Wastewater Treatment Using Bio – Inspired Photocatalyst

Deepika Swamia, Satish Kumar a,b

aInter Disciplinary Programme in Climate Studies, IIT Bombay , bEnvironment Research Lab, IIT Roorkee; India

Email ID of Corresponding Author: dsdeepika782@gmail.com

Biggest problem faced by world today is only energy and water so both of these problems need

to be explored for their solution. So, in order to solve the purpose, Bio-inspired photocatalysts

seem to be the best solution. Here the approach was to develop bioinspired photocatalyst with

solar light activity for treating heavy metals, organic and inorganic pollutants in water. During

the treatment procedure, there was very less consumption of chemicals, no sludge production and

only solar energy was used. Inorganic nano-particle synthesis using biological approach is of

great value due to its flexibility, mild reaction conditions, water solubility and non-toxicity of

produced nanomaterials. Among nanoparticles, Titanium dioxide (TiO2) is one of the most

promising photocatalysts because of its high photocatalytic efficiency, low cost, non toxicity,

chemical inertness, and long-term stability against photocorrosion and chemical corrosion.

Efficiency of Photocatalyst is enhanced by increasing its crystallite size, surface area and by

doping it with some transition metal such as Ag, Fe, Mo, Ru, Os, Re and V. Transition metal

doping of TiO2 was done with silver, which results in formation of band gap traps and prevents

recombination of electrons from conduction band or holes from valance band, due to which

hydroxyl and superoxide radicals are produced in much larger amount and thus more degradation

of organic compounds take place. Now this doped TiO2 photocatalyst was templated using

biological substance i.e. bacteria in order to enhance the surface area and treatment properties of

the respective biophotocatalyst.

“Biotemplating” has been emerged as an emerging, unique approach for organization and

synthesis of nanostructures into well-defined architectures. During the study, three types of

photocatalysts were prepared: TiO2 (X), Biotemplated TiO2 (Y) and Biotemplated TiO2 doped

with silver (Z). Treatment of paper mill primary effluent was performed using all three catalysts

and results obtained were quite efficient and viable; 78% reduction in COD, 82% reduction in

BOD and 45% reduction in AOX was achieved via catalyst Z. Catalyst Z proved to be more

efficient than X and Y due to both biotemplating and doping with silver. Afterward, catalysts

were characterized by Fe-SEM, XRD, EDX and FTIR and all the spectra obtained were

themselves elucidating the outcomes obtained. Spectra obtained show that the efficiency of

catalyst Z was highest due to increase in surface area as analyzed by Fe-SEM and the hydrophilic

bonding between catalyst and bacterial cell wall (predicted by FTIR) was responsible for

degradation of pollutants from water. All the catalysts were compared in their efficiency for

degradation of dyes, pollutants, organic substances and for their anti-corrosive property.

Personal Biodata:

I have done B.Tech in Biotechnology from DeenBandhu Chhotu Ram University of Science and

Technology and Gold-medalist during M.Tech program (Energy and Environmental

management) from Kurukshetra University, Kurukshetra. Presently, I am pursuing research

(PhD) from Indian Institute of Technology, Bombay in discipline of Climate Studies with major

focus on “Impact assessment of Bioenergy Projects in India”.