Non-toxic Procedure Research Articles

Construction of Functionalized Oxindoles by Quinone-Carbonate Synergistically Triggered Intermolecular Radical Coupling.

We disclose a rapid and nontoxic procedure to construct various oxindoles. This method harnesses the power of a catalytic amount of quinone in synergy with Cs2CO3, showcasing remarkable compatibility with a wide range of functional groups. Mechanistic investigations reveal that it operates via a radical pathway, likely initiated by the single-electron transfer from quinone-Cs2CO3 complexes. This pivotal electron transfer event leads to the generation of a crucial alkyl radical intermediate, contributing to the overall success and efficacy of the transformation.

Molecular Design Using Selected Concentration Effects in Optically Activated Fluorescent Matrices.

Molecular physics plays a pivotal role in various fields, including medicine, pharmaceuticals, and broader industrial applications. This study aims to enhance the methods for producing specific optically active materials with distinct spectroscopic properties at the molecular level, which are crucial for these sectors, while prioritizing human safety in both production and application. Forensic science, a significant socio-economic field, often employs hazardous substances in analyzing friction ridges on porous surfaces, posing safety concerns. In response, we formulated novel, non-toxic procedures for examining paper evidence, particularly thermal papers. Our laboratory model utilizes a polyvinyl alcohol polymer as a rigid matrix to emulate the thermal paper's environment, enabling precise control over the spectroscopic characteristics of 1,8-diazafluoro-9-one (DFO). We identified and analyzed the cyclodimer 1,8-diazafluoren-9-one (DAK DFO), which is a non-toxic and biocompatible alternative for revealing forensic marks. The reagents used to preserve fingerprints were optimized for their effectiveness and stability. Using stationary absorption and emission spectroscopy, along with time-resolved emission studies, we verified the spectroscopic attributes of the new structures under deliberate aggregation conditions. Raman spectroscopy and quantum mechanical computations substantiated the cyclodimer's configuration. The investigation provides robust scientific endorsement for the novel compound and its structural diversity, influenced by the solvatochromic sensitivity of the DFO precursor. Our approach to monitoring aggregation processes signifies a substantial shift in synthetic research paradigms, leveraging simple chemistry to yield an innovative contribution to forensic science methodologies.

Poly(Vinyl Alcohol)/Bovine Serum Albumin Hybrid Hydrogels with Tunable Mechanical Properties.

In this study, a new strategy was adopted for obtaining polymer/protein hybrid hydrogels with shape stability and tunable mechanical or rheological characteristics by using non-toxic procedures. A chemical network was created using a poly(vinyl alcohol)(PVA)/bovine serum albumin (BSA) mixture in aqueous solution in the presence of genipin and reduced glutathione (GSH). Then, a second physical network was formed through PVA after applying freezing/thawing cycles. In addition, the protein macromolecules formed intermolecular disulfide bridges in the presence of GSH. In these conditions, multiple crosslinked networks were obtained, determining the strengthening and stiffening into relatively tough porous hydrogels with tunable viscoelasticity and a self-healing ability. A SEM analysis evidenced the formation of networks with interconnected pores of sizes between 20 μm and 50 μm. The mechanical or rheological investigations showed that the hydrogels' strength and response in different conditions of deformation were influenced by the composition and crosslinking procedure. Thus, the dynamics of the hybrid hydrogels can be adjusted to mimic the viscoelastic properties of the native tissues. The dynamic water vapor-sorption ability, swelling behavior in an aqueous environment, and bioadhesive properties were also investigated and are discussed in this paper. The hybrid hydrogels with tunable viscoelasticity can be designed on request, and they are promising candidates for tissue engineering, bioinks, and wound dressing applications.

Efficient Wet Adhesion through Mussel‐Inspired Proto‐Coacervates

AbstractAdhesion underwater is a major challenge. Mussel‐inspired complex coacervates functionalized with L‐3,4‐dihydroxyphenylalanine (L‐DOPA) are proposed for underwater adhesives through versatile chemistry of DOPA, however, simple, efficient, controllable, and nontoxic procedures to harness them are still under investigation. In this study, inspired from the mussel byssus formation process, coacervate adhesives are formed underwater by simple injection of an acidic proto‐coacervate of DOPA functionalized polyelectrolytes on underwater surfaces. The proto‐coacervate is initially an acidic liquid, it increased in pH due to water diffusion, resulting in coacervation driven by electrostatic interaction, without the requirement for pH adjustment or organic solvents. Additionally, the pH of liquid–liquid phase separation is tuned by substituting polyelectrolytes with different pKa, which satisfied different pH requirement in real life. The coacervate‐based adhesives on glass substrates exhibit strengths comparable to commercial glues when dry and to mussel glue when wet, showing high biocompatibility in human epidermis in vitro.

