Yusuf Kaya

Biosorption of chromium(VI) from aqueous solution by cone biomass of Pinus sylvestris

Biosorption of chromium(VI) on to cone biomass of Pinus sylvestris was studied with variation in the parameters of pH, initial metal ion concentration and agitation speed. The biosorption of Cr(VI) was increased when pH of the solution was decreased from 7.0 to 1.0. The maximum chromium biosorption occurred at 150 rpm agitation. An increase in chromium/biomass ratio caused a decrease in the biosorption efficiency. The adsorption constants were found from the Freundlich isotherm at 25 degrees C. The cone biomass, which is a readily available biosorbent, was found suitable for removing chromium from aqueous solution.

Biosorption of lead (II) from aqueous solution by cone biomass of Pinus sylvestris

Abstract Biosorption of lead (II) onto a cone biomass of Pinus sylvestris was studied with variation in the parameters of pH, initial metal ion concentration and impeller speeds. Lead removal rate was increased at pH 4.0 and was sharply decreased when pH of the solution was decreased to 2.0. Impeller speed studies indicated maximum lead biosorption at 150 rpm and the biosorption equilibrium was established after about 1 h. The adsorption constants were found from the Freundlich isotherm at 25°C. An increase in lead/biomass ratio caused a decrease in biosorption efficiency. The cone biomass, which is a readily available biosorbent, was found suitable for removing of lead in aqueous solution.

Application of Eriobotrya japonica (Thunb.) Lindley (Loquat) seed biomass as a new biosorbent for the removal of malachite green from aqueous solution

A new biosorbent, Eriobotrya japonica (loquat) seed biomass, has been investigated in order to remove malachite green (MG) from aqueous solutions. The factors affecting the biosorption process such as adsorbent dosage, pH of the solution and contact time were studied. The results showed that as the dose of loquat seed increased, the percentage of MG biosorption decreased accordingly. The experimental data suggested that the maximum pH for efficient biosorption of MG was 5.0. The biosorption process was relatively fast and equilibrium was achieved after about 60 min. Freundlich and Langmuir adsorption isotherm models were used for adsorption equilibrium data and based on the Langmuir isotherm plots the maximum bisorption capacity (Q(max)) value was calculated to be 57.47 mg/g at 20 degrees C. The biosorption kinetics was determined by fitting pseudo-first-order and pseudo-second-order kinetic models to the experimental data, with the second-order model providing the best description of MG biosorption onto loquat seed. Various thermodynamic parameters such as free energy change DeltaG(0), enthalpy of sorption DeltaH(0) and entropy DeltaS(0) were estimated. The positive value of DeltaH(0) and negative values of DeltaG(0) show the sorption process is endothermic and spontaneous. The positive value of DeltaS(0) shows the increased randomness at the solid-liquid interface during the biosorption of dyes onto loquat seed.

Some environmental aspects of marine disposal systems with particular reference to UK waters

Abstract Disposal to the marine environment is generally regarded as an effective means of disposing of sewage effluent. In recent years legislation has been introduced to enable marine disposal in a more controlled and environmentally acceptable manner. The discharger must prove to the regulatory authorities that the proposed discharges comply with the relevant legislation. This paper concentrates on the environmental aspects of marine disposal systems and gives examples from the UK. Emphasis is given to mathematical modelling techniques used to assess compliance with relevant legislation. Data requirements for model set up and calibration are discussed, together with assessment of the level of calibration achieved for two specific coastal applications. An improved representation of wind stress effects on the water column and requirements for a special radiation condition at open boundaries to render the boundary transparent to outgoing transients are also discussed.

Phytotoxical effect of Lepidium draba L. extracts on the germination and growth of monocot (Zea mays L.) and dicot (Amaranthus retroflexus L.) seeds

Laboratory experiments were performed to determine phytotoxic potentials of white top (Lepidium draba) methanol extracts (root, stem and leaf) on germination and early growth of corn (Zea mays) and redroot pigweed (Amaranthus retroflexus). Furthermore, the effects of different methanol extracts of L. draba on the phytohormone (indole-3-acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA) and zeatin) levels of corn and redroot pigweed were investigated. It was observed that all concentrations of methanol extracts of root, stem and leaf of L. draba inhibited germination, radicle and plumule elongation when compared with the respective controls. Besides this, the degree of inhibition was increased in concert with increasing concentrations of extracts used. On the other hand, phytohormone levels changed with the application of different extract concentrations. Comparing with the control, the GA levels significantly decreased while the ABA levels increased in all the application groups. Zeatin and IAA levels showed changes depending upon the applied extracts and concentrations.

Acute irritant contact dermatitis caused by Plantago major

Plantago major, also known as plantain, is a weed found in temperate zones worldwide. P. major leaves have been associated with various biological properties ranging from anti-inflammatory, antimicrobial, and anti-tumour to wound healing (1). Acute irritant contact dermatitis is the most frequent type of plantrelated dermatitis, but as reactions of this type have not previously been recorded in the literature from P. major, we present two cases here.

Genetic diversity within and among Lepidium draba populations from Eastern Anatolia based on RAPD analysis.

Genetic variation and structure of six natural populations of Lepidium draba L. from Eastern Anatolia were assessed using random amplified polymorphic DNA (RAPD) markers. For RAPD analysis, 12 primers generated 218 reproducible bands across the six populations analyzed, of which 73 bands (33.3%) were polymorphic. The mean Nei’s gene diversity value for all six populations was 0.1771. Shannon’s information index varied with population (0.2278–0.3082), averaging 0.2608. Analysis of molecular variance (AMOVA) showed that genetic diversity was greater within populations (58.66%) than among populations (30.68%). In addition, the variation between groups was 10.33%. The genetic differentiation among populations (GST) was 0.3210, indicating that most genetic diversity occurs within populations. Gene flow (Nm) was low, at only 0.5288.