Synthesis, Characterization and Sorption Ability of Epoxy Resin-Based Sorbents with Amine Groups

Water pollution by toxic substances, such as azo dyes, is a serious environmental problem that needs to be addressed. This study presents the synthesis and characterization of new polymeric sorbents, based on the epoxy resin Epidian® 5 (Ep5), as a potential adsorbent for the removal of the toxic azo dye C.I. Acid Violet 1 (AV1). Triethylenetetramine (TETA) was applied as a cross-linking agent in the amounts of 1 g (6.67 wt %), 1.5 g (10 wt %), and 2 g (13.33 wt %). The use of a compound with amino groups allows for the simultaneous functionalization of the obtained material. The reaction was carried out in an environment of ethylene glycol, with the addition of a porophore solvent (toluene) and bis(2-ethylhexyl)sulfosuccinate sodium salt (S). The attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) revealed the existence of a strong band in the 828–826 cm−1 range corresponding to the second-order amine group, which indicates their incorporation into the epoxy structure. The glass transition and decomposition temperatures of the resins decreased with the increasing amounts of amine in the material. The thermogravimetry (TGA) analysis demonstrated that all products are thermally stable up to 340 °C. The surface morphology and microstructural properties of the obtained sorbents were determined using scanning electron microscopy (SEM) images and showed an irregular star shape, with dimensions ranging from 400 to 1000 µm. The adsorption capacities of Ep5-TETA1, Ep5-TETA1.5, Ep5-TETA2 and Ep5-TETA1.5 + S for AV1 evaluated during batch experiments were found to be 2.92, 3.76, 7.90 and 3.30 mg/g, respectively.

The solubilization and extraction parameters of erythromycin from aqueous phase into mixed AOT/SB3-18 reverse micelle phase

<p>A liquid anionic-zwitterionic surfactant-based aqueous two-phase extraction was developed and applied for the extraction of erythromycin. Erythromycin solubilization from aqueous to reverse micelle phase was studied. Zwitterion SB3-18 surfactant was added to ionic solution of bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) to form an organic mixed micellar phase. Erythromycin was then added to the mixtures and two clear phases were formed. The parameters affecting erythromycin solubilization including AOT concentration (20.0 ̶ 120.0 g/L), zwitterion concentration (6.0 ̶ 16.0 g/L), NaCl concentration (0.0 ̶ 25.0 g/L) and aqueous pH (6.0 ̶ 9.0) were investigated via statistical software. Solubilization of erythromycin into mixed reverse micelle could be easily evaluated by the measurement of erythromycin concentration in the organic phase. The results showed that AOT and zwitterion concentration governed the erythromycin solubilization by a factor of 4.562 based on the Pareto chart.</p><p>Chemical Engineering Research Bulletin 19(2017) 123-128</p>

Hydrophobic Gentamicin-Loaded Nanoparticles Are Effective against Brucella melitensis Infection in Mice

ABSTRACTThe clinical management of human brucellosis is still challenging and demandsin vitroactive antibiotics capable of targeting the pathogen-harboring intracellular compartments. A sustained release of the antibiotic at the site of infection would make it possible to reduce the number of required doses and thus the treatment-associated toxicity. In this study, a hydrophobically modified gentamicin, gentamicin-AOT [AOT is bis(2-ethylhexyl) sulfosuccinate sodium salt], was either microstructured or encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles. The efficacy of the formulations developed was studied bothin vitroandin vivo. Gentamicin formulations reducedBrucellainfection in experimentally infected THP-1 monocytes (>2-log10unit reduction) when using clinically relevant concentrations (18 mg/liter). Moreover,in vivostudies demonstrated that gentamicin-AOT-loaded nanoparticles efficiently targeted the drug both to the liver and the spleen and maintained an antibiotic therapeutic concentration for up to 4 days in both organs. This resulted in an improved efficacy of the antibiotic in experimentally infected mice. Thus, while 14 doses of free gentamicin did not alter the course of the infection, only 4 doses of gentamicin-AOT-loaded nanoparticles reduced the splenic infection by 3.23 logs and eliminated it from 50% of the infected mice with no evidence of adverse toxic effects. These results strongly suggest that PLGA nanoparticles containing chemically modified hydrophobic gentamicin may be a promising alternative for the treatment of human brucellosis.

The Morphology, Structure and Electrical Properties of Polypyrrole Nanofibers via Electrospinning

One-dimensional nanostructured polypyrrole (PPy) nanofibers were electrospun using a solution of PPy/polyvinyl alcohol (PVA); and PVA was used as the carrier in order to improve processability of PPy. In order to improve the performance of nanofibers, PPy were chemically synthesized by using different dopants, such as toluene sulfonate (TSNa), dodecyl-benzene sulfonic acid sodium salt (DBSNa), dodecyl sulfonic acid sodium salt (DSNa) and di-(2-ethylhexyl) sulfosuccinate sodium salt (DEHS). The morphology, structure and electrical conductivity of the fabricated nanofibers was investigated using SEM, FTIR and four-probe method, respectively. The results show that the diameters of doped PPy/PVA nanofibers are in the range of 50-190 nm. The electrical conductivity of the obtained doped PPy/PVA nanofibers was about 161-222 S/cm. DEHS doped PPy can not only make the obtained PPy be soluble in some organic solvents, but also improve the electrical conductivity of nanofibers when it is compared with that of TSNa, DSNa, DBSNa as dopants.