Synthesis and characterization of a novel TiO2@chitosan/alginate nanocomposite sponge for highly efficient removal of As(V) ions from aqueous solutions: Adsorption isotherm, kinetics, experiment and adsorption mechanism optimization using Box-Behnken design.

This research uses a novel TiO2@CSC.Alg composite sponge was created by encasing TiO2 nanoparticles in the natural polymers alginate and chitosan, resulting in a nanocomposite that is both ecologically friendly and biocompatible. Using the generated nanocomposite as a new environmentally friendly adsorbent, As(V) heavy metal ions were effectively removed from aqueous media. The following techniques were used to analyse the physicochemical properties of the obtained materials: pHZPC, FTIR, XRD, BET, SEM, and XPS. Utilizing nitrogen adsorption/desorption isotherms, the TiO2@CSC.Alg composite sponge's textural properties were identified. This revealed a BET surface area of 168.42 m2/g and a total pore volume of 1.18 cc/g, indicating its porous nature and potential for high adsorption capacity. Examine the effects of temperature, pH, dose, and beginning concentration on adsorption. The adsorption characteristics were determined based on equilibrium and adsorption kinetics measurements. The adsorption process was both pseudo-second-order (PSOE) and Langmuir isothermally fit. Chemisorption was the adsorption method since the adsorption energy was 25.45 kJ·mol-1. An endothermic and spontaneous adsorption process was indicated by more metal being absorbed as the temperature increased. The optimal conditions for adsorption were optimized via Box-Behnken design software to be pH of 5 in the solution, a dosage of 0.02 g of the TiO2@CSC.Alg composite sponge per 25 mL, and an arsenate (As(V)) solution the adsorption capacity was 202.27 mg/g are ideal for efficient adsorption. These parameters are critical in achieving the maximum adsorption capacity of the composite sponge for arsenate, which could be beneficial for water purification applications. Utilizing Design-Expert software's response surface methodology (RSM) and Box-Behnken design (BBD), the adsorption process was optimized with the fewest planned tests. After six successive cycles of adsorption and desorption, the adsorbent stability was confirmed by the adsorbent reusability test without any noticeable decrease in removal efficacy. Additionally, it displayed good efficiency, the same XRD and XPS data before and after reuse, and no change in chemical composition.

Industrial dye absorption and elimination from aqueous solutions through bio-composite construction of an organic framework encased in food-grade algae and alginate: Adsorption isotherm, kinetics, thermodynamics, and optimization by Box-Behnken design.

A potential bio-adsorbent material for removing Rhodamine B (RB) from aqueous solution is Ru-MOF@FGA/CA beads. The adsorption capability of the material is probably enhanced by the use of a natural substance made of food-grade algae (FGA) and calcium alginate (CA), which has been cross-linked and loaded with ruthenium metal-organic frameworks (Ru-MOF). The Ru-MOF@FGA/CA beads were analyzed by XPS, PXRD, FT-IR, and SEM. The nitrogen adsorption-desorption isotherm analysis of the Ru-MOF@FGA/CA beads before and after the adsorption of RB revealed that had a surface area of 682 m2/g, a pore size of 2.92 nm, and a pore volume of 1.62 cc/g, that decreased after adsorption as the surface area reduced to 468.62 m2/g, while the pore volume reduced to 0.76 cc/g. indicating that the RB molecules occupied the available space within the pores of the material. The decrease in both surface area and pore volume specifies that the Ru-MOF@FGA/CA beads' pores were able to effectively adsorb the RB molecules. The adsorption of RB against the Ru-MOF@FGA/CA beads is affected by pH, adsorbent dose, starting RB concentration, and salinity. Controlling these factors can enhance the adsorption capability and effectiveness of the beads for RB removal. With an adsorption energy of 22.6 kJ/mol, the adsorption of RB onto the Ru-MOF@FGA/CA beads was determined to be a chemisorption process, demonstrating a strong bond among the adsorbent and the adsorbate. The pseudo-second-order kinetics and Langmuir isotherms were used to suit the adsorption process. Because the adsorption procedure was endothermic, it increased as the temperature increased. By using this information, the adsorption conditions may be improved, and the beads' ability to absorb RB can be increased. Up to six reuses of the Ru-MOF@FGA/CA beads are possible without affecting their chemical makeup and maintaining analogous PXRD and FT-IR data after each reuse. The adsorption process can be optimized through the application of the Box-Behnken design (BBD) approach and may entail H-bonding, electrostatic forces, n-π stacking, and pore filling. The exceptional stability of the beads makes them useful for creating long-lasting and efficient adsorbents that remove contaminants from water.

