Mg-Al Layered Double Hydroxide (LDH) as an Adsorbent for Removal of Itaconic Acid from Aqueous Solutions: Equilibrium and Kinetic Study

Abstract

This study aims to remove itaconic acid, one of the important members of carboxylic acids, from its aqueous solutions by using an adsorption method. Recently the Layered Double Hydroxide (LDH), which has attracted attention in many areas, was synthesized by the co-precipitation method and used as an adsorbent. The effects of the adsorption time, LDH amounts, adsorption temperature, and initial acid concentration changes on the adsorption efficiency were examined. In one-stage batch adsorption experiments performed under different conditions, approximately 70% of itaconic acid was removed from the aqueous phase using 1 g of LDH. Various adsorption isotherm models such as Langmuir, Freundlich, and Temkin were applied to the obtained experimental data. Since R 2 values are greater than 0.98, it can be said that the experimental data fit all three isotherm models. Kinetic studies were carried out using timedependent measurements. Adsorption behavior was kinetically investigated using pseudo-first-order, pseudo-second-order, and Elovich models. The kinetics of the adsorption of itaconic acid by LDH was found to be the best defined by the pseudo-second-order model.

Efficient Recovery of Itaconic Acid Using Weak and Strong Anion Exchange Resins from Aqueous Solutions

“…Previously, Magalhães et al showed that both Langmuir and Freundlich isotherm models can describe the IA adsorption onto SBA exchange resins. Similarly, significantly high R 2 values (∼0.99) were obtained with these two and Temkin isotherm models for IA adsorption on Mg–Al layered double hydroxide. , Isotherm analysis of the equilibrium data shows that the highest R 2 values (>0.99) were obtained with the Langmuir isotherm model for all tested resins (Table and Figure ). In other words, the Langmuir model was the best-fitting model for the experimental results for the recovery of IA using anion exchange resins.…”

“…The separation of carboxylic acids from aqueous-based media by ion exchange or adsorption methods using various types of anion exchange resins is well documented, − but there are only a few studies focusing on the separation of IA; therefore, the number of the resins tested for IA recovery is limited. ,− The goal of this study was to evaluate four commercially available anion exchange resins for the efficient ion exchange or adsorption of IA from aqueous solutions. For this purpose, three weak basic anion exchangers and a strong basic anion exchanger were tested; the effects of several process parameters were investigated, highest yields and capacities were noted, and the recovery mechanism was examined by using various isotherm and kinetic models as well as thermodynamic analysis of the data.…”