The competitive adsorption properties of the heavy metal ions Pb(II), Cu(II), and Cd(II) ions in binary and ternary systems on black carbon (BC) isolated from the burning residue of wheat straw were studied in batch systems. The BC samples were characterized by Fourier transform infrared spectroscopy (FTIR). Equilibrium and kinetic adsorption data showed that the selectivity of metal ions on BC followed the order of Pb(II) > Cu(II) > Cd(II). Kinetic studies were performed, and the rate kinetics was fitted well with the pseudosecond-order model. The Freundlich adsorption isotherm was applicable to the adsorption process, and its constants were evaluated.

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Batch adsorption experiments were carried out using nonliving biomass of Porphyra yezoensis Ueda (red alga) for the removal of Congo red from aqueous solutions at 258C. The effects of process parameters such as contact time, adsorbent concentration and ionic strength were investigated. The raw biomass and Congo red loaded biomass were characterized by Fourier transform infrared spectroscopy (FTIR). The pseudo first order, pseudo second order and intraparticle diffusion models were tested. The results showed that adsorption of Congo red followed pseudo second order kinetics very well. Langmuir and Freundlich equations were applied to the data related to the adsorption isotherms, and the observed maximum adsorption capacities (q m ) were 71.46 mg/g at 258C. Adsorbent concentration and ionic strength had a marked effect on Congo red adsorption.