Preparation of Adsorbent from Mechanochemical Reaction-Based Waste Seashell with Sodium Oxalate and Its Application in Pb Ion Adsorption

Abstract

Waste seashell (scallop shell)-based adsorbent was prepared via mechanochemical reaction with sodium oxalate using ball milling. The oxalate-modified seashell-based adsorbents (OS) were prepared by varying the molar ratio of calcium and oxalate to 0.5, 1, and 2. Sodium oxalate was used as the aqueous solution in ball milling. Lead ion adsorption was conducted with the prepared adsorbent. The adsorption behavior of lead ions was investigated in terms of adsorption kinetics and adsorption equilibrium. The time course of the amount of Pb adsorbed agreed well with Langmuir rate equation. The adsorption equilibrium relationship of OS adsorbent and Pb agreed well with the Langmuir adsorption isotherm. Increasing with the molar ratio, the saturated amount of Pb adsorbed increased slightly from 5.45 × 10–3 to 6.23 × 10–3 mol/g. Under the present experimental conditions, the maximum equilibrium adsorption was 5.93 × 10–3 mol/g, which is greater than that reported in the literature.