Volume 54, Issue 3

In this study, a thermo-tolerant and alkaline lipase enzyme was purified from Lactobacillus brevis and immobilized onto modified γ-Fe 3 O 4 florisil nanoparticles (γ-Fe 3 O 4 MF NFs) and the usability of free lipase (FL) and immobilized lipases (IML) as detergent additives was investigated. Lipase enzyme was purified by fractional precipitation using 20% ammonium sulfate, DEAE-Sephadex ion-exchange chromatographic column, and Sephacryl S200 gel filtration chromatographic techniques. Then, the enzyme was purified, which resulted in 135.2-fold purification. Its molecular mass was determined to be 57 kDa by SDS-PAGE. The covalent immobilization of purified lipase was done using γ-Fe 3 O 4 MF NPs. γ-Fe 3 O 4 MF NPs and IML were characterized by using SEM, TEM, FT-IR, and XRD. IML showed a good thermo-stability and its activities were calculated as 80% at 60°C. The free and IML enzymes were most stable at alkaline pHs in the range of 7.0–10.0. Also, IML is more stable towards metal ions compared to free lipase enzyme. Washing performances of some detergent formulations were investigated in the presence and absence of Lipase. Olive oil was removed by the detergent alone and by the detergent and IML at ratios of 45% and 72%, respectively. The study on removal of oil stain from cotton cloths indicated that the removal of oil was superior in the presence of IML and IML with detergent, when compared to the detergent alone.

The conformations of secondary and tertiary structures of cellulase in the presence of eleven commonly used surfactants were determined by Raman spectroscopy and the results were discussed. The results indicated that anionic surfactants had a stronger influence on the cellulase conformations than nonionic surfactants. Thus anionic surfactants showed a stronger inactivation on the cellulase activity. Furthermore, Zeta potential distributions of cellulase in solutions of surfactants were tested by Dynamic Light Scattering (DLS). The DLS results indicated that the interaction between anionic surfactants and cellulase was attributed to electrostatic attraction. By adding cellulase to a liquid, non-cellulase-containing detergent, the detergency of the liquid detergent could be increased. Further studies on the sample swatches by optical microscopy and scanning electron microscopy (SEM) were undertaken in this paper.

In this study, ionic liquid (IL), specifically ethylammonium nitrate (EAN), was used instead of water to form nonaqueous microemulsions with cyclohexane and the nonionic surfactant Triton X-100 (TX-100). The phase behavior of the ternary system was investigated, and the microemulsions of ionic liquid-in-oil (IL/O) and oil-in-ionic liquid (O/IL) and the bicontinuous microregion were identified through traditional electrical conductivity measurement. The micropolarities of the IL/O microemulsions were determined via UV–Vis spectroscopy with methyl orange as an absorption probe. Results indicated that the polarity of the reverse micelles remained constant but that of the IL/O microemulsions increased when IL pools were formed. Fourier transform infrared spectroscopy was used to study the interaction mechanism between TX-100 and EAN molecules in IL/O microemulsions. We demonstrated that IL/O microemulsions may be promising for application due to the unique features of ILs and microemulsions.

In recent times, long chain amido sulfobetaine surfactants are a very attractive subject, but their unique self assembly properties as well as the rheological behavior of the mixture of these surfactants with other surfactant types are less documented. In this paper, the rheological behavior of the erucyl amido sulfobetaine (EASB) in mixture with long chain cationic surfactants was evaluated. The results indicated that in spent acid solution, the rheological responses of erucyl amido sulfobetaine (EASB) in the presence of cationic surfactants were improved. The effect of surfactants concentration and temperature were also studied.

The interest to determine the ionization degree of counterion initiates the need to study the relationship between counterion binding constant (R X Br ) and the growth of self-assembly micellar structure. This paper discussed the microscopic evidence for the correlation of counterion binding constant values and micellar structure of cationic surfactants in the presence of phenolates and 2-ethyl phenolates ions in flexible nanoparticle (FN)-system of ionized phenyl salicylate-catalyzed piperidinolysis. The sizes of micelles were determined by particle size analysis. Transmission electron microscopy (TEM) results showed a spherical micellar structure for phenolates and 2-ethyl phenolates ions at counterion binding constant values 6.3 ± 1.0 and 24.0 ± 1.1 respectively. A study using a semi-emperical kinetic technique in published article proved that the suggested micellar structures at respective counterion binding constant values corresponded with the present microscopic evidence.

