HeveaMET: New GREEN biosorbent to Remove Heavy Metals

MEGAT AHMAD KAMAL B MEGAT HANAFIAH of UiTM used the leaves of rubber trees to remove Cu(II) and Ni(II) ions from wastewater.

This study produced a biosorbent called HeveaMET obtained from rubber leaf powder, chemically modified with NaOH, to remove Cu(II) and Ni(II) ions from wastewater.

The presence of heavy metals in the environment is of major concern because of their toxicity, bioaccumulation, and threat to human life and environment. The removal of heavy metals from our environment especially wastewater, is shifted from using electrolysis, chemical precipitation, electroflotation, oxidation-reduction, solvent extraction and ion-exchange to the use of biosorbents.

In recent years, many low cost biosorbents obtained from lignocellulosic agricultural by-products have been investigated for their biosorption capacity towards heavy metals. Agricultural wastes are now becoming viable alternatives since they are abundantly available, much cheaper and have various functional groups such as carboxylic acid, ester, carboxylate, hydroxyl, phenolic and amino that can act as adsorption sites for heavy metal ions.

In Malaysia, more than 1.2 million ha of lands are planted with rubber trees and every year, mature rubber leaves (brownish in color) will fall to the ground during the dry season (January to March) producing a huge amount of solid waste. The conversion of this type of plant waste into a low cost heavy metal biosorbent offers a cost effective and green alternative to existing technologies to treat metal laden wastewater.

In this work, the data obtained from column experiment indicated that 10 g of HeveaMET was able to remove 7.1 and 11.1 L of Cu(II) and Ni(II) ions at 10 mg/L concentration, respectively. HeveaMET was able to be regenerated using 0.1 M HCl or HNO3 and reused for three cycles. The main mechanisms involved in heavy metals removal were ion-exchange, complexation and physical adsorption. Due to the high volumes of Cu(II) and Ni(II) that could be treated and the low cost of production (~ RM5/kg), HeveMET ha.

Reported by Megawati Omar
Research Management Institute
UiTM
Shah Alam

Published: 02 Dec 2009

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