Development of a ghatti gum/poly (acrylic acid)/TiO2 hydrogel nanocomposite for malachite green adsorption from aqueous media: Statistical optimization using response surface methodology

The primary goal of this study is to prepare and characterize a ghatti gum/poly(acrylic acid)/TiO2 (GG/poly(AA)/TiO2) hydrogel nanocomposite for adsorption of the dye malachite green (MG) from the aqueous phase in a discontinuous system. A variety of approaches were used to investigate the structure, morphology, and thermomechanical characteristics of the synthesized hydrogel nanocomposite. Response surface methodology (RSM) was performed to analyze the impact of three processing parameters, namely adsorbent dosage, dye concentration, contact duration, and their interactions on MG dye adsorption capacity. Analysis of variance was used to assess the experimental findings, which revealed that the quadratic regression model was statistically acceptable. The integration of TiO2 nanoparticles into the hydrogel matrix improved its thermal stability, mechanical strength, and performance in adsorbing MG dye from water. The kinetics and isotherm were evaluated, and the adsorption process was well fitted with pseudo-second order and Temkin isotherm models, respectively. Using the Langmuir equation, the maximum adsorption capacity at 45 °C within 50 min was calculated to be 2145 mg/g. Thermodynamic analysis at 25-45 °C revealed that the MG dye was spontaneously absorbed by the hydrogel nanocomposite. The prepared hydrogel nanocomposite demonstrated excellent reusability without a noticeable loss in MG dye adsorption capability for 6 cycles.