Molecular dynamics simulation of novel diamino-functionalized hollow mesosilica spheres for adsorption of dyes from synthetic wastewater

Applications of hollow nanostructures in water treatment considering organic, inorganic, and bacterial pollutants

One of the major issues of modern society is water contamination with different organic, inorganic, and contaminants bacteria. Finding cost-effective and efficient materials and methods for water treatment and environment remediation is among the scientists' most important considerations. Hollow-structured nanomaterials, including hollow fiber membranes, hollow spheres, hollow nanoboxes, etc., have shown an exciting capability for wastewater refinement approaches, including membrane technology, adsorption, and photocatalytic procedure due to their extremely high specific surface area, high porosity, unique morphology, and low density. Diverse hollow nanostructures could potentially eliminate organic contaminants, including dyes, antibiotics, oil/water emulsions, pesticides, and other phenolic compounds, inorganic pollutants, such as heavy metal ions, salts, phosphate, bromate, and other ions, and bacteria contaminations. Here, a comprehensive overview of hollow nanostructures' fabrication and modification, water contaminant classification, and recent studies in the water treatment field using hollow-structured nanomaterials with a comparative attitude have been provided, indicating the privilege abd detriments of this class of nanomaterials. Eventually, the future outlook of employing hollow nanomaterials in water refinery systems and the upcoming challenges arising in scaling up are also propounded.

Comparison of cytotoxicity of Miltefosine and its niosomal form on chick embryo model

Various drugs have been used for the treatment of leishmaniasis, but they often have adverse effects on the body's organs. In this study, we aimed to explore the effects of one type of drug, Miltefosine (MIL), and its analogue or modifier, liposomal Miltefosine (NMIL), on several fetal organs using both in silico analysis and practical tests on chicken embryos. Our in silico approach involved predicting the affinities of MIL and NMIL to critical proteins involved in leishmaniasis, including Vascular Endothelial Growth Factor A (VEGF-A), the Kinase insert domain receptor (KDR1), and apoptotic-regulator proteins (Bcl-2-associate). We then validated and supported these predictions through in vivo investigations, analyzing gene expression and pathological changes in angiogenesis and apoptotic mediators in MIL- and NMIL-treated chicken embryos. The results showed that NMIL had a more effective action towards VEGF-A and KDR1 in leishmaniasis, making it a better candidate for potential operative treatment during pregnancy than MIL alone. In vivo, studies also showed that chicken embryos under MIL treatment displayed less vascular mass and more degenerative and apoptotic changes than those treated with NMIL. These results suggest that NMIL could be a better treatment option for leishmaniasis during pregnancy.

Dynamic Light Scattering and Its Application to Control Nanoparticle Aggregation in Colloidal Systems: A Review

Colloidal systems and their control play an essential role in daily human activities, but several drawbacks lead to an avoidance of their extensive application in some more productive areas. Some roadblocks are a lack of knowledge regarding how to influence and address colloidal forces, as well as a lack of practical devices to understand these systems. This review focuses on applying dynamic light scattering (DLS) as a powerful tool for monitoring and characterizing nanoparticle aggregation dynamics. We started by outlining the core ideas behind DLS and how it may be used to examine colloidal particle size distribution and aggregation dynamics; then, in the last section, we included the options to control aggregation in the chemically processed toner. In addition, we pinpointed knowledge gaps and difficulties that obstruct the use of DLS in real-world situations. Although widely used, DLS has limits when dealing with complicated systems, including combinations of nanoparticles, high concentrations, and non-spherical particles. We discussed these issues and offered possible solutions and the incorporation of supplementary characterization approaches. Finally, we emphasized how critical it is to close the gap between fundamental studies of nanoparticle aggregation and their translation into real-world applications, recognizing challenges in colloidal science.

