Studi pengaruh dealuminasi pada karakteristik adsorpsi zeolit alam terhadap ion ogam Na(I) dan Cd(II) dalam medium air
PARDOYO, Prof.Dr. Narsito
2004 | Tesis | S2 Ilmu KimiaTelah dilakukan penelitian untuk mempelajari pengaruh dealuminasi pada karakteristik adsorpsi zeolit alam terhadap ion logam Na(I) dan Cd(II) dalam medium air. Beberapa perlakuan terhadap zeolit alam dikerjakan dengan cara pencucian dengan akuades(Z-11), perendaman dengan KMnO4 dan H2SO4 pada 800C(Z-22) serta perendaman dengan KMnO4, H2SO4 dan HCl pada 800C(Z-33). Analisis struktur zeolit alam dilakukan menggunakan difraktometer sinar-X dan spektrofotometer FTIR. Perubahan karakter akibat perlakuan dideteksi dengan menentukan nilai hilang pada pemijaran, kadar SiO2 dan Al2O3, rasio Si/Al, keasaman dan kapasitas tukar kation. Kapasitas adsorpsi dan energi adsorpsi ditentukan dengan model adsorpsi isoterm Langmuir. Laju adsorpsi dihitung menggunakan pendekatan model kinetika Langmuir- Hinshelwood. Mekanisme adsorpsi ion Na(I) dan Cd(II) dipelajari dengan metode fraksinasi bertahap dengan mendesorpsi ion Na(I) dan Cd(II) yang telah teradsorpsi oleh ketiga adsorben menggunakan beberapa reagen tertentu. Kontribusi mekanisme adsorpsi ditentukan pada beberapa mekanisme berikut : pemerangkapan, pertukaran kation, ikatan hidrogen, pembentukan kompleks dan mekanisme lain. Hasil penelitian menunjukkan struktur Z-22 makin bersih dari pengotor organik dan mengalami dealuminasi pada tingkat yang rendah sehingga meningkatkan nilai sifat fisikokimia. Struktur Z-33 mengalami kerusakan akibat dealuminasi pada tingkat yang signifikan sehingga menurunkan nilai sifat fisikokimia. Dealuminasi pada zeolit alam mempengaruhi nilai kapasitas dan laju adsorpsi. Nilai kapasitas adsorpsi Z-22 dan Z-33 terhadap ion Na(I) berturut-turut 27,98 mg/g dan 16,97 mg/g sedangkan untuk Cd(II) berturut-turut 5,87 mg/g dan 8,99 mg/g. Nilai tetapan laju adsorpsi Na(I) pada Z-22 dan Z-33 berturut-turut 2,92.10-2 menit-1 dan 0,58.10-2 menit-1 sedangkan untuk Cd(II) 0,6.10-4 menit-1 dan 7,0.10-4 menit-1. Adsorpsi ion Na(I) dan Cd(II) pada zeolit alam berlangsung secara kimia dengan kisaran energi di atas 20,92 kJ/mol. Adsorpsi ion Na(I) dominan berlangsung melalui mekanisme pertukaran kation dengan kontribusi 69,12% untuk Z-11, 79,10% untuk Z-22 dan 66,75% untuk Z-33. Adsorpsi ion Cd(II) pada zeolit alam cenderung berlangsung melalui mekanisme pembentukan kompleks dengan kontribusi berturut-turut 67,06%, 57,78% dan 62,98% untuk Z-11,Z-22 dan Z-33.
It has been intensively researched for investigating the influence of dealumination on the adsorption characteristics of natural zeolite for Na(I) and Cd(II) metal ions in aqueous medium. Three procedures were done to treat natural zeolite, viz., washing in aquadest to produce Z-11, soaking with KMnO4 and H2SO4 at 800C producing Z-22 and soaking with KMnO4, H2 SO4 and HCl at 800C as Z-33. X-ray diffractometer and FTIR spectrophotometer were utilized for identifying the structure. The changes of many natural zeolite characteristics due to the treatments were evaluated with determining of lost on ignition, SiO2 and Al2O3 content, Si/Al ratio, acidity and cation exchange capacity. The capacity and energy of adsorption established by Langmuir model for adsorption isotherm while the rate of adsorption calculated by Langmuir-Hinshelwood kinetics approach. The adsorption mechanisms of Na(I) and Cd(II) ion were simply studied by a sequential fractionation method which Na(I) and Cd(II) ion adsorbed by three kinds of adsorbents were desorbed by several suitable reagents. The contribution of adsorption mechanisms then, examined at many types of finite mechanisms included entrapment, cation exchange, hydrogen bonding formation, complex formation and others. Result showed that Z-22 and Z-33 have been decreased in organic contaminant matter and nonframework aluminum hence increased the many physico-chemical properties value of Z-22. However, the structure of Z-33 was absolutely damaged because of dealumination process therefore declined in physico-chemical properties. The dealumination process seriously affected the capacity and rate of adsorption. The value of Na(I) and Cd(II) ion adsorption capacity on Z-22 and Z-33 were 27,98 mg/g, 16,97 mg/g, 5,87 mg/g and 8, 99 mg/g respectively whereas the value of adsorption rate were 2,92.10-2 menit-1, 0,58.10-2 menit-1, 0,6.10-4 menit-1, and 7,0 10-4 menit-1 in a row. The adsorption of Na(I) and Cd(II) ion were involved in chemical adsorption with energy more than 20,92 kJ/mol. The adsorption of Na(I) ion mainly via cation exchange mechanism with contribution of 69,12%, 79,10%, 66,75% for Z-11, Z-22 and Z-33 respectively. In the other hand, Cd(II) ion was adsorbed by complex formation with 67,06%, 57,78%, 62,98% in contribution for Z-11, Z-22 and Z-33.
Kata Kunci : Adsorpsi Isoterm Ion Na(I) dan Cd(II),Zeolit Alam
