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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]

Abstract: In this work, the treatment of paper machine whitewater obtained from paper production by using loose and tight Nanofiltration (NF) membranes in a lab-scale plant with a plate and frame module was investigated. The NF membranes were evaluated for fouling, flux decline due to concentration polarization and their suitability for removing of components present in wastewater. The loose NF membrane was used for the first step under different transmembrane pressure (8 to 32bars) and pH (3, 5.6 and 10) values. The best filtration performances were provided under a pressure of 32bar and a pH of 5.6. The fouling mechanism at different transmembrane pressures and pH values was investigated by “Hermia''s model”. Also, fouling on pores and on the surface of NF membranes was characterized by Scanning electron microscopy (SEM) and contact angle measurements, respectively. For the advanced treatment of permeate obtained from the loose NF membrane that provided the lowest fouling and flux decline, a tight NF membrane was used in the second step. Even better retentions were achieved from experiments with this NF membrane. Results obtained in this study showed that the combination loose and tight NF membranes achieved reuse of paper machine white water for use as shower water of paper machine. [Copyright &y& Elsevier]

Adsorption beds containing granular activated carbon and organic polymer resin are used widely to remove organic pollutants from wastewaters and water streams. Adsorption polymers are becoming alternatives to activated carbon for removal of surfactants by adsorption techniques. This study investigated the adsorption characteristics of cetyl trimethylammonium bromide (CTAB) as a cationic surfactant for selected concentrations below and above critical micelle concentration (CMC). A series of column tests were performed to determine the breakthrough curves by using two different adsorbents: (1) Hydraffin CC 8 x 30 as a commercial granular activated carbon (GAC) and (2) Lewatit VPOC 1064 MD PH as a commercial organic polymer resin. In the experiments, the volumetric flow rate was maintained at 10.5 mL/min (approximately 2 m3/ m2 x h). Loading of adsorbents was continued until breakthrough was 10% of the feed concentration. The breakthrough took place at 488 bed volume (BV) below CMC (C0 = 40 mg/L) and 39 BV above CMC (C0 = 400 mg/ L) onto GAC. The organic polymer resin, however, showed a higher adsorption capacity than GAC (1412 BV below CMC and 287 BV above CMC). From the Logit method, the value of adsorption rate coefficient (K) and adsorption capacity coefficient (N) were obtained.

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.

Samples of 12 edible fish species from the Marmara Sea were analyzed for organochlorines (PCBs, DDTs, HCB, HCHs, toxaphene, etc.). The results showed that the total concentrations ranged from 329.41 ng/g fat to 1453.87 ng/g fat. DDT group components made up almost half or more of organochlorine contamination. Levels in red mullet were compared with those from neighbor seas. The sum of DDTs as well as HCHs concentrations were markedly lower than in the Black Sea but higher in the Aegean Sea and Mediterranean. Thus, inflow from the Black Sea might be considered as a contamination source for DDT and HCH contamination. On the other hand, total PCB concentration (sum of congeners 28, 52, 101, 118, 138, 153 and 180) detected in this study was comparable or lower than those from the Aegean Sea and Mediterranean. Toxaphene was a minor contaminant. Measured values were below maximum residue levels for human consumption.