زهرا لطفعلي زاده

In this study, cellulose-based aerogels were synthesized from corn husk and eva‎luated as an adsorbent for their efficiency in removing Congo Red dye from aqueous solutions. Cellulose was extracted from corn husks and subsequently dissolved in a NaOH/Urea system. Borax was employed as a crosslinker, while two types of composite components, nano alumina and biochar, were incorporated into the aerogel matrix to investigate their effects on the structural and adsorption properties. The impact of the borax/cellulose ratio (1:1 and 3:1), type of composite component (nano alumina, biochar), and percentage of composite component (2% and 8%) on dye removal efficiency was studied. It was found that in the presence of a constant amount of nano alumina and biochar, the dye removal efficiency decreases by 3.25% and 4.42%, respectively, by increasing the ratio of borax to cellulose from 1:1 to 3:1. In addition, the aerogel containing 2% nano alumina showed the highest absorption capacity (94.08%), while the aerogel containing 8% biochar had a better color efficiency (93.5%) than the sample containing 2% biochar (91.08%). Field Emission Scanning Electron Microscopy (FESEM) revealed increased porosity in composite aerogels containing nano alumina and biochar compared to the blank aerogel. Cellulose aerogel contained 8% biochar was selected for further adsorption tests due to its efficient removal efficiency (93.5%) and easier accessibility with high porosity (96.8%) and low density (0.054 g/cm³). Brunauer–Emmett–Teller (BET) analysis indicated a porous structure with an average pore diameter of 53.108 nm and specific surface area (SBET) of 3.84 m2/g. Adsorption experiments demonstrated that equilibrium was reached after 7 hours, and adsorption capacity decreased with increasing temperature, suggesting exothermic behavior. Optimal adsorption occurred at pH 7, and the adsorption capacity increased with higher dye concentrations due to the availability of more dye molecules. The experimental data were best described by the Langmuir isotherm model, with a maximum adsorption capacity (qm) of 36.92 mg/g. Kinetic studies indicated that the adsorption followed a pseudo-second-order model. Thermodynamic analysis confirmed that the adsorption process was exothermic, with positive entropy change (ΔS > 0) and negative Gibbs free energy (ΔG < 0), indicating spontaneity of the process.

آئروژل , قرمز كنگو , جذب سطحي , ضايعات ذرت , كامپوزيت

aerogel , Congo red , adsorption , Corn residue , composite

Zahra Lotfalizade

Dr. Reza Norouzbeigi