Adsorption of paraquat and pirimiphos-methyl by montmorillonite modified with tetradecylammonium chloride and intragallery templating method

Abstract

Adsorption of paraquat and pirimiphos-methyl in water was performed on four adsorbents including montmorillonite (Mt), organoclay (TDA-Mt) from intercalation of Mt with tetradecylammonium chloride, and mesoporous Mt from intragallery templating method (with and without Ti addition). The adsorbents were characterized by X-ray diffraction, N 2 adsorptiondesorption, and transmission electron microscopy. Paraquat adsorption isotherms followed Langmuir model and the adsorption capacity was as follows: TDA-Mt > Mt > mesoporous TiMt > mesoporous Mt. The adsorption mechanism on TDA-Mt and Mt might be via ion exchange. The adsorption on mesoporous samples was on the external surface with negative charge. The presence of Ti enhanced the adsorption capacity. Pirimiphos-methyl adsorbed on negative charge of the external surface of Mt samples. The adsorbed amount increased with the initial concentration due to a strong intermolecular interaction.

Paraquat Degradation From Contaminated Environments: Current Achievements and Perspectives

“…Currently, adsorption and degradation are the two main methods to remove/reduce paraquat from aquatic environment. Previous studies concluded that the adsorption of paraquat mainly depends on activated carbon (Sieliechi and Thue, 2015), activated bleaching soil (Tsai et al, 2004), modified zeolite (Pukcothanung et al, 2018), montmorillonite (Gu et al, 2015) and organoclay (Guegan et al, 2015; Keawkumay et al, 2017). On the other hand, physicochemical paraquat degradation methods depend on titanium dioxide, ozone, ultraviolet radiation and various advanced oxidation processes (AOPs) (Hamad et al, 2016; Gao et al, 2017; Javier et al, 2017).…”

Paraquat Degradation by Biological Manganese Oxide (BioMnOx) Catalyst Generated From Living Microalga Pediastrum duplex AARL G060

“…Biological methods may provide limited paraquat degradation (e.g., microorganisms utilize and degrade <1% of paraquat in soil particles ( Roberts et al, 2002 ; Huang et al, 2019 ); therefore, abiological processes may be required to facilitate natural paraquat degradation. Previous studies included various methods for paraquat removal, such as adsorption on modified zeolites, activated carbon, and organoclay ( Guégan et al, 2015 ; Sieliechi and Thue, 2015 ; Keawkumay et al, 2016 ; Pukcothanung et al, 2018 ). On the other hand, physicochemical processes using titanium dioxide, ozone, and various advanced oxidation processes showed potential for paraquat removal and reduction of the physical and chemical effects of this pesticide on the environment and health ( Florêncio et al, 2004 ; Mandal et al, 2010 ; Wang and Xu, 2012 ; Deng and Zhao, 2015 ; Hamad et al, 2016 ).…”