Potential Removal of Some Insecticides from Water using Microalgae and their Determination by a Validated UV-Vis Spectrophotometric Method

Abstract

The present study evaluates the efficiency of microalgae Chlorella vulgaris and Ulva lactuca for removing fenamiphos, imidacloprid and oxamyl from water. The influence of pH, incubation time, insecticide and biomass concentration on the degradation of insecticides were considered valuable factors in the study. The biosorption experiments were performed by adding 100, 500, and 900 mg/L of alga to the insecticide aqueous solution (50, 250, and 450 mg/L). The experiments were performed at different pHs; 5, 7, and 9 with a time course; of 5, 10, and 15 min. UV-Vis spectrophotometric method was conducted for quantifying insecticides. The optimum conditions from the Plackett-Burman test were obtained at 15 min, pH 5, 50 mg/L insecticide concentration, and 900 mg/L biomass that exhibited a removal percentage of 66.20 % and 61.91% for fenamiphos with C. vulgaris and U. lactuca, respectively, While, 5 min, pH 9, 50 mg/L pesticide concentration and 900 mg/L algae biomass with the removal of 40.76, 28.44% and 70.28-70.07 % of imidacloprid and oxamyl for C. vulgaris and U. lactuca, respectively. This study proved that the removal of insecticides by fresh water and marine microalgae C. vulgaris and U. lactuca is both effective and biomass of algae dependent. Thus, C. vulgaris and U. lactuca showed a potential reduction of insecticides in polluted water samples. This study will open new channels for a more indepth understanding of how to remove the insecticide pollutants in the aquatic environment based on microalgae technology.