In this study, the use of the weakly basic anion exchange resins of phenol-formaldehyde (Amberlyst A 23), polyacrylate (Amberlite IRA 67) and polystyrene (Lewatit MonoPlus MP 62) matrices for removal of the reactive dye Remazol Black B (RBB) from aqueous solution and wastewater were investigated. RBB sorption on the anion exchangers was a time dependent process. Color reduction percentiles of 75.2, 33.9 and 25.1% in wastewater treatment were found after 216 h of phase contact time with Lewatit MonoPlus MP 62, Amberlyst A 23 and Amberlite IRA 67, respectively. Inorganic salts and anionic surfactant action influenced RBB uptake by the anion exchangers. The amounts of dye retained by the anion exchangers increased with a rise in temperature. The maximum sorption capacities calculated from the Langmuir model were 66.4, 282.1 and 796.1 mg g−1 for Amberlite IRA 67, Amberlyst A 23 and Lewatit MonoPlus MP 62, respectively. Regeneration of phenol-formaldehyde and polystyrene resins were possible using 1 M NaOH, 2 M KSCN, 1M KSCN in 40–60% methanol as well as 1 M NaOH in 60% methanol. [...]
Aminosilane modified silica was prepared and investigated for the adsorption of textile dyes such as C.I. Acid Orange 7 (AO7), C.I. Reactive Black 5 (RB5) and C.I. Direct Blue 71 (DB71) from aqueous media and wastewaters. The values of the sorption capacities obtained from the Langmuir isotherm model were: 5.3 mg g-1, 58.7 mg g-1 and 72.2 mg g-1 for AO7, DB71 and RB5, respectively. The affinity series of the dyes for the modified silica can be presented as follows: C.I. Reactive Black 5 > C.I. Direct Blue 71> C.I. Acid Orange 7. The influence of anionic surfactant (SDS) and sodium chloride on dye sorption was investigated in a system containing 100 mg L-1 dye and 0.1-1 g L-1 SDS or 1-25 g L-1 NaCl. The sorption capacities decrease with increasing concentration of SDS in the solution. Retention of AO7 and RB5 was reduced in the presence of NaCl. A satisfactory agreement of the experimental data with the pseudo second-order kinetic model was found. Effectiveness of the aminosilane modified silica in raw textile wastewater purification was confirmed.
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