HYDROTALSIT Zn-Al-EDTA SEBAGAI ADSORBEN UNTUK POLUTAN ION Pb(II) DI LINGKUNGAN Zn-Al-EDTA Hydrotalcite as Adsorbent for Pb(II) Ion Pollutant in The Environment)

Abstract

ABSTRAK

Polusi ion Pb(II) di dalam lingkungan perairan cenderung naik seiring peningkatan jumlah industri smelter dan daur ulang aki bekas. Penelitian ini bertujuan untuk menguji kemampuan hidrotalsit Zn-Al-EDTA sebagai adsorben ion Pb(II) dalam air secara mendalam. Hidrotalsit Zn-Al-NO₃ disintesis dengan metode kopresipitasi dan hidrotermal pada temperatur 100 °C selama 15 jam. Hidrotalsit Zn-Al-EDTA diperoleh dengan penukaran ion. Keasaman larutan, kinetika dan kapasitas adsorpsi diteliti. Hidrotalsit Zn-Al-EDTA memiliki d₀₀₃ sebesar 14,52 Å sementara Zn-Al-NO₃ sebesar 8,90 Å. Spektra FTIR menunjukkan keberadaan serapan gugus C=O pada bilangan gelombang 1684,77 cm^-1. Kondisi optimum adsorpsi ion Pb(II) terjadi pada pH 4, waktu kontak 60 menit dan kapasitas adsorpsi diperoleh 2,07 mg/g pada konsentrasi awal 10 mg/L dengan berat adsorben 0,100 g. Adsorpsi ion Pb(II) oleh hidrotalsit Zn-Al-EDTA mengikuti reaksi pseudo orde dua dengan tetapan laju adsorpsi sebesar 8,90 g mmol^-1min^-1. Adsorpsi ion Pb(II) oleh Zn-Al-EDTA terjadi karena  pembentukan khelat Pb-EDTA di dalam struktur hidrotalsit. Hasil ini diharapkan mampu memberikan kontribusi yang lebih luas di dalam pengendalian konsentrasi Pb(II) di lingkungan.

ABSTRACT

Polution by Pb(II) ion in the water environment tends to increase due the increase in the number of lead smelter and lead acid battery recycling industries. This work aims at studying in details the ability of Zn-Al-EDTA hydrotalcite as adsorbent for Pb(II) ion in the environment. The Zn-Al-NO₃ hydrotalcite was synthesized first by coprecipitation method followed by hydrothermal treatment at 100 °C for 15 h. The Zn-Al-EDTA hydrotalcite was later obtained by ion exchange process. The solution pH, kinetics and adsorption capacity were studied. The XRD data showed that Zn-Al-EDTA and Zn-Al-NO₃ hydrotalcites have d₀₀₃ of 14.52 and 8.90 Å, respectively. The FTIR spectra suggested that C=O group was observed with absorption band at 1684.77 cm^-1. The optimum condition for adsorption of Pb(II) ion by Zn-Al-EDTA hydrotalcite was obtained at pH 4, contact time of 60 minutes and adsorption capacity of 2.07 mg/g at  initial concentration of 10 mg/L for each 0.100 g of adsorbent. The Pb(II) ion adsorption by Zn-Al-EDTA follows pseudo second order of reaction with reaction rate constant of 8,90 g mmol^-1min^-1. The increase in adsorption of Pb(II) ion by hydrotalcite Zn-Al-EDTA is believed to be due to the formation of chelate complex between Pb(II) and  EDTA in the interlayer space of hydrotalcite Zn-Al-EDTA. This finding is expected to find broad applications for controlling Pb(II) in the environment.