Efficient removal of copper-based biopesticides from potential agricultural wastewaters by alginate-based biocomposites

This work presents advances in the formulation of biopesticides, which play an important role in sustainable agriculture. The use of a biosurfactant extract obtained from corn steep liquor (CSL) enabled the preparation of more functional copper-based biopesticides containing copper oxychloride (Cu-Oxy) or cuprous oxide (Cu 2 O) from low-cost commercial agrochemicals rather than more expensive pure ingredients reported in the literature. Correlation analysis revealed that these novel biopesticides exhibited greater copper solubilization in water compared to formulations made with pure ingredients, suggesting a potential increase in fungitoxic activity and a dose reduction for pest control. In addition, multivariate analysis indicates that all prepared biopesticides shown a similar behavior, thus forming a single separate group of control pesticides prepared in ultrapure water. Calcium alginate spheres impregnated with grape marc (IGM-CAS) are proposed for the first time as a promising biomaterial for effective removal of copper-based pesticides stabilized with a biosurfactant extract from potential agricultural wastewaters. The most favorable adsorption conditions provided removal percentages of 91.3 and 99.3 % of Cu-Oxy and Cu 2 O biopesticides, respectively, compared to the raw wastewater. Adsorption kinetics of all tested biopesticides onto IMG-CAS agreed with a pseudo-second-order model with determinations coefficients always close to unit (r 2 = 0.999). The information about intraparticle diffusion mechanisms in the bioadsorption process was also interpreted and the morphological changes occurring on the surface of the eco-adsorbent after the adsorption process have been observed by scanning electron microscopy. • Addressing copper removal from water containing biosurfactant-formulated pesticides. • Alginate and grape marc compost achieve >90 % copper removal indicating chemisorption dominance. • Circular waste valorization involving biosurfactants and composted grape marc bioadsorbents. • Multivariate analysis shows a consistent pattern for all copper-based biopesticides utilized in their formulation. • Clean water and responsible consumption by mitigating pesticides and agro-industrial waste.