Synthesis of furan-modified cationic cellulose for stereo-specific imprinting and separation of S-indacrinone via Diels-Alder reaction.

This study introduces a novel approach for the separation of indacrinone (IC) enantiomers, crucial in treating edema, hypertension, and hyperuricemia. A cationic biopolymer from furan-2-ylmethylhydrazine-cellulose (FUH-CE), derived from cyanoethyl cellulose (CEC), serving as a substrate in molecular imprinting. A key innovation is the use of the Diels-Alder reaction for efficient cross-linking with bis(maleimido)ethane (BME). This chemical strategy resulted in molecularly imprinted microparticles with high selectivity for the S-IC enantiomer, which can be eluted by adjusting the solution's pH. Extensive characterization confirmed the chemical modifications and selective binding efficacy of these biopolymers. Utilizing separation columns, our method achieved an impressive chiral resolution of (±)-IC, with an enantiomeric excess (ee) of 95 % for R-IC during the loading phase and 97 % for S-IC during elution. Under optimized conditions, the biopolymer demonstrated a maximum binding capacity of 131 mg/g at pH 6. This advanced approach represents a significant advancement in chiral separation technology, offering a robust and efficient technique for the selective isolation of enantiomers. This method not only enhances potential targeted therapeutic applications but also provides a scalable solution for industrial chiral separations.

Selective uranyl ion-imprinting with clickable amidoxime-functionalized pullulan.

Manufacturing a highly effective sorbent for removing UO22+ ions from aqueous effluents is vital for safeguarding the environment and recovering valuable resources. This research presents an innovative strategy employing adsorbents derived from pullulan, specifically tailored with furfuryl-amidoxime (FAO), to improve their affinity for UO22+ ions. The formation of a UO22+ ion-imprinted sorbent (U-II-P) was achieved by crosslinking the UO22+/FAO-modified pullulan (FAO-P) complex with bis(maleimido)ethane (BME) via click Diels-Alder (DA) cyclization, enhancing its attraction and specificity for UO22+ ions. Detailed characterization of the synthesis was performed using NMR and FTIR spectroscopy, and the sorbent's external textures were analyzed using scanning electron microscopy (SEM). The U-II-P sorbent showcased outstanding preference for UO22+ over other metallic ions, with the most efficient adsorption occurring at pH 5. It exhibited a significant adsorption capacity of 262 mg/g, closely aligning with the predictions of the Langmuir adsorption model and obeying pseudo-second-order kinetic behavior. This investigation underlines the effectiveness of FAO-P as a specialized solution for UO22+ ion extraction from wastewater, positioning it as a viable option for the remediation of heavy metals.

Ion-imprinted aminoguanidine-chitosan for selective recognition of lanthanum (III) from wastewater.

