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The adsorption of a cationic (CTAB, cetyl trimethylammonium bromide) and an anionic surfactant (SLES, sodium dodecylethersulfate) from aqueous solution onto organic polymer resin (Lewatit VPOC 1064 MD PH) was studied. A series of batch experiments were performed to determine the sorption isotherms of surfactants to organic polymer resin. The experimental studies were analyzed by Langmuir and Freundlich isotherms. Furthermore, the isotherm parameters, average percentage errors (epsilon) of model data, and separation factor (R (L)) were calculated. Other factors influencing the adsorption capacity (contact time, adsorbent amount, and initial surfactant concentration) were also discussed. The experimental data fitted very well to the Langmuir equilibrium model in the studied concentration range. The calculated R (L) values showed that the adsorption of both surfactants were favorable. Among the surfactants, CTAB showed higher adsorption capacity onto organic polymer resin compared to SLES (Q (0) = 250 and 34.36 mg g(-1), respectively).

Ion-exchange is an alternative process for uptake of heavy metals from aqueous solutions. In the present study, the sorption of nickel(II) ions from aqueous solution was investigated by using Lewatit MonoPlus SP 112 (strongly acidic, macroporous cation-exchange resin) in a batch adsorption system as a function of pH (2.0-8.0), initial nickel concentration (50-200 mg/L), resin dosage (0.5-2.0 g/L), contact time (0.5-3h), and temperatures (298-318K). The data were analyzed on the basis of Lagergren pseudo-first order, pseudo-second order (Types 1-5), Elovich and external, Weber-Morris intraparticle, pore-surface mass diffusion models. The experimental data showed that the maximum pH for efficient sorption of nickel(II) was 6.0. At the optimal conditions, nickel(II) ions sorption on the resin was decreased when the initial metal concentration increased. The results indicated that the resin dosage strongly affected the amount of nickel(II) ions removed from aqueous solution. The adsorption process was very fast due to 80% of nickel(II) sorption was occurred within 30 min and equilibrium was reached at about 90 min. Freundlich and Langmuir adsorption isotherm models were used for sorption equilibrium data and the maximum adsorption capacity (171 mg/g) of Lewatit MonoPlus SP 112 was obtained from Langmuir isotherm. The thermodynamic parameters (DeltaG degrees, free energy change; DeltaS degrees, enthalpy change; and DeltaH degrees, entropy change) for sorption of nickel(II) ions were evaluated. The rise in temperature caused a partly increase in the value of the equilibrium constant (K(c)) for the sorption of nickel(II) ions. Moreover, column flow adsorption study was also studied. Breakthrough curves were obtained from column flow studies by using both synthetic solution and rinsing bath water of filter industry. The column regeneration was carried out for two sorption-desorption cycles. The eluant used for regeneration of the cation-exchange resin was 7% (w/w) HCl. The experimental results demonstrated that Lewatit MonoPlus SP 112 cation-exchange resin could be used effectively for the removal of nickel(II) ions from aqueous medium.

Abstract: The objective of this study was to investigate the use of organic polymer resin Lewatit VP OC 1163 to remove the pesticides MCPA, 2,4-D, and Metalaxyl. Freundlich and Langmuir isotherm models were applied to experimental equilibrium data obtained from three measurements (SAC254, COD, and KMnO4 Demand) of pesticide adsorption. The adsorption capacities of the pesticides studied followed the order: Metalaxyl>2,4-D>MCPA. S-type isotherms were obtained, which indicates a moderate interaction between adsorbate molecules and adsorbent. A series of column tests were performed to determine the breakthrough curves using organic polymer resin Lewatit VP OC 1163. The good adsorbability of Metalaxyl on Lewatit VP OC 1163 could be confirmed by the column experiments. The ionic characters of MCPA and 2,4-D are responsible for the short breakthrough times in the Lewatit VP OC 1163 column. It has been concluded that lower the pK a value, the greater is the adsorption for the uncharged (neutral) organic polymer resin. The key parameters that can be derived from this overview are thus, in order of relative influence: pK a, solubility, and hydrophobicity. [Copyright &y& Elsevier]