title: Chemo-mechanical modification of cottonwood for Pb(2+) removal from aqueous solutions: Sorption mechanisms and potential application as biofilter in drip-irrigation.
abstract: Using biomass (e.g. crop residues) and its derivatives as biosorbents have been recognized as an eco-friendly technique for wastewater decontamination. In this study, mechanically modified cottonwood was further activated with KOH to improve its sorption of Pb(2+). In addition, its potential as a biofilter to safeguard radish (Raphanus sativus, L.) against Pb-stress was evaluated in a gravity-fed drip irrigation system. Physiochemical properties of the chemo-mechanically activated cottonwood (CMACW) and the mechanically activated cottonwood (MACW) before and after sorption process were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), digital selected-area electron diffraction (SAED) and Fourier transform infrared spectroscopy (FTIR). After activation, several sorption mechanisms (i.e. precipitation, electrostatic outer- and inner-sphere complexation) were responsible for the higher sorption capacity of CMACW as compared with MACW (8.55 vs. 7.28 mg g(-1)). Sorption kinetics and isotherms fitted better with the pseudo-second-order and Langmuir models as compared with the pseudo-first-order and Freundlich models, respectively. In the gravity-fed drip irrigation system, the CMACW biofilter reduced the accumulation of Pb in radish roots and shoots and avoided reaching the toxic limits in some cases. Soil types had a significant effect on Pb(2+) bioavailability because of the difference in sorption ability. Findings from this study showed that CMACW biofilter can be used as a safeguard for wastewater irrigation.
authors.affiliation: Soils Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mosa
authors.affiliation: Soils Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt.
authors.forename: Ayman
authors.initials: A
authors.lastname: El-Ghamry
authors.affiliation: Institute of Soil Science and Forest Nutrition, Freiburg University, Freiburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Trüby
authors.affiliation: Soils Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Omar
authors.affiliation: Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, United States. Electronic address: bg55@ufl.edu.
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
authors.affiliation: Soils Department, Faculty of Agriculture, Mansoura University, 35516 Mansoura, Egypt.
authors.forename: Abdelhamid
authors.initials: A
authors.lastname: Elnaggar
authors.affiliation: Tropical Research and Education Center, University of Florida, Homestead, FL 33031, United States; Soil and Water Science Department, University of Florida, Gainesville, FL 32611, United States.
authors.forename: Yuncong
authors.initials: Y
authors.lastname: Li
mesh_terms: D000327:Adsorption; D057914:Agricultural Irrigation; D018533:Biomass; D006878:Hydroxides / Q000737:chemistry; D007700:Kinetics; D007854:Lead / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D032107:Populus / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry; D031224:Raphanus / Q000254:growth & development*; D012987:Soil / Q000737:chemistry; D012996:Solutions; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006878:Hydroxides; D007854:Lead; D017680:Potassium Compounds; D012987:Soil; D012996:Solutions; D062065:Wastewater; D014874:Water Pollutants, Chemical; C029943:potassium hydroxide
keywords: Biofilter; Chemical modification; Cottonwood; Mechanical modification; Radish; Soil