15879

1634 دكتري

دكتري

علوم خاك

اصفهان : دانشگاه صنعتي اصفهان

1399

چهارده، [119]ص.: مصور، جدول، نمودار

مهران شيرواني، حسين شريعتمداري

محمد ديناري

محمد علي حاج عباسي، محسن حميدپور، مهران غياثي

1399/07/28

كتابنامه

كشاورزي

مهندسي كشاورزي

1399/07/28

2642335

Interactions of lead with montmorillonite STx 1b in the presence of some chelating ligands Farzad Parsadoust F parsadoust@ag iut ac ir Sept 21 2020 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 Iran1st Supervisor Mehran Shirvani shirvani@cc iut ac ir2nd Supervisor Hossein Shariatmadari shariat@cc iut ac ir Associate Professor of Soil Science Department of Soil Science College of Agriculture IsfahanUniversity of Technology Professor of Soil Science Department of Soil Science College of Agriculture Isfahan University ofTechnologyAbstractEnvironmental contamination with heavy metals is a growing global concern as metalshave adverse impacts on both human health and the ecosystem Lead Pb is one of themost common and toxic metals released into the environment from various industrialactivities Over the last few decades a growing concern has been raised about theenvironmental impacts of EDTA and its metal chelates because their biodegradation isvery limited to particular conditions Various biodegradable ligands have recently beenintroduced and used in various industries and agriculture Investigation of the reactionsof heavy metals with clay minerals in the presence of these ligands in model systemscan help to better understand the behavior of the metals in soil environments In thisstudy the interactions of Pb with montmorillonite STx 1b in the presence of EDTA andenvironmental friendly ligands GLDA and MGDA were investigated This research wasconducted in three different studies In the first study the adsorption kinetics of Pb attwo concentrations of 0 25 and 1 mM on STx 1b in the presence and absence theligands were investigated The results showed that the maximum Pb adsorption rate onthe STx 1b increased with increasing Pb concentration while the use of ligandsdecreased the maximum adsorption rate The Pb adsorption kinetics on the STx 1b wasbiphasic with the initial fast phase occurring within 3 h and the slow adsorption phaseoccurring within 12 h until the equilibrium time The adsorption kinetics of Pb weredescribed by pseudo first order pseudo second order power function parabolicdiffusion Elovich and chemisorption diffusion models The best fitted model was thepseudo second order model The results of speciation performed by the PHREEQCcomputer model showed that the dominant species in the Pb GLDA Pb MGDA andPb EDTA systems were the anionic forms of PbGLDA2 PbMGDA and PbEDTA2 respectively It seems that the formation of these stable chelates in solution resulted in adecrease in Pb adsorption on STx 1b The decreasing trend of Pb adsorption on STx 1bfollowed the decrease in the stability constant of the ligands with Pb as EDTA MGDA GLDA In the second study equilibrium sorption of Pb Pb MGDA Pb GLDA and Pb EDTA by Montmorillonite STx 1b was investigated Equilibrium data 10

مهران شيرواني، حسين شريعتمداري

محمد ديناري

محمد علي حاج عباسي، محسن حميدپور، مهران غياثي