Various organic and inorganic pollutants are present in seawater which can be treated by applying green chemistry principles in water treatment process instead of the conventional chemical pretreatment method. Development of an environmentally friendly process is becoming more important day by day as the environmental concerns and awareness increased. Photocatalytic oxidation reaction is preferred due to its lower cost, reduces the production of harmful byproducts and the reaction breaks down the pollutants, therefore no residue of the pollutant remains as waste. This report aims to study the possibility of reducing the total carbon and total inorganic carbon present in seawater by photocatalytic oxidation reaction after the reduction of chloride by the reaction of seawater with silver nitrate.