Meyyappan Revathi

In the present study, cobalt nano particles were synthesized by an ecofriendly and cost effective method using Cadiospermum halicacebium leaf extract. The leaf extract acts as both reducing and capping agent. The biosynthesised cobalt nanoparticles were characterized by using various techniques such as UV-visible spectro photometry, Fourier transform infrared spectrometry, XRD and Scanning electron microscopy. The spectroscopic methods confirmed the formation of cobalt nano particles and the microscopic technique confirmed the shape and size of the cobalt nano particles. The anticancer activity of samples on Hela and VERO cell line were determined by the MTT assay.

Removal of copper ions (Cu(II)) from synthetic electroplating rinse water (SEPRW) by using modified ion-exchange resin was investigated. Modification of the cationic exchange resin was carried out by impregnating polyethyleneimine (PEI). Impregnation was confirmed by scanning electron microscopy–energy dispersive X-ray analysis and Fourier transform infrared spectroscopy analyses. Batch studies were conducted to optimize the various experimental parameters such as contact time, pH, and dosage. The influence of other process parameters including the presence of chelating agent ethylene diamine tetra acetic acid (EDTA) and co-ions were examined. A maximum adsorption capacity (Q_max) of 667.5 mg g⁻¹ was observed at the optimum conditions. Cu(II) removal efficiency of the polyethyleneimine modified ion-exchange resin (PMR) was compared with the unmodified resin (UMR). After the impregnation of PEI, adsorption capacity of the resin varied and the removal rate of Cu(II) removal became fast. Continuous column experiments were conducted in a glass column of desired dimensions. The maximum Cu(II) uptake was obtained at the bed height of 1.65 dm and flow rate of 0.015 L min⁻¹. The breakeven point of the column was obtained after the treatment of 19.5 L of SEPRW. Adam–Bohart and Yoon Nelson models were applied to the column data and desorption studies were conducted in batch mode using hydrochloric acid (HCl), nitric acid (HNO₃) and sulphuric acid (H₂SO₄) as eluant.

Removal of copper, nickel, and zinc ions from synthetic electroplating rinse water was investigated using cationic exchange resin (Ceralite IR 120). Batch ion exchange studies were carried out to optimize the various experimental parameters (such as contact time, pH, and dosage). Influence of co‐existing cations, chelating agent EDTA on the removal of metal ion of interest was also studied. Sorption isotherm data obtained at different experimental conditions were fitted with Langmuir, Freundlich, Redlich–Peterson, and Toth models. A maximum adsorption capacity of 164 mg g⁻¹ for Cu(II), 109 mg g⁻¹ for Ni(II), and 105 mg g⁻¹ for Zn(II) was observed at optimum experimental conditions according to Langmuir model. The kinetic data for metal ions adsorption process follows pseudo second‐order. Presence of EDTA and co‐ions markedly alters the metal ion removal. Continuous column ion exchange experiments were also conducted. The breakeven point of the column was obtained after recovering effectively several liters of rinse water. The treated rinse water could be recycled in rinsing operations. The Thomas and Adams–Bohart models were applied to column studies and the constants were evaluated. Desorption of the adsorbed metal ions from the resin column was studied by conducting a model experiments with Cu(II) ions loaded ion exchange resin column using sulfuric acid as eluant. A novel lead oxide coated Ti substrate dimensionally stable (DSA) anode was prepared for recovery of copper ions as metal foil from regenerated liquor by electro winning at different current densities (50–300 A cm⁻²).