Çevre Sularından Arsenik Uzaklaştırılması İçin Süpermakrogözenekli Hidrojellerin Hazırlanması
Özet
Arsenic is a naturally occuring element that is present throughout the environment. The demonstration of its high toxicity and adverse effects on human health makes arsenic one of the most challenging environmental problems. Therefore, regulatory authorities revised their permissible limits of arsenic in drinking water to 10 μg/L. Arsenic is present in water mainly in the forms of arsenate (As5+) and arsenite (As3+). Arsenic imprinted cryogel columns were prepared for the removal of two species of arsenic (As3+ and As5+) from environmental sources by the assistance of complexing monomer, N-methacryloyl-(L)-cysteine (MAC), due to the high affinity of arsenic towards thiol groups (-SH) of cysteine. As3+ and As5+ complexed with MAC monomer separately, to possess two different arsenic imprinted cryogel columns as As3+-IIP and As5+-IIP. The presence of MAC monomer in the cryogel structure and the success of complexation were confirmed by the elemental analysis (192.8 μmol MAC/g), FTIR and Raman spectroscopy. The specific surface area of the As-IIP cryogel was found to be 35.6 m2/g with a swelling ratio of 92.5 %. The maximum arsenic adsorption capacities of As3+-IIP and As5+-IIP cryogels were 372.5 μg As3+/g at pH 5.0 and 189.4 μg As5+/g at pH 8.0, respectively. The selectivity experiments of As3+-IIP and As5+-IIP cryogels in the presence of PO43-, SO42- ve NO3- anions were studied in order to determine the relative selectivity coefficients (K’). As3+-IIP and As5+-IIP cryogels were applied to environmental sources and arsenic removal efficiency were reported up to 95 %. Finally, As3+-IIP and As5+-IIP cryogels were used many times for the reusability experiments and the findings showed that there was a negligible decrease in adsorption capacity.