Synthesis of hybrid silver–doped graphene oxide material as a superior antibacterial performance and cadmium ion sensor

In this study, in-situ method was applied for synthesizing silver-doped graphene oxide (Ag/GO). The material was extensively characterized by X-ray diffraction, Transmission electron microscopy, Scanning electron microscope, Raman spectroscopy, energy-dispersive X-ray spectroscopy, and UV-Vis spectroscopy. The characterization analysis results demonstrated that Ag/GO nanocomposite was successfully synthesized, revealing the formation of AgNPs on GO sheets with an average diameter ranging from 15 to 30 nm. The Ag/GO nanocomposite exhibited excellent antibacterial effect against three strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa), and Gram-positive (Staphylococcus aureus) bacteria using the zone inhibition method. Moreover, the Ag/GO nanocomposite was also useful for the detection of Cd2+ ions in an aqueous solution with a detection limit of 10.15 mg/L. This study developed an eco-friendly route for the fabrication of Ag/GO nanocomposite using a non-toxic procedure that could be a great potential for biomedical-related applications and colorimetric detection of heavy metal present in water.

Photoimmunotherapy: A New Paradigm in Solid Tumor Immunotherapy

In recent years, the incidence of cancer has been increasing worldwide. Conventional cancer treatments include surgery, chemotherapy, and radiation, which mostly kill tumor cells at the expense of normal and immune cells. Although immunotherapy is an accurate, rapid, efficient tumor immune treatment, it causes serious adverse reactions, such as cytokine release syndrome (CRS) and neurotoxicity. Therefore, there is an urgent need to develop an effective and nontoxic procedure for immunotherapy. The clinical combination of phototherapy and immunoadjuvant therapy can induce immunogenic cell death and enhance antigen presentation synergy. It also causes a systemic antitumor immune response to manage residual tumors and distant metastases. Photoimmunotherapy (PIT) is a tumor treatment combining phototherapy with immunotherapy based on injecting a conjugate photosensitizer (IR700) and a monoclonal antibody (mAb) to target an expressed antigen on the tumor surface. This combination can enhance the immune response ability, thus having a good effect on the treatment of residual tumor and metastatic cancer. In this review, we summarize the recent progress in photoimmunotherapy, including photoimmunoconjugate (PIC), the activation mechanism of immunogenic cell death (ICD), the combination therapy model, opportunities and prospects. Specifically, we aim to provide a promising clinical therapy for solid tumor clinical transformation.

Green synthesis of trimetallic oxide nanoparticles and their use as an efficient catalyst for the green synthesis of quinoline and spirooxindoles: Antibacterial, cytotoxicity and anti-colon cancer effects

The three-metallic oxide (Cu/Cr/Ni) nanoparticles were prepared using Echinops persicus plant extract via a simple, biocompatible, cost-effective, and non-toxic procedure, and their catalytic activity was evaluated over the synthesis of biologically active quinoline and spirooxindole derivatives. The synthesized nanoparticles were characterized by various analytical methods including UV–Vis, FTIR, EDX, XRD, FE-SEM, DLS, and TEM analyses. Effective parameters involved in the reactions were designed by Design-Expert 10.0.7 software. The Cu/Cr/Ni nanoparticles were used as an efficient catalyst for the preparation of quinolines and spirooxindoles under solvent-free conditions with good to excellent efficiencies. Furthermore, due to the rich phenolic content of Echinops persicus flower extract, the antibacterial properties of nanoparticles against E. coli, S. aureus, and B. cereus were studied by MIC as well as well diffusion methods. In addition, the cytotoxicity and anti-colon cancer activity of the nanoparticles was studied on human colon cancer (HT29) cells based on the MTT assay. The results and observations clearly showed that Cu/Cr/Ni NPs have noteworthy catalytic and antibacterial activity, completely superior to their corresponding single-metal nanoparticles.

Nanoclay Reinforced Biomaterials for Mending Musculoskeletal Tissue Disorders.

