Efficient Removal of Brilliant Green Dye Using Mesoporous Attapulgite Clay: Investigating Adsorption Kinetics, Isotherms, and Mechanisms

The study involved the effectiveness of Iraqi attapulgite (IQATP) clay as an environmentally friendly material that easily adsorbs brilliant green (BG) dye from water systems and is identified by various complementary methods (e.g., FTIR, SEM‐EDS, XRD, ICP‐OES, pH pzc , and BET), where the result reported that the IQATP specific surface area is 29.15 m 2 /g. A systematic analysis was selected to evaluate the impact of different effective adsorption performance variables on BG dye decontamination. These variables included IQATP dosage (0.02–0.8 g/L), solution pH (3.05–8.15), contact time (ranging from 2 to 25 min), and initial BG dye concentration from 20 to 80 mg/L. The parameters of kinetic profiles were best represented by the (P‐2‐O) model with the determination of coefficient ( R 2 , 0.99), and the corresponding equilibrium data of dye provided a good fit of the Freundlich adsorption model with a maximal multilayer IQATP adsorption capacity ( Q max , = 1.41 mg/g) under optimum conditions (temperature 318 K, pH 3.05, optimum equilibrium time 25 min, and IQATP dosage 0.2 g/L) for BG dye removal. Thermodynamic parameters, including Δ G = −5.67, −6.10, and −7.56 kJ/mol, Δ H = 29.89 kJ/mol, Δ S = 118.73 J/mol·K, and activation energy Ea = 14.38 kJ/mol, were calculated to understand the adsorption process. This trend indicates an endothermic, spontaneous, and favorable adsorption profile for basic dye by IQATP. The adsorption mechanism was elucidated, indicating the involvement of electrostatic attractions, hydrogen bonding, and n − π interactions in the adsorption of cationic dye. Desorption experiments of BG by IQATP with five repetition cycles showed a great desorption percentage when using 0.1 M hydrochloric acid (HCl), as the eluting agent. Overall, the findings highlight IQATP as a promising and desirable natural adsorbent for the efficient removal of cationic dyes.