In the current study, the removal of Cd(II), Pb(II) and Cu(II) ions from industrial effluent was investigated using powdered Moringa stenopetala seed husk. The surface functionality, morphology, crystallinity, thermal stability, the surface charge and surface area of the powdered Moringa stenopetala seed husk was studied using FTIR, SEM, XRD, TGA, zeta potential and BET, respectively. Processing parameters, namely contact time, adsorbent dosage, concentration, pH, agitation speed, temperature and particle size were investigated using the batch adsorption method. The maximum adsorption percentage for Cd(II), Pb(II) and Cu(II) ions from synthetic wastewater was found to be 99.1, 99.4 and 99.1%, compared to 95.3, 95.5 and 94.1%, respectively, for adsorption of these metal ions from real wastewater. The maximum adsorption capacity was found to be 52.63, 47.62 and 31.25 mg/g adsorbent for Cd(II), Pb(II) and Cu(II), respectively. The Freundlich isotherm provided a better fit for the adsorption equilibrium data than the Langmuir isotherm, while the kinetics were well defined by the pseudo-second-order model (R² = 1). Furthermore, the positive value of the enthalpy change (ΔH) indicated that the adsorption of metal ions on the adsorbent was endothermic. The negative values of the Gibbs free energy change (ΔG) confirmed that the adsorption process on the surface of the adsorbent was spontaneous.

Limited studies have been done on silk fibroins of wild silkworm species owing to their relative insolubility in many solvents. In this study, the solubility of Argema mimosae wild silk fibroin in different salts (LiBr, LiCl, Ca(NO₃)₂, and CaCl₂) dissolved in formic acid under varying temperatures was investigated. The dissolution conditions under which the solubility was optimum were optimized using a central composite design approach. The optimum range for solvation of the fibroin were visualized using contour plots. The influence of temperature and salt concentration were found to significantly influence the solvation of the fibroin. Following the successful dissolution of the fibroin, the regenerated silk fibroin solutions were cast to obtain water insoluble films which were used in investigating optimum electrospinning conditions. Average nanofiber diameters in the 110–141 nm range were obtained under optimum electrospinning conditions. The silk forms were characterized using the FTIR, TGA, XRD, and SEM to understand their properties. The investigations revealed that formic acid—salt solvents were effective in the solvation of the wild silk fibroin. Some of the dissolution conditions induced mild effects on the silk fibroin while others were harsh. Furthermore, processing to nanofibers resulted in the degradation of the β-sheets producing nanofibers rich in α-helices. However, post-treatment using methanol and water vapor were effective in restoring β-sheet crystallinity.