Design and mechanism of action of multifunctional BPE’s with high performance in the separation of hazardous metal ions from polluted water Part I: Chitosan-poly(N-vinylcaprolactam) and its derivatives

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 359; pp. 840 - 851
• Main Authors: García, Oscar Gabriel Zavala, Oropeza-Guzmán, Mercedes Teresita, Argüelles Monal, Waldo M., López-Maldonado, Eduardo Alberto
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2019
• Subjects: Biopolyelectrolytes; Chitosan; Heavy metals; Macromolecular metal complex; Poly (N-vinylcaprolactam); Zeta potential; Macromolecular metal complex; Poly (N-vinylcaprolactam); Chitosan; Zeta potential; Biopolyelectrolytes; Heavy metals
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2018.11.134

[Display omitted] •Macromolecular metal complex principles applied to design of chelating coagulant flocculant agent.•Coordination chemistry principles applied to design and modification of biopolyelectrolyte.•Zeta potential is a method to validate the chemical transformation of biopolielectrolyte.•The dendronization of chitosan gives it a high multifunctional performance for the separation of hazardous metal ions. This paper presents the design and mechanism of action of multifunctional biopolyelectrolytes (BPE’s) with high performance in the separation of hazardous metal ions from polluted water. The first part of a series of BPE’s is the chitosan-poly(vinylcaprolactam) and its derivatives that were synthethized based on chitosan (Ch) and poly (N-vinylcaprolactam) (PNVCL) to obtain three chitosan derivative (Ch’s derivatives), phosphonomethylated chitosan and dendrimeric chitosan and a copolymer of ChPNVCL. The chemical synthesis was carried out varying their chemical structure and surface charge density. They are proposed as innovative multifunctional biopolyelectrolytes were evaluated in aqueous medium and performance in the separation of seven metal cations frequently present in plating wastewater. The physicochemical characterization included FTIR, MP-EAS, SEM-EDS of Ch, PNVCL and Ch's derivatives and the flocs recovered after solid-liquid separation, as well as, analysis of colloidal stability and zeta potential. The zeta potential measurements were used as a key tool to perform the design of the multifunctional chitosan derivatives, predict their behavior in the coagulation flocculation of simulated wastewater and determine their BPE-metal ion interaction mechanisms. The investigation of the multifunctional performance of the BPE shows that dendronized chitosan (ChDCOOH) has functional activities such as chelating coagulant and flocculant, being a macromolecule bearing suitable ligand groups that can interact with heavy metal ions. The ChDCOOH has a coagulation-flocculation window (97–140.2 mg/L) allowed the simultaneous separation of the seven metal ions at pH 4.7: Cr3+ (0.00) > Pb2+ (0.05) > Cu2+ (0.60) > Ni2+ (1.51) > Zn2+ (3.42) > Ca2+ (5.60) > Cd2+ (4.78), and fast of the seven metal ions; clarification (423 %T/h) and sedimentation kinetics (140.0 mm/h).