title: Removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan.
abstract: The removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan (TCS) was studied in this article. The synthesized TCS was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), element analysis, N2 adsorption-desorption, scanning electron microscopy (SEM) and X-ray photoelectron spectrophotometer (XPS). Moreover, the influence of solution pH, contact time, initial heavy metal concentration, and solution temperature on the adsorption process was examined, and the adsorbent reusability and adsorption mechanisms were also studied. The results showed that TCS adsorbed greater amount of Pb(II) and Cd(II) ions than the raw chitosan. The adsorption amounts of Pb(II) and Cd(II) ions were affected by increasing solution pH and temperature. The maximum adsorption capacities of the TCS for Pb(II) and Cd(II) ions were found to be 325.2 and 257.2 mg/g, respectively. The endothermic adsorption fitted the pseudo-second-order kinetics equation and the adsorption isotherms could be well described by Langmuir model. The metal ions adsorption mechanism was concluded to be mainly dominated by complexation reaction process. The desorption study indicated that the target adsorbent was easy to be regenerated.
authors.affiliation: College of Science, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Manlin
authors.initials: M
authors.lastname: Li
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China. Electronic address: rh.lee@nwsuaf.edu.cn.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, 104 Sturgis Hall, Baton Rouge, LA 70803, USA.
authors.forename: Jim J
authors.initials: JJ
authors.lastname: Wang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Amjad
authors.initials: A
authors.lastname: Ali
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry* / Q000302:isolation & purification*; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead / Q000737:chemistry* / Q000302:isolation & purification*; D012663:Semicarbazides / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D012663:Semicarbazides; D012996:Solutions; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D007854:Lead; C005151:thiosemicarbazide; D048271:Chitosan
keywords: Adsorption; Chitosan hydrogel; Thiosemicarbazide