Metal Removal from Wastewater Using Sludge from a Natural Stabilization Pond as Biosorbent

GIARRATANO, ERICA; OLIVERA, NELDA LILA; FALESCHINI, MAURICIO; GIL, MÓNICA NOEMÍ; FALESCHINI, MAURICIO; BRUNI, CECILIA; GIL, MÓNICA NOEMÍ; GIARRATANO, ERICA; BRUNI, CECILIA; OLIVERA, NELDA LILA

INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH

UNIV TEHRAN

Lugar: Tehran; Año: 2019 vol. 13 p. 581 - 595

1735-6865

The present work was focused on evaluating the potential use of a sludge produced in a municipal natural facultative pond as biosorbent to remove metal ions (Pb2+, Cd2+, Ni2+, and Cr6+) from aqueous solutions. The inluences of diferent initial conditions of pH, metal concentration, mass biosorbent, and contact time were studied to ind the optimum conditions for the biosorption process. The sludge has diferent functional groups such as hydroxyl, carboxyl, and amide groups that could play major roles in the adsorption of metallic ions according to the FTIR results. Kinetic experimental data itted very well thepseudo-second-order equation (R2 = 0.995 − 1), which implied that chemisorption is the rate-controlling step of adsorption process. The equilibrium isotherms were evaluated in terms of maximum adsorption capacity and adsorption ainity by the application of Langmuir and Freundlich equations. Despite experimental data itted well to both adsorption isotherm models, the Langmuir one was the best-itted to characterize equilibrium adsorption (R2 = 0.992?s0.999) evidencing monolayer adsorption. The maximum uptake capacities calculated from Langmuir isotherm were 19.88, 11.49, and 7.70 mg/g for Pb, Cd, and Ni at pH 6, respectively, and 3.55 mg/g for Cr at pH 2. The goal of this research was to achieve a double positive environmental impact by promoting the use of a solid residue of high availability and low extraction cost to clean a liquid residue, which can then be reused or discharged healthily into the environment.