Nanoclay-reinforced biomaterials have sparked a new avenue in advanced healthcare materials that can potentially revolutionize treatment of musculoskeletal defects. Native tissues display many important chemical, mechanical, biological, and physical properties that engineered biomaterials need to mimic for optimal tissue integration and regeneration. However, it is time-consuming and difficult to endow such combinatorial properties on materials via feasible and nontoxic procedures. Fortunately, a number of nanomaterials such as graphene, carbon nanotubes, MXenes, and nanoclays already display a plethora of material properties that can be transferred to biomaterials through a simple incorporation procedure. In this direction, the members of the nanoclay family are easy to functionalize chemically, they can significantly reinforce the mechanical performance of biomaterials, and can provide bioactive properties by ionic dissolution products to upregulate cartilage and bone tissue formation. For this reason, nanoclays can become a key component for future orthopedic biomaterials. In this review, we specifically focus on the rapidly decreasing gap between clinic and laboratory by highlighting their application in a number of promising in vivo studies.

Phytosynthetic Fabrication of Lanthanum Ion-Doped Nickel Oxide Nanoparticles Using Sesbania grandiflora Leaf Extract and Their Anti-Microbial Properties

Over the past few years, the photogenic fabrication of metal oxide nanoparticles has attracted considerable attention, owing to the simple, eco-friendly, and non-toxic procedure. Herein, we fabricated NiO nanoparticles and altered their optical properties by doping with a rare earth element (lanthanum) using Sesbania grandiflora broth for antibacterial applications. The doping of lanthanum with NiO was systematically studied. The optical properties of the prepared nanomaterials were investigated through UV-Vis diffuse reflectance spectra (UV-DRS) analysis, and their structures were studied using X-ray diffraction analysis. The morphological features of the prepared nanomaterials were examined by scanning electron microscopy and transmission electron microscopy, their elemental structure was analyzed by energy-dispersive X-ray spectral analysis, and their oxidation states were analyzed by X-ray photoelectron spectroscopy. Furthermore, the antibacterial action of NiO and La-doped NiO nanoparticles was studied by the zone of inhibition method for Gram-negative and Gram-positive bacterial strains such as Escherichia coli and Bacillus sublitis. It was evident from the obtained results that the optimized compound NiOLa-04 performed better than the other prepared compounds. To the best of our knowledge, this is the first report on the phytosynthetic fabrication of rare-earth ion Lanthanum (La3+)-doped Nickel Oxide (NiO) nanoparticles and their anti-microbial studies.

Cyrene™ as an Alternative Sustainable Solvent for the Preparation of Poly(lactic-co-glycolic acid) Nanoparticles.

Toxic and environmental harmful organic solvents are widely applied to prepare poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NP) in standard preparation methods. Alternative non-toxic solvents suffer from disadvantages like high viscosity and plasticizing effects. To overcome these hurdles, Cyrene™ as a new sustainable, non-toxic and low viscous solvent was used to formulate PLGA NPs. A new preparation method was developed and optimized. Small sized blank NPs around 220nm with a narrow size distribution and highly negative charge (<-23mV) were obtained. To test the application for drug delivery, the lipophilic model drug atorvastatin was encapsulated in high drug loads with comparable physicochemical characteristics as the blank NPs, and a total drug release within 24h. No changes of the crystallinity or plasticizing effects could be observed. Highly purified NPs were obtained with a residual Cyrene™ content <2.5%. Finally, the biocompatibility of Cyrene™ itself and of the NPs formed in the presence of Cyrene™ was demonstrated in a hen's egg test. Conclusively, the use of Cyrene™ as solvent offers a simple, fast and non-toxic procedure for preparation of PLGA NPs as drug delivery systems circumventing the downsides of standard methods.

Synthesis of ketamine from a nontoxic procedure: a new and efficient route

Ketamine [2-(2-chlorophenyl)-2-methylamino-cyclohexan-1-one] has been used in both veterinary and human medicine. In this research, a new and efficient protocol has been developed for the synthesis of ketamine, by using hydroxy ketone intermediate. Synthesis of this drug has been done in five steps. At first, the cyclohexanone was made to react with 2-chlorophenyl magnesium bromide reagent followed by dehydration in the presence of an acidic ionic liquid, 1-methyl-3-[2-(dimethyl-4-sulfobutyl-ammonium) ethane] imidazolium hydrogen sulfate to obtain 1-(2-chlorophenyl)-cyclohexene. The oxidation of the synthesized alkene by potassium permanganate gave corresponding hydroxy ketone intermediate. The imination of this intermediate by methyl amine and finally the rearrangement of the obtained imine at elevated temperature resulted in the synthesis of ketamine. All of the intermediates and the product were characterized by 1H-NMR and IR spectroscopies. No need to use toxic bromine (which is used in most of the reported procedures for the synthesis of ketamine), high reaction yields and use of commercially available and safe materials and no need to use corrosive acids in the dehydration step are some of the advantages of this procedure over the common reported ones for the snthesis of ketamine. An efficient five-step protocol for the synthesis of ketamine was developed. Cyclohexanone reacted with 2-chlorophenyl magnesium bromide, followed by dehydration with acidic ionic liquid. Oxidation of the alkene gave corresponding hydroxy ketone intermediate. The imination of this intermediate and rearrangement of the obtained imine finally produced ketamine.

