Schiff-base derived chitosan impregnated copper oxide nanoparticless: an effective photocatalyst in direct sunlight by Narayanan, V. Sathiya, Prasath,K., P. Varun, Ravichandran, K., Easwaramoorthy, D., Shahnavaz, Zohreh, Mohammad, Faruq, Al-Lohedan, Hamad A., Paiman, Suriati, Won, Chun Oh, Sagadevan, Suresh