Removal Characteristics of Tanic Acid Adsorbed on MIEX Resin

Abstract

Tannic acid (TA) is a component of natural organic matter (NOM) and is ubiquitously present in most surface and groundwater due to the decomposition of plant biomass [1][2]. Previous research has demonstrated that TA is toxic for aquatic organisms such as algae, phytoplankton, fish, and invertebrates, which can cause serious environment problems [3]. Particularly, TA can react with chlorine and form carcinogenic disinfection by-products (DBPs) during the conventional chlorination disinfection process of drinking water [4][5]. Therefore, it is necessary to seek effective methods for reducing and removing TA from raw water. [12,16] have been utilized to remove TA from water and wastewater. Among different adsorbents, the anion ion-exchange resin is considered one of the most effective methods due to its high removal efficiency [17]. As a novel anion ionexchange resin, magnetic ion exchange (MIEX) resin can be a potential candidate for TA removal with its promising technology for NOM removal from drinking water [18].Pol. J. Environ. Stud. Vol. 26, No. 3 (2017) This study evaluated the removal characteristics of tanic acid (TA) adsorbed on MIEX resin by batch experiments. MIEX resin can effectively remove TA from raw water at pH 6-9. Chloride and sulfate have adverse effect on the removal of TA. Conversely, bicarbonate can further the removal of TA. The Elovich model is the most suitable for depicting the kinetic process, and liquid film diffusion dominates the adsorption rate. The Freundlich model is reliable for describing the adsorption equilibrium. Adsorption is an endothermic, entropy-driving, and thermodynamically spontaneous process. The energy changes confirm the physical adsorption and dominate adsorption behavior. The sodium chloride solution (0.5%) can effectively regenerate the MIEX resin saturated TA, and the regenerated resin can be used circularly. Therefore, MIEX resin is a promising adsorbent for the removal of TA from raw water.

Performances and Mechanism of Methyl Orange and Congo Red Adsorbed on the Magnetic Ion-Exchange Resin

“…In addition, the intraparticle diffusion is the sole rate-limiting step if the plot passes through the origin. Otherwise, some other diffusion mechanisms such as liquid film diffusion or surface diffusion may be also involved besides intraparticle diffusion . The fitted results are shown in Figure , and the calculated constants are shown in Table .…”

“…Otherwise, some other diffusion mechanisms such as liquid film diffusion or surface diffusion may be also involved besides intraparticle diffusion. 29 The fitted results are shown in Figure 2, and the calculated constants are shown in Table 5.…”

“…Moreover, it is easy for the MIEX resin to separate from water due to containing magnetic cores (γ-Fe 2 O 3 ), although its particle size is so small. Previous research studies showed that the MIEX resin was mainly used to remove dissolved organic matter and inorganic anion ions from water and wastewater. ,, As an anion resin, the MIEX resin may be a potential candidate as an adsorbent for the quick removal of anion dyes. To our knowledge, however, up to now, few studies on the adsorption behavior of anion dyes onto the MIEX resin are evaluated and reported.…”

Adsorption of humic acid fractions by a magnetic ion exchange resin

“…ΔS 0 values are all positive, implying an increase in the degree of confusion on the solid-liquid interface after adsorption. This suggests that the adsorption of different HA fractions on MIEX resin occurred spontaneously (Tan et al 2009), as it is known that the larger the value of ΔS 0 , the easier the adsorption occurs (Ding et al 2017). Obviously, ΔS 0 value of HA3 was larger than those of HA1 and HA2, indicating that the spontaneous reaction of the high MW HA fraction on MIEX resin was easier.…”

“…The experimental procedure of each HA fraction is similar to that described in section 2.4.3. The activation energy (E a , kJ/mol) of each HA fraction adsorbed on MIEX resin can be calculated according to Equation ( 12) (Ding et al 2017):…”