Developing a sorbent for the removal of La3+ ions from wastewater offers significant environmental and economic advantages. This study employed an ion-imprinting process to integrate La3+ ions into a newly developed derivative of aminoguanidine-chitosan (AGCS), synthesized via an innovative method. The process initiated with the modification of chitosan by attaching cyanoacetyl groups through amide bonds, yielding cyanoacetyl chitosan (CAC). This derivative underwent further modification with aminoguanidine to produce the chelating AGCS biopolymer. The binding of La3+ ions to AGCS occurred through imprinting and cross-linking with epichlorohydrin (ECH), followed by the extraction of La3+, resulting in the La3+ ion-imprinted sorbent (La-AGCS). Structural confirmation of these chitosan derivatives was established through elemental analysis, FTIR, and NMR. SEM analysis revealed that La-AGCS exhibited a more porous structure compared to the smoother non-imprinted polymer (NIP). La-AGCS demonstrated superior La3+ capture capability, with a maximum capacity of 286 ± 1 mg/g. The adsorption process, fitting the Langmuir and pseudo-second-order models, indicated a primary chemisorption mechanism. Moreover, La-AGCS displayed excellent selectivity for La3+, exhibiting selectivity coefficients ranging from 4 to 13 against other metals. This study underscores a strategic approach in designing advanced materials tailored for La3+ removal, capitalizing on specific chelator properties and ion-imprinting technology.

Green Synthesis of Magnetic Supramolecules ß-Cyclodextrin/Iron Oxide Nanoparticles for Photocatalytic and Antibacterial Applications.

Iron oxide nanoparticles (Fe3O4NPs) are a fascinating field of study due to their wide range of practical applications in environmental and medical contexts. This study presents a straightforward, environmentally friendly method for producing Fe3O4NPs utilizing ß-cyclodextrin (ß-CD) as a reducing and capping agent. This approach results in the rapid and effective eco-friendly synthesis of ß-CD/Fe3O4NPs. The properties and characteristics of ß-CD/Fe3O4NPs were investigated using various methods, including ultraviolet-visible (UV/vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetry analysis (TGA), and vibrating-sample magnetometry (VSM). The absorption of ß-CD/Fe3O4NPs caused a distinct peak at 349 nm, as evidenced by the results of UV/vis studies. This peak was attributed to the absorption of surface plasmon resonance. The crystalline nature of ß-CD/Fe3O4NPs was confirmed through XRD analysis. The SEM and TEM analyses have verified the geometry and structural characteristics of ß-CD/Fe3O4NPs. The ß-CD/Fe3O4NPs exhibited remarkable effectiveness in the decomposing efficiency (%) of methylene blue (MB) dye with 52.2, 94.1, and 100% for 0.2, 0.4, and 0.6 g ß-CD/Fe3O4NPs, respectively. In addition, the highest efficiency in hunting radicals was observed (347.2 ± 8.2 mg/g) at 100 mg/mL ß-CD/Fe3O4NPs; the combination of ß-CD/Fe3O4NPs exhibited remarkable effectiveness in inhibiting the growth of some bacteria that cause infections. The capabilities of ß-CD/Fe3O4NPs for various applications showed that these materials could be used in photocatalytic, antioxidants, and antibacterial. Additionally, the eco-friendly synthesis of these materials makes them a promising option for the remediation of harmful pollutants and microbes.

Design of ion-imprinted cellulose-based microspheres for selective recovery of uranyl ions.

Herein, cellulose was selected as the raw material for the production of sorbent microspheres for the selective separation of uranyl (UO22+) ions by ion-imprinting technique due to their low cost, biodegradability, and renewability. To begin, an amidoxime cellulosic derivative (AOCE) is synthesized by a Michael addition followed by an amidoximation reaction, both of which are homogeneous reactions. In the end, microspheres of ion-imprinted U-AOCE sorbent were made by mixing the developed AOCE derivative with UO22+, crosslinking the UO22+ polymer complex with glyoxal, and eluting the coordinated ions with H+/EDTA. U-AOCE smartly recognized the target ions for fitting the cavities generated during the UO22+-imprinting process, resulting in a much greater adsorption capacity of 382 ± 1 mg/g and enhanced adsorption selectivity for UO22+. A pseudo-second-order model fit the data well in terms of kinetics, while the Langmuir model adequately explained the isotherms, indicating chemisorption and adsorption via UO22+ chelation. The coordination between UO22+ and both the -NH2 and -OH groups of the amidoxime units is the primary adsorption process, as shown by NMR, XPS, and FTIR studies. For UO22+ biosorption from aqueous effluents, the results of this study deliver new guidance for the design of biosorbents with high removal capability and excellent selectivity.

