Effective and sustainable bioremediation of molybdenum pollutants from wastewaters by potential microalgae

Abstract

Due to industrialization and growing population have greatly affected the quality of natural water resources globally. Molybdenum is a harmful metal that can cause serious health issues when exposed to >10 ppm levels. Several industries routinely discharged it, hence posing the environmental problems. For discharged industrial effluents, there are not any environmentally friendly and sustainable treatment method have developed for removing molybdenum hazards. The objective of this study was to design a green, sustainable approach for removing the molybdenum pollutant and to offset the treatment cost by obtaining values from microalgal by-products. Chlorella sorokiniana TU5 and Picochlorum oklahomensis, two fast-growing microalgal strains, were used for molybdenum treatment. The maximum removal efficiency was 115.65 mg L−1 with biomass and lipid yield of 2.35 g L−1 and 579.3 mg L−1, respectively, after 14 days of growth and further exposure to molybdenum pollutant. The molybdenum removal capacity was further increased by optimizing crucial factors, pH and temperature before removing biomass from the aqueous phase. Zeta potential study helped to determine the pH range that appropriately facilitate the strongest possible ionic bonds, leading to the enhanced molybdenum adsorption. In order to verify molybdenum adsorption and comprehend the dominating and quantitative interactions, FTIR was carried out to analyze the reactive groups in the algal cell surface. The current work analyses to control external parameters for improving the adsorption efficiency during harvesting of microalgal biomass, which efficiently improved the removal of molybdenum (V) from the liquid phase. The proposed technique aims to improve the bioremediation efficiency of molybdenum and other inorganic contaminants at an industrial scale by using microalgal treatment.