New pyridyl and aniline-functionalized carbamoylcarboxylic acids for removal of metal ions from water by coagulation-flocculation process

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 451; p. 138396
• Main Authors: Montaño-Medina, César Ulises, Lopéz-Martínez, Luis Miguel, Ochoa-Terán, Adrián, López-Maldonado, Eduardo Alberto, Salazar-Gastelum, Moisés I., Trujillo-Navarrete, Balter, Pérez-Sicairos, Sergio, Cornejo-Bravo, José M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2023
• Subjects: Biodegradability; Carbamoylcarboxylic acids; Coagulation; Flocculation; Heavy metals; Zeta potential; Carbamoylcarboxylic acids; Zeta potential; Biodegradability; Flocculation; Heavy metals; Coagulation
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.138396

[Display omitted] •Monomeric carbamoylcarboxylic ligands have great capacity to heavy metal ions removal.•Carbamoylcarboxylic ligands exhibit a good six-heavy metal ions simultaneous removal.•Chemical structure of carbamoylcarboxylic ligands influences their removal efficiency.•Instability phenomena in flocs evolution are the sedimentation and clarification.•Carbamoylcarboxylic ligands are biodegradable materials. In this work, a library of new aniline and pyridyl functionalized carbamoylcarboxylic acids were synthesized, physicochemically analyzed and evaluated as ligands for the simultaneous removal of environmental interest cations. The effect of the structural characteristics of these functionalized ligands over the simultaneous removal performance of metal ions (Cr3+, Pb2+, Cd2+, Cu2+, Ni2+, Zn2+ and Ca2+) was established. The metal ion-ligand association constants calculated from zeta potential (102 to 104 M−1) and UV–vis (103 to 107 M−1) demonstrate a strong affinity of these ligands towards metal ions. The micro-Jar test for cation removal shows these new functionalized carbamoylcarboxylic acids L1-L12 show average removal efficiencies of 100 % Cr3+, 73 % Pb2+, 42 % Zn2+, 50 % Ni2+, 42 % Cd2+, 39 % Cu2+ and 30 % Ca2+. The quantification of destabilization phenomena through transmittance and backscattering measurements allowed to evaluate the mechanisms of colloidal instability to all ligands. Among the twelve ligands, L9 showed the best removal performance at pH = 4.0 with an overall removal capacity (19.28 mg Mn+ removed/mg of L9), clarification kinetics (55.99 T%/h) and sedimentation ratio (117.6 mm/h). The flocs recovered from the coagulation-flocculation tests were analyzed by scanning electron microscopy and dispersive energy spectroscopy with mapping finding the dispersion patterns of metals on the surface. A BOD5/COD = 0.44 indicates that L9 is a biodegradable compound. Based on the results, aniline and pyridyl functionalized carbamoylbenzoic acids have great potential to be applied in the wastewater treatment industry containing multiple cations.