Nejayote biopolyelectrolytes multifunctionality (glucurono ferulauted arabinoxylans) in the separation of hazardous metal ions from industrial wastewater

Abstract The scarcity and contamination of water by suspended nanoparticles and hazardous metal ions demand more performant technologies to reduce space, time and cost of wastewater treatment. For example, it is desirable to find eco-friendly chemicals that warranty simultaneous separation of colloidal particles and hazardous metallic contaminants for a more sustainable recovery of water quality. As the second part of a series of physicochemical studies about multifunctional biopolyelectrolytes (BPEs), in this paper, we present three of the main features of the glucurono ferulauted arabinoxylans (GFAXs) from nejayote: simple extraction, physicochemical characterization and multifunctional performance when used in a wastewater treatment unit. The polyelectrolytic and macrochelating properties of the GFAXs were studied through zeta potential measurements to predict and understand the multifunctional performance of GFAXs in a conventional coagulation-flocculation unitary operation. Two real cases were approached: the wastewater from silicon wafer cutting process (SWCP) and the wastewater from electroplating baths (EPB). Nejayote GFAXs showed high coagulant, flocculant and macrochelating activity in the simultaneous separation of Si4+, Al3+, Cr3+, Ni2+, Mg2+, Ca2+, Ni2+, Cd2+, Pb2+, Cu2+, Zn2+ and Fe2+. The water treatment tests demonstrate the high performance of the GFAXs in the coagulation-flocculation of the wastewater according to the following parameters: EPB wastewater at pH = 5.0 (optimal dose = 55–65 mg GFAXs/L, clarification = 380 T%/h and sedimentation kinetics = 110.4 mm/h); SWCP wastewater at pH = 5.5 (optimal dose = 30.0–32.5 mg GFAXs/L, clarification = 295 T%/h and sedimentation kinetics = 89.4 mm/h). With these results, nejayote GFAXs showed to be a sustainable solution for the wastewater treatment from semiconductor and metal finishing industry with high content of hazardous metal ions and SiO2 nanoparticles.