Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

Abstract

Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II).

Optimization of synthesis condition for carboxymethyl cellulose‐based hydrogel from rice straw by microwave‐assisted method and its application in heavy metal ions removal

“…On the other hand, the negative value of Δ S ° suggests that decreased randomness at the solid–liquid interface during adsorption of Fe 3+ ions onto CMC‐g‐AMPS hydrogel. The result is similar to previous studies . In addition, the negative value of Δ S ° also reflects the poor affinity of Fe 3+ ion towards CMC‐g‐AMPS hydrogel .…”

“…The decrease of q e with the rise in temperature results in increased mobility of the ions and a decrease in the retarding force acting on the removal ions. This result may also confirm the exothermic nature of CMC‐g‐AMPS hydrogel …”

“…Figure shows that the adsorption capacity of CMC‐g‐AMPS hydrogel for Cu 2+ , Pb 2+ and Fe 3+ ions increased with increasing initial heavy metal ions concentration from 25 to 2200 mg L ‐1 , after which the adsorption capacity remained nearly constant. These results were due to an increasing amount of metal ion concentration accelerating the diffusion of the metal ion into the polymeric network because of the enhanced driving force of the concentration gradient . The equilibrium adsorption data of Cu 2+ , Pb 2+ and Fe 3+ were subjected to two different adsorption isotherms, namely, Langmuir and Freundlich isotherms.…”

“…These results were due to an increasing amount of metal ion concentration accelerating the diffusion of the metal ion into the polymeric network because of the enhanced driving force of the concentration gradient. 46,47 The equilibrium adsorption data of Cu 2+ , Pb 2+ and Fe 3+ were subjected to two different adsorption isotherms, namely, Langmuir and Freundlich isotherms. The Langmuir isotherm equation is the most commonly used for monolayer adsorption on the surface with a finite number of identical sites.…”

Adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on photocatalytically modified diatomaceous ceramic adsorbents

“…Pollution of ground and surface waters with toxic metals ions leachate from industries and urban dumpsites is a major problem since most heavy metals like copper, cobalt, cadmium, chromium, lead, etc. are not biodegradable and hence they tend to accumulate in living organisms with an enduring toxic and carcinogenic effect on the body (Pfeiffer 1997;Desai and Kaler 2008;Araya et al 2005;Johnson et al 1992;Moradi et al 2012;Kim et al 2006;Mendy et al 2012). Water pollution and its remediation are principal health issues, and various procedures have been proposed including chemical precipitation, membrane filtration, ion exchange, coagulation, electrocoagulation, and adsorption.…”