Partitioning of mono- and divalent ions between polyelectrolyte hydrogel and bulk solution

Abstract

The partitioning of chemical substances between two different phases is one of the funda- mental effects applied in many branches of chemistry. The partitioning of ions between polyelectrolyte hydrogel and surrounding supernatant is an energy-efficient and perspec- tive way of recycling such ions and an effective tool e.g. for water desalination as well. In this diploma thesis, the partitioning of 1+ and 2+ counterions between strong and weak polyacidic hydrogels and supernatant was studied, as well as swelling of the aforemen- tioned hydrogels at both low and high concentrations of the counterions in the super- natant. The experiments performed at low salt concentrations in 10mM NaCl ionic buffer showed that the gel swelling is influenced only by the presence of added NaCl up to the vol- ume transition concentration of 2+ counterions. Above the volume transition concentra- tion the effects of 2+ counterions are much more pronounced and when the NaCl ef- fect is screened, the swelling behaviour of the studied hydrogels is universal regardless of the crosslink density and falls onto a master curve. The concentration-independent partition coefficient of the studied counterions was determined as well. During the exper- iments performed using a weak polyacidic hydrogel at high concentrations of 1+...

Rozde ̌lova ́nı ́ chemicky ́ch la ́tek mezi dve ̌ ru ̊zne ́ fa ́ze je jednı ́m ze za ́kladnı ́ch jevu ̊ vyuz ̌ı ́va- ny ́ch v mnoha odve ̌tvı ́ch chemie. Rozde ̌lova ́nı ́iontu ̊mezi polyelektrolytovy ́ hydrogel a okol- nı ́ roztok patr ̌ı ́ k energeticky nena ́roc ̌ny ́m a perspektivnı ́m zpu ̊sobu ̊m jejich recyklace a rovne ̌z ̌ k u ́c ̌inny ́m na 'stroju ̊m napr ̌. k odsolova ́nı ́ vody. V te ́to diplomove ́ pra ́ci bylo stu- dova ́no staticke ́ rozde ̌lova ́nı ́ 1+ a 2+ protiiontu ̊ mezi slabe ́ a silne ́ polykysele ́ hydrogely a okolnı ́ roztok, a botna ́nı ́ te ̌chto hydrogelu ̊ pr ̌i nı ́zky ́ch a vysoky ́ch rovnova ́z ̌ny ́ch kon- centracı ́ch protiiontu ̊ v okolnı ́m roztoku. Be ̌hem experimentu ̊ pr ̌i nı ́zky ́ch koncentracı ́ch 1+ a 2+ protiiontu ̊ sledujı ́cı ́ch jejich rozde ̌lova ́nı ́ mezi silny ́ polykysely ́ hydrogel a 10mM vodny ́ roztok NaCl bylo zjis ̌te ̌no, z ̌e botna ́nı ́ tohoto gelu je do urc ̌ite ́ koncentrace 2+ pro- tiiontu ̊ ovlivne ̌no pouze pr ̌ı ́tomny ́m NaCl. Nad touto koncentracı ́ je jiz ̌ vliv 2+ protiiontu ̊ patrny ́ vy ́razne ̌ji a pr ̌i odstı ́ne ̌nı ́vlivu NaCl vykazuje botna ́nı ́tohoto hydrogelu univerza ́lnı ́ chova ́nı ́ vzhledem ke koncentraci iontu ̊ neza ́visle na mnoz ̌stvı ́ crosslinkeru. Rovne ̌z ̌ byl stanoven distribuc ̌nı ́ koeficient...