Commercial TiO2 P25 was obtained from Evonik. Ultrapure water (18MΩ.cm-1) was used throughout the whole experiments. 2.2. Synthesis of photocatalysts The TiO2 nanoparticles were prepared by the sol-gel method described below: 3.9 ml of TiCl4 was slowly added into 10 milliliter of absolute ethanol in reaction vesel, this reaction performed under fume hood at 0°C with vigorous stirring due to exothermic reaction,the high volatilityof TiCl4and also therelease of hydrogen chloride. Then, water was added dropwise during the mixing process.
Hence, a calcium chloride and cotton were filled inside a drying tube. The condenser was wrapped with parafilm and a paper towel to avoid moistures from entering. The reagent will act as nucleophilic addition to acetone and work up with hydrochloride acid to synthesize 2-methylhexanol. Throughout this process, the solution turns dark grey and develop white precipitates. This step indicate that Grignard reagent was generated, and the extra white precipitates were magnesium.
DMF was used as a solvent and AIBN (0.5% w/w of total monomer) as free radical initiator .The reaction was carried out at 70±2° C for 6 hour with constant stirring. After completion of the process it was cooled to room temperature and resultant polymer solution was poured in the large amount of methanol with stirring when polymer precipitated out. It was filtered and washed with methanol. The polymer was purified by repeated precipitation using methanol from solution in DMF and then it dried. 2.3 Preparation of PS
After 30 minutes, tubes were taken out and kept in ice-cold water for 30 minutes. These were centrifuged at 3000 rpm for 15 minutes. The absorbance of the supernatant was read at 540 nm at room temperature against appropriate blank. Blank consist of 1 ml distilled water, 0.5 ml of 30% TCA, and 0.5 ml of 0.8% TBA. TBARS values were expressed as n moles malonaldehyde (MDA)/mg protein.
To start an experiment of adsorption isotherm, Cu(II) aqueous solution of 100 ml with the predetermined varying initial concentration of Cu(II) in the range of 6.5-370.5 mg/l and the best activator composition of NaOH was put into the erlenmeyer flask and stirred using a magnetic stirrer at 75 rpm, room temperature of 298.15 K (± 2 K), 1 atm and normal pH. The experiment was stopped at 119 mins contact time for sampling. The samples of 1 ml were placed in a 20-ml vial and diluted with 10 ml distilled water, and filtered using a syringe filter. The filtrate was placed in 10-ml vial for the AAS analysis. To determine the concentration Cu(II) in the samples from the AAS reading, dilution factor was taken into
The mixture was finally made upto 5 mL with distilled water and placed in hot water bath at 95ºC for 1 h. After cooling, 1 mL of distilled water and 5 mL of the mixture of n-butanol and pyridine (15:1, v/v) was added. The mixture was vortexed and after centrifugation at 4000 rpm for 10 minutes, the absorbance of the organic layer (upper layer) was measured in UV-Vis spectrophotometer (Shimatzu) at 532 nm against blank using distilled water. TBA when allowed to react with MDA aerobically formed a colored complex [MDA-(TBA) 2 complex] which was measured with spectrophotometer. MDA concentration (measured as TBARS) was calculated as
The electrochemical behaviour of copper-1,10-phenanthroline (phen) complex in aqueous and in water-acetone mixed solutions was studied by CV-thin layer spectroelectrochemistry. In aqueous solution, [Cu(II)(phen)2]2+ complex electrochemically reduced to [Cu(I)(phen)2H2O]+ with maximum absorption at 405nm, and followed by a reversible chemical reaction. The formal potential, E0=0.078V, the number of electron transferred, n=1.0, and the equilibrium constant of the following chemical reaction, K=0.107 (0.005), were determined. In water-acetone mixed solution, [Cu(II)(phen)2]2+ reduced to [Cu(I)(phen)2]+ with maximum absorption at 435 nm. Keywords: CV-thin layer spectroelectrochemistry; copper-1,10-phenanthroline complex 1.
This is given in Equation 15. (dC_A)/dV=r_A/Q (15) Conductivity In the experiment the concentration of the mixture is measured by the means of a conductivity probe. The conductivity referred to in this case is electrical conductivity. This is the ability of ionised compounds to transfer electrical current in an aqueous solution. It is measured in units of mS/cm.
2.2.1 Preparation of sPEG from polyoxyethylene (20) sorbitanmonolaurate (tween-20) Star shaped polyoxyethylene (sPEG) was synthesized according to the literature with some changes . Briefly, 8 g of polyoxyethylene (20) sorbitan monostearatev were dissolved in 20 ml of THF in a round bottom flask and then 1 g of KOH was added as hydrolysis agent. After refluxing about 24 h, the solution was concentrated and added to a mixture of acidic water/hexane (1 : 1). The aqueous phase in which the sPEG is dissolved was separated by a separation funnel from hexane. Next, the aqueous phase was neutralized with HCl and extracted with dichloromethane.
Increase in ions concentration enhances the electrical conductivity of water, and the conductivity of water is an expression of its ability to conduct an electric current. Generally, the amount of dissolved solids in water determines the electrical conductivity. Electrical conductivity (EC) is actually measures the ionic process of a solution that enables it to transmit current, and it is measured in micro-siemens per centimeter (μS/cm). According to WHO standards EC value should not exceeded 400 μS/cm (micro-siemens per centimeter) (Mohsin et al., 2013). It is related to the ionic content of the sample which is in turn a function of dissolved solids concentration, the relevance of easily performed conductivity measurements is apparent.