Sintesis Zn-Al-Fe-Hidrotalsit dan aplikasinya pada sorpsi-desorpsi asam humat
SUWITO, Dr. Sri Juari Santosa, M.Eng
2006 | Tesis | S2 Ilmu KimiaTelah dilakukan kajian sintesis Zn-Al-Fe-hidrotalsit dan aplikasinya pada sorpsi desorpsi asam humat. Kajian sintesis Zn-Al-Fe-hidrotalsit meliputi kajian tentang rasio kation Fe3+dengan Al3+, di mana rasio kation divalen (Zn2+) dan trivalen (Al3+ + Fe3+) sama dengan 2, pH sintesis, karakterisasi padatan hasil sintesis dengan difraksi sinar X dan Spektroskopi FTIR, dan stabilitas Zn-Al-Fehidrotalsit dalam berbagai pH medium. Kajian sorpsi desorpsi asam humat dipelajari dengan mengkaji pola, kinetika, kapasitas, energi adsorpsi, dan desorpsi asam humat pada Zn-Al-Fe-hidrotalsit. Adsorbat asam humat yang digunakan dalam penelitian ini diisolasi dari tanah gambut Kota Jayapura Papua dengan menggunakan larutan NaOH 0,1 M. Hasil penelitian menunjukkan bahwa Zn-Al-Fe-hidrotalsit dapat disintesis sekitar pH 6,8. Zn-Al-Fe-hidrotalsit stabil pada pH medium di atas 5. di mana kandungan besi menurunkan stabilitas Zn-Al-Fe-hidrotalsit. Dua tipe Zn- Al-Fe-hidrotalsit yang dibuat, yaitu Zn-Al-Fe-hidrotalsit dengan Fe3+/Al3+ =1, (HT 61) dan Zn-Al-Fe-hidrotalsit dengan Fe3+/Al3+ = 2, (HT 62). Asam humat tanah gambut Kota Jayapura mempunyai keasaman total 18.583 mmol/kg yang terbagi ke dalam keasaman COOH sebesar 3.244 mmol/kg dan keasaman fenolat sebesar 15.339 mmol/kg. Pola adsorpsi asam humat yang teradsorpsi oleh Zn-Al- Fe-hidrotalsit cenderung menurun pada rentang pH 3 – 11. Konstanta laju adsorpsi asam humat pada HT 61 adalah 1,1744 x 10-5, sedangkan pada HT 62 adalah 9,1828 x 10-6 detik-1. Kapasitas adsorpsi HT 61 sebesar 0,171 mmol/g dan HT 62 sebesar 0,1862 mmol/g. Energi adsorpsi asam humat pada adsorben HT 61 diperoleh 33,72 kJ/mol dan pada adsorben HT 62 sebesar 34,78 kJ/mol. Karakterisasi asam humat hasil desorpsi dari adsorben HT 61 dan HT 62 menunjukan adanya pengotor logam pada asam humat hasil desorpsi
Study of Zn-Al-Fe-hydrotalcite synthesis and its application to the sorption-desorption of humic acid has been carried out. In the synthesis, some parameter including ratio of Fe3+ to Al3+ (with the divalent and trivalent cation ratio of 2), and pH were investigated. Characterization of product was performed by XRD and FTIR Spectroscopy methods. The sorption-desorption study was conducted by investigating the adsorption pattern, kinetics, capacity and energy of adsorption-desorption of humic acid on Zn-Al-Fe-hydrotalcite. The humic acid was isolated from Jayapura-Papua peat soil using NaOH 0.1 M. Results showed that Zn-Al-Fe-hydrotalcite could be synthesized at pH 6.8. The Zn-Al-Fe-hydrotalcite was at pH above 5. The presence of iron could decrease stability of the Zn-Al-Fe-hydrotalcite. Two types of Zn-Al-Fehydrotalcite were obtained i.e Zn-Al-Fe-hydrotalcite (HT 61) with Fe3+/Al3+ ratio of 1 and Zn-Al-Fe-hydrotalcite (HT 62) with Fe3+/Al3+ ratio of 2. Total acidity of the humic acid was 18,583 mmol/kg, and it was distributed into the acidity of COOH 3,244 mmol/kg and phenolic-OH 15,339 mmol/kg. The adsorption pattern of humic acid on Zn-Al-Fe-hydrotalcites tended to decrease with increasing pH from 3 to11. The adsorption rate constants of humic acid at HT 61 and HT 62 adsorbents were 1.1744 x 10-5 s-1 and 9.1828 x 10-6 s-1 respectively. The adsorption capacity of HT 61 and HT 62 adsorbents were 0.171 mmol/g and 0.186 mmol/g, respectively. The adsorption energy of humic acid on the HT 61 and HT 62 were 33.72 kJ/mol and 34.78 kJ/mol, respectively. Characterization of humic acid eluted from HT 61 and HT 62 adsorbents were performent by using FTIR spectroscopy showed the existence of contaminant of metals.
Kata Kunci : Sintesis Zn,Al,Fe,Hidrotalsit,Sorpsi Desorpsi,Asam Humat, Zn-Al-Fe-Hydrotalcite, sorption-desorption, humic acid