Biorational strategies for the management of insect pests of spice crops

Pest control strategies based on relatively non-toxic procedures that preserve the health of the ecosystem and minimizes negative effects on beneficial organisms, and utilize microbial pathogens and their products, plant natural products, semiochemicals, biotechnological strategies and reduced-risk pesticides can be termed as ‘biorational strategies’. This review consolidates the information available on the use of biorational strategies for the management of insect pests of spice crops such as Piper nigrum (black pepper), Elettaria cardamomum (cardamom), Zingiber officinale (ginger), Curcuma longa (turmeric), Coriandrum sativum (coriander), Cuminum cyminum (cumin) and Foeniculum vulgare (fennel). The review also identifies the current gaps in knowledge and the opportunities and challenges in using biorational strategies for the production of clean spices, reflecting the global concern over pesticide misuse.

Effective killing of bacteria under blue-light irradiation promoted by green synthesized silver nanoparticles loaded on reduced graphene oxide sheets.

Graphene oxide (GO) materials loaded with silver nanoparticles (AgNPs) have drawn considerable attention due to their capacity to efficiently inactivate bacteria though a multifaceted mechanism of action, as well as for presenting a synergetic effect against bacteria when compared to the activity of AgNPs and GO alone. In this investigation, we present an inexpensive and environmentally-friendly method for synthesizing reduced GO sheets coated with silver nanoparticles (AgNPs/r-GO) using a coffee extract solution as a green reducing agent. The physical and chemical properties of the produced materials were extensively characterized by scanning electron microscopy (SEM), field-emission gun transmission electron microscopy (FEG-TEM), ultraviolet and visible absorption (UV-Vis), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ion release determination. The results demonstrated that AgNPs/r-GO composites were successfully produced, revealing the formation of micrometer-sized r-GO sheets decorated by AgNPs of approximately 70nm diameter. Finally, bactericidal and photobactericidal effects of the AgNPs/r-GO composites were tested against Staphylococcus aureus, in which the results showed that the composites presented antimicrobial and photoantimicrobial activities. Moreover, our results demonstrated for the first time, to our knowledge, that an efficient process of bacterial inactivation can be achieved by using AgNPs/r-GO composites under blue light irradiation as a result of three different bacterial killing processes: (i) chemical effect promoted by Ag+ ion release from AgNPs; (ii) photocatalytic activity induced by AgNPs/r-GO composites, enhancing the bacterial photoinactivation due to the excited-Plasmons of the AgNPs when anchored on r-GO; and (iii) photodynamic effect produced by bacterial endogenous photosensitizers under blue-light irradiation. In summary, the present findings demonstrated that AgNPs/r-GO can be obtained by a non-toxic procedure with great potential for biomedical-related applications.

One-step maltose-functionalization of magnetic nanoparticles based on self-assembled oligopeptides for selective enrichment of glycopeptides

