Sintesis dan Karakterisasi Material ZIF-67 Terenkapsulasi ZIF-8 sebagai Adsorben Kromium (VI) dengan Vari

Abstract

Chromium is one of the heavy metals used in the textile industry. Chromium metal (especially hexavalent chromium) has high toxicity and is difficult to degrade in the aquatic environment. Nowadays, adsorption technique is the most efficient treatment in the removal of chromium pollution from water. Zeolitic Imidazole Framework has a large surface area. The adsorption process occurs due to electrostatic attraction followed by ion exchange. Based on the explanation above, researchers are interested in developing ZIF-67 encapsulated ZIF-8 material to adsorb chromium metal from a solution. The stages in this research were carried out by synthesizing ZIF-67, synthesizing ZIF-67@ZIF-8 and adsorbing chromium (VI) from solutions with varying concentrations of 10, 20, 30 and 40 ppm. Synthesis was carried out by epitaxial growth method on ZIF-67@ZIF-8 material. Characterization was performed on the material and chromium (VI) solution including FTIR, XRD, SEM-EDX, TEM, BET and AAS testing. BET analysis on ZIF-67@ZIF-8 proved that the pores of the material are in the micro pore range (1.1018 nm) with a surface area of 1227.85 m2/g. SEM-EDX analysis of ZIF-67@ZIF-8 showed a rhombic dodecahedral morphology with elemental composition of carbon, nitrogen, oxygen, cobalt and zinc. TEM analysis results show the presence of core-shells in ZIF-67 encapsulated ZIF-8 material. FT-IR analysis of ZIF-67@ZIF-8 material shows the presence of metal and ligand bonds at wave numbers 422 cm-1 and 690-754 cm-1; Cr N absorption band appears at 524 cm-1 and Cr-O at 902 cm-1 after ZIF-67@ZIF-8 adsorbs chromium which proves the interaction between Cr(VI) and ZIF-67@ZIF-8 material. XRD analysis showed the crystallinity of the adsorbent and typical peaks 14.74; 16.46; 18.06; 22.17; 24.57; 26.70 showed the typical structure of ZIF-67@ZIF 8. The results of AAS analysis showed that the adsorption of chromium by ZIF 67@ZIF-8 material reached 99,13% at a concentration of 30 ppm, making it better than adsorption by ZIF-67. ZIF-67@ZIF-8 is proven to be effective as Cr(VI) adsorbent and has potential for waste treatment applications.