Isolation and chemical modification of cellulose from wheat straw for the removal of diclofenac potassium from wastewater

In the current study, cellulose fibers were extracted from wheat straws by subjecting wheat straw to acid hydrolysis, alkaline hydrolysis and bleaching with sodium chlorate and hydrogen peroxide. The extracted cellulose pulp was chemically modified with aniline to prepare aniline grafted cellulose. Both raw and aniline functionalized cellulose obtained from what straws were utilized for the removal of diclofenac potassium (DCF-p) from aqueous solution. The adsorbents were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The effect of concentration, time, pH and adsorbent dose on diclofenac potassium removal were studied during batch adsorption experiments and the optimum values of these parameters were determined. Removal efficiencies of 80.6% and 98.8% were obtained for raw and chemically modified cellulose respectively for the removal of DCF-p from aqueous solution. The exceptional adsorption efficiencies of modified cellulose compared to raw cellulose can be attributed to the presence of aromatic ring and amine functional groups incorporated into the cellulose skeleton during chemical modification. The isotherm study shows that the experimental data of DCF-p adsorption onto raw and chemically modified cellulose fitted with Freundlich isotherm model (R² = 97) indicating chemisorption. The kinetics study shows that the adsorption of DCF-p onto raw and chemically modified cellulose follows pseudo-second kinetic order model. Owing to high adsorption capacity and removal efficiency, aniline modified cellulose could be used as an effective adsorbent for the removal of diclofenac potassium from industrial wastewater.