A series of Au-Pd/TiO2 catalysts were synthesized in different weight % using sol-immobilization method. Of the range studied 1%Pd/TiO2 catalyst achieved 86.4% conversion of phenol to CO2 in a standard batch-slurry system utilizing UV. However under recycle or continuous operation Pd leaching from catalyst surface led to gradual deactivation. Au-Pd nanoparticles supported on TiO2 P25 were stable and recyclable, here Au species were found to help to anchor Pd species on TiO2, and no observable Pd leaching occurred. Utilizing UV, 1%Pd/TiO2 showed faster rate of phenol degradation in comparison to Au-Pd/TiO2, while 1%Au/TiO2 and 0.5%Au-0.5%Pd/TiO2 showed faster phenol degradation rates under visible light. The TiO2 P25 support was also found to be active, stable and recyclable in phenol degradation utilizing UV; and was hence considered suitable for continuous operation. However poor oxygen mass transfer led to the formation and lay-down of polymeric species when using a Trickle bed approach. Operation in the Taylor flow regime was demonstrated to increase oxygen saturation and significantly reduced deactivation. Hence continuous photocatalytic degradation of phenol could be achieved using TiO2 under Taylor Flow conditions.

The treatment of pollution using eco-friendly and sustainable methods is one of the bases of biotechnology. The work reports the use of periwinkle snail shell (PS) as carrier to immobilize Pseudomonas macerans and Bacillus subtilis for the biodegradation of 1-methyl naphthalene in aqueous medium. The biodegradation of 1-methyl naphthalene (500 mg L-1) were monitored after 36 h and 72 h by determining the concentration of carbonic acid (by titrimetric method) following the release of carbon (IV) oxide. The pH as well as the Fourier Transform-infrared (FT-IR)of the metabolites from the bioreactors/reactors were also studied. The pH of all the supernatants in the bioreactors/reactors decreased with time. There was increase in the concentration of H2CO3 due to the biodegradation of 1-methyl naphthalene by immobilized Pseudomonas macerans and Bacillus subtilis on 1.0 g and 2.0 g of PS. However, the use of immobilized Pseudomonas macerans on PS resulted to significant biodegradation of 1-methylnaphthalene (range of 0.61-0.81 mg/L H2CO3) compared to degradation alone with PS after 72 h. FTIR of the metabolite at end products show new peaks within 3372-3268 cm-1 and within 1643-1640cm-1 , these bands are attributed to overlapping of hydroxyl (OH) and carbonyl (C=O) stretching in carboxylic acid respectively, this implies that 1-methyl naphthalene got converted to carboxylic acid. Therefore, the use of carbonaceous wastes for localization in order to enhance biodegradation of hydrocarbons can be harnessed for mop-up of oil spills.