Comparative sorption capacity of Pb(II) and Cd(II) by natural zeolite in phosphoric acid medium

Abstract

A B S T R A C TZeolite, a well-known inorganic compound, was used for Pb(II) and Cd(II) sorption. For this purpose, the model system composed with "H 3 PO 4 -Pb 2+ -Cd 2+ " medium was selected and applied with various amounts of both heavy metal salts. The results revealed that sorption capacity of the sorbent was higher for Pb 2+ cation than in the diluted phosphoric acid (20% H 3 PO 4 ) for all periods. The absorption of toxic metal ions was measured by atomic absorption spectroscopy. Different physical and chemical analysis techniques such as Fourier Transform infrared, scanning electron microscope, DTA, and XRD showed that natural state of zeolite in a diluted phosphoric acid (20% H 3 PO 4 ) system underwent protonation and hydroxylation to produce additional OH − groups that are active in the sorption process and no destruction was observed in the structure.

Cadmium and iron removal from phosphoric acid using commercial resins for purification purpose

“…However, in the case of solutions containing low levels of metal ions (below a few hundred mg L −1 ), sorption processes may be interesting and competitive. Activated carbon and clays are frequently used for the purification of phosphoric acid from organic impurities (Nasr et al 2005;Trabelsi and Tlili 2017) or metal ions (El-Bayaa et al 2011;Kussainova et al 2019;Kussainova et al 2016;Tjioe et al 1988), including metal-loaded clays (Hamza et al 2016). However, sorbents can be also operated for metal removal from crude phosphoric acid (Alexandratos and Zhu 2016;El-Bayaa et al 2011;Heres et al 2018;Kouzbour et al 2019;Zhu and Alexandratos 2015).…”