Removal of paraquat from aqueous solutions by plant extracts as an ecofriendly approach

Paraquat is a very water-soluble herbicide widely used in agricultural and nonagricultural lands. The removal of paraquat from polluted water is very essential. Hence, three experiments were arranged separately to investigate the ability of plant extracts include Aloe vera, Portulaca grandiflora, kalanchoe daigremontiana, Sedum rubotinctum, Brassica rapa var. rapa, Helxine soleirolii, Brassica oleracea var. capitata, Crassula ovate, Aptenia cordifolia, Tradescantia albiflora to the removal of paraquat (PQ) from water. In the 1st experiment, High-performance liquid chromatography was used to determine the removal rate of PQ by using plant extracts. In the 2nd and 3rd experiments, PQ solutions were subjected to plant extracts treatments and then spray on the leaves of littleseed canarygrass (Phalaris minor) under greenhouse and field conditions, respectively. In general, the results of these experiments revealed that all plant extracts resulted in higher PQ removal from water compared to control. The maximum removal of PQ was observed at pH 11, 25 °C, 30 Min, and 0.2 mL in the presence of plant extracts. In the presence of P. grandiflora, C. ovate, k. daigremontiana, A. cordifolia, H. soleirolii, Aloe vera, S. rubotinctum, B. oleracea var. capitata, B. rapa var. rapa, and T. albiflora plant extracts, PQ removal from water increased to 68.34%, 65.45%, 63.97%, 59.81%, 59.29%, 55.44%, 52.06%, 50.34%, 48.86%, and 46.44% under normal conditions and 79.71%, 78.61%, 78.00%, 75.83%, 74.66%, 72.12%, 71.57%, 71.02%, 69.35%, and 68.73% under optimum conditions, respectively. Results of the 2nd and 3rd experiments were demonstrated a decrease in PQ performance on littleseed canarygrass control. It can be concluded that plant extracts can reduce the residual of PQ in water bodies.