Removal of heavy metal ions form acidic electrolyte for stainless steel electropolishing via adsorption using Polish peats

Abstract

The use of natural materials for wastewater treatment is a rapidly evolving issue. Natural materials are often low-cost or waste materials, and they are readily available. In the case of industrial wastewater treatment, the use of natural sorbents for the removal of heavy metals has shown positive results for many of the materials tested. However, there are ample reports in the literature of successes based solely on prepared solutions and laboratory trials, which may not actually be as effective when applied under industrial conditions. In the present work, the possibility of using Polish peat from 5 health resorts (Połczyn Zdrój, Goczałkowice Zdrój, Wieniec Zdrój, Kamień Pomorski and Kołobrzeg) as a sorbent for heavy metals in industrial wastewater from the steel electropolishing process is investigated. The materials were characterized and then sorption tests using both laboratory and industrial wastewater solutions were performed. The peat used turned out to be an effective material for both model laboratory and industrial wastewater characterized by high initial concentrations of metals such as iron, chromium, nickel, and copper. Removal rate for initial concentration of 1000 mg/dm3 was 99% for chromium and iron, and 66% for nickel and cooper. The total removal capacity was 30.7 mg/g and indicated the following order Fe(III) > Cr(III) > Cu(II) > Ni(II) in the wide range of industrial electrolyte for stainless steel electropolishing. The method of conducting the research and characteristics of the materials open up new opportunities for removing heavy metal ions in an acidic environment without prior pH correction.