Selective removal of uranyl ions using ion-imprinted amino-phenolic functionalized chitosan.

The recovery of uranium from aqueous effluents is very important for both the environment and the future of nuclear power. However, issues of sluggish rates and poor selectivity persist in achieving high-efficiency uranium extraction. In this study, uranyl (UO22+) ions were imprinted on an amino-phenolic chitosan derivative using an ion-imprinting method. First, 3-hydroxy-4-nitrobenzoic acid (HNB) units were joined to chitosan via amide bonding, followed by reducing the -NO2 residues into -NH2. The amino-phenolic chitosan polymer ligand (APCS) was coordinated with UO22+ ions, then cross-linked with epichlorohydrin (ECH), and finally the UO22+ ions were taken away. When compared to non-imprinted sorbent, the resulting UO22+ imprinted sorbent material (U-APCS) recognized the target ions preferentially, allowing for much higher adsorption capacities (qm = 309 ± 1 mg/g) and improved adsorption selectivity for UO22+. The FTIR and XPS analyses supported the pseudo-second-order model's suggestion that chemisorption or coordination is the primary adsorption mechanism by fitting the data well in terms of kinetics. Also, the Langmuir model adequately explained the isotherms, suggesting UO22+ adsorption in the form of monolayers. The pHZPC value was estimated at around 5.7; thus, the optimum uptake pH was achieved between pHs 5 and 6. The thermodynamic properties support the endothermic and spontaneous nature of UO22+ adsorption.

Kappa-carrageenan for benign preparation of CdSeNPs enhancing the electrochemical measurement of AC symmetric supercapacitor device based on neutral aqueous electrolyte.

This study presents the development of an electrochemical supercapacitor with a cadmium selenide nanoparticles (CdSeNPs) electrode utilizing a straightforward and economical method based on kappa-carrageenan (κ-CGN). The structural, morphological, and optical characteristics of CdSeNPs were assessed. Activated carbon (AC) and green-prepared CdSeNPs were easily mixed to achieve excellent electrochemical properties. The nanoelectrode (AC@CdSe) was tested in an aqueous electrolyte of sodium sulfate (Na2SO4) with a concentration of 1 Molar. Specific capacitance (Csp) for the AC electrode and the AC@CdSe electrode at 1 A g-1 was calculated to be 103 and 480 F g-1, respectively. Besides, the symmetric supercapacitor AC@CdSe/AC@CdSe device has a high specific energy of 52 Wh kg-1 and a maximum specific power of 2880 W kg-1, with a specific capacitance of 115.5 F g-1. With a coulombic efficiency of between 82 % and 100 %, the device continues to maintain excellent capacitance after 10.000 cycles.

One-pot microwave synthesis of chitosan-stabilized silver nanoparticles entrapped polyethylene oxide nanofibers, with their intrinsic antibacterial and antioxidant potency for wound healing.

Different physical and chemical techniques could be used to prepare chitosan/Silver nanoparticle (CHS/AgNPs) nanocomposite. The microwave heating reactor was rationally adopted as a benign tool for preparing CHS/AgNPs owing to less energy consumption and shorter time required for completing the nucleation and growth particles. UV-Vis, FTIR, and XRD, provided conclusive evidence of the AgNPs creation, while TEM micrographs elucidated that the size was spherical (20 nm). CHS/AgNPs were embedded in polyethylene oxide (PEO) nanofiber via electrospinning, and their biological properties, cytotoxicity evaluation, antioxidant, and antibacterial activity assays were investigated. The generated nanofibers have mean diameters of 130.9 ± 9.5, 168.7 ± 18.8, and 186.8 ± 8.19 nm for PEO, PEO/ CHS, and PEO/ CHS (AgNPs), respectively. Because of the tiny AgNPs particle size loaded in PEO/CHS (AgNPs) fabricated nanofiber, good antibacterial activity with ZOI against E. coli was 51.2 ± 3.2, and S. aureus was 47.2 ± 2.1 for PEO/ CHS (AgNPs) nanofibers. Non-toxicity was observed against Human Skin Fibroblast and Keratinocytes cell lines (>93.5 %), which justifies its great antibacterial potential to remove or prevent infection in wounds with fewer adverse effects.

