Thiourea Adsorbent for Efficient Removal of Mercury (II)

Abstract

AbstractThe removal of heavy toxic metals from industrial effluents is extremely important, especially for mercury (Hg), which is classified as a highly toxic even at low concentrations. For this purpose, novel thiourea chelating resins were synthesized as sorbent for Hg (II). Six different polymers of formo‐phenolic types were characterized and evaluated for their chelating properties with respect to Hg (II) extraction. Batch adsorption studies of mercury (II) as a function of pH, initial metal ion concentration, temperature, and time showed that thiourea formo‐phenolic polymers have a good affinity for Hg removal and a high adsorption capacity. Adsorption isotherms (Langmuir and Freundlich) and kinetic models (pseudo‐first and pseudo‐second order) were used to interpret the sorption behavior of the materials. The Langmuir model yielded the best fit with a maximum adsorption capacity of 300 mg/g. Desorption studies were performed with aqueous thiourea solution and showed that the adsorbent is indeed regenerable and can be effectively used for up to three adsorption‐desorption cycles with negligible loss of performance. This study confirmed the potential of thiol‐modified formo‐phenolic resins in sorbent engineering with promising applications in the remediation of mercury‐contaminated water.