title: Adsorption behavior of direct red 80 and congo red onto activated carbon/surfactant: process optimization, kinetics and equilibrium.
abstract: Adsorptions of congo red and direct red 80 onto activated carbon/surfactant from aqueous solution were optimized. The Box-Behnken design (BBD) has been employed to analyze the effects of concentration of surfactant, temperature, pH, and initial concentration of the dye in the adsorption capacity. Their corresponding experimental data could be evaluated excellently by second order polynomial regression models and the two models were also examined based on the analysis of variance and t test statistics, respectively. The optimum conditions were obtained as follows: Cs=34.10 μM, T=50°C, pH=3.5, and CCR=160 mg/L for the congo red system, and Cs=34.10 μM, T=50°C, pH=6.1, and CDR80=110 mg/L for the direct red 80 system. And in these conditions, the measured experimental maximum adsorption capacities for the congo red and direct red 80 removals were 769.48 mg/g and 519.90 mg/g, which were consistent with their corresponding predicted values, with small relative errors of -2.81% and -0.67%, respectively. The adsorption equilibrium and kinetics for the two dye adsorptions onto AC/DDAC were also investigated. The experimental data were fitted by four isotherm models, and Langmuir model presented the best fit. The kinetic studies indicated that the kinetic data followed the pseudo-second-order model.
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China; School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, China; Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637002, China. Electronic address: ncczj1112@126.com.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China; School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, China. Electronic address: zgc166929@sohu.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Guo
authors.affiliation: Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637002, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637002, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Li
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D003224:Congo Red / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D013501:Surface-Active Agents; C009798:C.I. direct red 80; D002606:Charcoal; D003224:Congo Red
keywords: Activated carbon/surfactant; Adsorption kinetics; Box–Behnken design; Congo red; Direct red 80; Isotherms