Pb(II), Cd(II) and Zn(II) adsorption on low grade manganese ore

Abstract

Low grade manganese ore (LMO) of Orissa containing 58.37% SiO 2 , 25.05% MnO 2 , 8.8% Al 2 O 3 , and 5.03% Fe 2 O 3 as the main constituents was taken to study its adsorption behaviour for Pb(II), Cd(II) and Zn(II) from aqueous solutions. The XRD studies showed the crystalline phases to be quartz, β-MnO 2 , δ-MnO 2 and Fe 2 O 3. Batch adsorption studies were carried out by varying the experimental parameters which included contact time, pH, adsorbate and adsorbent concentrations and temperature. The time data fitted well to pseudo second order kinetics for Pb(II), Cd(II) and Zn(II) adsorption. With the increase in adsorbent dose, loading capacities decreased. With the increase in pH from 2.0 to 5.5, Pb(II) adsorption increased while Cd(II) and Zn(II) adsorption increased till an initial pH of 3.0. Positive ΔH° values confirmed the adsorption process to be endothermic and positive ΔS° values suggest the increased randomness at the solid-solution interface during the adsorption of cations on the sample. The adsorption data showed good fit to both Langmuir and Freundlich isotherm models for the three cations. The Langmuir monolayer capacities for Pb(II), Cd(II) and Zn(II) were estimated to be ~142.85, 59.17 and 98.0 mg per gram of LMO sample respectively. From the XRD studies of loaded samples, it was observed that Pb((II) adsorption affects silica phase whereas Cd(II) adsorption affects both silica and β-MnO 2 phases. With Zn(II) adsorption both the intensity and peak position of silica phase were disturbed. From the electron probe micro analysis (EPMA) it was observed that Pb(II), Cd(II) and Zn(II) adsorption are more prone to silica, iron oxide and β-MnO 2 phase respectively though their distribution in other phases was also marked but to a lesser extent. Due to high loading capacities obtained for Pb(II) and Zn(II), low grade manganese ore can be regarded as a potential adsorbent for these metals.

ORR Electrocatalysis on Cr3+, Fe2+, Co2+-Doped Manganese(IV) Oxides

“…It is worth noting that CoOOH (heterogenite, P bnm; PDF-2 card #26-0480, a = 0.4353, b = 0.9402, c = 0.2840 nm) is isostructural to MnOOH (PDF-2 card #24-0713, a = 0.4560, b = 0.1070, c = 0.2870 nm), and ramsdellite MnO 2 polymorph (PDF-2 card #82-2169, a = 0.9322, b = 0.445, c = 0.2848 nm). Goethite, α-FeO(OH), also exhibits an orthorhombic symmetry (Pnma) with unit cell parameters a = 0.995, b = 0.301, c = 0.462 nm unlike CrOOH [41]. The existence of solid solutions of manganese and cobalt of oxide-hydroxide nature was additionally confirmed by our further XRD analysis of data for heavy doped by cobalt samples of manganese dioxide published in [42].…”

One step paired electrochemical synthesis of iron and iron oxide nanoparticles

“…The average size of the particles was in agreement with the SEM and TEM results. Because of special electrical and magnetic properties of iron, which is ferromagnetic, and iron oxide, which is weakly ferromagnetic, these nanoparticles have a variety of applications [3,4]. The saturation magnetization (M s ) of nanoparticles depends on the size and morphology of the particles and at room temperature decreases with reduction of particle size [17].…”

“…Iron and iron oxides are widely used nanomaterials in various fields, including catalysts, pigments, coatings, gas sensors, sorbents in water and wastewater treatments, magnetic data storage devices in electronics, audio and video recording and drug delivery in medicine [3,4]. There are various methods to prepare iron and iron oxide * E-mail: ordoukhanian@pnu.ac.ir nanoparticles such as chemical precipitation [5,6], thermal decomposition of organometallic compounds [7,8], gas phase condensation [9], solgel [10], microemulsion [11] and electrochemical techniques [12,13].…”

Synthesis of iron oxide nanoparticles in a continuous flow spiral microreactor and Corning® advanced flow™ reactor

“…The colloidal NPs have applications in a variety of fields including biosensors, catalysis, targeted drug delivery system, detection of genes, conducting inks, magnetic resonance imaging, energy storage devices such as fuel cells, batteries etc., medical diagnostics, and antimicrobial agents [2][3][4][5][6][7][8][9][10][11][12][13]. In recent years, interest in the efficient synthesis of magnetic iron oxide NPs has increased significantly due to the wide range of applications in the field of magnetic storage devices, chemical processing industries, biotechnology, water purification, and biomedical applications like thermal therapy, chemotherapy, diagnostic magnetic resonance imaging, magnetofection, and drug delivery [12][13][14][15][16][17][18][19][20][21]. The common forms of iron oxide generally found are maghemite (γ-Fe 2 O 3 ), hematite (α-Fe 2 O 3 ), magnetite (Fe 3 O 4 ), and oxo-hydroxide (FeOOH) [22,23].…”