Synthesis and characterization of photo-crosslinkable cinnamate-functionalized pectin.

The polysaccharide pectin (PC) was functionalized with the photo-responsive cinnamic acid hydrazide (CN) to produce the photo-crosslinkable PC-CN hydrogel material that was then evaluated as a carrier for encapsulation of the drug model aspirin. Cinnamic acid hydrazide was first prepared and then incorporated with the abundant -COOCH3 groups on the pectin chain via hydrazide linkage. The obtained polymeric derivatives have been characterized by means of instrumental techniques including FTIR and NMR. The obtained PC-CN hydrogels with different cinnamic functionality were also freeze-dried and examined by SEM, which indicated more coherent hydrogel texture by increasing the cinnamic functionalization. The effect of the photo-curing time, as well as the functionalization degree, on the swelling and gelation of the obtained hydrogel was also studied to evaluate the potential of the developed material in drug delivery systems using aspirin as a common and available drug model. The developed PC-CN hydrogel materials exhibited high potential as a drug carrier that enables the control of the drug release via optimizing both the degree of cinnamic functionality and the photo-curing time.

Preparation of chromium (III) ion-imprinted polymer based on azo dye functionalized chitosan.

The main aim of this work is the preparation of azo dye modified chitosan that was subsequently used in the ion-imprinting of Cr(III) ions to finally obtain ion-selective sorbent able to selectively combine with Cr(III) ions from water when coexisting with other similar metal ions. The azo dye derived from resorcinol and p-aminobenzoic acid was prepared and then linked to the chitosan amino groups by amide linkages utilizing EDC/NHS coupling agent. A polymeric complex of the azo dye chitosan derivative AZCS and Cr(III) ions was then prepared and treated with glyoxal solution, which cross-link the main chitosan chains in form of micro-spherical beads in presence of the coordinated Cr(III) ions that were later expelled out of the texture of the beads using acidified EDTA eluent solution while preserving the spatial and geometrical shape of the resulting Cr(III) ions chelating sites.

Development and characterization of photo-responsive cinnamoly modified alginate.

A photo-crosslinkable hydrogel derived from cinnamoyl modified alginate (Alg-CN) was prepared via hydrazide intermediate and employed as an efficient drug carrier using the painkiller drug paracetamol. Methyl ester of the alginic acid was first prepared and converted into the corresponding hydrazide intermediate (Alg-Hyd) and then the cinnamoyl units were incorporated using cinnamoyl chloride. The synthesized derivatives were characterized by spectral and instrumental methods to confirm their suggested chemical structures. The obtained Alg-CN derivatives displayed initiator-free crosslinking capabilities upon the UV exposure for adequate periods of time, which was demonstrated due to the formation of cyclobutane bridges connecting the alginate polysaccharide chains through the [2π+2π] cycloaddition reaction carried out by the CHCH units of the inserted cinnamoyl moieties. The cross-linking of the Alg-CN was monitored by observing the lowering of the UV spectral band related to the cinnamoyl units and then the gelation efficiency along with the swelling degree was investigated over the UV light exposure time. Moreover, the developed hydrogel derivatives present considerable potentials as drug carriers that enable the control of the drug release by varying the degree of hydrogel cross-linking either by cinnamoyl functionalization or UV light exposure time.

Amidoxime modified chitosan based ion-imprinted polymer for selective removal of uranyl ions.

