Adsorption of selected toxic metals by modified peanut shells

Abstract

The objective of this study was to modify peanut shells to enhance their adsorptive properties toward the metal ions cadmium (Cd 2 ), copper (Cu 2 ), nickel (Ni 2 ), lead (Pb 2 ) and zinc (Zn 2 ). Milled peanut shells were initially washed with water or 0.1 N NaOH or left unwashed. Following these treatments or lack of treatment, the shells were either left unmodi®ed or modi®ed by a heat treatment in the presence of either 1.0 M phosphoric acid or 0.6 M citric acid. Modi®ed peanut shells were evaluated either for adsorption ef®ciency or for adsorption capacity using the ®ve metal ions listed above. Adsorption ef®ciencies and capacities were compared with ef®ciencies and/or capacities for the commercial chelating or cation exchange resins Amberlite 200, Amberlite IRC-718, Duolite GT-73, and carboxymethylcellulose. For the adsorption ef®ciencies of individual metal ions, modi®ed peanut shells met or exceeded the adsorption values for cadmium, copper, nickel or zinc ions compared with the commercial resins Duolite GT-73 and carboxymethylcellulose. In a solution containing all ®ve metal ions, modi®ed peanut shells met or exceeded the adsorption ef®ciencies for cadmium, copper and lead ions compared with Duolite GT-73, Amberlite IRC-718 and carboxymethylcellulose. Adsorption capacities of modi®ed peanut shells met or exceeded the adsorption capacity of Duolite GT-73 for lead ions only. Citric or phosphoric acid-modi®ed peanut shells showed a preference for Cu 2 and Pb 2 and appear promising as potentially inexpensive adsorbents for selected metal ions.

Sequestration of Heavy Metals from Water with Layered Metal Sulfides

“…In addition, reactions of KMS-2 with CdA C H T U N G T R E N N U N G (NO 3 ) 2 [molar ratio CdA C H T U N G T R E N N U N G (NO 3 [10], respectively); S15: -S-S-mesoporous silica (from reference [20]); Mg-MTMS: -SH clay (from reference [7]); SOL-AD-IV: -SH organoceramic composite (from reference [9]); Duolite GT-73: -SH resin (from references [8,22] …”

Mercury(II) removal from aqueous solutions and wastewaters using a novel cation exchanger derived from coconut coir pith and its recovery

“…Many chemical modifications have therefore being thought of to improve the physical and chemical properties and also to increase the adsorption potential, which include esterification, graft copolymerization, cross-linking and quarternisation. Incorporation of different functional groups onto chemically modified lignocellulosic materials such as peanut shell, orange residue, sawdust and banana stalk has already been reported [6][7][8][9][10].…”

Efficient removal of Cd2+ from aqueous solutions using by-product of biodiesel production

“…New technologies for the removal of metals from wastewater using low-cost sorbents, produced from agricultural waste, have been studied, and these include: corncobs [4], olive stone waste [5], peanut shells [6], rice husks [7], soybeans hulls [8], spent grain [9] and sunflower stems [10].…”