Merkapto Grubu Modifiye Edilmiş Hidroksietilselüloz'un Sentezi ve Arsenik Adsorpsiyonunda Kullanılmasının Araştırılması
Özet
In this thesis study, the thio-hydroxyethylcellulose (HESSH) polymer bearing thiol (-SH) side groups were synthesized between hydroxy groups of hydroxyethyl-cellulose (HES) and carboxylic acid groups of thioglycolic acid (TGAS). The synthesized HESSH polymer was characterized by FT-IR, XPS, SEM, TGA, DSC, surface area studies (BET). HESSH polymer samples were ligated with Cu(II) and Fe(II) ions to obtain the ligand modifier adsorbents, which are HESSCu and HESSFe. The HESSCU and HESSFe samples were characterized by FT-IR, SEM and EDX studies and their effectiveness in removing arsenic ions were investigated.
The thiolation of the HES polymer was determined by the formation of 1729 cm-1 carbonyl and 2550 cm-1 thiol bands on the FT-IR spectra of the HESSH polymer. The amount of active -SH (6,35 mmol SH/g HESSH) in the thiolated samples was found via the reaction of the HESSH polymer with Ag+ ions (Volhard method). The thermal properties of the HES and HESSH polymers were investigated, and the DSC and TGA thermograms of the samples were recorded. The glass transition temperatures (Tg) of HES and HESSH polymers were found to be 118 oC and 17 oC, respectively.
SEM images of HES and HESSH polymers were recorded, and it was observed whether the chemical modification resulted in degradation of surface structures and HES was observed to turn into a more porous structure after thiolization.
The thermal stability of HES and HESSH was determined by recording TGA-DTG thermograms. The TGA thermogram showing one stepwise thermal destructive resultant loss of HES was observed. When the HESSH TGA-DTG thermogram is examined, it is seen that the HESSH gives a thermal decay thermogram of three digits which is centered and shaped as shoulders at 207 ºC, 243 ºC and 304 ºC.
In the characterization of the HESSH surface analysis method XPS, the presence of -SH groups was detected with peaks at 163,1 eV at S 2p, the sulfide characteristic binding energy.
HessFe adsorbent adsorbed 52,0 ve 66,8 (As)/g-HESSFe for As (V) at pH 5-6 and 62,5 and 65,2 mg (As)/g-HESSFe at pH 7-8.
HESCU adsorbent is adsorbed at pH 5.0; 6.0; 7.0; 8.0 values of 63,5; 73,5; 67,8 and 69,2 mg (As)/g-HESSFe, respectively. When working with As(V) solubles in high concentrations such as 113 ppm, the adsorption values for HESSFe and HESSCu adsorbents were determined as 93,4; 96,7 mg (As)/g-HESSM.
Adsorption of Cu(II), Pb(II), Cd(II) and Hg(II) ions with HESSH polymer was tested. Adsorbtion capasity of HESSH is 82,4 mg (Pb)/g-HESSH, 96,7 mg (Cu)/g HESSH and is not efffective for Cd(II) adsorption at pH 6.0. It is determined that HESSH adsorbed 53,0; 79,4; 29,7 and 40,5 mg (Hg)/g HESSH For pH 2.0; 4.0; 6.0; and 8.0 respectively.