Towards a sustainable transformation of municipal wastewater treatment plants into biofactories using advanced NH3-N recovery technologies: A review

Ammonia (NH3), as a prevalent pollutant in municipal wastewater discharges, can impair aquatic life and have a negatively impact on the environment. Proper wastewater treatment and management practices are essential to protect ecosystems and keep human populations healthy. Therefore, using highly effective NH3-N recovery technologies at wastewater treatment plants (WWTPs) is widely acknowledged as a necessity. In order to improve the overall efficiency of NH3 removal/recovery processes, innovative technologies have been generally applied to reduce its concentration when discharged into natural water bodies. This study reviews the current status of the main issues affecting NH3 recovery from municipal/domestic wastewater discharges. The current study investigated the ability to recover valuable resources, e.g., nutrients, regenerated water, and energy in the form of biogas through advanced and innovative methods in tertiary treatment to achieve higher efficiency towards sustainable wastewater and resource recovery facilities (W&RRFs). In addition, the concept of paradigm shifts from WWTP to a large/full scale W&RRF has been studied with several examples of conversion to innovative bio-factories producing materials. On the other hand, the carbon footprint and the high-energy consumption of the WWTPs were also considered to assess the sustainability of these facilities.

Simulation on oily contamination removal by ozone using molecular dynamics

Ozone (O₃) is characteristic of high oxidative activity. It displays a high potential value in sterilization and decontamination. Although O₃ has been widely investigated for its efficiency and environmentally friendly effectiveness, the fundamental issue regarding the complicated microscopic interaction mechanism between O₃ and contaminant molecules remains largely unaddressed. We addressed this knowledge gap through molecular dynamics (MD) simulation at the molecular scale. Results indicated that five representative hydrocarbon molecules (n-hexadecane, phytane, terpane, naphthalin and acenaphthylene) on a rough silica (SiO₂) surface were almost removed after about 300 ps simulation. And the aromatic molecules were easier to be removed than aliphatic ones. The hydroxyl oxidation reaction was demonstrated as a predominant mechanism. As the large dose of O₃ was supplied by atmospheric air dielectric barrier discharge (DBD) plasma, this work provided an important theoretical reference for better using plasma technology for oily contaminant removal.

An Interpenetrating Polymer Network Hydrogel Based on Cellulose, Applied to Remove Colorant Traces from the Water Medium: Electrostatic Interactions Analysis

The main objective of this work was the removal of eosin Y and green malachite from an aqueous medium by using a cellulose-based biodegradable interpenetrated network (IPN). The IPN was obtained by the sequenced synthesis method. In the first step, cellulose was crosslinked with epichlorohydrin (ECH). In the second step, the obtained gels were swollen in a reactive mixture solution, which was based on the monomers 2-hydroxyethyl methacrylate (HEMA) and 1,6- hexanediol diacrylate (HDDA). After this, swelling equilibrium was reached through the gels' exposition to UV radiation. An infrared spectroscopy (FTIR) was used to analyze the bond stretching, which confirmed the IPN's formation. The swelling kinetics in aqueous mediums with different pH values showed a high swelling at a basic pH value and a low response in neutral and acidic media. The IPNs showed an improvement in water uptake, compared to the networks based on PHEMA or cellulose. The IPN was used to remove dyes from the water. The results showed that a high percentage of green malachite was removed by the IPN in six minutes of contact time. The experimental results were confirmed by the docking/modeling method of the system (IPN/Dye). The different physical interactions between the IPN and the dyes' molecules were investigated. The interactions of the hydrogen bonds with malachite green were stronger than those with eosin Y, which was in good agreement with the experimental results.

Cytotoxicity of Amphotericin B and AmBisome: In Silico and In Vivo Evaluation Employing the Chick Embryo Model

