pH Dependence of Lead Adsorption on Zeolites

Abstract

The adsorption of Pb on zeolites A4, X, Y and mordenite was studied at various initial pH with the purpose of assessing the pH dependence of Pb adsorption. The adsorption was conducted using 0 -0.6 mM Pb(NO3)2 in the presence of 100 mM NH4NO3 and pH adjustment done using HNO3. The coexisting NH4NO3 served as a representative of other cations available in nature. The study was conducted at initial solution pH ranging from 3 -5. Adsorption results were analyzed using Langmuir isotherm analysis. Adsorption was noted to be dependent on pH with increasing adsorption as pH increased from 3 -5 for zeolites A4, X and Y. The adsorption of Pb on mordenite on the other hand did not show any dependence on pH since it was almost constant within the studied pH range. The adsorptive capacities were 2500, 2000, 588 and 179 mmol•kg −1 for A4, X, Y and mordenite, respectively. The results of this study can be used in designing or planning for the clean-up of polluted water using adsorption techniques. An important attribute of these findings was that the samples studied were shown to have the capacity of removing even very low concentration of Pb, a property which is hardly achievable by most adsorbents.

Physical Characterisation of a Natural Zeolite using a Scanning Electron Microscopy: A Preliminary Study

“…A number of reports (Kabwadza-Corner et al, 2015;Krol, 2020) indicated that the most important characteristics of zeolite are its surface area and crystal structure. Zeolite has a complex three dimensional network of tetrahedrous SiO4 and AlO4 -which creates lattices or cavities that can trap various ionic pollutants and organic molecules (Atikah, 2017;Belova, 2019).…”

Preparation of rare-earth-free luminescent material from partially Ag⁺-exchanged zeolite X

“…14) The K + adsorbed zeolite sample was exchanged again with NH 4 + ions using a 1 M NH 4 Cl solution. The CEC was determined by measurement of the K + ion concentration in a desorbed and washed solution by atomic absorption spectrometry (Hitchi ZA 3300).…”

“…2) Zeolites have adsorption capacity for heavy metals adsorption such as copper 3) and lead, 4) as well as for silver ion. 5) Many studies were focused on silver exchanged zeolites, due to their function as catalyst, for example Ag exchanged ZSM-5 as catalyst for CO oxidation, 6) or photocatalytic decomposition of NO into N 2 and O 2 , 7) or silver doped zeolite Y as antibacterial.…”