Determining the influence of the medium reaction and the technique of magnetite modification on the effectiveness of heavy metals sorption

Inna Trus,Olena Hlushko,Nikolai Gomelya,Nataliya Magas,Ganna Trokhymenko

doi:10.15587/1729-4061.2019.188295

Abstract

Development of reliable, environmentally safe and economically advantageous methods of water purification from heavy metals is the primary task for environmental protection. The effectiveness of sorption treatment and additional treatment of natural waters from ions of heavy metals with the use of modified magnetite was studied. The samples of magnetite obtained at the ratio of concentrations of iron (II) and iron (III) of 1:2; 1:1 and 2:1 and the samples modified by sodium sulfide were used as a sorbent. Experimental studies revealed that the sorption capacity of magnetite by ions of heavy metals increases at the increase in the ratio [Fe2+]/[Fe3+] from 1:2 to 2:1. The influence of pH of the medium on the effectiveness of sorption of heavy metal ions on magnetite was studied. It was shown that the sorption capacity of magnetite for ions of copper, zinc, nickel and cadmium increases at the increase in pH of the medium from 6.0 to 8.6 due to partial hydrolysis of heavy metal ions. An increase in sorption capacity of magnetite occurs when it is modified by guanidine, thiosemicarbazide and sodium sulfide, which makes it possible to reduce residual concentrations of heavy metals to μg/dm3. The use of magnetite modified by sodium sulfite, obtained at К=2, makes it possible to completely remove cadmium ions from water and reduce copper concentration to 1.2 μg/dm3. This proves the appropriateness of using these sorbents for additional treatment or deep purification of water from ions of heavy metals. It was shown that it is appropriate to use magnetite for extraction of heavy metal ions from water in the presence of hardness ions, which do not affect the selectivity of this sorbent for ions of heavy metals. Thus, based on the obtained results of sorption purification of water from ions of heavy metals while using magnetite, we proposed a fundamental technological circuit for treatment of wastewater of nuclear power plants at discharge to water bodies

Highlights

As a result of prolonged growth of anthropogenic loading, the environment gets polluted
It is established that sorption capacity of magnetite-based sorbents for ions of copper, zinc, nickel and cadmium depends on pH of the medium
That sorption capacity of magnetite-based sorbents for heavy metals ions depends on the ratio of concentrations of Fe2+ and Fe3+(K) ions in the reactive mixture

Summary

Introduction

As a result of prolonged growth of anthropogenic loading, the environment gets polluted. At the discharge of untreated or insufficiently treated galvanic drains into rivers, lakes and other surface water bodies, which contain a significant amount of heavy metals in its composition, the environment suffers huge damage. This leads to disruption of functioning of active sludge at municipal wastewater treatment plants, loss of natural ability of water bodies to Eastern-European Journal of Enterprise Technologies ISSN 1729-3774. High level of contamination of water sites with mineralized waters and toxic substances requires the development of effective measures to reduce this impact In this regard, the problem of rational nature use and the transition to the use of environmentally friendly energy-efficient technologies is acute

Literature review and problem statement

The aim and objectives of the study

Results of studies of water purification from ions of heavy metals

Findings

Conclusions