Investigations on microbial and photocatalytic method for removal of formaldehyde from aqueous solution

Abstract

newlineFormaldehyde is used in wide range of manufacturing processes such as paper manufacturing, textile processing, wood processing, petrochemical, production of leather, synthetic resins, medicinal products, synthesis of pentaerythritol and ethylene glycol etc. Industries utilize Formaldehyde in order to generate wastewater containing variable concentrations, ranging from few to hundreds of milligrams per litre. Nowadays, there are more stringent regulations are required for the treatment of industrial effluents containing Formaldehyde. These can be treated by physical, chemical and biological methods. Formaldehyde is highly toxic in nature, creates toxic impact to living organisms and causes cancer and sick-house syndrome. Therefore, effluent containing Formaldehyde should be treated before discharging in to the environment. The main goal of the present work is to evaluate and compare the efficiency of biological as well as photocatalytic methods for the treatment of Formaldehyde. Formaldehyde degrading bacterium Bacillus cereus - MN658860 was isolated from industrial waste effluent water and identified by cell and colony morphologies, biochemical properties and 16S rDNA sequence analysis. Then, the Formaldehyde biodegradation characteristics were evaluated in a batch process under aerobic conditions. The experiments were performed with Bacillus cereus to reveal its activity retained with respect to Formaldehyde degradation. The experimental studies were conducted in a batch process using aqueous solution of Formaldehyde under aerobic conditions with different experimental conditions: pH value (6.5, 7.0 and 7.5) and inoculum concentration (5%, 10% and 15%) with an initial Formaldehyde concentration of 100, 200, and 300 mg/L. The batch process was performed with immobilized beads and immobilised beads with surface growth in the temperature controlled orbital shaker at 37°C for 2 days at 200 rpm to determine the effect of parameters on percentage degradation. The experimental results reveal that Bacillus cereus exhibit