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Osman Gulnaz

Publications and source records attributed to Osman Gulnaz.

6 recordsLinked to original sources
PubMed2005

The reuse of dried activated sludge for adsorption of reactive dye.

Adsorption processes are alternative effective methods for removal of textile dyes from aqueous solutions. The adsorption ability of adsorbent affects by physico-chemical environment for this reason in this paper effect of initial pH, dye concentrations, temperature and dye hydrolyzation were determined in a batch system for removal of reactive dye by dried activated sludge. The Langmuir isotherm model was well described of adsorption reactive dye and maximum monolayer adsorption capacity (at pH 2) of activated sludge was determined as 116, 93 and 71mgg(-1) for 20 degrees , 35 degrees and 50 degrees C, respectively. Initial pH 2, 20 degrees C and 30min contact time are suitable for removal of reactive dyes from aqueous solutions. Activated sludge was characterized by FT-IR analysis and results showed that active sludge has different functional groups and functional groups of activated sludge are able to react with dye molecules in aqueous solution. The pseudo first-order, second-order and intraparticle diffusion kinetics were used to describe the kinetic data. The pseudo second-order kinetic model was fit well over the range of contact times and also an intra particle diffusion kinetic model was fit well but in the first 30min. The dye hydrolyzation was affected adsorption capacity of biomass and adsorption capacity of biomass decreased with dye hydrolyzation from 74 to 38mgg(-1).

Adsorption↗
PubMed2005

Adsorption of Cd(II), Cu(II) and Ni(II) ions by Lemna minor L.: effect of physicochemical environment.

The free floating macrophyte Lemna minor L. was harvested locally. Untreated, acid pretreated (H2SO4), alkali pretreated (NaOH) biomass were used for adsorption of copper, cadmium and nickel ions from aqueous solutions. The effect of initial pH, initial metal concentration and multi metal interaction were carried out in a batch system. The equilibrium adsorption was reached within 40-60 min. The Langmuir and Freundlich models were used for describing of adsorption isotherm data. The maximum adsorption capacities of alkali pretreated biomass were determined as 83, 69 and 59 mg g(-1) for the Cd(II), Cu(II) and Ni(II) ions, respectively. The pseudo first- and second-order intraparticle diffusion models were used to describe the adsorption kinetics. The experimental data fitted to pseudo second-order kinetic. Adsorption capacity decreased with acid pretreatment; however alkali pretreatment was not affected significantly adsorption capacity and adsorption capacity a little increased according to native biomass. The FT-IR results of Lemna biomass showed that biomass has different functional groups and these functional groups are able to react with metal ions in aqueous solution.

Adsorption↗
PubMed2005

Study of Cu(II) biosorption by dried activated sludge: effect of physico-chemical environment and kinetics study.

Biosorption is a recent technology used to remove heavy metal ions from aqueous solutions. The biosorption of copper ions from aqueous solution by dried activated sludge was investigated in batch systems. Effect of solution pH, initial metal concentration and particle size range were determined. The suitable pH and temperature for studied conditions were determined as 4.0 and 20 degrees C, respectively. The theoretical max biosorption capacity of activated sludge was 294 mg g-1 at 20 degrees C for <0.063 mm particle size. The equilibrium data fitted very well to both Langmuir and Freundlich isotherm models. The pseudo first and second-order kinetic models were used to describe the kinetic data. The experimental data fitted to second-order kinetic model. The particle size and initial metal concentration were effected the biosorption capacity of dried activated sludge. An increase in the initial metal concentration increases of biosorption capacity, which also increases with decreasing particle size. Dried activated sludge has different functional groups according to the FT-IR results.

Adsorption↗
PubMed2004

Comparison of several advanced oxidation processes for the decolorization of Reactive Red 120 azo dye in aqueous solution.

In this study UV/TiO2, electro-Fenton (EF), wet-air oxidation (WAO), and UV/electro-Fenton (UV/EF) advanced oxidation processes (AOPs) have been applied to degrade Reactive Red 120 (RR120) dye in aqueous solution. The most efficient method on decolorization and mineralization of RR120 was observed to be WAO process. Photocatalytic degradation of RR120 by UV/TiO2 have been studied at different pH values. At pH 3 photocatalytic degradation kinetics of RR120 successfully fitted to Langmuir-Hinshelwood (L-H) kinetics model. The values of second order degradation rate (k") constant and adsorption constant (K) were determined as 4.525 mg L(-1) min(-1) and 0.387 L mg(-1), respectively. Decolorization efficiency observed in the order of WAO > UV/TiO2 = UV/EF > EF while WAO > UV/TiO2 > UV/EF > EF order was observed in TOC removal (mineralization). For all AOPs, it was found that degradation products in reaction mixture can be disposed safely to environment after 90 min treatment.

Adsorption↗
PubMed2004

Sorption of basic dyes from aqueous solution by activated sludge.

The adsorption of dyes in the solutions using activated sludge might be a promising approach in wastewater treatment units. The adsorption of Basic Red 18 and Basic Blue 9 from aqueous solution by dried activated sludge was investigated with in a batch system. The activated sludge had the highest dye uptake capacity, having the monolayer adsorption capacity 285.71 and 256.41 mg g(-1) for Basic Red 18 and Basic Blue 9, respectively, at pH value of 7.0 and 20 degrees C. Langmuir and Freundlich adsorption models were used for the mathematical description of the adsorption equilibrium and the equilibrium data fixed very well with both the Langmuir and Freundlich models. The R(L) values showed that, activated sludge was favorable for the adsorption of basic dyes. The suitability of the kinetic models for the adsorption of dyes on the activated sludge was also discussed. It was clear that the adsorption kinetics of dyes to dried activated sludge obeyed pseudo second-order adsorption kinetics.

Adsorption↗