Fast and selective removal of trace concentrations of bismuth (III) from water onto procaine hydrochloride loaded polyurethane foams sorbent: Kinetics and thermodynamics of bismuth (III) study

Abstract

Bismuth (III) species are included in the list of potential toxins for motor neurons. Thus, fast and selective method for removal of bismuth (III) species has been developed. The method was based upon the formation of tetraiodobismuthate [BiI 4] − aq in the test aqueous solution in the presence of KI-H 2SO 4 followed by subsequent extraction of [BiI 4] − aq by procaine hydrochloride (PQ +·Cl −) immobilized polyurethane foams (PUFs). The rate of removal of bismuth (III) ions from aqueous solution by procaine hydrochloride (PQ +·Cl −) immobilized polyurethane foams (PUFs) were studied in batch conditions employing Weber–Morris, Lagergren, Bhattacharya and Venkobachar, and Bt models. The rate of sorption of bismuth (III) was rapid initially within 5–15 min and reached a maximum in 30 min compared to other solid sorbent. Initially, the uptake of [BiI 4] − aq onto PQ +·Cl − loaded PUFs was fast followed by kinetically first–order sorption with an overall rate constant, k = 0.132 ± 0.033 min −1. Thus, film and intraparticle transport are the two steps that might be influence bismuth (III) sorption. The negative values of Δ G of the retention step of bismuth (III) dictate that the uptake of the analyte onto the used sorbent is spontaneous phenomena. Exothermic nature of bismuth (III) sorption is governed by the negative value of Δ H. The positive value of Δ S reflects the organized uptake of bismuth (III) on the used sorbent in a more random fashion. The PUFs offers unique advantages of [BiI 4] − aq retention over conventional solid sorbents in rapid and effective separation of trace concentration of bismuth (III) from aqueous media. Thus, the developed PQ +·Cl − treated PUFs sorbent could be packed in column for removal of bismuth (III) species from industrial wastewater.