Chemical modification of commercial kaolin for mitigation of organic pollutants in environment via adsorption and generation of inorganic pesticides

Contamination of water supplies with different organic pollutants from industrial and agricultural activities has received high concern recent years. Thus, efficient removal of these organic pollutants and minimize their usage in environment are highly recommended. Herein, we report hydrothermal chemical modifications of commercial kaolin (CK) in presence of sodium hydroxide (alkaline-modified kaolin; AMK) and disodium hydrogen phosphate (phosphate-modified kaolin; PMK) reagents. Interestingly, these chemical modifications altered the physicochemical characteristics of CK in term of morphology, surface area and functionality which enhanced the adsorption capability of organic pollutants (i.e. methylene blue; MB) as well as offered an alternative inorganic pesticide that might reduce the consumption of organic pesticides. The results showed that, the equilibrium of MB adsorption is well described by Langmuir isotherm with maximum monolayer capacity of 434.78 and 476.19 mg/g for AMK and PMK, respectively. Furthermore, AMK and PMK revealed reasonable latent entomotoxic effect against cotton leafworm (S. littoralis) compared to a highly toxic organic pesticide (i.e. Methomyl). Therefore, the naturally abundant kaolin can be utilized efficiently to mitigate the organic pollutants in environment through sequestering of organics and generation of alternative inorganic pesticides for green plant protection.