Application of New Synthesized Materials Based on Anionic Clays for Industrial Effluent Decoloration

Abstract

This work reports hydrotalcite and zinc-substituted hydrotalcite (MeAlLDHs) anionic clays as novel catalytic formulations for some environmental applications regarding specific industrial coloured effluents. In this context, layered double hydroxides, covered or with tailored compositions, were synthesized, characterized using advanced analytical analysis techniques (XRD, FTIR, SEM) and tested in specific environmental applications. More specifically, LDHs samples were tested as catalysts for different treatments of coloured effluents, especially some advanced oxidation processes (i.e.heterogeneous advanced oxidation processes with H2O2of Orange 16 dye-containing effluent). The influence of some operating factors such as catalyst type, concentration of hydrogen peroxide, presence of ferrous ions or UV light, contact time was studied, and the adequate operating values were established. Results show that Orange 16 removal is more than 70%, in specific operating conditions, for two of new tested materials (ZnAlLDH 3:1, and MgAlLDH 3:1). Moreover, the action of UV radiation was found efficient in decomposition of Orange 16 dye in the presence of all four tested catalytic materials, improving with more than 40-50% the color removal.

Environmental System Engineering (Ese): Modeling and Optimization of a Textile Effluent Discoloration Process by Sorption

“…A high number of research works reported that various solid materials can adsorb different organic substances (e.g., dyes, alcohols, amino acids, polymers, persistent organic compounds etc. ), heavy metal ions, and other contaminants from different industrial effluents by adsorptive processes of physical (physical adsorptions), chemical (chemisorptions) or biological nature (biosorptions), or mixed/hybrid adsorptive processes of all these, respectively [5][6][7][8][9][10][11][12]. From cost-efficiency and performance reasons, the cheap adsorbents which contain high quantities of carbon in their chemical structure, available in nature, or as production wastes, can remove different polluting loads from effluents (especially, industrial effluents), and recover useful retained species from the high adsorptive material due to its simple regeneration capacity.…”

“…The colour of textile wastewater was expressed by the absorbance under a blank with distillate water at the three characteristic wavelengths (436, 525 and 620 nm) as in SR ISO 7887-97 standard, or by the Hazen color index which represents the conversion of absorbance at 456 nm into Hazen units [HU] (i.e. 0.069 (A 456 ) corresponds to 50 [UH])[5][6][7][8][9][10][11]. For industrial wastewater is obligatory measuring of absorbance at 436 nm in supernatant (apparent color) or filtrate (real color).…”