Sustainable use of locally available red earth and black cotton soils in retaining Cd2+ and Ni2+ from aqueous solutions

The relative performance of two soils as a sustainable material to attenuate the transport of heavy metal ions,cadmium (cd2+) and nickel (ni2+),from aqueous solutions has been evaluated. red earth soil (rs) and black cotton soil (bcs) originating from india,were selected,and batch equilibrium tests including sorption kinetics and leaching studies were conducted. langmuir isotherm was found to be more suitable than freundlich isotherm for both the soils. kinetic data were fitted on four models namely pseudo first order,pseudo second order,elovich and intraparticle diffusion. correlation coefficients obtained by all models fitted well in the following ranking: elovich> intraparticle diffusion > pseudo second order > pseudo first order. based on extensive experimental data,it is concluded that the ranking on sorption was of the order cd > ni for both the soils,and bcs exhibited relatively higher retention levels compared to rs. it is further concluded that bcs can be used as a substitute to filter material,rs a substitute to main liner material in attenuating cd2+ and ni2+ from an industrial landfill leachate. © iran university of science and technology 2016.