In order to improve the dispersion and increase the compatibility between CaCO 3 nanoparticles and a polyethylene terephthalate (PET) matrix, hydrophobic calcium carbonate (CaCO 3 ) nanoparticles were successfully prepared via a carbonization reaction with stearic acid (SA) as the modifying agent. PET/CaCO 3 nanocomposites were prepared by further in situ polymerization of purified terephthalic acid (PTA), ethylene glycol (EG) and CaCO 3 nanoparticles. The surface modification of CaCO 3 , the microstructure and the properties of nanocomposites were investigated by water contact angles measurements TEM, FTIR, XRD, SEM, TGA and DSC. SEM examination of the fractured surfaces of nanocomposites showed that CaCO 3 modified by SA achieved well dispersed in the PET matrix. Moreover, compared to the nanocomposite filled with the blank CaCO 3 , the resulting nanocomposite filled with the modified CaCO 3 exhibit a better thermal stability and a superior crystallization property.

Calcium carbonate is considered as the most frequent scale commonly occurring in cooling water systems. To reduce calcium carbonate scale in an environment–friendly way, a copolymer consisting of acrylic acid (AA)-acrylamide (AM)-polypropylene glycol and maleic anhydride (PPGAZMA) was developed to inhibit this phenomenon. The structure of the AA-AM-PPGAZMA was characterized by FT-IR method. The performance of AA-AM-PPGAZMA inhibition process was evaluated from static experiment method. Results indicated that excellent ability to control inorganic minerals, with approximately 71.1% calcium carbonate inhibition under the optimum conditions. Also the effect of the copolymer addition on the crystals of calcium carbonate scales morphology was examined through scanning electron microscopy (SEM). SEM illustrated that great changes in the size and morphology of the calcium carbonate scales took place under the influence of AA-AM-PPGAZMA. SEM and XRD results identify that not only the scales shape and size changed but also that the scales forms altered to an extent.

This study focuses on the properties of mixed micelles of di-sodium salt of 3-({2-[(2-Carboxy-ethyl)-dodecanoyl-amino]-ethyl}-dodecanoyl-amino)-propionic acid (symbolized as DLMC) in solution systems (DLMC/DTAB and DLMC/AEO 6 ). The micro-polarity of the mixed micelles was determined by the fluorospectrophotometer. When the concentration is above CMC, the micellar micro-polarity and the aggregation number (N m ) of the mixed micelles were measured by a steady state fluorescence quenching method. The average hydrodynamic radius (R h ) of the mixed micelles was studied by means of dynamic light scattering. The results show that the micro-polarity of micelle nucleus decreases obviously with increasing concentration. The aggregation number of DLMC mixed systems is smaller than that of single surfactants. The difference of the proportion of the two surfactants has little effect on the aggregation number of mixed systems. It is easy to generate molecular aggregates with lower curvature from DLMC than the corresponding monomeric surfactant (DTAB), and DLMC can generate huge linear micelles at low concentrations when mixed with other surfactants.

Macrocyclic metal complexes viz., Co(II), Ni(II), Cu(II) and Zn(II) have been prepared using a macrocyclic Schiff base as ligand, which was derived from Isatin, 4-aminoantipyrine and o -phenylenediamine. Further, the complexes have been characterized by elemental analysis, magnetic susceptibility, molar conductance, mass spectrometry, FT-IR-, Far-IR-, UV-Vis-, EDX spectroscopy, 1 H NMR and 13 C NMR, ESR spectroscopy and SEM. The octahedral geometry of the complexes has been revealed by the spectral data of UV-Vis and ESR as well as by the results of the magnetic susceptibility measurements. Antimicrobial screening tests indicated that the Zn(II) metal complexes showed an excellent antimicrobial activity compared to the other studied metal complexes. The nuclease activity of the metal complexes showed that the Co(II) complex has effectively cleaved DNA. The optimized molecular structure, bond length, bond angle, dihedral angle, chemical reactivity and total energy have been evaluated using the density functional theory (DFT) with B3LYP functional level.

In this work, quaternary ammonium gemini surfactants with different spacers and lipophilic tails were synthesized by using imidazole and halogenated hydrocarbons as raw materials. The surfactants were characterized by EA, IR, and ESI-MS. Physico-chemical properties including critical micelle concentration (CMC), surface tension at CMC (γ CMC ), saturated adsorption amount (Γ max ), occupied area per molecule (A min ), standard free energy of micellization (ΔG 0 m ) and adsorption (ΔG 0 ads ), as well as the oil/water interfacial tension were completely studied. The prepared surfactants could efficiently lower the interfacial tension at water/air interfaces and oil/water interfaces. The results indicate that the ability of reducing the surface tension was affected by the surfactant arrangement, which could be further adjusted by a spacer and lipophilic tail. Accordingly, four surfactants were chosen as the representatives to evaluate the displacement efficiency in flooding experiments via using the authentic sandstone microscopic model.