Kinetic investigation of TiO2 mediated photocatalytic degradation of Para nitrophenol
Introduction
In the manufacture of dyes, medicines and pesticides, nitrophenols are widely used as chemical intermediates. These are stable, carcinogenic and toxic. Para nitrophenol(PNP) is one of them and the presence of it in the environment is harmful for the living being.
The technique heterogeneous photocatalysis belonging to advanced oxidation process have proved to be one of the most effective treatment methods for the removal of pollutants from wastewater. In this process strong oxidizing agent hydroxyl radicals are produced which oxidizes a wide variety of organic pollutants into innocuous end products such as carbon dioxide, water and mineral acids………
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1/(k_app )=1/k_(c ) 1/K_LH + C_0/k_c (I)
Where C0 is the initial concentration of organic pollutants, k_app is the apparent rate constant, kc is the rate constant of surface reaction and KLH is the Langmuir-Hinshelwood adsorption equilibrium constant.
The objective of this work is to study the kinetics of photodegradation of PNP using TiO2 as photocatalyst based on L-H model.
Materials and methods
Materials
Commercial grade PNP was purchased from ………….. TiO2 obtained from ………. All the chemicals were used without further purification. De-ionized water was used to prepare the solutions.
Photoreactor
A 100mL beaker was used as the reactor having inside diameter 4.3cm and height 5.5cm. The reactor was placed on a magnetically stirred plate and a UV lamp emitting radiation of 254nm was positioned over the reactor with 15cm distance from the surface of solution. The total system was enclosed in a wooden box. This box is called the lamp house, whose inside surface was covered by aluminum foil to increase the intensity of