Abstract
In the present work, Zeolite A was modified by using hexadecyltrimethylammonium bromide (HDTMABr) for adsorption of the Congo red (CR) dye from synthetic aqueous solutions. The Modified Zeolite A (MZA) was characterized by XRD, SEM, and FTIR. The influence of solution pH (in the 4-12 range), ionic strength (0.1-1 M), contact time (180 min), initial CR concentration (20-60 mg/L), temperature (24-36 °C), and an adsorbent dose (1-3 g m/L) on the % dye removal and adsorbent capacity were studied. A combined effect of the initial CR concentration and temperature on the CR removal % by MZA was also studied by applying response surface methodology (RSM). Experimental values were in a good agreement with those predicated by a second-order quartic model. A maximum of 99.24% dye removal and adsorbent capacity of 21.11 mg/g was achieved under the following conditions: pH = 7, initial CR concentration = 60 mg/L, temperature = 24 °C, ionic strength = 0.1 M, adsorbent dose = 3 g/L and 90 min contact time. The equilibrium data were subjected to the Langmuir, Freundlich and Temkin isotherms, with the latter providing the best fit while kinetic adsorption studies were conducted by applying three models. The results indicated that the removal process was best described by the pseudo-second-order model. The present study demonstrates that modified MZA can be utilized for the highly efficient CR dye removal.
Highlights
Environmental pollution by chemical waste is a major problem in the manufacturing process, necessitating that all harmful discharges be treated to minimize their harmful effects (Netpradit et al ; Albayati et al )
A commercial zeolite was successfully modified by hexadecyltrimethylammonium bromide (HDTMABr), characterized by XRD, Scanning electron microscope (SEM), and Fourier Transform Infrared (FTIR) and was used for the Congo red (CR) removal from an aqueous solution
The following conclusions were reached based on the obtained findings: 1. The removal process was affected by the solution pH, contact time, initial dye concentration, temperature and the adsorbent amount
Summary
Environmental pollution by chemical waste is a major problem in the manufacturing process, necessitating that all harmful discharges be treated to minimize their harmful effects (Netpradit et al ; Albayati et al ). In many industries, such as plastic, textile, cosmetic, rubber, paper, and so on, organic chemicals are typically used for coloring products. Chemical structures of waste products, and dyes released from those industries are resistant to degradation and difficult to treat by most known methods Release of those effluents into the aquatic surroundings is extremely dangerous (Abbas et al ; Al-Dahri et al ).
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