Synthesis and Application of Boron‐Based Sr ₂ Mg(BO ₃ ) ₂ for the Efficient Adsorptive Removal of Reactive Red 195 from Aqueous Solutions

Abstract The increasing environmental burden of dye‐contaminated effluents underscores the urgent need for sustainable and cost‐effective treatment strategies, particularly in developing regions. Among various approaches, adsorption remains the most practical and efficient technique for the removal of persistent, water‐soluble dyes. In this study, a boron‐based mineral, distrontium magnesium diborate [Sr 2 Mg(BO 3 ) 2 ], synthesized via the solution combustion method, was evaluated for the adsorption of the anionic azo dye Reactive Red 195 (RR‐195) from aqueous solutions. The synthesized adsorbent was characterized using FTIR, SEM, and XRD analyses. Batch adsorption experiments were performed to examine the effects of contact time, adsorbent dosage, pH, and temperature on dye removal efficiency. Under optimized conditions (0.10 g adsorbent, 30 min, 25 °C, pH 6.40), a maximum removal efficiency of 91.7% was achieved. Error analysis of non‐linear isotherm models indicated that, adsorption of RR‐195 onto Sr 2 Mg(BO 3 ) 2 was best described by the non‐linear Dubinin–Radushkevich isotherm ( R 2 = 0.880, q m = 14.14 mg·g −1 ) and followed the pseudo‐second‐order kinetic model ( R 2 = 0.847; k 2 = 0.095 g·mg −1 ·min −1 ). These findings indicate a heterogeneous surface and confirm that the adsorption process proceeds predominantly via a physisorption mechanism. Thermodynamic analysis indicated spontaneous and exothermic adsorption (ΔG° < 0; Δ H ° = −27.37 kJ·mol −1 ; Δ S ° = −82.90 J·mol −1 ·K −1 ). Overall, the results demonstrate that Sr 2 Mg(BO 3 ) 2 is a promising adsorbent for the removal of azo dyes and potentially other anionic contaminants from aqueous solutions.