Single-step in situ seed-mediated biogenic synthesis of Au, Pd and Au-Pd nanoparicles by etlingera elatior leaf extract

The rapid formation of stable Au-Pd bimetallic nanospheres are based on a single-step, seed-mediated, growth method using Etlingera elatior leaf extract as a reducing, stabilizing and capping agent. The success of this synthesis is attributed to reduction potential difference of Au and Pd, where Pd initially form seeds in the reaction mixture, followed by growth of Au around the Pd seeds forming Au-Pd bimetallic nanoparticles. Consequently, monometallic Au nanoparticles with mixtures of shapes can be well controlled. The used of Etlingera elatior as a reducing agent is a simple one-pot environmentally friendly reaction, non-toxic and safe method without the need of additional surfactant, capping or stabilizing agent. The synthesized Au-Pd, Au and Pd nanoparticles were characterized via UV-vis, FTIR, XRD, CV, TEM and EDX analysis. TEM analysis revealed that Au-Pd nanoparticles consisted of only nanospheres with mean size of 17.8 ± 9.9 nm, as opposed to the Au nanoparticles that have mixtures of anisotropic nanoshapes with mean size of 15.8 ± 6 nm. FTIR spectroscopic analysis of the biosynthesized Au, Pd and Au-Pd nanoparticles confirmed the surface adsorption of the bioactive components in the leaf extract that acted as the reducing agent and stabilizer for the metal nanoparticles

An Aminated Bacterial Biosorbent Capable of Effectively Binding Negatively Charged Pollutants in Aqueous Solution

The main aim of this work was to enhance the biosorption capacity of Corynebacterium glutamicum for the remediation of wastewaters containing Reactive dyes. Amine groups were found to be responsible for accommodating negatively charged Reactive Red 4 (RR4) molecules via electrostatic interaction. Thus, increasing the number of amine groups on C. glutamicum , via amination, resulted in an enhanced RR4 biosorption capacity. The pH-edge experiments revealed that acidic conditions (pH = 2) favoured the biosorption of RR4 molecules. Isotherm experiments indicated that the aminated C. glutamicum exhibited the highest RR4 uptake, i.e. 133.8 mg/g at pH 2, compared to 96.8 mg/g for raw C. glutamicum. Of the two isotherm models considered, the Toth model provided a better description of the experimental isotherms, with high correlation coefficients and low percentage error values. Kinetic experiments revealed the importance of the initial dye concentration, with equilibrium being rapidly attained after ca. 1 h for all the concentrations examined. The non-linear form of the pseudo-second-order model described the biosorption kinetic data, with high correlation coefficients and low percentage error values compared to the pseudo-first-order model. Desorption was successful achieved at pH 10, with > 90.2% elution efficiencies for both the raw and aminated biomasses

Ionic liquid-assisted cellulose coating of chitosan hydrogel beads and their application as drug carriers

Abstract The present study proposes a simple yet effective method of cellulose coating onto chitosan (CS) hydrogel beads and application thereof as drug carriers. The beads were coated with cellulose dissolved in 1-ethyl-3-methylimidazolium acetate, an ionic liquid (IL) via a one-pot one-step process. Water molecules present in the CS beads diffused outward upon contact with the cellulose–IL mixture and acted as an anti-solvent. This allowed the surface of the beads to be coated with the regenerated cellulose. The regenerated cellulose was characterized by FE-SEM, FT-IR, and XRD analyses. To test potential application of the cellulose-coated CS hydrogel beads as a drug carrier, verapamil hydrochloride (VRP), used as a model drug, was impregnated into the beads. When the VRP-impregnated beads were immersed in the simulated gastric fluid (pH 1.2), the VRP was released in an almost ideal linear pattern. This easily fabricated cellulose-coated CS beads showed the possibility for application as carriers for drug release control

The Preparation of Modified Industrial Waste Polyacrylonitrile for the Adsorptive Recovery of Pt(IV) from Acidic Solutions

Sorption technique is one of the most effective methods for recovering precious metals from wastewater solutions; however, its main drawbacks of the traditional sorbents are the slow kinetics and relatively low sorption capacities. As a solution, thin sorbent fibers have been highlighted because they can lead to fast adsorption kinetics due to their high surface areas and numerous binding sites. In this sense, the applicability of an industrial waste polyacrylonitrile (PAN) textile was examined to recover Pt(IV) from acid solutions. In order to enrich cationic functional groups on the surface of a PAN textile, the textile was chemically modified via polyethylenmine (PEI) coating. Afterwards, using PEI-coated PAN fiber, batch sorption experiments (isotherms and kinetics) and column experiments were conducted to evaluate its sorption performance toward Pt(IV). It was clearly revealed in column experiments that the PEI-coated waste PAN textile (WPAN) has fast kinetics and good performance for Pt(IV) recovery