Biosorption kinetic studies of heavy metal ions from aqueous solution by a mixture of vegetable waste (abstract)

Biosorption potential of a new bio sorbent prepared from vegetable waste composed of mixture of potato and carrot peels for the removal of heavy metals such as Ni (II) and Cu (II) from aqueous solution was determined. Batch experiments were conducted to optimize parameters i.e. initial pH, temperature, contact time, initial metal concentration and bio sorbent dose and it was observed that maximum adsorption of nickel (78%) was achieved by stirring the contents for 75 min at pH 4 and 35 deg. C by using 3.0 g of bio sorbent while in the case of copper maximum removal of copper occurred at pH 2, temperature of 50 deg. C, contact time of 45 minutes, metal concentration of 30 ppm and bio sorbent dose of 2.5 g. Kinetic studies of these reactions showed that they follow a pseudo-second order reaction, while these systems fit well in the Langmuir isotherm model and Freundlich isotherm model for Ni (II) and Cu (II) ions respectively. Both neat and metal loaded bio sorbent samples were analyzed using FT-IR spectrophotometer and X-Ray Florescence spectrometer in order to confirm the bio sorption of Ni (II) and Cu (II) and results have revealed that the metals are present in the spent bio sorbent. (author)