Highly efficient extraction of large molecular-weight keratin from wool in a water/ethanol co-solvent

A large number of wool fiber by-products, short and coarse wool fibers are difficult to spin and are disposed of by the wool industry, creating a burden on the environment. In this study, L-cysteine hydrochloride and sodium sulfite were used as reducing agents to extract keratin from natural wool in an ethanol-water mixed system. The molecular weight of the extracted keratin is up to 130 kDa with a high yield of 67%. It has been proven that the reducing agent destroyed partial disulfide bonds, ethanol destroyed partial hydrogen bonds and hydrophobic interactions, and the α-helix chain was converted into a β-folded chain and random coil after extraction by instrumental analysis using a Fourier transform infrared spectrometer and X-ray diffraction. The recombination of small keratin molecules can be proven by the increase in protein particle size and molecular weight via a particle size analyzer and SDS-PAGE respectively.

Role of the newly synthesized brightener in modification of surface properties of Zn-Ni alloy electrodeposited on steel substrate

In the present study, a new brightener was synthesized by condensation of salicylaldehyde and cysteine hydrochloride (SC). To examine the influence of SC on the nucleation mechanism of Zn-Ni alloy, electrodeposition, cyclic voltammetric and chronoamperometric studies were carried out. The model of Schariffker and Hills was used to analyze current transients which explained the electrocrystallization process of Zn-Ni alloy. It is revealed that Zn-Ni electrocrystallization process in presence of SC is regulated by instantaneous nucleation mechanism. The corrosion studies were done for the bright and dull zinc-nickel alloy coatings in 3.5 wt.% NaCl solution, using potentiodynamic polarization and electro­chemical impedance spectroscopic techniques. The phase structure, surface morphology and brightness of the deposit were characterized by means of X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and reflectance studies. These studies revealed the role of SC in producing a bright Zn-Ni alloy coating on mild steel substrate and also showed its improved corrosion resistant nature.