The batch adsorption study was conducted in 250 mL stoppered Erlenmeyer flasks in an isothermal bath shaker with varying controlled temperature (30–50 C). For this, 200 mL of bentazon herbicide solution with different initial concentrations, predetermined adsorbent dose and solution pH were placed in above mentioned flask. The initial solution pH was adjusted by drop-wise addition of 0.1 M HCl or 0.1 M NaOH and solution pH was measured using a pH meter (EUTECH Instruments, Model Ecoscan, Singapore). The optimum dose (0.2 g) of adsorbent was selected from our preliminary experiments. The mixture was then shaken at desired contact time at 120 rpm [22]. At the end of the shaking,