the potential of gundelia seeds waste as an emerging sustainable adsorbent for methylene blue-polluted water treatment

Gundelia, a genus of flowering plants native to the mediterranean region, particularly in iraq, holds promise as a sustainable adsorbent for the treatment of dye-polluted water. this study explores the potential of gundelia seeds (gs) waste as a biobased adsorbent for removing methylene blue dye from synthesized wastewater. utilizing various analytical techniques, including scanning electron microscopy (sem), fourier transform infrared (ftir) spectroscopy, and x-ray diffraction analysis (xrd), we assessed gs as an active adsorbent with performance comparable to fabricated and expensive composites. key parameters such as ph (3-11), ph at the point of zero charge, temperature (298-328 k), dose (0.02-0.1 g), dye concentration (10-50 ppm), and contact time (10-40 min) were systematically investigated. the point of zero charge was determined to be at ph 8, with the highest removal efficiency observed at ph 11. a contact time of 30 minutes yielded a removal rate of approximately 90 %, with an adsorption capacity of 11.07 mg/g. the highest adsorption capacity, 30.57 mg/g, was attained under conditions of 50 ppm dye concentration, 0.02 g dose, and a 40-minute contact time. the study examined three isotherm models, namely langmuir, freundlich, and temkin; all demonstrating a high fit, with langmuir exhibiting preferability. on the other hand, five kinetic models were explored; the pseudo second-order model provided the most accurate description of the adsorption process.