Regeneration of spent activated carbon obtained from home filtration system and applying it for heavy metals adsorption. Issue 4 (August 2017)

• Record Type: Journal Article
• Authors: Da'na, Enshirah; Awad, Awatif
• Is Part Of: Journal of environmental chemical engineering. Volume 5:Issue 4(2017:Dec.)
• Page Start: 3091
• Page End: 3099
• Publication Date: 2017-08
• Subjects: AC regenerated activated carbon -- pHZCP zero charge point -- pHi initial pH -- pHe equilibrium pH -- q adsorption capacity (mg g−1) -- qe equilibrium adsorption capacity (mg g−1) -- qm monolayer adsorption capacity (mg L−1) -- qt Cu2+adsorbed (mg g−1) at time t -- V solution volume (L) -- C iInitial concentrations (mg L−1) -- Ce equilibrium concentrations (mg L−1) -- m adsorbent weight (g) -- MCu copper molecular weight (g/mol) -- KL langmuir constant (L g−1) -- KF freundlich dimensionless constant -- Kd equilibrium dimensionless distribution coefficient -- kp1 pseudo first-order adsorption rate constant (min−1) -- kp2 pseudo second-order adsorption rate constant (g mg−1 min−1) -- kid intraparticle diffusion rate constant (mg g−1 min−0.5) -- n Freundlich dimensionless constant -- ΔH° change in enthalpy (KJ mol−1) -- ΔS° change in enthalpy (J mol−1 K−1) -- ΔG° change in Gibbs free energy (KJ mol−1) -- R ideal gas constant (8.314 JK−1 mol−1) -- T temperature (K); Activated carbon -- Adsorbent -- Adsorption -- Desorption -- Heavy metals -- Regeneration; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2017.06.022
• Languages: English
• ISSNs: 2213-2929

Abstract

Highlights: Spent activated carbon from home filters is environmental problem. Chemical regeneration of spent activated carbon is promising. Regenerated activated carbon did not lose its adsorption ability. Copper adsorption is exothermic and follow pseudo second order model. After ten successive adsorption desorption cycles only 13.3% capacity lost. Abstract: Recently, important progress has been achieved in adsorption of heavy metals from wastewater. However, recycling of the spent adsorbents did not get much attention. Thus, the main goal of this contribution is to address the feasibility of recovering spent activated carbon collected from exhausted home filtration systems. Spent activated carbon was regenerated by acidic-basic treatment. The regenerated activated carbon was tested for adsorption of copper under different conditions including: Temperature, initial concentration, mass of adsorbent, solution pH, and time. Results indicated that Cu 2+ uptake dramatically increased by increasing initial concentration, pH (up to 5.5), and decreasing temperature from 333 K to 293 K. Thermodynamic analysis indicated a spontaneous (ΔG° < 0) and exothermic (ΔH° < 0) process. Both Freundlich and Langmuir isotherms fitted Cu 2+ adsorption on regenerated activated carbon indicating that both physical and chemical adsorption contribute in the separation process. Kinetic analysis revealed that pseudo first-order model is better in fitting results than pseudo second-order model with R 2 value of 0.982 compared to 0.974 for the pseudo second-order model. Furthermore, intraparticle model showed that adsorption of copper occurs in three steps including boundary layer diffusion, porous diffusion, and adsorption on the surface. After ten successive adsorption-desorption sequences, the adsorption efficiency was 87% of the first cycle.