Rapid Removal of Acid Red 88 by Zeolite/Chitosan Hydrogel in Aqueous Solution

Abstract

In the present study, we developed a new adsorbent product with zeolite crosslinked chitosan (ZL–CH hydrogel) to remove acid red 88 (AR88) in an aqueous solution. The effects of several factors, such as the comparison of ZL–CH hydrogel and the absence of chitosan, pH, adsorbent dosage, initial AR88 concentration, contact time, and ion strength, were determined. Obtained results showed that ZL–CH hydrogel improved AR88 removal compared to the absence of chitosan, with an adsorption capacity of 332.48 mg/g in equilibrium time of 1 min, and adding ionic strength had no significant effect. However, with optimal conditions at pH 2.0, dry ZL–CH became hydrogel due to protonation of amino and hydroxyl groups through hydrogen bonds in the AR88 solution. Volume fraction and interaction force decreased with increasing porosity, leading to an increase in adsorption capacity and swelling ratio. Experimental data of the adsorption process showed the Freundlich isotherm model. The equilibrium for adsorption and swelling kinetics studies showed and fitted a pseudo-second-order model. NaOH was successful as a desorbing agent with 93.8%, and it followed the pseudo-second-order kinetics model. The recycling process indicates great potential for AR88 removal.

Synthesis, Adsorption Isotherm and Kinetic Study of Alkaline- Treated Zeolite/Chitosan/Fe3+ Composites for Nitrate Removal from Aqueous Solution—Anion and Dye Effects

“…We can see that the highest dye percent removals at pH 10 for MB and pH 2 for AR88 were 44% and 99%, respectively. This result is similar to [ 40 ] and [ 49 ] for MB and AR88 removal, respectively. Interestingly, fact that when the solution was mixed with azo dye (AR88) at pH 2 ( Figure 11 a), the solution turned into hydrogels, followed by the maximum nitrate removal of 86.65%.…”

“…However, it would decrease the adsorbate’s mass transfer resistance. Consequently, the percent removal is decreased [ 39 , 49 , 50 , 51 ].…”

“…The results showed that an increased initial AR88 concentration would increase nitrate removal, followed by an increase in the swelling ratio, and there was no significant change in AR88 removal ( Figure 12 ). The swelling ratio is followed in Equation (8) [ 49 ]. This indicates that azo dye group molecules are essential in capturing nitrate through hydrogel via ZLCH-Fe adsorption.…”

A Novel Approach, Based on the Combined Action of Chitosan Hydrogel and Laccases, for the Removal of Dyes from Textile Industry Wastewaters

“…This conclusion is confirmed by the observation that the data shown in Figure 2b are better fitted by a linear model, in comparison to those reported in Figure 2a,c. These results are in agreement with previous studies concerning the adsorption of dyes on chitosan-based hydrogels [22,40,41].…”

A Carbonized Zeolite/Chitosan Composite as an Adsorbent for Copper (II) and Chromium (VI) Removal from Water

“…They were constructed using an interconnected tetrahedral alumina (AlO 4 ) structure and silica (SiO 4 ). Some authors have used chitosan/zeolite composites to effectively eliminate pollutants, such as dyes [ 24 , 25 ], ammonium [ 16 ], fluoride [ 26 ], and heavy metals [ 27 ].…”