title: A model to describe Cr(VI) kinetics biosorption.
abstract: In this work, the effect of pH control on kinetics of Cr(VI) sorption onto grape stalks has been studied. A set of experiments were performed at a constant pH 3+/-0.1 which was assured by means of a Programmable Logic Controller (PLC). In a second set of experiments the initial pH was adjusted to pH 3 and then pH was allowed to freely evolve during the sorption process. Both sets of experiments were carried out at different temperatures within the range 5-50 degrees C. Constant temperature was assured by water recirculation from a thermostatic bath. Results demonstrated that pH has high influence on kinetics only at the lowest temperatures studied. A model based on a complex reaction sequence which takes into account Cr(VI) sorption, reduction of Cr(VI) to Cr(III), sorption of the formed Cr(III) which includes the pH variation during the sorption process has been proposed to model Cr(VI) kinetics sorption onto grape stalk waste. Furthermore, the robustness of the model has been tested.
authors.affiliation: Department of Applied Mathematics, Escola Politècnica Superior, Universitat de Girona, Avda. Lluís Santaló, s/n, 17071 Girona, Spain. jordi.poch@ima.udg.edu
authors.forename: Jordi
authors.initials: J
authors.lastname: Poch
authors.forename: Isabel
authors.initials: I
authors.lastname: Villaescusa
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry*; D004867:Equipment Design; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D018547:Plant Stems; D012984:Software; D013054:Spectrophotometry, Atomic / Q000379:methods; D013696:Temperature; D013816:Thermodynamics; D027843:Vitis
chemical_list: D007220:Industrial Waste; D002857:Chromium