title: Adsorption of malachite green by magnetic litchi pericarps: A response surface methodology investigation.
abstract: In this work, we synthesized a novel magnetic adsorbent containing litchi pericarps, denoted as MLP, for the removal of malachite green (MG) from solution. The factors influencing MG adsorption, such as contact time, adsorbent dosage, and initial dye concentration, were optimized using the Box-Behnken response surface methodology (RSM). The adsorption isotherms as well as the kinetics and thermodynamics of the adsorption of MG onto MLP are discussed. The results showed that MLP has a maximum adsorption efficiency of 99.5% when the temperature, pH, contact time, adsorbent dosage, and initial MG concentration were optimally set as 25 °C, 6.0, 66.69 min, 5.14 g/L, and 150 mg/L, respectively. The best model to describe this process is the Langmuir isotherm, with the maximum adsorption capacity being 70.42 mg/g. In addition, the kinetics of MG adsorption onto MLP followed a pseudo-second-order model; moreover, thermodynamic analysis suggested that MG adsorption onto MLP is spontaneous and endothermic. Finally, it was found that the new magnetic adsorbent can be separated easily and rapidly from mixed solutions in the presence of an external magnetic field.
authors.affiliation: Water Conservancy and Civil Engineering College, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Water Conservancy and Civil Engineering College, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China.
authors.forename: Jinqiu
authors.initials: J
authors.lastname: Qi
authors.affiliation: Water Conservancy and Civil Engineering College, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China.
authors.forename: Ruixue
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Water Conservancy and Civil Engineering College, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Water Conservancy and Civil Engineering College, Shandong Agricultural University, Tai'an, Shandong, 271018, PR China. Electronic address: lixiaochen02@163.com.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Li
mesh_terms: D000327:Adsorption; D007700:Kinetics; D032125:Litchi / Q000737:chemistry*; D008280:Magnetics; D008962:Models, Theoretical; D012394:Rosaniline Dyes / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D012394:Rosaniline Dyes; D012996:Solutions; D014874:Water Pollutants, Chemical; C005095:malachite green
keywords: Analysis of variance; Magnetic litchi pericarps; Malachite green; Response surface methodology; Separation