Leishmaniasis has been identified as a significant disease in tropical and subtropical regions of the world, with Iran being one of the disease-endemic areas. Various treatments have been applied for this disease, and amphotericin B (Amp B) is the second line of treatment. Side effects of this drug have been reported in various organs. The present study investigated the effects of different types of Amp B on fetal organs using in silico and in vivo assays (chicken embryos). In vivo analysis was done by checking pathological changes, angiogenesis, and apoptosis alterations on eggs treated by Amp B and AmBisome. In silico approach was employed to predict the affinity of Amp B and AmBisome to the vascular endothelial growth factor A (VEGF-A), its receptor (KDR1), apoptotic-regulator proteins (Bcl-2-associated X protein (Bax), B-cell lymphoma (Bcl-2), and Caspase-8. The ADME-toxicity prediction reveals that AmBisome possesses a superior pharmacological effect to Amp B. The best result of all the dockings in the Molegro Virtual Docker (MVD) was obtained between Bax, Bcl-2, Caspase-8, KDR1, and VEGF-A targets. Due to the lower Egap (HOMO–LUMO) of AmBisome, the chemical reactivity of AmBisome was higher than that of Amp B. In vivo analysis showed that embryos that received Amp B exhibited less vascular density than AmBisome. Amp B alone significantly increased the expression of apoptosis and decreased angiogenesis genes compared to AmBisome. The histopathology analysis of the treated embryos showed a reduction in the blood vessel collapse and an increase in degenerative and apoptotic–necrotic changes in the embryonic tissues. Overall, the results suggest the potential benefits of AmBisome over Amp B, which might be a better treatment strategy to treat leishmaniasis during pregnancy.

Neural-based modeling adsorption capacity of metal organic framework materials with application in wastewater treatment

We developed a computational-based model for simulating adsorption capacity of a novel layered double hydroxide (LDH) and metal organic framework (MOF) nanocomposite in separation of ions including Pb(II) and Cd(II) from aqueous solutions. The simulated adsorbent was a composite of UiO-66-(Zr)-(COOH)2 MOF grown onto the surface of functionalized Ni50-Co50-LDH sheets. This novel adsorbent showed high surface area for adsorption capacity, and was chosen to develop the model for study of ions removal using this adsorbent. A number of measured data was collected and used in the simulations via the artificial intelligence technique. Artificial neural network (ANN) technique was used for simulation of the data in which ion type and initial concentration of the ions in the feed was selected as the input variables to the neural network. The neural network was trained using the input data for simulation of the adsorption capacity. Two hidden layers with activation functions in form of linear and non-linear were designed for the construction of artificial neural network. The model's training and validation revealed high accuracy with statistical parameters of R2 equal to 0.99 for the fitting data. The trained ANN modeling showed that increasing the initial content of Pb(II) and Cd(II) ions led to a significant increment in the adsorption capacity (Qe) and Cd(II) had higher adsorption due to its strong interaction with the adsorbent surface. The neural model indicated superior predictive capability in simulation of the obtained data for removal of Pb(II) and Cd(II) from an aqueous solution.

Design and synthesis of heterocyclic azole based bioactive compounds: Molecular structures, quantum simulation, and mechanistic studies through docking as multi-target inhibitors of SARS-CoV-2 and cytotoxicity

Two heterocyclic azole compounds, 3-(2,3-dihydrobenzo[d]thiazol-2-yl)-4H-chromen-4-one (SVS1) and 5-(1H-indol-3-yl)-4-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (SVS2) were obtained unexpectedly from 2-aminothiophenol and 4-oxo-4H-chromene-3-carbaldehyde (for SVS1), and (E)-2-((1H-indol-3-yl)methylene)-N-methylhydrazine-1-carbothioamide in the presence of anhydrous FeCl₃ (for SVS2), respectively. The compounds were well characterized by analytical and spectroscopic tools. The molecular structures of both the compounds were determined by single crystal X-ray diffraction (XRD) study. The results obtained from density functional theory (DFT) study revealed the molecular geometry and electron distribution of the compounds, which were correlated well with the three-dimensional structures obtained from the single crystal XRD. DMol³ was used to calculate quantum chemical parameters [chemical potential (µ), global hardness (η), global softness (σ), absolute electronegativity (χ) and electrophilicity index (ω)] of SVS1 and SVS2. Molecular docking study was performed to elucidate the binding ability of SVS1 and SVS2 with SARS-CoV-2 main protease and human angiotensin-converting enzyme-2 (ACE-2) molecular targets. Interestingly, the binding efficiency of the compounds with the molecular targets was comparable with that of remdesivir (SARS-CoV-2), chloroquine and hydroxychloroquine. SVS1 showed better docking energy than SVS2. The molecular docking study was complemented by molecular dynamics simulation study of SARS-CoV-2 main protease-SVS1 complex, which further exemplified the binding ability of SVS1 with the target. In addition, SVS1, SVS2 and cisplatin were assessed for their cytotoxicity against a panel of three human cancer cells such as HepG-2 (hepatic carcinoma), T24 (bladder) and EA.hy926 (endothelial), as well as Vero (kidney epithelial cells extracted from an African green monkey) normal cells using MTT assay. The results showed that SVS2 has significant cytotoxicity against HepG-2 and EA.hy926 cells with the IC₅₀ values of 33.8 μM (IC₅₀ = 49.9 μM-cisplatin and 8.6 μM-doxorubicin) and 29.2 (IC₅₀ = 26.6 μM-cisplatin and 3.8 μM-doxorubicin), respectively.

