Experimental investigation of the removal of cobalt heavy metal from aqueous solutions using thermally modified dolomite powder

Saadi, Mohammad; Mohammadi, Parinaz; Khajenoori, Maryam

doi:10.30466/jwec.2025.55810.1005

Experimental investigation of the removal of cobalt heavy metal from aqueous solutions using thermally modified dolomite powder

Document Type : Research Article

Authors

Mohammad Saadi ¹

Parinaz Mohammadi ¹

Maryam Khajenoori ²

¹ Faculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan, Iran

² Faculty of Chemical, Petroleum and Gas Engineering, Semnan University, Semnan 3513119111, Iran

10.30466/jwec.2025.55810.1005

Abstract

This research aims to make a thermally modified dolomite absorbent with stable properties and high porosity to increase the capacity and efficiency of removing cobalt from water bodies. First, raw dolomite was thermally modified and then washed with a buffer borax solution, and boric acid for MgO was removed from the newly created pores. This treatment led to changes in the chemical composition of the surface and the porosity of natural materials that increased the active surface and absorption properties of dolomite. The results showed that unmodified dolomite has a limited adsorption capacity with a final residual cobalt concentration of 0.852 mg/L. FTIR, SEM, and BET analysis adsorbent surface properties, permeable morphology, and qualitative phase identification. Also, the effect of three operational parameters of initial solution concentration, contact time and temperature was evaluated in the ranges of (10-20-30-50-70-100-200 ppm), (5-10-20-30-45-60-90-240 min) and (30-40-50 °C), respectively. The experiments showed the maximum removal efficiency at a concentration of 10 ppm, a time of 240 min, and a temperature of 30 oC. In addition, increasing the contact time from 5 to 240 minutes leads to the maximum cobalt removal percentage of 99.218%. The investigation of equilibrium isotherms is in good agreement with the Langmuir model, and kinetic and thermodynamic studies showed that the absorption process follows pseudo-second kinetics and is exothermic.

Keywords

Cobalt

Aqueous solution

Adsorption

Thermally modified dolomite

Subjects