Scalable Surface Area Characterization by Electrokinetic Analysis of Complex Anion Adsorption

TL;DR

This paper introduces a scalable, in situ electrokinetic method for characterizing the specific surface area of particles in water by analyzing anionic adsorption effects on zeta potential, validated on alumina powders.

Contribution

The study presents a novel electrokinetic approach that correlates zeta potential shifts with surface area, enabling in situ analysis in aqueous environments, which is a significant advancement over traditional techniques.

Findings

Zeta potential variation follows an inverse hyperbolic sine behavior.

A nearly linear correlation between a surface-area-dependent parameter and conventional surface area measurements.

Method applicable for in situ surface area characterization in aqueous suspensions.

Abstract

By means of the in situ electrokinetic assessment of aqueous particles in conjunction with the addition of anionic adsorbates, we develop and examine a new approach to the scalable characterization of the specific accessible surface area of particles in water. For alumina powders of differing morphology in mildly acidic aqueous suspensions, the effective surface charge was modified by carboxylate anion adsorption through the incremental addition of oxalic and citric acids. The observed zeta potential variation as a function of the proportional reagent additive was found to exhibit inverse hyperbolic sine-type behavior predicted to arise from monolayer adsorption following the Grahame-Langmuir model. Through parameter optimization by inverse problem solving, the zeta potential shift with relative adsorbate addition revealed a nearly linear correlation of a defined surface-area-dependent parameter with the conventionally measured surface area values of the powders, demonstrating that the proposed analytical framework is applicable for the in situ surface area characterization of aqueous particulate matter. The investigated methods have advantages over some conventional surface analysis techniques owing to their direct applicability in aqueous environments at ambient temperature and the ability to modify analysis scales by variation of the adsorption cross section.