Field Trials of Low-Cost Bi-TiO2-P25 Solar Photo Catalyst for Water Treatment

A low-cost, easy to make Bi-TiO₂-P25 composite is synthesized via a reverse micelle sol-gel route and is tested for its ability to be activated under solar light. The photocatalyst is coated on recycled glass chips and glass slides (used as substrates) and is tested for degradation of 4-Chlorophenol (4-CP) and the removal of Escherichia coli (E. coli) from water. Field tests are conducted in rural India for solar photo catalytic reduction of microbial contaminants in natural water. Two water sources are tested: well water used for drinking, with an initial count of 4800 colony-forming unit (CFU)/100 mL for total coliforms, and pond water, used for washing and bathing, with an initial count of 92,000 CFU/100 mL for total coliforms and 3000 CFU/mL for E. coli. These water samples are filled into commercial polyethylene terephthalate (PET) bottles along with the catalyst coated chips and are exposed to sunlight. It is observed that the total coliform count have been reduced by up to 99% and E. coli by up to 99.9% in just 2 h, with excellent results in reusability tests. This study demonstrates the potential of solar photo catalysis to be used in real world drinking water treatment and will promote future advancements in this field.