Theoretical and Experimental Insights into the Possible Interfacial Interactions between β-Glucan and Fat Molecules in Aqueous Media

Excessive body fat and high cholesterol are one of the leading reasons for triggering cardiovascular risk factors, obesity, and type 2 diabetes. Beta-glucan (BG)-based dietary fibers are found to be effective for lowering fat digestion in the gastrointestinal tract. However, the fat capturing mechanism of BG in aqueous medium is still elusive. In this report, we studied the dietary effect of barley-extracted BG on docosahexaenoic acid (DHA, a model fat molecule) uptake and the impact of the aqueous medium on their interactions using computational modeling and experimental parameters. The possible microscale and macroscale molecular interactions between BG and DHA in an aqueous medium were analyzed through density functional theory (DFT), Monte-Carlo (MC), and molecular dynamics (MD) simulations. DFT analysis revealed that the BG polymer extends hydrogen bonding and nonbonding interactions with DHA. Bulk simulation with multiple DHA molecules on a long-chain BG showed that a viscous colloidal system is formed upon increasing DHA loading. Experimental size and zeta potential measurements also confirmed the electrostatic interaction between BG-DHA systems. Furthermore, simulated and experimental diffusion and viscosity measurements showed excellent agreement. These simulated and experimental results revealed the mechanistic pathway of how BG fibers form colloidal systems with fat molecules, which is probably responsible for BG-induced delayed fat digestion and further halting of fatty molecule absorption in the GI tract.

Multifunctional 3D cationic starch/nanofibrillated cellulose/silver nanoparticles nanocomposite cryogel: Synthesis, adsorption, and antibacterial characteristics

We report a new 3D nanocomposite cryogel combines the advantages of cationic starch (Cs), nanofibrillated cellulose (NFC) and silver nanoparticles (Ag NPs). Cs was the main component of the cryogel while NFC was used as a filling agent to enhance the mechanical properties of the produced cryogel. Both Cs and NFC endow the cryogel with adsorption properties while Ag NPs enhances its antibacterial properties. Ag NPs was green synthesized with the aid of microwave radiation using NFC as reducing and stabilizing agent. The prepared Ag particles were free of impurities with sizes <10 nm and good stability in solution. Two different concentrations of the prepared Ag NPs were added to a mixture of Cs and NFC and subjected to freeze drying to get porous cryogel (3D microstructure). The Ag NPs free cryogel has highly porosity smooth surface with large surface area. Adding Ag NPs decreased these features and increased the 3D roughness. Optimum adsorption of reactive blue 49 was observed after 30 min of contact with 1.5 g/L of the cryogel at pH 1. The adsorption kinetics and isotherm were best described by the pseudo-first-order and Freundlich equations, respectively. All prepared cryogels have notable antibacterial properties that were significantly improved by adding Ag NPs. Overall, the new 3D composite cryogel can efficiently remove dyes and bacteria from wastewater.

