through physicochemical processes. Due to their large specific surface area and small size, NPs can easily enter the human body, posing significant health risks. In this work, we prepared NiFe2O4 nanosheets-decorated carbon nanofibers (NiFe2O4@CNF) via electrospinning, carbonization, hydrothermal growth, and low-temperature calcination for NPs removal. Characterization techniques, including SEM, FTIR, XRD, XPS, and zeta potential analysis, assessed the surface morphology, functional groups, crystal structure, chemical composition, and surface charge of the NiFe2O4@CNF adsorbent. Adsorption kinetics, isotherms, and thermodynamics studies demonstrated that the adsorption process follows pseudo-second-order kinetics and the Langmuir model, indicating chemisorption and monolayer adsorption with a maximum adsorption capacity of 147.842 mg/g. Thermodynamic data confirmed that the reaction is spontaneous and endothermic. Additionally, the practical application of the adsorbent was evaluated by studying the effects of pH, competing ions, and different water bodies on adsorption behavior, all showing high removal efficiency and robust performance. Computer simulations further provided understanding into the driving forces and the binding sites of adsorption. These results underscore the efficacy of NiFe2O4@CNF for NPs removal and provide critical insights for designing advanced environmental remediation materials.

Characterization of Langmuir Monolayers for Nanodiamonds Surface‐Modified with 12‐Hydroxystearyl Chains and the Occurrence of Structural Colors

AbstractThe surfaces of nanodiamond particles are modified using natural castor oil‐derived 12‐hydroxystearic acid, which has thixotropic solvent properties. 12‐Hydroxystearyl chain‐modified nanodiamonds (12OHSt‐ND) are spread from a dispersion medium onto ultrapure water to afford Langmuir monolayers (a single‐particle layer) of 12OHSt‐ND exhibited a two‐dimensional phase transition from an expanded phase to a condensed phase. The surface morphology of the single‐particle layer shows a dispersed form of aggregated particles, while the layered regularity of the multilayers shows high periodicity. The surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is more pronounced than that of the single‐particle layer of stearic acid‐modified nanodiamonds. The origin of the surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is predicted to be the vertical conformation of the modified chains achieved via hydrogen bonding between the modified chains. In addition, the stepwise multilayers of 12OHSt‐ND exhibit various structural colors depending on the number of layers.

Biosorptive removal of toxic nitrate ion from wastewater using Albizia lebbeck seed pods: Isotherm and equilibrium studies

A major environmental issue that contaminates drinking water and endangers human health is nitrate pollution. In this study, goethite, citric acid, tartaric acid was employed to modify Albizia lebbeck seed pod for the biosorption of nitrate ion. The developed unmodified Albizia lebbeck (UALB), citric acid modified Albizia lebbeck (CALB), tartaric acid modified Albizia lebbeck (TALB), and goethite acid modified Albizia lebbeck (GALB) were characterized using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and point of zero charge (pHpzc) to determine the structural morphology, functional group, and adsorbent surface charge. The adsorption nitrate ion onto the biosorbents was found to be dependent on the operating parameters. The findings revealed that the maximum percentage removal of nitrate ion was 80.8 % at pH 7 for UALB, 80.3 % at pH = 4.0 for CALB, 70.30 % at pH = 3.0 for TALB and 76 % at pH 7 for GALB. The adsorption experimental data for nitrate ion adsorption onto ULAB, CALB, TALB, and GALB were best described by the Langmuir isotherm model. The UALB exhibited the highest Langmuir monolayer adsorption capacities with a value of 344.827 mg/g. Therefore, the unmodified form of Albizia lebbeck (UALB) which is economical, and sustainable provides an efficient alternative method for nitrate removal in aqueous environment.

