title: Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms.
abstract: We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R(2)>0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 °C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 °C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 °C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal.
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent Dimitrie Mangeron Street, 700050 Iasi, Romania.
authors.forename: Raluca Maria
authors.initials: RM
authors.lastname: Hlihor
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent Dimitrie Mangeron Street, 700050 Iasi, Romania.
authors.forename: Mariana
authors.initials: M
authors.lastname: Diaconu
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Automatic Control and Computer Engineering, Department of Computer Engineering, 27 Prof. Dr. Docent Dimitrie Mangeron Street, 700050 Iasi, Romania.
authors.forename: Florin
authors.initials: F
authors.lastname: Leon
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Chemical Engineering, 73 Prof. Dr. Docent Dimitrie Mangeron Street, 700050 Iasi, Romania.
authors.forename: Silvia
authors.initials: S
authors.lastname: Curteanu
authors.affiliation: University of Minho, Department of Biological Engineering, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Tavares
authors.affiliation: "Gheorghe Asachi" Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent Dimitrie Mangeron Street, 700050 Iasi, Romania; Academy of Romanian Scientists, 54 Splaiul Independentei, RO-050094 Bucharest, Romania. Electronic address: mgav@tuiasi.ro.
authors.forename: Maria
authors.initials: M
authors.lastname: Gavrilescu
mesh_terms: D000465:Algorithms; D018533:Biomass; D002104:Cadmium / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008670:Metals / Q000032:analysis; D008962:Models, Theoretical; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D060388:Support Vector Machine; D013696:Temperature; D013816:Thermodynamics; D014242:Trichoderma / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification
chemical_list: D007477:Ions; D008670:Metals; D012996:Solutions; D014874:Water Pollutants, Chemical; D002104:Cadmium