To address the objective of disinfecting water, copper nanoparticles (Cu‐NPs) have been synthesized and impregnated on activated carbon (AC). This material when packed in a continuous column can potentially satisfy the need of a household‐scale water disinfection unit.
Accordingly, Cu‐NPs of 6.11 nm mean diameter were deposited in the form of discrete NPs, on plasma treated AC, with a Cu loading of 2.1 wt.%, in Cu‐AC. We could achieve selective impregnation of Cu‐NPs on the external surface of plasma treated AC as plasma treatment generates surface function groups on the AC surface. These superior qualities of our hybrid could achieve complete killing of 104 CFU/ml of E. coli cells in only 10 minutes of contact, on using 8 mg/ml of Cu‐AC in batch mode. A flow‐column (with 8 cm diameter and 25 cm height) designed on the basis of this batch contact time could achieve disinfected water at a high flow rate of 4.13 L/h, even when operated non‐stop, for over 7 days. Simultaneously, it could maintain a very low steady state Cu concentration (83.7 µg/L) in the disinfected water, much below the permissible limit of 1000 µg/L for drinking water.
We could achieve: (i) selective impregnation of Cu‐NPs on AC with controlled degree of oxidation, (ii) maximum flow rate of E. coli‐free drinking water in a continuously operating column, packed with Cu‐AC granules and (iii) complete E. coli cell‐killing and Cu concentration within the permissible limit of drinking water over a very long duration.