Ion-imprinting strategy was utilized in the development of UO2(II) imprinted amidoxime modified chitosan sorbent (U-AOCS) that can selectively remove UO2(II) from water. First, cyanoactic acid was linked to the chitosan -NH2 groups and then the inserted -CN groups were converted into amidoxime moieties, which chelate the UO2(II) ions and then the polymer chains were cross-linked by glyoxal. The UO2(II) ions have been then eluted leaving their matching recognition sites. The prepared U-AOCS along with the control NIP displayed maximum capacities toward the UO2(II) ions around 332 and 186 mg/g, respectively, and the isotherms were interpreted better by the Langmuir model in both adsorbents. Moreover, the selective uptake of the uranyl ions in multi-ionic aqueous solutions containing the tetravalent Th(IV) ions, trivalent Al(III), Eu(III), and Fe(III) ions, beside the divalent Pb(II), Co(II), Ni(II), Cu(II) ions confirmed the successful creation of a considerable UO2(II) ions selectivity in the U-AOCS construction. In addition, the U-AOCS adsorbent displayed economic feasibility by maintaining around 95 % of its initial efficiency after the regeneration and reuse for 5 adsorption/desorption cycles.

Designing and characterization of copper (II) ion-imprinted adsorbent based on isatin functionalized chitosan.

An isatin functionalized chitosan derived ion-imprinted adsorbent (Cu-CIS) was designed by tailoring Cu(II) ions imprinted cavities within the modified polysaccharide network matrix that are able to capture Cu(II) ions selectively in aqueous solution. The chelating power of chitosan toward the Cu(II) ions was first enhanced via isatin functionalization, which was cross-linked using epichlorohydrin (ECH) after loading the Cu(II) ions. The selective metal ions binding sites are then formed by eluting the coordinated Cu(II) ions using EDTA to finally produce the Cu-CIS selective sorbent. The equilibrium isotherms have been utilized to anticipate the maximum capacity of the Cu-CIS sorbent and compare it with that of the blank non-imprinted sorbent NI-CIS. In addition, the significance of inserting the Cu(II) ions recognition cavities within the adsorbent matrix was pointed out by performing the adsorption in a multi-ionic solution mixture containing Co(II), Ni(II), Pb(II), Cd(II) and Cu(II) ions and the obtained selectivity coefficients in case of Cu-CIS revealed remarkable selectivity potentials toward the Cu(II) ions compared to NI-CIS. Moreover, at the consecutive performance of a Cu-CIS absorbent for five cycles, it was found that it still held 97% of its initial capacity enabling promising applications in both water treatment and Cu (II) ions recycling.

Chiral separation of (±)-methamphetamine racemate using molecularly imprinted sulfonic acid functionalized resin.

In the present study, a sulfonic acid functionalized enantio-selective resinous material was developed for effective chiral separation of (±)-methamphetamine racemate. R-methamphetamine-sulfonamide phenolic derivative was first prepared and fully characterized utilizing instrumental and spectroscopic techniques, then the sulfonamide was implemented in an acid catalyzed condensation copolymerization with phenol and formaldehyde. The resulted resinous material was then exposed to successive alkaline and acidic treatments in order to remove the R-methamphetamine enantiomer out of the resin matrix and obtaining the molecularly imprinted enantio-selective material, which was also investigated by scanning electron microscope, FTIR and XPS spectroscopy. The maximum selective extraction of the R-methamphetamine enantiomer was achieved at pH 7. The adsorption isotherms indicated an adsorption capacity of 233 ±â€¯1 mg/g and followed the well-known Langmuir model. Also, the enantio-separation experiment of the racemic mixture was performed by column technique and both the supernatant loading and the eluant recovery solutions indicated an enantiomeric excess of 80% and 67% related to S- and R-methamphetamine, respectively.

Amino functionalization of carboxymethyl cellulose for efficient immobilization of urease.

