Adsorption and Photocatalytic Degradation Kinetics of Gaseous Cyclohexane in an Annular Fluidized Bed Photocatalytic Reactor

Abstract

The adsorption and photocatalytic degradation kinetics of gaseous cyclohexane using nano-titania agglomerates were investigated in an annular fluidized bed photocatalytic reactor (AFBPR). A series of adsorption and photocatalytic degradation kinetic equations were developed to explore the relationship of adsorption/degradation efficiency and operating variables based on Langmuir adsorption law and photocatalytic elementary reactions. The adsorption equilibrium constant, adsorption active sites, and apparent reaction rate coefficient of cyclohexane were determined by linear regression analysis with variation of gas velocity and relative humidity (RH). It has been demonstrated that the initial concentration, RH, and gas velocity have obviously influenced the adsorption/photocatalytic degradation efficiency and corresponding kinetic parameters. In the adsorption process, the variation of adsorption sites and adsorption efficiency with gas velocity indicated that the adsorption controlling step was related to gas velocity. In the photocatalytic degradation process, the relationship of photocatalytic degradation efficiency and RH indicates that the water molecule played a promotion role in photocatalytic degradation of cyclohexane below a humidity inflection point, while it played an inhibition role in photocatalytic degradation of cyclohexane after this point. In addition, the optimal operating conditions were determined according to the maximum degradation efficiency with respect to RH at 20% and the fluidization number at 1.62.

Acceleration of Trimethylamine Removal Process Under Synergistic Effect of Photocatalytic Oxidation and Surface Discharge Plasma Reactor

“…For a given flowrate, we note that the TRE proportionally decreases with inlet concentration. This is due to the availability of the photocatalytic sites at this concentration range . At high values of TMA inlet concentration, the TRE will tend to a limit.…”

Sequential‐based process modelling of VOCs photodegradation in fluidized beds

“…[6][7][8][33][34][35][36][37][38] Less attention has been paid to mineralization, particularly in FBPRs. [6][7][8][33][34][35][36][37][38] Less attention has been paid to mineralization, particularly in FBPRs.…”

“…[39] The mentioned effect of RH on CO 2 yield could be explained as follows: at RH of 45 %, OH radicals improve the mineralization through the decomposition of intermediates towards CO 2 , but with the further increase in RH, competitive adsorption between the intermediates and water molecules aggravates the CO 2 yield. [6,8] The kinetic parameters of L-H mechanism are listed in Table 4. However, more experiments should be carried out to identify the intermediates and the effect of RH on their decomposition.…”

“…Some simplifications have been adopted in Equation (8); for example, the possible interference of intermediates and by-products has been neglected in Equation (8). It should be noticed that there is no general expression that could predict the reaction rate due to the complex mechanism of reactions.…”

“…Adsorption, condensation, and catalytic combustion are conventional methods that have some drawbacks, such as low removal efficiency and high operating costs. [6][7][8][9] PCO of acetone in air flow using titanium dioxide has previously been studied and the effect of various parameters on its photocatalytic efficiency has been reported. [2] The PCO process is normally operated at ambient temperature and pressure leading lower energy consumption as compared with conventional processes such as incineration.…”