Isotherm, Kinetics and Thermodynamics of Cu(II) and Pb(II) Adsorption on Groundwater Treatment Sludge-Derived Manganese Dioxide for Wastewater Treatment Applications

Abstract

The ubiquitous occurrence of heavy metals in the aquatic environment remains a serious environmental and health issue. The recovery of metals from wastes and their use for the abatement of toxic heavy metals from contaminated waters appear to be practical approaches. In this study, manganese was recovered from groundwater treatment sludge via reductive acid leaching and converted into spherical aggregates of high-purity MnO2. The as-synthesized MnO2 was used to adsorb Cu(II) and Pb(II) from single-component metal solutions. High metal uptake of 119.90 mg g−1 for Cu(II) and 177.89 mg g−1 for Pb(II) was attained at initial metal ion concentration, solution pH, and temperature of 200 mg L−1, 5.0, and 25 °C, respectively. The Langmuir isotherm model best described the equilibrium metal adsorption, indicating that a single layer of Cu(II) or Pb(II) was formed on the surface of the MnO2 adsorbent. The pseudo-second-order model adequately fit the Cu(II) and Pb(II) kinetic data confirming that chemisorption was the rate-limiting step. Thermodynamic studies revealed that Cu(II) or Pb(II) adsorption onto MnO2 was spontaneous, endothermic, and had increased randomness. Overall, the use of MnO2 prepared from groundwater treatment sludge is an effective, economical, and environmentally sustainable substitute to expensive reagents for toxic metal ion removal from water matrices.

Nonlinear Isotherm and Kinetic Modeling of Cu(II) and Pb(II) Uptake from Water by MnFe2O4/Chitosan Nanoadsorbents

“…Adsorption, however, remains a feasible alternative, especially in developing countries, because it is environmentally benign, simple, inexpensive, and does not produce large sludge quantities [15]. In recent decades, various natural and synthetic adsorbents have been examined for their ability to remove heavy metals from contaminated solutions [16][17][18][19], yet separating these adsorbents from the water matrix entails a complex process and additional cost.…”

Activated Olive Stones as a Low-Cost and Environmentally Friendly Adsorbent for Removing Cephalosporin C from Aqueous Solutions

“…The amount of CPC loaded onto the AOS at any time t, q t (mg/g), and at equilibrium, q e (mg/g), was estimated from the following relationships [ 38 ]: where C 0 , C e and C t are the initial, equilibrium and time t concentrations of CPC in the solution (mg/L), V is the volume of CPC solution (L), and m is the mass of adsorbent (g). Data obtained from these experiments were used to test the different equilibrium, kinetic, and adsorption mechanism models and to obtain the thermodynamic parameters.…”

“…The amount of CPC loaded onto the AOS at any time t, q t (mg/g), and at equilibrium, q e (mg/g), was estimated from the following relationships [38]:…”

Simultaneous Removal of Metal Ions from Wastewater by a Greener Approach

“…Adsorption, in any case, remains a feasible alternative, particularly in developing nations, since it is environmentally benign, simple, inexpensive, and does not produce large sludge quantities [11,12]. In recent decades, various natural and manufactured adsorbents have been examined for their ability to eliminate heavy metals from contaminated solutions [13][14][15][16][17][18][19][20]; however, separating these adsorbents from the aqueous solution entails a complex process with additional costs, and structure stability should be emphasized [20].…”