Magnetic nanoparticles (MNPs) have been widely explored in enrichment of low-abundance glycoproteins/glycopeptides prior to mass spectrometry analysis in glycoproteomics. Currently, most functional groups for recognizing glycoproteins/glycopeptides are usually immobilized on the nanomaterial surface based on covalent modification, which suffers from multistep treatment, surface-dependence, and harsh conditions. In this work, we first report a facile and rapid method for surface functionalization and subsequent glycopeptides enrichment via one-step assembly of maltose-modified oligopeptides with a sequence of Ala-Glu-Ala-Glu-Ala-Lys-Ala-Lys (AEK8-maltose). In physiological conditions, AEK8-maltose readily self-organized into a complete coating layer dominated by β-sheets on the surface of SiO2@Fe3O4 and C@Fe3O4 MNPs, which remain intact to repeat washing with acidic organic and aqueous solutions extensively used in the sample enrichment treatments. Thus, the resulting AEK8-maltose functionalized MNPs show excellent performance in enrichment of glycopeptides in standard glycoprotein digests (24 glycopeptides from horseradish peroxidase (HRP), 31 glycopeptides from immunoglobulin (IgG)) and human serum digests (282 glycopeptides), including rapid enrichment speed (5 min), high detection sensitivity (0.001 ng/μL HRP), high selectivity (mass ratios of HRP and bovine serum albumin (BSA) digests up to 1:150), good enrichment recovery (over 86.3%), remarkable stability (repeatable for more than 8 times), and excellent renewability, which are better than or comparable with the literature results reported to date. The current work based on self-assembling oligopeptides provides a mild, economic and nontoxic procedure for one-step surface functionalization of various nanomaterials.

261-OR: Core-Shell Spherification: A New Microencapsulation Platform for Hyaluronic Acid and PEGDA

Cell microencapsulation associated with islet transplantation is a rapidly expanding field. Traditional alginate microspheres still suffer from poor biocompatibility, and microencapsulation of more advanced hydrogels is challenging due to their slower gelation rates. We have developed a novel, non-cytotoxic, non-emulsion based method to produce hydrogel microspheres compatible with a wide variety of materials, called Core-Shell Spherification (CSS). Here, we demonstrate fabrication of microspheres via CSS derived from two slow-hardening hydrogels: hyaluronic acid (HA) and polyethylene glycol diacrylate (PEGDA). HA microspheres were manufactured with two different crosslinking methods: thiolation and methacrylation. Microspheres of methacrylated HA (MeHA) had the greatest swelling ratio, the largest average diameter and the lowest diffusion barrier. In contrast PEGDA microspheres had the smallest diameters, the lowest swelling ratio and the highest diffusion barrier, while microspheres of thiolated HA (ThHA) had characteristics that were in between the other two groups. To test the ability of the hydrogels to protect cells while promoting function, diabetic NOD mice received xenotransplants via intraperitoneal injections of PEGDA or MeHA microencapsulated canine islets. PEGDA microspheres reversed diabetes for the length of the study (up to 16 weeks). In contrast, islets encapsulated in MeHA microspheres at the same dose restored normoglycemia, but only transiently (3-4 weeks). Non-encapsulated canine islet transplanted at the same dose did not restore normoglycemia for any length of time. In conclusion, CSS appears to offer several advantages to current cell encapsulation technologies, including a non-toxic microencapsulation procedure compatible with various hydrogel types. Disclosure F. Karanu: Employee; Self; LIkarda LLC. S. Harrington: Employee; Self; Likarda, LLC. L. Ott: Employee; Self; Likarda, LLC.

A simple non-toxic ethylene carbonate fluorescence in situ hybridization (EC-FISH) for simultaneous detection of repetitive DNA sequences and fluorescent bands in plants

The major drawbacks of standard plant fluorescence in situ hybridization (FISH) designed for double-stranded DNA probes include requirement for experimentally determined heat denaturation of chromosomes at high temperatures and at least overnight hybridization. Consequently, processing with chromosomal preparations may easily result in heat-induced deterioration of chromosomal structural details, is time-consuming, and involves the use of toxic formamide and formaldehyde. Here, I have described a simple and appealing non-toxic procedure with ethylene carbonate (EC)—a formamide-substituting solvent and double-stranded repetitive DNA probes. Applying EC as a component of the hybridization solution at 46 °C not only allowed successful overnight hybridization but also gave a possibility to reduce the hybridization time to 3 h, hence converting the technique into a 1-day procedure. Importantly, the EC-FISH tended to preserve well chromosome structural details, e.g., DAPI-positive bands, thus facilitating simultaneous FISH mapping and chromosome banding on the same slide. The procedure requires no formaldehyde and RNA-se treatment of chromosomes, and no heat denaturation of chromosomal DNA. The key condition is to obtain high-quality cytoplasm-free preparations. The method was reproducible in all the plants studied (Allium, Nigella, Tradescantia, Vicia), giving a species-specific signal pattern together with clear DAPI bands on chromosomes. The procedure described here is expected to give a positive stimulus for improving gene-mapping approaches in plants.

