Abstract
In this work, the biosorption behavior of acid red 27 (AR27) dye using Eichhornia crassipes leaves (LECs) in a packed-bed column was investigated by varying relevant operational parameters and assessment of mathematical models. Results showed that the zero-charge point of LECs was 2.37 and that optima pH and volumetric flux of the influent solution for AR27 biosorption were 2.0 and 56.5 hbox {L}/hbox {m}^{2}cdot hbox {h}, respectively. The maximum specific and volumetric biosorption capacities were observed at influent AR27 concentrations and with LEC bed heights ranging between 50 and 400 mg/L and 2 and 8 cm, respectively. It was also found that if LEC bed height was increased and volumetric flux and AR27 concentration of the influent solution decreased, service and saturation time increased. Modeling results revealed that the Thomas, bed depth service time, Yoon–Nelson, dose-response, and logistic models accurately described the dynamic performance of the packed-bed column in terms of pH, AR27 concentration, and volumetric flux of influent AR27 solution, as well as that of LEC bed height. The findings revealed that LECs exhibited remarkable potential for the biosorption of AR27 from aqueous solutions in a packed-bed column and could potentially be useful for the treatment of AR27-laden wastewater.
Highlights
Dyes are widely used in the textile, food, pharmaceutical, plastic, cosmetics, photographic and paper industries, with the textile industry representing the largest consumer of d yes[1,2]
This azo dye has been banned in the United States of America by the Food and Drug Administration (FDA) and its use is strictly controlled in many other countries[11,12]
The highest mass of removed Acid red 27 (AR27), and highest specific and volumetric biosorption capacities of AR27 were observed at volumetric fluxes of 37.67 L/m2 h (31 ±1.55 g, 62 ±3.1 mg/g, and 11,668 ±583.4 mg/L, respectively) and 56.5 L/m2 h (33.63 ±1.68 g, 67.25 ±3.36 mg/g, and 12,611 ±630.55 mg/L, respectively) (Table 3), with no statistically significant difference in either the masses of AR27 removed or volumetric and specific capacities observed with the two different volumetric fluxes ( p > 0.05 ). These results indicate that the maximum biosorption capacity of the packed-bed column is not used efficiently at very high volumetric fluxes of influent AR27 solution
Summary
Dyes are widely used in the textile, food, pharmaceutical, plastic, cosmetics, photographic and paper industries, with the textile industry representing the largest consumer of d yes[1,2]. Acid red 27 (AR27) is a highly water-soluble anionic azo dye that is used extensively in industries to color natural and synthetic textiles, and produce leather, paper, food, beverages, confectionery, pharmaceuticals[6,7], cosmetics, phenol-formaldehyde resins, and photographic images[8]. These industrial activities produce large amounts of wastewater contaminated with AR27. Adsorption/biosorption appears to be a more viable and attractive technology for the removal of dyes from industrial effluents because of its unique properties, which include effectiveness, ease of operation, flexibility, adaptability, simplicity of design, cost-effectiveness, efficiency, efficacy, insensitivity to toxic pollutants, eco-friendliness[9,21], and adsorbent/biosorbent r egeneration[18]
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