Effect of the pH and temperature on the biosorption of lead(II) and cadmium(II) by sodium-modified stalk sponge of Zea mays.

OBJECTIVE: The present work was carried out to investigate the effects of temperature, initial pH, initial concentration, and contact time on the biosorption of lead (Pb) and cadmium (Cd) by modified stalk sponge of Zea mays using a batch technique.

METHODS: The biomass was chemically modified with a 0.1 M NaCl solution. The lead and cadmium sorption process was evaluated at 20°C, 30°C, 40°C, and 50°C.

RESULTS: The results showed that the modified stalk sponge of Z. mays had a good capacity for biosorption of Pb(II) and Cd(II). The kinetic behavior was described by the pseudo-second-order model for both metallic species. The experimental isotherms obtained at different temperatures were fit with Langmuir and Freundlich models. Thermodynamic parameters ΔH(0) and ΔS(0) were calculated using the van't Hoff equation, and the results show that Pb(II) and Cd(II) sorption by modified stalk sponge of Z. mays is an exothermic and spontaneous process.