(205d) Removal of Phenol from Wastewater of Petroleum Refinery By Using Advanced Oxidation Process

Advanced oxidation processes (AOPs) are promised techniques for treatment of wastewater which containing refractory contaminants. In the present study an experimental work and kinetic study have been carried out to investigate performance of Lab-scale trickle bed reactor for phenol degradation of wastewater effluent from a petroleum refinery in Baghdad. Several process variables are effecting on the system performance. These selected variables are: initial concentration of phenol (5 to 15 mg/L), temperature (120 to 160 ^oC), pressure (0.2 to 0.9 Mpa), air flow rate (0.01 to 0.03 L/min), pH of solution (3 to 10), liquid flow rate (0.6 x10^-3 to 1.66x10^-3 L/min), and flow modes are down-flow and up-flow. The experimental set-up is mainly consists of a stainless steel reactor of dimensions (13 mm ID x 160 mm L), packed with 5 gram activated carbon (0.8 mm particle diameter) as catalyst. The optimum experiments were obtained by using 3-level, 4-factor Box-Behnken design (BBD), with aid of modified response surface methodology (RSM).Results showed that phenol degradation was enhanced by increasing of temperature, increasing of pressure, and increasing of gas flow rate, while initial concentration of phenol and liquid flow rate would give negative images. High removal of phenol at about 97% was obtained at optimum operating condition of; LHSV=7 h^-1, temperature=160°C, oxygen partial pressure= 0.9 MPa, and phenol concentration= 5 mg/L. Down-flow mode has been proven more effective than up-flow mode for reactor performance. Kinetics of the reaction behaved as pseudo first order reaction with respect to phenol concentration,and with 0.6 order with respect to oxygen solubility. Activation energy was equal to77.7 kJ/mol, and pre-exponential factor was equal to (1.826*10⁹ L/kg-cat .h). It was observed that deactivation constant (k_do) was equal to (2.9*10¹¹ min ^-1),was about (114.43 kJ/mol). When catalyst deactivation had been taken into account, the oxygen order was equal to 1.67 and the frequency factor was about (4.2*10⁹ L/kgcat.h), also the activation energy was (95.35 kJ/mol). The kinetic parameters (i.e., k and E) were estimated at each operating temperature by using statistical analysis method. Catalyst effectiveness and deactivation rate were also estimated. Reasonable agreements have been found when compared the simulated results with the experimental data.