BIOSORPTION OF CHROMIUM (VI) IONS USING SUSTAINABLE EGGSHELL IMPREGNATED PANDANUS AMARYLLIFOLIUS ROXB. ADSORBENT

Abstract

The conventional methods used for heavy metals removal from wastewater are cost inefficient
and non-ecofriendly. Thus, biosorption using waste materials was proposed in this study. The
study was carried out to remove chromium (VI), Cr (VI) ions using raw eggshell and hybrid
eggshell-pandan biosorbent. The result obtained showed that the hybrid sorbent had higher
efficiency in removal of Cr (VI) ions. The experimental results had indicated that in order to
achieve the optimum Cr (VI) ions removal percentage of 17.78%, the optimum conditions
required for the raw eggshell sorbent were 140 minutes of contact time, 0.5 g of sorbent, room
temperature, pH 5 and initial concentration of 0.8 mg/L Cr (VI) ions solution. While for hybrid
eggshell-pandan sorbent, an optimum removal percentage at 37.88% could be achieved when
the contact time is 140 minutes, with 0.5 g dosage, 50°C, pH 4 and initial concentration of 0.8
mg/L Cr (VI) ions solution. The study showed that the adsorption of Cr (VI) ions onto the hybrid
sorbent follows the pseudo-second-order kinetic model of Legergren, Freundlich isotherm model
and the thermodynamic study showed negative values of Gibb’s energy, positive value of
enthalpy (16.68 kJ/mol) and entropy change (0.0473 kJ/mol). In short, the hybrid eggshellpandan
sorbent has greater potential as a biosorbent in removing Cr (VI) ions compared to that
of raw eggshell sorbent.