Development and assessment of isatin hydrazone-functionalized/ion-imprinted cellulose adsorbent for gadolinium (III) removal.

It is of tremendous economic and environmental significance to obtain a powerful adsorbent for the extraction of Gd3+ from wastewater. Adsorbents derived from cellulosic materials functionalized with specific chelators show great promise for the removal of heavy metal ions from wastewater. The selectivity of these sorbents for metal ions is, however, still rather poor. Here, we present a technique for trapping Gd3+ ions from wastewater by synthesizing Gd3+ ion-imprinted polymers based on isatinhydrazone-functionalized cellulose (Gd-ISH-CE). Not only did isatinhydrazone work as a tridentate ligand to directly provide ligand vacancies and build hierarchy pores on Gd-ISH-CE, but it also enabled cross-linking through the epichlorohydrine cross-linker thanks to its very effective NH2 functionalization. The as-prepared Gd-ISH-CE with ISH functionality shows a high adsorption capacity of 275 mg/g and a rapid equilibration time of 30 min for Gd3+ due to its plentiful binding sites and hierarchical pore structure. Furthermore, Gd-ISH-CE shows very selective capture of Gd3+ over competing ions. By integrating the benefits of ion-imprinting and chelator functionalization methodologies in an effortless manner, this study presents a practical approach to the development of superior materials for Gd3+ recovery.

Development and evaluation of thiosalicylic-modified/ion-imprinted chitosan for selective removal of cerium (III) ion.

Chitosan was used in this study as the bio-based product for the development of microparticles for the specifically targeted removal of cerium ions (Ce3+) by ion-imprinting technology. A thiosalicylic hydrazide-modified chitosan (TSCS) is produced via cyanoacetylation of chitosan, followed by hydrazidine derivatization to finally introduce the thiosalicylate chelating units. Ion-imprinted Ce-TSCS sorbent microparticles were prepared by combining the synthesized TSCS with Ce3+, crosslinking the polymeric Ce3+/TSCS complex with glutaraldehyde, and releasing the chelated Ce3+ using an eluent solution containing a mixture of EDTA and HNO3. Ce-TSCS had a capacity of 164 ± 1 mg/g and better removal selectivity for Ce3+ because it was smart enough to figure out which target ions would fit into the holes made by Ce3+ during the imprinting process. The kinetic data were well suited to a pseudo-second-order model, and the isotherms were well described by the Langmuir model, both of which pointed to chemisorption and adsorption through Ce3+ chelation. XPS and FTIR analyses demonstrate that the predominant adsorption mechanism is the coordination of Ce3+ with the -NH-, -NH2, and -SH chelating units of the thiosalicylic hydrazidine. These findings provide fresh direction for the development of sorbent materials that can effectively and selectively remove Ce3+ from aqueous effluents.

Biodegradable wound dressing-based collagen/hyaluronic acid loaded antibacterial agents for wound healing application.

Three biodegradable wound dressing based on binary Collagen (COL), Hyaluronic acid (HA) crosslinked loaded with silver nanoparticles (AgNPs), Gentamicin (GENT) and AgNPs/GENT successfully prepared using freeze drying technique. Chemical evaluations for synthesized membranes were carried out using FTIR- ATR. While physical properties were evaluated through swelling and degradation percent. Antibacterial activity was evaluated against G+, G-, yeast and fungi. Finally, cytotoxicity and wound healing evaluations were carried out against skin fibroblast normal cell line, while anti-inflammatory evaluated using RAW 264.7 macrophage cell line. The three produced membrane showed physically interaction between polymer network and the loaded antibiotic. Swelling properties showed superior results for three membranes. Degradability of prepared sheets was rapidly no more than three days. Toxicity evaluations and anti-inflammatory showed superior results for all examined samples except mixed with AgNPs and Gentamicin (GENT). Antibacterial activity showed resistance to G+, G- and yeast. All prepared sheet showed safe towards cell except COL/HA/AgNPs/GENT. Wound healing studied showed efficient of both COL/HA/AgNPs and COL/HA/GENT compared to blank and mixed membrane COL/HA/AgNPs/GENT. The obtained results recommended COL/HA loaded individually either AgNPs or Gentamicin (GENT) as antibacterial and wound healing sheet rather than mixed prepared membrane.