Synthesis, characterization, cytotoxicity studies, theoretical approach of adsorptive removal and molecular calculations of four new phosphoramide derivatives and related graphene oxide

In this study, four novel phosphoramide ligands (L1-L4) are synthesized and characterized by ³¹PNMR, ¹HNMR, MASS, and FT-IR spectroscopies. In vitro cell growth inhibition is studied by the MTT assay to evaluate the cytotoxicity of ligands against MCF-7 cell line; the result of the assay demonstrates that all ligands significantly suppress the proliferation of breast cancer cells in a concentration-dependent manner. The calculated IC₅₀ values are in the range of 3.6-10.77 µg ml^-1, of which the lowest value is attributed to L1. Then a facile approach was developed to functionalize graphene oxide (GO) surface by L1. The data which are obtained by XRD, FT-IR, and EDX analysis confirmed the deposition of phosphoramide on the surface of GO. The cell viability of GO-L1 compound at different concentrations is investigated in 24 h experiment. Excellent synergistic antitumor effects of GO and L1 lead to a decrease in IC₅₀ value up to 2.13 μg ml^-1. The Quantum calculations of compounds are used to study energies and HOMO and LUMO values, dipole moments (µ), global hardness (η), global softness (σ), and electrophilicity index (ω) using DMol³ module in Material studio2017. The docking calculations are performed to describe the mode of the binding to DNA and DNA polymerase IIα. Adsorption calculations of ligands (L1-L4) on GO sheet in the presence of water showed that L1 and L2 were located on GO via π electrons of anisole ring. While, L3 and L4 were located on GO by π - π interactions of aniline ring.

Environmentally friendly acetic acid/steam explosion/supercritical carbon dioxide system for the pre-treatment of wheat straw

It is well established that pretreatment of lignocellulosic biomass is required to achieve an effective enzymatic saccharification process. At the present time, most of the touted pre-treatment technologies would cause environmental pollution and unsustainable water use for the pretreated material prior to enzymatic saccharification. To address these shortcomings, the pretreatment technology which combines the supercritical CO₂, SC-CO₂ (a green solvent), acetic acid, and steam explosion was used to assess the pretreatment of wheat straw for enzymatic saccharification. The effects of solvent concentration, impregnation temperature and time, pre-treatment time, and temperature, as well as SC-CO₂ pressure, contact time, and temperature, were evaluated. The results identified that at the optimum SC-CO₂ pressure of 18 MPa, the highest amount of reducing sugars (RS) was produced from the cellulosic pulp using Acetic acid/Steam/SC-CO₂ at 200 °C for 30 min, a value 20% more than the pulp produced with the Water/Steam/SC-CO₂. The effectiveness of the pretreatment process was attributed not only to delignification and defibrillation but also to the exposure of the cellulose structure evidenced from the proportion of the β-glycosidic linkages as shown by FTIR. Passing SC-CO₂ after the pretreatment reduces the amounts of fermentation inhibitors and eliminates the use of wash water.

Resource recovery from landfill leachate: An experimental investigation and perspectives

This work investigates the performances of coconut shell waste-based activated carbon (CSWAC) adsorption in batch studies for removal of ammoniacal nitrogen (NH₃-N) and refractory pollutants (as indicated by decreasing COD concentration) from landfill leachate. To valorize unused resources, coconut shell, recovered and recycled from agricultural waste, was converted into activated carbon, which can be used for leachate treatment. The ozonation of the CSWAC was conducted to enhance its removal performance for target pollutants. The adsorption mechanisms of refractory pollutants by the adsorbent are proposed. Perspectives on nutrient recovery technologies from landfill leachate from the view-points of downstream processing are presented. Their removal efficiencies for both recalcitrant compounds and ammoniacal nitrogen were compared to those of other techniques reported in previous work. It is found that the ozonated CSWAC substantially removed COD (i.e. 76%) as well as NH₃-N (i.e. 75%), as compared to the CSWAC without pretreatment (i.e. COD: 44%; NH₃-N: 51%) with NH₃-N and COD concentrations of 2750 and 8500 mg/L, respectively. This reveals the need of ozonation for the adsorbent to improve its performance for the removal of COD and NH₃-N at optimized reactions: 30 g/L of CSWAC, pH 8, 200 rpm of shaking speed and 20 min of reaction time. Nevertheless, treatment of the leachate samples using the ozonated CSWAC alone was still unable to result in treated effluents that could meet the COD and NH₃-N discharge standards below 200 and 5 mg/L, respectively, set by legislative requirements. This reveals that another treatment is necessary to be undertaken to comply with the requirement of their effluent limit.

