Sequential Removal of Cu²⁺ and Glyphosate from Aqueous Effluents Using Palygorskite

Glyphosate is a herbicide whose presence in water bodies entails environmental and health risks¹. Palygorskite is a promising adsorbent, but organophilization is required to bind anionic herbicides². Exploiting the affinity of glyphosate for Cu²⁺, a sequential treatment was proposed: palygorskite removes Cu²⁺ from one effluent, and the Cu²⁺-palygorskite subsequently adsorbs glyphosate from another. Two full factorial 2² designs were performed. The first varied Cu²⁺ concentration (25, 150 ppm) and time (0.5, 6 h) using 1 g of clay, with maximum uptake at 150 ppm and 0.5 h. The second assessed glyphosate concentration (50, 100 ppm) and time (0.5, 6 h) on Cu²⁺-palygorskite, yielding ~30% removal at 50 ppm and 6 h, accompanied by ~20% Cu²⁺ desorption. These findings indicate the potential of Cu²⁺-palygorskite for sequential treatment of distinct effluents. Further studies should elucidate interaction mechanisms and optimize conditions to enhance removal and minimize copper leaching.