Study on the Adsorption Mechanism of Cobalt and Nickel in Manganese Sulfate by δ-MnO₂

Abstract

Manganese has excellent performance in removing metal ions from aqueous solutions, but there are few studies on the adsorption and removal of heavy metal impurities in metal salt solutions. In this paper, the adsorption of cobalt and nickel ions in MnSO4 solution by δ-MnO2 prepared from two different manganese sources was studied. The optimum adsorption conditions were as follows: When the concentration of Mn2+ was 20 g/L, δ-MnO2 addition was 10 g/L, Co2+ concentration was 80 mg/L, Ni2+ concentration was 80 mg/L, reaction time was 60 min, reaction temperature was 80 °C, and pH value was 7, the adsorption rate of Co2+ and Ni2+ reached more than 80%. The manganese dioxide adsorbed by heavy metals was analyzed and detected. The results showed that MnOOH appeared in the phases of both kinds of δ-MnO2, and their morphologies were dense rod-like structures with different lengths and flake-like structures of fine particles. Co and Ni were distributed on the surface and gap of MnO2 particles, and the atomic percentage of Co was slightly higher than that of Ni. The new vibration peaks appeared near wave numbers of 2668.32, 1401.00, and 2052.19 cm–1, which were caused by the complexation of cations such as Co2 + and Ni2 + with hydroxyl groups. Some cobalt and nickel appeared on the surface of δ-MnO2, and the surface oxygen increased after adsorption. The above characterization revealed that the adsorption of cobalt and nickel in manganese sulfate by δ-MnO2 was realized by the reaction of its surface hydroxyl with metal ions (M) to form SOMOH.

Towards sustainable battery recycling: selective dynamic adsorption of nickel(II) and cobalt(II) in an adsorbent fixed-bed reactor at elevated temperature

“…These can be produced by surface modification of the adsorbents with target-directed ligands [12][13][14]. Several studies have already shown the general possibility to bind Ni(II) and Co(II) by such adsorbents in batch experiments [10,11,[14][15][16][17][18][19]. These discontinuous investigations of the adsorbents deliver valuable information about the adsorption equilibria and the microkinetics of the respective adsorption process.…”

Iodine and Nickel Ions Adsorption by Conjugated Copolymers Bearing Repeating Units of Dicyclopentapyrenyl and Various Thiophene Derivatives

“…Nickel, in particular, can cause adverse health complications to the lungs, kidneys, mucous membranes, as well as the reproductive and nervous systems [33]. Several separation techniques have been developed to remove heavy metal ions from aqueous media, such as precipitation [34,35], ion exchange [36], membranes [37], and adsorption [38], with the latter being widely employed because of its simplicity and cost-effectiveness [39]. In this work, we report the synthesis of new conjugated copolymers bearing repeating units of dicyclopenta[cd,jk]pyrenyl units and thiophene derivatives using a versatile palladiumcatalyzed cyclopentannulation reaction for the efficient removal of iodine from the air and nickel ions from water.…”

Towards Sustainable Battery Recycling: Selective Separation of Nickel(II) and Cobalt(II) in an Adsorbent Fixed-Bed Reactor

“…These can be produced by surface modi cation of the adsorbents with target-directed ligands [8]. Several studies have already shown the general possibility to bind Ni(II) and Co(II) by such adsorbents in batch experiments [7,[9][10][11][12][13]. These discontinuous investigations of the adsorbents deliver valuable information about the adsorption equilibria and the microkinetics of the respective adsorption process, but if they are not supplemented by continuous studies, they can also lead to erroneous interpretations.…”