Molecular separation of ions from aqueous solutions using modified nanocomposites

Herein, two novel porous polymer matrix nanocomposites were synthesized and used as adsorbents for heavy metal uptake. Methacrylate-modified large mesoporous silica FDU-12 was incorporated in poly(methyl methacrylate) matrix through an in-situ polymerization approach. For another, amine-modified FDU-12 was composited with Nylon 6,6 via a facile solution blending protocol. Various characterization techniques including small-angle X-ray scattering, FTIR spectroscopy, field emission-scanning electron microscopy, transmission electron microscopy, porosimetry, and thermogravimetric analysis have been applied to investigate the physical and chemical properties of the prepared materials. The adsorption of Pb(II) onto the synthesized nanocomposites was studied in a batch system. After study the effect of solution pH, adsorbent amount, contact time, and initial concentration of metal ion on the adsorption process, kinetic studies were also conducted. For both adsorbents, the Langmuir and pseudo-second-order models were found to be the best fit to predict isotherm and kinetics of adsorption. Based on the Langmuir model, maximum adsorption capacities of 105.3 and 109.9 mg g-1 were obtained for methacrylate-modified FDU-12/poly(methyl methacrylate) and amine-modified FDU-12/Nylon 6,6, respectively.

Synthesis of novel adsorbent based on tetrasulfide-functionalized fibrous silica KCC-1 for removal of Hg(II) cations

Hg(II) has been identified to be one of the extremely toxic heavy metals because of its hazardous effects and this fact that it is even more hazardous to animals than other pollutants such as Ag, Au, Cd, Ni, Pb, Co, Cu, and Zn. Accordingly, for the first time, tetrasulfide-functionalized fibrous silica KCC-1 (TS-KCC-1) spheres were synthesized by a facile, conventional ultrasonic-assisted, sol–gel-hydrothermal preparation approach to adsorb Hg(II) from aqueous solution. Tetrasulfide groups (–S–S–S–S–) were chosen as binding sites due to the strong and effective interaction of mercury ions (Hg(II)) with sulfur atoms. Hg(II) uptake onto TS-KCC-1 in a batch system has been carried out. Isotherm and kinetic results showed a very agreed agreement with Langmuir and pseudo-first-order models, respectively, with a Langmuir maximum uptake capacity of 132.55 mg g^–1 (volume of the solution = 20.0 mL; adsorbent dose = 5.0 mg; pH = 5.0; temperature: 198 K; contact time = 40 min; shaking speed = 180 rpm). TS-KCC-1was shown to be a promising functional nanoporous material for the uptake of Hg(II) cations from aqueous media. To the best of our knowledge, there has been no report on the uptake of toxic Hg(II) cations by tetrasulfide-functionalized KCC-1 prepared by a conventional ultrasonic-assisted sol–gel-hydrothermal synthesis method.

Synthesis of Manganese Ferrite/Graphene Oxide Magnetic Nanocomposite for Pollutants Removal from Water

These days, environmental pollution, notably water pollution, has increasingly caused severe human health problems. The major water pollutants are heavy metals. MnFe2O4/GO nanocomposite was prepared in the current work via in situ method and tested to remove lead ion Pb2+ and neutral red (NR) dye from water. The prepared nanocomposite was characterized using different techniques, including X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectra, and vibrating sample magnetometer. The prepared nanocomposite showed high adsorption capacity toward Pb2+ and NR dye removal according to Langmuir fitting indicating the monolayer homogeneous adsorption of pollutants over the adsorbent surface and can be separated easily with an external magnet. The effect of different factors, including contact time, pH, initial concentration, and adsorbent dose on the adsorption, were also studied. The increased concentration of pollutants led to increased adsorption capacity from 63 to 625 mg/g for Pb2+ ions and from 20 to 90 mg/g for NR dye. The increased adsorbent dose led to increased removal efficiency from 39% to 98.8% and from 63% to 94% for Pb2+ and NR dye, respectively. The optimum pH for the adsorption of both pollutants was found to be 6.0. The reusability of MnFe2O4/GO nanocomposite was studied for up to five cycles. The nanocomposite can keep its efficiency even after the studied cycles. So, the prepared magnetic nanocomposite is a promising material for water treatment.

