Characterization of Moroccan cactus juice toward its use as a green flocculant in wastewater treatment

Abstract

The present work is dedicated to the characterization of Moroccan cactus juice, which shows encouraging performance in wastewater treatment. Various techniques were used to highlight the chemical and physical properties of this natural product. Elemental analysis of cactus juice using inductively coupled plasma emission spectroscopy revealed the presence of numerous minerals. Fourier Transform Infrared, ultraviolet, and nuclear magnetic spectroscopies demonstrate the presence of many carbohydrate components. Identification of volatile compounds by gas chromatography reveals the presence of Gibb-3-ene-1,10-dicarboxylic acid, ethyl gallate, 3TMS derivative, ethyl ester and 1-(2-Isopropyl-phenyl)-3,6,6-trimethyl-1,5,6,7-tetrahydro–indazol. Thermogravimetric analysis indicates three peaks at 100, 200 and 600 °C, corresponding to the mass loss of water, polysaccharides, and organic matter, respectively. The rheological characterization of cactus juice suggests that this liquid exhibits shear-thinning behavior, which is governed by the Casson model. The results of the Zeta potential measurement demonstrate the anionic character of cactus juice as a flocculant, with −25 mV as a value of zeta potential. Its use as a flocculant in organic matter removal shows that the chemical Oxygen demand decreases significantly with the increase of the added cactus juice dose, confirming, therefore, its flocculating behavior.