Potential Of Modified Gambir As Adsorbent For The Removal Of Selected Heavy Metal Ions From Aqueous Solutions
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Date
2014-01
Authors
Tong, Kim Suan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In this study, gambir extracted and gambir pulp has been chemically modified with
formaldehyde (FGA) and hydrochloric acid (AGPA), respectively. Adsorbents were
physically and chemically characterized by FTIR, BET, TGA, SEM, EDS and pHpzc.
The surface of FGA was found to be granular and honeycombed shape while AGPA was
in spherical and compacted shape. The pHpzc values for FGA and AGPA were found to
be 3.90 and 3.62, respectively. Hydroxyl (-OH) and carboxyl (-COOH) groups were
detected by FTIR. The effects of pH, adsorbent dosage, initial concentration, contact
time and temperature on adsorption were studied. The optimum conditions of pH for
metal ions adsorption onto both FGA and AGPA were found to be pH 5.0 (Cu2+, Pb2+
ions) dan pH 6.0 (Ni2+, Co2+ ions), respectively. Meanwhile, the optimum conditions of
adsorbent dosage for metal ions adsorption onto FGA were found to be 6.00 g/L (Cu2+
ions), 10.00 g/L (Pb2+ ions), 16.00 g/L (Ni2+, Co2+ ions) and for AGPA were found to be
10.00 g/L (Pb2+ ions), 12.00 g/L (Ni2+ ions), 16.00 g/L (Cu2+, Co2+ ions), respectively.
The initial adsorption process was rapid and reached equilibrium within 90 min for all
metal ions. Four types of kinetic models were applied to analyze kinetic data particularly
pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion. Pseudosecond
order was found to be the best model that fitted well the kinetic data and
predicted that chemisorptions took place in the process. Meanwhile, the intraparticle
diffusion stated that there was more than one diffusion process as in this study.
Description
Keywords
Gambir As Adsorbent , Heavy Metal Ions