Synthesis of multi-organo-functionalized fibrous silica KCC-1 for highly efficient adsorption of acid fuchsine and acid orange II from aqueous solution

Multi-functionalized fibrous silica KCC-1 (MF-KCC-1) bearing amine, tetrasulfide, and thiol groups was synthesized via a post-functionalization method and fully characterized by several methods such as FTIR, FESEM, EDX-Mapping, TEM, and N₂ adsorption-desorption techniques. Due to abundant surface functional groups, accessible active adsorption sites, high surface area (572 m² g^-1), large pore volume (0.98 cm³ g^-1), and unique fibrous structure, mesoporous MF-KCC-1 was used as a potential adsorbent for the uptake of acid fuchsine (AF) and acid orange II (AO) from water. Different adsorption factors such as pH of the dye solution, the amount of adsorbent, initial dye concentration, and contact time, affecting the uptake process were optimized and isotherm and kinetic studies were conducted to find the possible mechanism involved in the process. For both AF and AO dyes, the Langmuir isotherm model and the PFO kinetic model show the most agreement with the experimental data. According to the Langmuir isotherm, the calculated maximum adsorption capacity for AF and AO were found to be 574.5 mg g^-1 and 605.9 mg g^-1, respectively, surpassing most adsorption capacities reported until now which is indicative of the high potential of mesoporous MF-KCC-1 as an adsorbent for removal applications.

Synthesis, molecular dynamics simulation and adsorption study of different pollutants on functionalized mesosilica

Experimental and computational works were carried out on a new type of mesoporous silica. In the experimental section, functionalized hollow mesosilica spheres were prepared via a facile technique and then evaluated using some analytical techniques (FESEM, TEM, L-XRD, FTIR, BET-BJH, and TGA). The obtained results revealed that the synthesized material had hollow structure with a diamino-grafted porous shell. The molecular separation of crystal Violet (CV) and neutral Red (NR) dyes from water were investigated by adsorption process using the synthesized powder. Influence of adsorbent loading was evaluated as adsorption ability and dyes removal efficiency. Also, the obtained modeling results revealed appropriate fitting of data with non-linear Langmuir model. The theoretical studies were employed to study the adsorption and removal mechanism of cationic (CV and NR) and anionic (orange II (OII)) dyes using molecular dynamics calculations. Moreover, the simulation outcomes provided valuable information about quantum chemical properties including the HOMO-LUMO maps, chemical reactivity, global softness (σ) and hardness (η) for silica-linker-water-dyes components.

Application of Mineral Iron-Based Natural Catalysts in Electro-Fenton Process: A Comparative Study

The potential use of novel iron based mineral catalysts as an effective and available material for electrocatalytic oxidation of refractory contaminants by heterogeneous electro-Fenton (HEF) process was studied for the first time. For this purpose, four natural catalysts, namely ilmenite (FeTiO3), pyrite (FeS2), chromite (FeCr2O4), and chalcopyrite (CuFeS2) were selected as the source of ferrous iron (Fe2+) ions. The catalyst samples were appropriately characterized by X-ray diffraction (XRD) and RAMAN analysis. The degradation kinetics and mineralization rate of 0.2 mM antibiotic cefazolin (CFZ), as a contaminant of emerging concern, were comparatively investigated by HEF using the catalysts mentioned above. The effect of important experimental parameters such as catalysts loading and current on the process efficiency was investigated. Moreover, the performance of these new mineral catalysts was compared in term of CFZ degradation kinetics, mineralization power, mineralization current efficiency and electrical energy consumption. A greater enhancement in degradation/mineralization of CFZ was obtained when using chalcopyrite as the catalyst in HEF. The stability and reusability experiments demonstrated negligible decrease in catalytic activity of chalcopyrite after five consecutive runs. Besides, the rate constant for CFZ oxidation by hydroxyl radicals was estimated according the pseudo-first-order reaction kinetics. The empirical assessment, in addition to economic evaluation, confirmed that iron based mineral catalysts and specifically chalcopyrite could be an appropriate and cost-effective alternative catalyst for HEF due to its high catalytic activity, availability, eco-friendly nature and low energy consumption compared to other synthesized catalysts.