According to the considerable toxic impacts of diazinon on the human health and envi- ronment, removal of that is very essential. Magnetic nanomaterials are highly used due to their distinguished features which can be controlled by an external magnetic field. The magnetic guar gum and magnetic guar gum-montmorillonite was synthesized via a con- trolled coprecipitation method to obtain uniform and high efficient nanocomposite for di- azinon removal. The effect of pH, contact time and initial diazinon concentration on the removal of diazinon was examined. The adsorbent morphology and chemical composition were evaluated using SEM and FTIR. The size distribution of Fe 3 O 4 -guar gum and Fe 3 O 4 - guar gum-montmorillonite was from 56 to 92 nm and 70 to 128 nm respectively. Kinetic studies were checked by pseudo-first order, pseudo-second order and Elovich models. The adsorption behavior of diazinon was matched by the pseudo-second order kinetic model (R 2 ˃0.99). Langmuir, Freundlich, Temkin and Elovich isotherm models were checked by ad- sorption equilibrium data and Langmuir model indicated the best consistency with the ex- perimental results and the maximum adsorption capacity are 47.17 and 80.00 mg g −1 for the magnetic guar gum and magnetic guar gum-montmorillonite, respectively. Based on the results, magnetic guar gum-montmorillonite nanoadsorbent has high ability to diazi- non removal from aqueous solution.
