title: Experimental design for the optimization of copper biosorption from aqueous solution by Aspergillus terreus.
abstract: An experimental design methodology was applied to study the effects of temperature, pH, biomass dose, and stirring speed on copper removal from aqueous solutions by Aspergillus terreus in a biosorption batch system. To identify the effects of the main factors and their interactions on copper removal efficiency and to optimize the process, a full 2(4) factorial design with central points was performed. Four factors were studied at two levels, including stirring speed (50-150 min(-1)), temperature (30-50°C), pH (4-6) and biosorbent dose (0.01-0.175 g). The main factors observed were pH and biomass dose, along with the interactions between pH and biomass, and stirring speed. The optimal operational conditions were obtained using a response surface methodology. The adequacy of the proposed model at 99% confidence level was confirmed by its high adjusted linear coefficient of determination (R(Adj)(2)=0.9452). The best conditions for copper biosorption in the present study were: pH 6, biosorbent dose of 0.175 g, stirring speed of 50 min(-1) and temperature of 50°C. Under these conditions, the maximum predicted copper removal efficiency was 68.52% (adsorption capacity of 15.24 mg/g). The difference between the experimental and predicted copper removal efficiency at the optimal conditions was 4.8%, which implies that the model represented very well the experimental data.
authors.affiliation: Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Av. Universidad s/n, Cd. Universitaria, San nicolás de los Garza, NL 66451, México. felipe.cerinocr@uanl.edu.mx
authors.forename: F J
authors.initials: FJ
authors.lastname: Cerino-Córdova
authors.forename: A M
authors.initials: AM
authors.lastname: García-León
authors.forename: E
authors.initials: E
authors.lastname: Soto-Regalado
authors.forename: M N
authors.initials: MN
authors.lastname: Sánchez-González
authors.forename: T
authors.initials: T
authors.lastname: Lozano-Ramírez
authors.forename: B C
authors.initials: BC
authors.lastname: García-Avalos
authors.forename: J A
authors.initials: JA
authors.lastname: Loredo-Medrano
mesh_terms: D001230:Aspergillus / Q000378:metabolism*; D018533:Biomass; D003300:Copper / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods; D008962:Models, Theoretical; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; D003300:Copper