Optimasi Grafting Mesopori Silika Template Metil Ester Minyak Jarak Menggunakan 3 Aminopropiltrietoksisilan (APTES) sebagai Adsorben Ion Logam Berat

Abstract

Research has been carried out on the optimization of mesoporous silica template castor oil methyl ester (MS-TMEMJ) grafting using 3-aminopropyltriethoxysilane (APTES) compound. This study aims to evaluate the optimum time conditions of MS-TMEMJ grafting with APTES and analyze its adsorption efficiency and capacity on heavy metal ions Zn2+, Ni2+, Pb2+, and Cd2+ in aqueous solution at a concentration of 30 mg/L and pH 6. Grafting was made with time variations of 12 hours, 24 hours, 48 hours (room temperature, 28℃) and 12 hours (80℃). FTIR characterization of MS-TMEMJ showed vibrations of OH group at 3448 cm-1, asymmetric and symmetric vibrations of Si-O-Si (siloxane) group at 1111 cm-1. Si-OH (silanol) group at 802 cm-1, O-Si-O (siloxy) group at 470 cm-1 and OH bending vibration at 1604-1620 cm-1. After grafting MS-TMEMJ with APTES, new groups were found, namely C-H group vibrations from the APTES propyl chain at 2924-2854 cm-1 and supported by CH2 vibrations at 1473-1496 cm-1. N-H group vibration of APTES appeared at 1535-1565 cm-1. XRD characterization showed 2θ at 22-23o of MS-TMEMJ and MS-TMEMJ-APTES which means these materials are amorphous and decreased in intensity after grafting. Characterization of nitrogen adsorption desorption isotherm by BET method showed type IV isotherm. The surface area of MS-TMEMJ decreased after grafting with APTES. The MS-TMEMJ-APTES-48h adsorbent produced the highest adsorption efficiency on heavy metal ions Zn2+, Ni2+, Pb2+, Cd2+ which were 92.4%, 54.23%, 100%, 99.53% respectively and the adsorption capacity was 83.16 mg/g, 48.81 mg/g, 90 mg/g, 89.58 mg/g. The most adsorbed heavy metal ions by MS-TMEMJ-APTES adsorbent were Pb2+>Cd2+>Zn2+>Ni2+. Based on the characterization data, it shows that the grafting of MS-TMEMJ with APTES has been successfully carried out with the optimum time condition of 48 hours which produces the best adsorbent characteristics, because it has a uniform pore size distribution and greater amine density than other adsorbents, resulting in the highest adsorption efficiency and capacity.