Starch-supported gold nanoparticles and their use in 4-nitrophenol reduction

Gold nanoparticles (AuNPs) have been synthesized through a green synthesis method using mung bean starch (MBS) as both reducing and stabilizing agents. The chemical state was analyzed by X-ray photoelectron spectroscopy (XPS). The crystalline structures were characterized by X-ray diffraction (XRD). The thermal properties were measured by thermogravimetric analysis and differential thermal analysis (TGA/DTA). The surface morphology was investigated by scanning electron microscopy (SEM). In order to investigate the catalytic activity, the mung bean starch-supported AuNPs (MBS-AuNPs) was utilized as a heterogeneous catalyst in the reduction of 4-nitrophenol (4-NP) in the presence of sodium borohydride (NaBH4). The kinetic studies under the different experimental conditions were performed in order to determine the activation parameters from the Arrhenius and Eyring equations. It was found that the activation energy (Ea), activation enthalpy (ΔH#) and activation entropy (ΔS#) were calculated to be 47.42kJmol−1, 44.78kJmol−1 and −261.49kJmol−1, respectively. In addition, the catalytic activity was 73% reduction after recycling at the end of the fifth use. This work offers a non-toxic procedure for the synthesis of nanoparticles using starch-rich polymers with a great promise toward other potential applications.

Green biosynthesis of silver nanoparticles using Quercus brantii (oak) leaves hydroalcoholic extract

Context: There is an ever-growing need to develop green, non-toxic, and eco-friendly procedures for synthesis and assembly of nanoparticles (NPs) with the desired morphologies and sizes. The hydroalcoholic extract of Persian oak leaves [Quercus brantii Lindl. (Fagaceae)] contains high content of phenolic and flavonoid compounds with strong antioxidant activities, and it seems that this plant can be considered a good candidate for metal nanoparticle synthesis.Objective: The potential of Q. brantii leaves in the production of silver NPs and the effect of the extract ethanol concentration on the produced NPs were studied.Materials and methods: Quercus brantii leaves were freshly collected, air-dried at room temperature, powdered, and sieved. Hydroalcoholic extracts (70% and 96%) were prepared by percolation of the plant powder. The reaction mixtures contained (final concentrations): AgNO3 (1 mM) as the substrate, plant extract as the biocatalyst, and phosphate buffer (pH = 7, 100 mM) as the reaction medium. Silver ions were determined using atomic absorption analysis. Particle size distribution of NPs was analyzed using Nano-Zeta Sizer (Malvern Instruments Ltd, Malvern, UK). Samples for TEM were prepared by drop-coating the silver nanoparticle suspensions onto carbon-coated copper grids.Results: Hydroalcoholic extract (96%) of Q. brantii successfully produced quite small (as small as 0.83 nm and the mean size of 6 nm), spherical, and poly-dispersed NPs with low aggregates. The conversion was fast and completed in 5 h.Discussion and conclusion: This plant and the extraction method seem to be quiet attractive for industrial scale production of NPs.

Removal of hazardous azopyrazole dye from an aqueous solution using rice straw as a waste adsorbent: Kinetic, equilibrium and thermodynamic studies

In this research, activated carbonmade from rice straw (ACRS) was synthesized simply by a low cost and nontoxic procedure and used for the adsorption of hazardous azopyrazole dye. The effect of different variables in the batch method as a function of solution pH, contact time, concentration of adsorbate, adsorbent dosage and temperature were investigated and optimal experimental conditions were ascertaine. Surface modification of ACRS using scanning electron microscopy (SEM) was obtained. More than 75% removal efficiency was obtained within 75min at adsorbent dose of 0.5g for initial dye concentration of 30–100mgL−1 at pH 3. The experimental equilibrium data were tested by the isotherm models namely, Langmuir and Freundlich adsorption and the isotherm constants were determined. The kinetic data obtained with different initial concentration and temperature were analyzed using a pseudo-first-order and pseudo-second-order equations. The activation energy of adsorption was also evaluated and found to be +13.25kJmol−1 indicating that the adsorption is physisorption. The thermodynamics of the adsorption indicated spontaneous and exothermic nature of the process. The results indicate that ACRS could be employed as low-cost material for the removal of acid dyes from aqueous solution.

Artificial neural network (ANN) method for modeling of sunset yellow dye adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic and isotherm study

In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005–0.015g) and 5–40mg/L of sunset yellow dye over contact time of 0.5–30min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg–Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R2) of 0.998 were found for prediction and modeling of SY removal.The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10min contact time; an adsorbent dose of 0.015g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85mg/g for 0.005g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation.