REMOVAL OF Cr(III) FROM AQUEOUS SOLUTIONS USING ZEOLITE NaY PREPARED FROM RICE HUSK ASH

Abstract

The efficiency of the synthesized zeolite NaY from rice husk ash (RHA) in the removal of Cr(III) from aqueous solution was studied. Zeolite NaY was synthesized from RHA via seeding technique and the identification of its structure was done by X -ray diffraction (XRD) technique and the elemental analysis was carried out by X -ray fluorescence (XRF). The physicochemical properties which were related to the use of the zeolite NaY as a sorbent was also investigated. The synthesized zeolite NaY has higher cation exchange capacity (CEC) than the commercial zeolite NaY due to the higher amount of sodium content in the synthesized as well as the lower ratio of silica to alumina. The synthesized zeolite NaY together with the commercial one as comparison was used in the sorption of the Cr(III) in aqueous solution by batch sorption experiments. The kinetic study showed that the Cr(III) uptake by both zeolites were based on the pseudo second order model. Synthesized zeolite NaY exhibited greater sorption capacities than the commercial zeolite NaY since the former has higher surface area and cation exchange capacity (CEC) and lower ratio of silica to alumina which have a tendency to provide more exchange sites. Abstrak Keberkesanan zeolit NaY yang disintesis daripada abu sekam padi (RHA) untuk menyingkirkan kromium(III) dalam larutan akueus telah dikaji. Zeolit NaY disintesis daripada RHA melalui kaedah pembenihan dan strukturnya dianalisis melalui teknik pembelauan sinar-X (XRD) dan analisis unsur dijalankan melalui teknik sinar-X berpendarflour (XRF). Sifat-sifat fisiko-kimia yang berkaitan dengan penggunaan zeolit NaY sebagai penjerap juga dikaji. Zeolit NaY yang disintesis mempunyai kapasiti penukaran kation (CEC) yang lebih tinggi daripada zeolit NaY komersil disebabkan oleh kandungan natrium yang lebih tinggi kuantitinya dan nisbah silika terhadap alumina yang lebih rendah. Zeolit NaY yang telah disintesis dan zeolit NaY komersil yang dijadikan sebagai perbandingan digunakan untuk menjerap kromium(III) dalam larutan akueus melalui eksperimen secara berkelompok. Kajian kinetik pengambilan kromium(III) oleh kedua-dua zeolit adalah berdasarkan kepada model pseudo-tertib kedua. Zeolit NaY yang disintesis menunjukkan kapasiti penjerapan adalah lebih tinggi berbanding zeolit NaY komersil kerana zeolit NaY yang disintesis mempunyai luas permukaan dan kapasiti penukaran kation (CEC) yang lebih tinggi dan nisbah silika terhadap alumina yang lebih rendah yang menyebabkan ia berkecenderungan untuk mempunyai lebih banyak tapak penukaran.