Jack bean urease (EC.3.5.1.5) was effectively immobilized onto amino functionalized epichlorohydrin cross-linked carboxymethyl cellulose (ECH-CMC) beads that were fabricated by graft co-polymerization of polyacrylamide (PAm) onto ECH-CMC beads in presence of potassium persulfate (KPS)/thiourea (TU) combined redox initiator followed by Hoffmann degradation. The progress of the synthesis along with immobilization processes was investigated by FTIR spectra. Also, the morphological structures of the beads before and after urease immobilizations were examined using SEM. Immobilization efficiency and immobilized urease amounts were estimated as a function of the amino functionalization degrees. The effects of pH and temperature on urease activity were studied. The results showed that after immobilization the optimum pH and temperature displayed higher shifts to 8 and 45°C, respectively, which reveal a higher structural stability upon immobilization performance. Moreover, the kinetic studies indicated that the urea hydrolysis reaction, which catalyzed by urease enzyme displayed a good fit with Michaelis-Menten equation, and the kinetic parameters Km and vm were estimated to be 14±0.7mM and 2±0.2µmolNH3/min·mg immobilized urease, respectively. Furthermore, the immobilized urease maintained approximately 88% of its initial activity after the 10th reuse cycle.

Fabrication of photo-active trans-3-(4-pyridyl)acrylic acid modified chitosan.

Photo-active trans-3-(4-pyridyl)acrylic acid (PYA) modified chitosan (CSPA) was synthesized with different functionalization degrees and extensively examined using Fourier transform infrared spectra (FTIR), 1H and 13C nuclear magnetic resonance (NMR) in order to elucidate the chemical structure of the modified biopolymer. The modified CSPA with various substitution degrees were casted in form of thin membranes and cross-linked under photo-chemical condition by exposure to ultra-violet light via [2π+2π] cycloaddition reaction of the incorporated PYA units. The photo-induced reaction was examined using UV-vis light spectra and the cross-linked hydrogel were investigated using both XRD and scanning electron microscope (SEM). Also, the mechanical properties of the hydrogel membranes were studied by measuring the variations of both tensile strength and elongation against corss-linking densities.

Synthesis and characterization of photo-crosslinkable 4-styryl-pyridine modified alginate.

In this article photo-crosslinkablestyryl-pyridine modified alginate (ASP-Alg) was prepared and entirely investigated utilizing different instrumental techniques such as Elemental analysis, Fourier transform infrared (FTIR),(13)C and (1)H nuclear magnetic resonance (NMR), ultraviolet-visible light (UV-vis), X-ray diffraction (XRD) spectra and scanning electron microscope (SEM). Upon irradiation in the UV region, the casted ASP-Alg membranes were cross-linked through the [2π+2π] cycloaddition reaction of the inserted photo-active styryl pyridine moieties. Both cross-linking density and kinetics were monitored by examining the UV-vis light spectra of the irradiated membrane at predetermined time intervals and the obtained results were found to fit with the second order mathematical kinetic model, revealing the performance of the cross-linking via bimolecular [2π+2π] cycloaddition reaction. Also, the swelling behaviors along with biodegradability were also studied, and the results indicated the decrease of the swelling ratio and degradation rate by increasing the cross-linking density. Moreover, the mechanical properties were also examined under both wet and dry conditions.

Selective extraction of uranyl ions using ion-imprinted chelating microspheres.

In this work, uranyl complex with Schiff base derived from condensation of p-aminostyrene and salicyaldehyde (HASS) was synthesized. Both ligand and uranyl complex were characterized using elemental analysis, FTIR, (1)H and (13)C NMR spectra. The complex was then copolymerized with styrene and divinylbenzene cross-linker using potassium persulfate free radical initiator through emulsion polymerization technique. The uranyl ions were then leached out from the cross-linked network to finally produce uranyl ion-imprinted microspheres (U-PASS), which were investigated using SEM and FTIR. The effect of various significant parameters such as pH, temperature, contact times and initial uranyl concentration on the removal of uranyl from aqueous solution was examined and the results indicated that the adsorption was exothermic in nature and the kinetics of adsorption fit with the second-order kinetic model. Also, Langmuir adsorption isotherm exhibited the best fit with the experimental results with maximum adsorption capacity 147.8 mg/g. Moreover, the selectivity studies revealed that the ion-imprinted microspheres resin exhibited an obvious affinity toward the uranyl ions in presence of other interfering metal ions compared to the non-imprinted resin.