Metal-dependent nano-catalysis in reduction of aromatic pollutants.

Nanostructures have great potential in catalysis and their compositions may cause some interferences in the reactivity. Therefore, the present study focuses on comparison between three metallic nanoparticle-based Ag, Au, and Pd as nano-catalyst in reduction of aromatic pollutants. To neglect any interpenetration in their catalytic reactivity, the metallic nanoparticles were prepared via a consistent and reproducible one-step method with alkali-activated dextran. Interestingly, small sized/spherical AgNPs, AuNPs, and PdNPs were successively prepared with particle size of 3.4, 8.3, and 17.1 nm, respectively. The catalytic performance of the synthesized NPs was estimated for the reduction of p-nitroaniline and methyl red dye as different aromatic pollutants. Regardless of the particle size, there was a strong relation between catalytic action and the type of metal which followed the order of PdNP > AuNPs > AgNPs. Graphical Abstract.

pH responsive intelligent nano-engineer of nanostructures applicable for discoloration of reactive dyes.

Multifunctional polymers were commonly ascribed as intelligent materials due to the presence of different functional groups on the polymeric skeleton which causes the high sensitivity to the interchanging of physicochemical conditions. Herein, under different temperatures, monitoring the pH response of lignin as intelligent nano-engineer (reducer and stabilizer) for synthesis of size and shape regulated silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) & palladium nanoparticles (PdNPs) is systematically studied. The regulation of the particle size and stability of NPs were remarkably affected by acidity and basicity of the reaction medium at which they were prepared. TEM and zetasizer data showed that, highly size and shape regulated AgNPs & AuNPs is successively produced under acidic conditions with particle size of 13.8 and 5.7 nm, respectively. While basic conditions is more advisable in case of PdNPs to be produced with particle size of 4.5 nm. Catalytic performance of biphasic NPs in reductive discoloration of azo dye (reactive yellow dye 145) was followed the order of PdNPs > AuNPs > AgNPs. The half time for discoloration of dye with basic prepared NPs was dramatically decreased from 21.87 min for AgNPs and 18.34 for AuNPs to 1.45 min for PdNPs.

Instantly AgNPs deposition through facile solventless technique for poly-functional cotton fabrics.

Nowadays, functional clothes are employed for human body protection in addition to be fashionable clothes. Hence functionalization of clothes increases the attention of scientists and business. In the current study, poly-functional cotton fabric was carried out by instantly deposition of AgNPs using two solventless techniques namely; sorption and padding. Sorption technique was exhibited extremely high efficiency than padding one by ca. 10 times. By using the same concentrations of AgNO3, Ag content was ranged 69.3-6094.8 mg/kg and 33.8-609.3 mg/kg for sorption and padding, respectively. After AgNPs deposition, fabrics color was turned to gray-reddish yellow. By applying 5912.3 mgAg/kg fabric, bacterial reduction and UPF value were reached 99% and 12.59. Bacterial reduction and UPF were lessened to 90% and 10.19 after 20 washings. These findings proved that the direct AgNPs deposition into cotton using solventless/sorption technique is applicable in manufacturing of antibacterial/UV resistant fabrics with acquired decorative color.

Functionalization of medical cotton by direct incorporation of silver nanoparticles.

Medical cotton is usually used to clean skin, pack wounds and in other surgical tasks. Such important usages make imparting the antibacterial property to medical cotton is so essential research. The current research focuses on functionalization of medical cotton by direct incorporation of silver nanoparticles (AgNPs) in two-step process namely, pre-alkalization followed by sorption. Decorative color and antibacterial action were accomplished for medical cotton after in situ incorporation of AgNPs without using any other external reducing agent. AgNPs were produced due to the reduction action of alcoholic and aldehydic groups of cotton's skeletal blocks. Cotton fibers were acquired a decorative color attributed to surface plasmon resonance of AgNPs. The treated cotton was characterized by using electron microscope. Results showed that Ag(0) with size distribution of 0-160 nm was formed in the cotton fibers and their size majority (70%) was less than 80 nm. The reduction of Ag(+) to Ag(0) was confirmed by measuring the carboxylic and aldehydic contents. The treated cotton exhibited excellent antibacterial action at low silver contents. The absorbency of cotton was not affected by treatment. The produced medical cotton could be used to safe cleaning of wounds without getting any microbial infections.

Extraction and characterization of chitin and chitosan from local sources.

Chitin has been extracted from six different local sources in Egypt. The obtained chitin was converted into the more useful soluble chitosan by steeping into solutions of NaOH of various concentrations and for extended periods of time, then the alkali chitin was heated in an autoclave which dramatically reduced the time of deacetylation. Chitin from squid pens did not require steeping in sodium hydroxide solution and showed much higher reactivity towards deacetylation in the autoclave that even after 15 min of heating a degree of deacetylation of 90% was achieved. The obtained chitin and chitosan were characterized by spectral analysis, X-ray diffraction and thermo gravimetric analysis.