Electrodialytic Desalination of Tobacco Sheet Extract: Membrane Fouling Mechanism and Mitigation Strategies

Abstract

In the papermaking industry (reconstituted tobacco), a large number of tobacco stems, dust, and fines are discharged in the wastewater. This high salinity wastewater rich in ionic constituents and nicotine is difficult to be degraded by conventional biological treatment and is a serious threat that needs to be overcome. Electrodialysis (ED) has proved a feasible technique to remove the inorganic components in the papermaking wastewater. However, the fouling in ion exchange membranes causes deterioration of membranes, which causes a decrease in the flux and an increase in the electrical resistance of the membranes. In this study, the fouling potential of the membranes was analyzed by comparing the properties of the pristine and fouled ion exchange membranes. The physical and chemical properties of the ion exchange membranes were investigated in terms of electrical resistance, water content, and ion exchange capacity, as well as studied by infrared spectroscopy (IR) spectra, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses. The results indicated that the membrane fouling is caused by two different mechanisms. For the anion exchange membranes, the fouling is mainly caused by the charged organic anions. For the cation exchange membrane, the fouling is caused by minerals such as Ca2+ and Mg2+. These metal ions reacted with OH− ions generated by water dissociation and precipitated on the membrane surface. The chemical cleaning with alkaline and acid could mitigate the fouling potential of the ion exchange membranes.

A Review on Ion-Exchange Membranes Fouling during Electrodialysis Process in Food Industry, Part 2: Influence on Transport Properties and Electrochemical Characteristics, Cleaning and Its Consequences

“…This fact, together with the need to counteract the growth of colloidal structures inside IEM and on its surface, necessitate regular cleaning of membrane stacks of ED apparatuses [26]. Most often, HCl, NaOH, hypochlorides and other oxidants (peracetic acid, and P3 Active Oxonia ® (Ecolab, Saint Paul, MN, USA) solutions) are used for these purposes [27][28][29][30][31][32][33][34]. Moreover, cleaning is carried out at a high temperature (60-90 • C) [35][36][37].…”

“…IEMs conductivity, as a rule, decreases after prolonged exposure to liquid media typical for the food industry [22,23,[59][60][61]104,105]. In the case where a membrane is in contact with amino acids, carboxylic acids or anions of polybasic inorganic acids, the decrease in conductivity is not dramatic [58,104] and can be reversible if a dense layer of proteins or mineral precipitate does not form on the IEM surface [28,29,106]. The decrease in κ m is most often caused by electrostatic interactions and hydrogen bonds of foulants with fixed EIM groups.…”

A Review on Ion-Exchange Membrane Fouling during the Electrodialysis Process in the Food Industry, Part 1: Types, Effects, Characterization Methods, Fouling Mechanisms and Interactions

“…The EDS method is widely used for the identification of organic foulants or other substances on the IEM surface [81,82] (Figure 8). At the same time, drying of IEM, preceding, for example, SEM and EDS, has a destructive effect on the colloidal particles and the three-dimensional structure of most organic foulants.…”

Special Issue “Membrane Technologies for Sustainable Biofood Production Lines”

“…In their papers, Perreault et al [ 1 ], Ge et al [ 3 ], Wang et al [ 4 ], and Abou Diab et al [ 5 ], reported the fouling of membranes by respectively polyphenols and anthocyanins (UF membrane), charged organic anions (anion exchange membranes), and divalent ions (cation exchange membrane), amino acids, and peptide or hem-peptide (cation-exchange membrane). Concerning the mechanisms, the results of the study by Ge et al [ 3 ] indicated that the membrane fouling is caused by two different mechanisms: electrostatic interactions of charged organic anions with the anion exchange membranes and precipitation of Ca 2+ and Mg 2+ on the cation exchange membrane, by reaction with OH − ions generated by water dissociation. The chemical cleaning with alkaline and acid was proposed to mitigate these fouling and scaling [ 3 ].…”

“…Concerning the mechanisms, the results of the study by Ge et al [ 3 ] indicated that the membrane fouling is caused by two different mechanisms: electrostatic interactions of charged organic anions with the anion exchange membranes and precipitation of Ca 2+ and Mg 2+ on the cation exchange membrane, by reaction with OH − ions generated by water dissociation. The chemical cleaning with alkaline and acid was proposed to mitigate these fouling and scaling [ 3 ]. In their work, on the production of hydrolysate from bovine hemoglobin by electrodialysis with bipolar membrane (EDBM), Abou Diab et al [ 5 ] explained the fouling of perm-selective cation exchange by the fact that, according to the pH of the solution and the release of hem alone or protein fragments containing hem and peptides during hydrolysis, peptides may have first interacted electrostatically (positive residues) into the scattered cavities of the thin charged layer (forming the perm-selective layer).…”