The development and application of hybrid sorbents for determination and selective removal of arsenic(III) and arsenic(V) from water

Abstract

AcknowledgementsFirst of all, I would like to thank my supervisor, Prof. dr Ljubinka Rajakovic, for her guidance, patience and enthusiasm concerning this thesis. Without her support, thesis would not have been finished. Then I would like to thank all of the professors and staff at the department of Analytical chemistry. I would like to thank everybody working at the TMF for welcoming me and helping me with the different problems that occurred during my stay.I also want to thank all of my friends who were supporting me.At last, but not the least, I would like to thank my family. A special thanks to my wife for her support for all of my endeavors. THE DEVELOPMENT AND APPLICATION OF HYBRID SORBENTS FOR DETERMINATION AND SELECTIVE REMOVAL OF ARSENIC(III) AND ARSENIC(V) FROM WATER ABSTRACTThe aim of the thesis was the development and application of hybrid sorbents for determination of arsenic species in water and selective removal of arsenic from water. Water soluble arsenic species in natural water are inorganic (iAs) species, as arsenite, As(III) and arsenate, As(V).It is important to note that in neutral conditions, As(V) species are completely in ionic forms (H 2 AsO 4 -and HAsO 4 2-), while As(III) is in molecular form (H 3 AsO 3 or HAsO 2 ). This fact was the base for the application of anion exchange resin and selective hybrid resins for the separation, determenation and removal of iAs. As a result of anthropogenic pollution in water can be present organic (oAs) species as monomethylarsenic acid, MMAs(V) and dimethylarsenic acid, DMAs(V). Methods developed for iAs species should consider oAs species as interferences for the iAs determinations.In the frame of these tasks, efficiency of three types of resins were investigated: a strong base anion exchange (SBAE) resin and two hybrid (HY) resins, HY-Fe which integrates sorption activity of hydrated iron oxides (HFO) with the anion exchange function and HY-AgCl which integrates effects of chemical reaction with the anion exchange function. Two systems were employed: a batch and a fixed bed flow system. The selective bonding of arsenic species on three types of resins makes possible the development of the procedure for measuring and calculation of all arsenic species in water. In order to determine capacity of resins, the preliminary investigations were performed in batch system and fixed bed flow system. Resin capacities were calculated according to breakthrough points in a fixed bed flow system which is the first step in designing of solid phase extraction (SPE) module for arsenic speciation separation and determination.The investigations performed in the scope were focused on: I) separation of As(III) and As(V) species (in order to determine both arsenic species which are prevailing in natural waters), II) separation of organic arsenic species (in order to determine of DMAs(V) and MMAs(V) in natural waters) and III) collection, preconcentration and removal of all arsenic species.The main achievement of thesis is that three methods for arsenic species determinati...