Exploring electrochemical and sorptive aspects of interaction between dissolved sulfides and novel Fe-enriched aluminosilicate composites

Abstract

© 2018 Elsevier B.V. Three types of functional ceramic composites were designed, synthesized and probed for effective sulfide removal from aqueous solutions. The main goal was to examine complex influence of graphite, surpluses of Fe (∼4%) and micro-additions of Cu (∼0.2%) on the functional features of the composites. The structural, textural, morphological and surface characteristics of the composites were examined in detail by XRD, nitrogen sorption, SEM and FTIR. It has been shown that all composites are solid heterogeneous systems containing amorphous and crystalline phases (graphite, hematite, montmorillonite, quartz, etc.) with pronounced redox activity in contact with sulfide aqueous solutions. Great enhancment of sulfide consumption was detected for composites which contained graphite and it was established that reaction kinetics is fitted to irreversible second-order batch reaction with two reactants. After the treatment of 1 mM S2− solution, using composite dossage of 1 g/dm3, concentration dropped down to 0.02 mM. In addition, cyclic voltammetry at 50 mV/s revealed the key role of dopants in electrochemical aspect of the process. Obvious boost of S2− uptake is ascribed to numerous electrochemical, chemical and sorption processes on the composite's developed surface.