Investigation of the corrosion inhibitory effectiveness of castor leaf extract as a corrosion inhibitor for steel in a sulfuric acid environment

The Castor Leaf Extract (CLE) was prepared using pure water as the solvent and was obtained through the decoction method. CLE exhibits outstanding anti-corrosion nature as an inhibitor in H2SO4 media for X70 pipeline steel. The electrochemical test has shown that the inhibition efficiency of CLE can be up to 92.8 %. CLE, a mixed-type corrosion inhibitor, is capable of inhibiting both cathodic and anodic processes in the X70 pipeline steel/H2SO4 system. The morphology of the X70 steel surface turns into significantly flatter and brighter with increasing CLE. The adsorption of CLE at the X70 steel/H2SO4 interface follows the Langmuir monolayer adsorption model, which encompasses both physical and chemical adsorption processes. Theoretical calculations demonstrate that CLE is able to effectively protect X70 steel from corrosion by H2SO4 solution.

Gentian violet adsorption on a super magnetic nanocomposite (Fe2O3/Bentonite), non-linear kinetic and isotherm modeling

The health of humans may be at risk from textile wastewater's harmful dye effluents. Searching for effective and inexpensive adsorbents to treat these contaminated waters has attracted a lot of interest over the years. This work aimed to prepare a super nanocomposite based on raw bentonite to remove a cationic dye (gentian violet) from wastewater. Raw and Magnetic bentonite have been characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF). The specific surface area calculated by BET transform for both adsorbents show a high specific area for magnetic bentonite, four times higher than the raw one, it is estimated to 10.3452 and 41.6073 m2. g-1 for raw and magnetic bentonite respectively. A UV-Vis spectrophotometer has also characterized the gentian violet dye (GV). Kinetic non-linear models confirm that the adsorption phenomena are well modeled by the pseudo second order model, and thermodynamic studies show that it is also a spontaneous, endothermic, and inorganized process. The non-linear adsorption isotherm results were best fitted using the Langmuir isotherm, which refers to monolayer adsorption. The effect of some parameters, such as adsorbent mass, temperature, and contact time, has also been optimized. From these results, we concluded that supporting iron oxide on bentonite can increase the adsorption capacity, with a maximum Langmuir monolayer adsorption capacity qm= 137.39 mg. g-1.

Lanthanum hydroxide@cellulose membranes with tunable pore sizes for selective removal of dyes with the same charges

Adsorptive membranes for the efficient separation of dyes with the same charges are quite desirable. Herein, a novel membrane of lanthanum hydroxide/cellulose hydrogel coated filter paper (LC) was prepared through a facile strategy of dip-coating followed by freeze-shaping. With the aid of cellulose gel, the generated La(OH)3 achieved fine dispersion. In addition, the pore size of LC membrane could be regulated by altering the cellulose concentration or the lanthanum chloride dosage, which was crucial for its water flux. In particular, the obtained membrane possessed a high water flux (128.4 L m−2 h−1) and a high dye rejection (97.2 %) for anionic Congo red (CR) only driven by the gravity, which outperformed many previously reported membranes. More intriguingly, its dye rejection for anionic methyl orange (MO) was only 0.9 %, exhibiting high selectivity for dyes with the same charges. Single-solute adsorption experiments indicated that the CR adsorption on the membrane was best fitted by the pseudo-first-order kinetic model, and it followed the Langmuir monolayer adsorption mechanism.

Evaluation of the antitumor activity of albendazole using Langmuir-Blodgett monolayers as surface mediated drug delivery system

This study demonstrates the application of Langmuir and Langmuir-Blodgett films as biomimetic drug reservoirs and delivery systems to investigate the effect of an anthelmintic on cancer cell culture. The repurposing of benzimidazole anthelmintics for cancer therapy due to their microtubule-inhibiting properties has gained attention, showing promising anticancer effects and tumor-suppressive properties. Although widely used in medicine, the low aqueous solubility of benzimidazole compounds poses challenges for studying their effects on cancer cells, requiring incorporation into various formulations. Our study demonstrates that incorporating albendazole into stable Palmitic Acid Langmuir monolayers, forming Langmuir-Blodgett films, significantly affects the proliferation of liver carcinoma cells. This report presents the initial findings of the effect of an antitumoral drug on cancer cell culture using a simple and repeatable methodology.