Chemical Engineering Journal 127 (2007) 47–57 Experimental behaviour and design model of a fluidized bed reactor with immobilized peroxidase for phenol removal Jos´ e L. G ´ omez ∗ , Antonio B ´ odalo, Elisa G ´ omez, Asunci ´ on M. Hidalgo, Mar´ ıa G ´ omez, M. Dolores Murcia Chemical Engineering Department, University of Murcia, Campus de Espinardo, 30071 Murcia, Spain Received 6 July 2006; received in revised form 20 September 2006; accepted 23 September 2006 Abstract In this work, immobilized derivatives of soybean peroxidase, covalently bound to glass supports with different surface areas, were used in a laboratory scale fluidized bed reactor to study their viability for use in phenol removal. The influence of the different operational vari- ables on the process was also studied. When derivatives immobilized on supports with the highest surface area were used, 80% removal was achieved. Since knowledge of the removal process in the fluidized bed reactor and its simulation is vital before a continuous industrial scale process can be proposed, a reactor model based on the experimental results that predicts the system’s behaviour both in steady and transient state was developed. The model considers the fluidized bed reactor as a plug flow reactor in series with an ideal mixer and follows a kinetic law based on the observed external mass transfer resistances in order to work out the process rate. The values of the model parameters were obtained by fitting phenol conversion values obtained experimentally to the model, using the Curve- Expert, V 1.3, software. The good agreement obtained between the experimental and calculated values of phenol conversion demonstrates that the model is valid as a predictive model for using this reactor configuration. © 2006 Elsevier B.V. All rights reserved. Keywords: Fluidized bed; Design model; Soybean peroxidase; Immobilized peroxidase; Phenol removal 1. Introduction Phenolic compounds are among the most ubiquitous pol- lutants and they are widely known to be toxic and diffi- cult to degrade. They are usually found in the wastewaters of numerous industries, such as the pulp and paper, wood, steel and metals, petroleum refining, resins and plastic based industries [1–4]. Biological degradation with microorganisms and adsorption and biotreatment in active carbon in different reactor configu- rations have been the most widely used technologies until now for the purification of industrial effluents containing phenolic products. Several authors have described the use of fluidized bed reac- tors with granulated active carbon acting as both the adsorbent of ∗ Corresponding author. Tel.: +34 968 367351; fax: +34 968 364148. E-mail address: carrasco@um.es (J.L. G ´ omez). phenolic products and as support for phenol-degrading microor- ganisms [5–8]. Fluidized beds with microorganisms immobilized on differ- ent supports have also been used for removing phenol from wastewaters. Hirata et al. [9], described the kinetics of the bio- logical treatment of phenolic wastewaters in this type of reactor containing biofilms and suspended sludge. For highly polluted phenolic waters, Loh et al. [10], used an air lift fluidized bed reactor with Pseudomonas putida immobilized on pellets of expanded polyestyrene, concluding that biodegradation was lim- ited by oxygen transfer. Working with this reactor configuration, Ju´ arez-Ram´ ırez et al. [11], studied the kinetics of phenol degra- dation with Candida tropicalis immobilized on agar gel, finding that the degradation rate is higher than that obtained with the free cells. A comparative study of tank and fluidized bed reactors for phenol biodegradation was made by Gonz´ alez et al. [12], the latter enabling better control of the process and needing shorter hydraulic residence times. Furthermore, using the same type of immobilized microorganism, Pseudomonas putida, Gonz´ alez 1385-8947/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.cej.2006.09.021