Removal of some fungicides from aqueous solution by the biopolymer chitin

The adsorption of 4,4'-iso-propylidene diphenol (BPA), and diphenylolpropane 4,4'-dioxyaceticacid (BPAc) onto chitin has been investigated at 298.15 K. The uptake of BPA and BPAc from aqueous solutions has been determined by UV-visible spectroscopy. Adsorption isothermal data was interpreted by the Freundlich, Langmuir, BET, D-R and F-H equations. The constants of these equations have been determined. The rate of kinetic processes of BPA and BPAc onto chitin was described by using three kinetics adsorption models. The pseudo-first-order model and intraparticle diffusion were the best choice among the kinetic models to describe the adsorption behaviour of BPA and BPAc onto chitin. (c) 2006 Elsevier B.V. All rights reserved

Hydrolytic Behavior of La3+ and Sm3+ at Various Temperatures

The hydrolytic species of lanthanide ions, La3+ and Sm3+, in water at I = 0.1 mol center dot dm(-3) KCl ionic strength and temperatures of 298.15, 310.15 and 318.15 K were investigated by potentiometry. The hydrolytic species were modeled by the HySS simulation program. From the results, the hydrolytic species of each metal ion at different temperatures were calculated using the program HYPERQUAD2013. The hydrolysis constants (log(10) beta) of [La(OH)](2+) and La(OH)(3) were calculated as -8.52 +/- 0.46, -26.84 +/- 0.48, and log(10) beta values of [Sm(OH)](2+), [Sm(OH)(2)](+), Sm(OH)(3) were calculated as -7.11 +/- 0.21, -15.84 +/- 0.25 and -23.44 +/- 0.52 in aqueous media at 298.15 K, respectively. The dependence of the hydrolysis constants on the temperature allowed us to calculate the enthalpy, entropy, and Gibbs energy of hydrolysis values of each species

Adsorption kinetics of diazo-dye from aqueous solutions by using natural origin low-cost biosorbents

In the present study, the adsorption of diazo-dye onto natural origin low-cost biosorbents prepared from pyrolyzed petrified sediment (PPS), pyrolyzed sawdust from maple bark and chitin was investigated in aqueous solution. Trypan blue (TrB) was used as diazo-dye during the adsorption process. Effects of the operational parameters as contact time and type of adsorbents for the removal of TrB were studied using a batch process. The intraparticle diffusion model, the pseudo-first-order and the pseudo-second-order models were used to examine the kinetic data. Dynamic data of the dye adsorption were also fitted to the intraparticle diffusion model well. The order of the uptaken capacities of dye on these adsorbents was found as chitin > petrified sediment > maple sawdust. Langmuir, Freundlich, Temkin models were employed for fitting the equilibrium adsorption data of TrB. Langmuir and Temkin isotherms were found to represent the data best for the adsorption of TrB onto these adsorbents. The adsorption capacities of the adsorbents PPS, pyrolyzed maple bark sawdust and chitin were obtained to be 345, 72.5, 122 mg g(-1) at 298 K, respectively

Single and binary adsorption of reactive dyes from aqueous solutions onto clinoptilolite

The adsorption of Reactive Blue 21 (RB21) and Reactive Red 195 (RR195) onto clinoptilolite type natural zeolite (ZEC) has been investigated at 298.15K. The uptake of single and binary reactive dyes from aqueous solutions has been determined by UV-vis spectroscopy. Two mono-component (RB21 and RR195) and binary component (RB21 with RR195, and RR195 with RB21), isotherms were determined. The mono-component Langmuir isotherm model was applied to experimental data and the isotherm constants were calculated for RB21 and RR195 dyes. The monolayer coverage capacities of clinoptilolite for RB21 and RR195 dyes in single solution system were found as 9.652 and 3.186 mg/g, respectively. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir models. The rate of kinetic processes of single and binary dye systems onto clinoptilolite was described by using two kinetics adsorption models. The pseudo-second-order model was the best choice among the kinetic models to describe the adsorption behaviour of single and binary dyes onto clinoptilolite. (c) 2010 Elsevier B.V. All rights reserved

Leucine Complexes with Cerium: Stability Constants and Thermodynamic Parameters

The complexation of leucine (Leu) with Ce3+ was investigated using the potentiometric method at different ionic strengths (I = (0.10 and 1.00) mol dm(-3)) in KCl medium at elevated temperatures. The stability constants of the leucine complexes with Ce3+ at metal:ligand (M:L) molar ratios of 1:1, 1:3, and 1:5 were determined. From the data obtained, stability constants were calculated using the program HYPERQUAD2006 for proton-ligand and metal-ligand species. The formation of monomeric species was taken into consideration for Ce3+ at (25, 37, and 45)degrees C. Thermodynamic parameters were calculated for all possible leucine complexes. In conclusion, it is indicated that the formation of complexes change the value of the stability constants at various ionic strengths and temperatures

1 : 1 binary complexes of citric acid with some metal ions: Stability and thermodynamic parameters

The stability constants of the 1:1 binary complexes of citric acid with Cu2+, Ni2+ CO2+ Mn2+ and Ce3+ were determined potentiometrically at 15.0, 25.0, and 35.0 degrees C and at an ionic strength of 0.10 mol L-1 (NaClO4). UV-VIS spectroscopic studies were also performed in order to confirm the complexes formation and the stability constants of Cu-citric acid system determined potentiometrically. The thermodynamic parameters, Delta G(o), Delta H-o, and Delta S-o were reported for the complexes formation reactions. The enthalpy and entropy changes of all binary complexes are positive

Preparation of the Poly(styrene) Based Imidazole Containing Quaternary Chloroacetamide Modified Sorbent for Removal of Phenol

Crosslinked copolymer beads were prepared by suspension polymerization of 4-vinylbenzyl chloride (VBC) and ethyleneglycole dimethacrylate (EGDMA) mixtures. The resulting copolymer beads with quaternary amide functions were prepared in two steps: (1) modification of imidazole with PVBC and (2) quaternization of imidazole modified beads with chloroacetamide. The resulting polymer resin, which had a chloroacetamide content of 4.50 mmol/g, was effective in extracting phenol from aqueous solutions. The phenol sorption capacity was around 0.208 g phenol/g resin in non-buffered conditions. The adsorption conditions (initial phenol concentration and pH) were varied to evaluate the mechanism of adsorption of phenol on the prepared resin. This resin is also able to remove phenol completely even from highly diluted aqueous phenol solutions

Anti-proliferative and antitumor activity of organotin(IV) compounds. An overview of the last decade and future perspectives

Organotins(IV) exhibit significant in vitro anti-proliferative activity, while the in vivo tests are encouraging. The recent reports on the anti-proliferative activity of organotin(IV) compounds are summarized in this review. The period covered by this work goes back to 2009 until late 2018, while the earlier ones, are included over the previous review of our group published by S.K. Hadjikakou, N. Hadjiliadis, in Coord Chem Rev, 253 (2009) 235-249. During the last decade (2009-2018), > 300 organotin(IV) derivatives with oxygen-donor ligands, such as carboxylic acids, amino-acids, Non Steroidal Anti-inflammatory Drugs (NSAIDs), biological active derivatives or natural products, organotins(IV) with sulfur containing ligands such as thiones, thiosemicarbazones, dithiocarbamates, organotin(IV) compounds of oximes and organotins(IV) with amines or semicarbazones were screened for their anti-proliferative effect against various cancer cell lines and their results are included in numerous reports over this period. Although much work has been carried out on organotin(IV) derivatives with O-donor ligands, however significant fewer reports are found on organotins(IV) with oximes as ligands