Adsorption of non-steroidal anti-inflammatory drug (NSAID) by agro-industrial by-product with chemical and thermal modification: Adsorption studies and mechanism

•The adsorption of diclofenac potassium onto modified soybean hulls was evaluated.•The thermal treatment was studied by thermogravimetric analysis and residence time.•The experimental data fitted pseudo-first order and Sips models.•The adsorption mechanism occurs through hydrogen bonds and π-π interactions.•The modified soybean hulls presented a maximum adsorption capacity of 96.88 mg g−1.