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Pure and polymer coated (PVP and PVA) gold nanoparticles (AuNPs) with 0.001 and 0.002 M concentrations were synthesised by chemical method. Transmission electron microscopy (TEM) images showed that the size of nanoparticles is below 50 nm whereas the selected area electron diffraction (SAED) pattern indicated cubic structure with lattice parameter of 4.09 Å for each sample. The absorption bands for all these samples lie between 500 and 550 nm as observed from UV–vis spectra. The photoluminescence (PL) spectra taken at 300 nm excitation wavelength showed emission between 415 and 430 nm whereas the particle size determined from particle size analyser lies below 100 nm for all samples. The ultrasonic velocity measured as a function of temperature showed the decrement above 50 °C for PVP and PVA coated AuNPs. The antimicrobial activity for these above taken concentrations of gold samples showed negative effect, whereas higher concentration of AuNPs of 0.005 M showed the positive effect for gram-positive and gram-negative bacteria.

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The synergetic effect of photocatalytic, adsorption and antibacterial properties of ZnO@ACP and CuO@ACP samples are investigated in this study. The synthesized samples are initially studied for their elemental composition, crystalline phase and structure, surface morphology, optical band gap, functional groups, vibrational modes by EDAX, SEM, XRD, Raman, FTIR, UV-Vis spectroscopy and BET respectively. Methylene blue (MB) which is used as a dye in industries has been used in this work for its removal from waste water using the above prepared samples. We could degrade 63% of MB by adsorption under dark conditions with this samples. After illumination with UV radiation, it is seen that MB is degraded 93% by ZnO@ACP, 85% with CuO@ACP whereas 78% with activated charcoal. This reflects that ZnO and CuO nanoparticles embedded with activated charcoal shows increase in photocatalytic activity. Further, Langmuir-Hinshelwood model is used to calculate the kinetic rates of ZnO and CuO nanoparticles on embedded on ACP samples. The antimicrobial activity of synthesized samples is also tested against E. coli. bacteria whereas cell viability is tested using CHO (Chinese hamster ovary) animal cells at various concentrations. The results obtained shows 75% decrease in the growth of E. coli bacteria for ZnO@ACP and 60% decrease for CuO@ACP at a concentration of 250µg/ml whereas reduction in colony counts is 95% and 75%, respectively. we obtained 80-90% CHO cell viability proves that both these samples are not toxic to these cells.