Obtaining of Maghemite Containing Red Mud for Effective As(V) Adsorption

Andrei A Shoppert,Denis A Rogozhnikov,Irina V Loginova

doi:10.18502/kms.v6i1.8112

Abstract

   This paper describes the studies of the use of red muds as adsorbents for cleaning solutions from As(V). The red mud is a waste that contains a large amount of iron oxides and hydroxides, which are excellent adsorbents of arsenic, especially those possessing magnetic properties and large specific surface area. The purpose of the experiment was to study the possibility of obtaining an effective adsorbent by direct extraction of alumina from bauxite using the caustic alkali fusion method and optimization of the process. The main iron-containing phase of the red muds obtained by fusing bauxite with caustic alkali was maghemite, which has a large specific surface area. Arsenic adsorption experiments were carried out using red muds obtained through bauxite alkali fusing at different temperatures and time of fusion, as well as the mass ratio of caustic alkali to bauxite. The red muds obtained by fusing bauxite with caustic alkali at 400∘ C and NaOH to bauxite mass ration 1.5 within 70 minutes have the highest effectiveness removing arsenic. Their As(V) uptake capacity was over than 37 mg/g.    Keywords: red mud, maghemite, nanoparticles, As(V) adsorption, optimization     

Highlights

To date, red mud represent non-recyclable waste generated after processing of bauxite [1] occupying large areas of land, at the same time the red mud contains a big amount of valuable components
This bauxite is characterized by a high iron content, which makes it a good object to study the possibility of obtaining an iron oxide-based adsorbent from red mud
As can be seen from the data obtained, the mass ratio of NaOH to bauxite and the time of fusion have the greatest influence on the capacity of red mud, which is associated with a more complete interaction of caustic alkali with hematite in bauxite to form sodium ferrite

Summary

Introduction

To date, red mud (sludge from alumina industry) represent non-recyclable waste generated after processing of bauxite [1] occupying large areas of land, at the same time the red mud contains a big amount of valuable components. A large number of arsenic water treatment methods have been proposed such as oxidation and precipitation [22], coagulation [23], co-precipitation [24], the use of membranes and reverse osmosis [25], electrolysis [26] and ion exchange resins [27]. These methods are rather complicated, expensive or waste generating, and are less effective at very low concentrations. TECHNOGEN-2019 parameters were: temperature and duration of fusion, as well as the mass ratio of caustic alkali to bauxite

Experimental

Results and Discussion

Conclusions