A green chemistry approach through oxidative agent in combination with protease for dehairing: an enhanced path towards sustainability.

The dehairing is one of the essential steps in the leather-making operation where the hair is removed using lime and sodium sulphide by the conventional method. In the present investigation, dehairing of goat skins has been attempted using zinc oxide and protease at the level of 0.5%, which gave satisfactory results. The DSC peaks indicated that the curve at 116.60 °C confirmed that the process is endothermic adsorbing more amount of zinc oxide favouring the dehairing process. Similarly, the TGA peaks showed that the process is a diffusion-controlled one, revealing more amount of zinc oxide has been transported to the skin sample favouring better dehairing in the experiments. SEM analysis clearly showed that control sample had long hair follicles, whereas the experimental sample showed complete removal of hair with hair bulbs, confirming that the experimental process is superior to control sample. FTIR analysis confirms the peaks in the visible in the ranges of 1630–1632 cm−1, 1544–1540 cm−1, and 1238–1236 cm−1 related to deformation vibration of N–H for amide bonds I, II, and III that facilitated better removal of interfibrillar proteins along with dermatan sulphate. The dehairing process was very effective, which can replace sodium sulphide in the considerable amount. This dehairing system reduces the pollution loads of BOD, COD, TDS, TSS to the level of 48, 37, 22, 23, respectively, over conventional lime and sodium sulphide dehairing system. The experimental leather sample revealed comparable shrinkage temperature, colour properties and physical strength properties to the control sample. [ABSTRACT FROM AUTHOR]