Production of biologically active non-woven textiles from recycled polyethylene terephthalate.

Recently, various studies have focused on the development of multifunctional non-woven polyethylene terephthalate (PT; polyester) textiles. Herein, we introduce multifunctional non-woven polyester fabrics by pad dry curing silver nitrate (AgNO3 ) and aniline monomer into plasma-pretreated non-woven PT textile. This creates a nanocomposite layer of silver nanoparticles (AgNPs) and polyaniline (PANi) on the fabric surface. In order to prepare a non-woven fibrous mat, we applied the melt-spinning technique on previously shredded recycled PT plastic waste. On the surface of the cloth, PANi was synthesized by REDOX polymerization of aniline. Due to the oxidative polymerization, the silver ions (Ag+ ) were converted to Ag0 NPs. PANi acted as a conductor while AgNPs inhibited the growth of microorganisms. Microwave-assisted curing with trimethoxyhexadecylsilane (TMHDS) gave PT textiles with superhydrophobic properties. The morphological studies were performed using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The stiffness and breathability of finished non-woven PT textile materials were analyzed to establish their comfort levels. Both of Escherichia coli and Staphylococcus aureus were used to test the efficacy of the AgNPs-treated textiles as antimicrobial materials. Moreover, the processed polyester textiles showed excellent electrical conductivity and great ultraviolet-ray blocking.

Preparation of molecularly imprinted silica particles with amino functionality for chiral separation of (±)-naproxen.

Herein is the synthesis and effective use of an S-naproxen (S-NP) enantioselective adsorbent material with amino functionality for the enantioseparation of a (±)-NP racemic mixture. To begin, the S-NP enantiomer of (3-aminopropyl)triethoxysilane was used to create an amide derivative (S-NP-Si-NH2 ). In order to incorporate the S-NP enantiomeric species into the cross-linked material, the developed S-NP-Si-NH2 derivative was combined with tetraethoxysilane (TEOS) and subjected base-catalyzed sol-gel condensation polymerization procedure. The S-NP is released from the cross-linked matrix by alkaline hydrolysis and subsequent acidification, creating an enantioselective gap filled with cationic ions that are compatible with the S-NP during recombination. With the use of elemental analysis, nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, it was verified that the performed chemical processes on the monomeric precursor and the resulting S-NP molecularly imprinted material (S-NP-Sil) were successful. Furthermore, the morphology alterations were analyzed using scanning electron microscopy images of the sorbent surface. The produced adsorbent particles were also used in the chiral separation of a (±)-NP racemic combination utilizing a column approach, with encouraging separation results shown in both the first loading run (59% ee of R-NP) and the second elution run (85% ee of S-NP).

A Study of the Synthesis and Characterization of New Acrylamide Derivatives for Use as Corrosion Inhibitors in Nitric Acid Solutions of Copper.

The objective of this research was to explore the impact of corrosion inhibition of some synthetic acrylamide derivatives 2-cyano-N-(4-hydroxyphenyl)-3-(4-methoxyphenyl)acrylamide (ACR-2) and 2-cyano-N-(4-hydroxyphenyl)-3-phenylacrylamide (ACR-3) on copper in 1.0 M nitric acid solution using chemical and electrochemical methods, including mass loss as a chemical method and electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) as electrochemical methods. By Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1HNMR), and mass spectroscopy (MS) methods, the two compounds were verified and characterized. There is evidence that both compounds were effective corrosion inhibitors for copper in 1.0 M nitric acid (HNO3) solutions, as indicated by the PP curves, which show that these compounds may be considered mixed-type inhibitors. With the two compounds added, the value of the double-layer capacitance was reduced. In the case of 20 × 10-5 M, they reached maximum efficiencies of 84.5% and 86.1%, respectively. Having studied its behavior during adsorption on copper, it was concluded that it follows chemical adsorption and Langmuir isotherm. The theoretical computations and the experimental findings were compared using density functional theory (DFT) and Monte Carlo simulations (MC).

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.

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.