Application of Hydrophilic–Lipophilic Deviation Equations to the Formulation of a Mixed‐Surfactant Washing Agent for Crude Rice Bran Oil Removal from Spent Bleaching Earth

Abstract

In Thailand, spent bleaching earth (SBE) (20–40 wt.% remaining oil), an industrial waste from edible oil refineries, has usually been disposed of by improper landfilling at industrial sites. This study aims to formulate microemulsion‐based washing solutions from mixed surfactants for cleaning SBE contaminated with crude rice bran oil using the hydrophilic–lipophilic deviation (HLD) concept. Binary nonionic‐anionic surfactant mixtures consisting of System A (Dehydol LS3TH‐Levenol WX), System B (Dehydol LS5TH‐Levenol WX), and System C (Dehydol LS7TH‐Levenol WX) were formulated for use as microemulsion‐based washing formulations. A HLDmixed equation extended with the excess free energy term (GEX/RT) was developed and proposed for predicting the optimum salinity. The optimum salinities obtained from the HLDmixed equation were close to those obtained from the phase behavior. In the SBE washing study, the mixed‐surfactant systems showed a washing efficiency of 90% with low surfactant adsorption capacity on bleaching earth (qmax = 0.01–0.03 mol g−1). The mixed surfactants showed improved washing performance compared to that of the single‐surfactant system. This work highlights the utility of using the HLD concept in designing microemulsion‐based washing formulations from surfactants for the removal of vegetable oil from SBE.

Review: Implementing the hydrophilic–lipophilic deviation model when formulating detergents and other surfactant‐related applications

“…Hence, additional parameterization is required to design surfactant formulations with mixtures of anionic and nonionic surfactants. Panumonwatee et al (2021) demonstrated that when the mixtures of LE and AEs have dominantly anionic surfactant portion (0.2 mole fraction of nonionic surfactant), the G EX /RT varied from zero to small positive values suggesting the systems behaved ideally or with a slightly enhanced hydrophobicity relative to an ideal mixture, depending on the AE used. Kittithammavong et al (2021), in contrast, found that the G EX /RT of sodium dihexyl sulfosuccinate and AEs with EO groups between 1 and 9 appeared to both positively and negatively deviate from ideality when the AE mole fractions were less than 0.2.…”

“…Oil EACN can affect the ideality of surfactant mixing, as well. Additionally, Panumonwatee et al (2021) suggest that a mixed HLD equation specifically developed for alcohol ethoxylated-LE systems can be used to predict the experimentally determined S* and could be potentially used as a predictive screening tool to select the surfactant characteristics and formulation conditions for different applications. Another study by Chen et al (2022) investigated the microemulsion behavior of surfactant mixtures of sodium laureth sulfate, cocamidopropyl betaine and decyl glucoside (APG) with fragrance oil mixtures, which are commonly found in many consumer product cleanser formulations.…”

“…Another example of using HLD to formulate a surfactant blend is Panumonwatee et al (2021), who applied the HLD concept for washing crude rice bran oil from spent bleaching earth using a surfactant mixture with anionic and nonionic surfactants (sodium polyoxyethylene oleyl ether sulfate [LE] and AEs with different numbers of EO groups). Other work has shown that the HLD of anionic surfactant mixtures can be calculated using a linear mixing rule (Acosta et al, 2008).…”

“…When surfactant mixtures like these are studied experimental investigation is still required for specific anionic‐nonionic mixing ratios and oils. This is more obvious for AEs over 0.2 mole fraction, where the mixtures have a higher nonionic surfactant mole fraction, these systems greatly deviated from ideality depending on temperature and the number of EO groups on the surfactant molecule (Panumonwatee et al, 2021). This non‐ideal behavior is in agreement with many other works (Acosta & Bhakta, 2009; Kittithammavong et al, 2021; Salager et al, 2020) where the mixture became more hydrophilic than the ideal mixture with respect to changes in temperature.…”

Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties

“…The HLD equation’s characteristic curvature term is beneficial in defining the hydrophilicity and lipophilicity characteristics of a wide range of surfactants and additives and the surfactant mixture [ 183 ]. The HLD-based emulsion formulation has been investigated in a variety of research areas, including enhanced oil recovery and detergent cleaning, drug delivery, and hard surface cleaning [ 172 , 184 ]. However, there is nearly no research on bitumen emulsion formulation published.…”