The photocatalysts of Fe-ACF/TiO2 compositeswere prepared by the sol-gel method and characterizedby BET, XRD, SEM, and EDX. It showed that the BET surface area was related to adsorption capacity foreach composite. The SEM results showed that ferric compound and titanium dioxide were distributed on thesurfaces of ACF. The XRD results showed that Fe-ACF/TiO2 composite only contained an anatase structurewith a Fe mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in Fe-ACF/TiO2 composites. From the photocataytic degradation effect, TiO2 on activated carbon fiber surface modifiedwith Fe (Fe-ACF/TiO2) could work in the photo-Fenton process. It was revealed that the photo-Fenton reactiongives considerable photocatalytic ability for the decomposition of methylene blue (MB) compared to non-treatedACF/TiO2, and the photo-Fenton reaction was improved by the addition of H2O2. It was proved that thedecomposition of MB under UV (365nm) irradiation in the presence of H2O2 predominantly accelerated theoxidation of Fe2+ to Fe3+ and produced a high concentration of OH. radicals.

In this paper, non-treated ACF (Activated Carbon Fiber) /TiO2 and Zn-treated ACF/TiO2 were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/TiO2 composite contained only typical single and clear anatase forms while the Zn-treated ACF/TiO2 contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the ZnCl2 concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/TiO2 composites. The prominent photocatalytic activity of the Zn-treated ACF/TiO2 can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-TiO2 and Zn-ACF.

The photocatalytic degradation of methylene blue(MB) was investigated using TiO2 as photocatalyst and UV radiation. TiO2 supported with activated carbon(AC) was prepared by SOL-GEL method and depended on several parameters such as the mass ratio of TiO2/AC, pH and experimental time. The presence of the anatase and rutile crystal phase was determined by XRD analyses of the prepared TiO2. The degradation of MB with TiO2/AC was about 20% higher than that of AC alone. A variation of photodegradation was negligible under UV radiation conditions ( ≥ 40W). It was experimentally showed that the photodegradation rate was increased with increasing the amount of photocatalyst. The optimal catalyst was prepared by impregmation of 5wt%-TiO2 with AC and was calcined at 300℃, and showed about 99% removal efficiency for 3hrs.

The equilibrium and dynamic adsorption of methylene blue from aqueous solutions by activated carbons have been studied. The equilibrium studies have been carried out on two samples of activated carbon fibres and two samples of granulated activated carbons. These activated carbons have different BET surface areas and are associated with varying amounts of carbon oxygen surface groups. The amounts of these surface groups was enhanced by oxidation with HNO3 and O2 gas at 350℃ and decreased by degassing at increasing temperatures of 400˚, 650˚ and 950℃. The adsorption increases on oxidation of the carbon surface and decreases on degassing. The increase in adsorption has been attributed to the formation of acidic carbon-oxygen surface groups and the decrease in adsorption on degassing to their elimination. The dynamic adsorption studies have been carried out on the two granulated activated carbons using two 50 mm diameter glass columns at a feed concentration of 300 mg/L and at different hydraulic loading rates (HLR) and bed heights. The minimum achievable concentrations are comparatively lower while the adsorption capacities are higher for GAC-S under the same operating conditions. The adsorption capacity of a carbon increases with increase in HLR but the rate of increase decreases at higher HLR values.

Metachromatic properties of admixture of methylene blue(MB) and thionine in aqueous solution has been studied by fluorescence spectroscopy. In spite of nonfluorescence character has been MB itself, mixing MB to monomeric concentration of thionine, new coaggregation band has been formed in shorter wave length than fluorescence of thionine because of MB was redistributed to thionine aggregate. It suggested that coaggregate of MB and thionine were more tightly formed than the each dye aggregate.

Thermograms of methylene blue(MB) in L-α-lecithin vesicle and incorporated purple membrane vesicle(InPM) systems have been studied by photochemical reaction differential scanning calorimetry at 25~55℃. Phase transition temperatures of lecithin vesicle, purple membrane(PM), and InPM were found to be independent of illumination of light(436nm) at 39~40℃, but endothermic phase transition was found in InPM vesicle. In MB-InPM system, endothermic phase transition was found on unillumination of light at 40~42℃, but exothermic phase transition was found on steady illumination of light at 48~52℃. It was estimated that the light energy absorbed from MB on vesicular surface was transferred to PM, and the transferred energy was redistributed to hydrophobic site of membrane. Therefore, the exothermic phase transition was measured at high temperature because of the increased hydrophobicity of acyl chain.

Metachromatic properties of admixture of thionine and methylene blue(MB) in aqueous solution and phospholipid bilayer membrane have been studied by absorption spectroscopy. When thionine and MB were mixed, new coaggregate has been formed because of MB was redistributed to thionine aggregate. In phosphlipid bilayer membrane system, the highly concentrated thionine was easily formed the coaggregation with MB moiety independent of MB concentration, and absorption band of admixture were more transferred to short wavelength than aqueous system. In monomeric thionine concentration, the coaggregation band was observed at the middle wavelength between the site of monomeric thionine and the site of dimeric MB in the presence of lipid bilayer membrane.

Background : For the green approach of nanoparticles synthesizing, plant based technology has been considered as cost-effective and eco-friendly mass production. The oriental medicinal crop, Kalopanax septemlobus (Thunb.) Koidz. (Korean name: 음나무), the deciduous tree and a family of Araliaceae. Endemic tree of Asian countries, K. septemlobus being used for the treatment of various diseases. Phytochemicals of K. septemlobus such as polyphenols has highly probability of reducing agent for biosynthesizing nanoparticles. Methods and Results : In this study, we applied K. septemlobus ZnO nanoparticles (Ks-ZnO NPs) with procedures including green approach one-pot synthesis. For the characterization of nanoparticles, UV–Vis, FTIR, XRD, SEM and TEM were used. The formation of ZnO nanoparticles, the aurface plasmon resonance were observed at 372 ㎚ in UV-Vis spectroscopy. The presence of functional groups which as a capping agent and formation of ZnO nanoparticles were confirmed in FTIR result. The crystallization and morphology showed by XRD, TEM and SEM respectively. The photocatalytic activity of ZnO nanoparticles, was determined using Methylene blue (MB) dye degradation under UV irradiation (365 ㎚) which resulted rate constant is (−k) 0.1215 with 97.5% of degradation in 30 min. Conclusion : The result shows that phytochemicals in K. septemlobus extract have a potential as a reducing agent to form ZnO nanoparticles. The ZnO NPs are capable to degrade MB with in brief time.

The adsorption characteristics of the methylene blue (MB) were studied using three activated carbons such as ACA and ACB with similar specific surface area (1,185 and 1,105 m2/g), and ACC with relatively high specific surface area (1,760 m2/g). The surface chemical properties of these activated carbons were investigated by X-ray photoelectron spectroscopy (XPS). The results indicated that ACA had more functional groups (with phenol, carbonyl, and carboxyl etc.) than ACB (with carbonyl and carboxyl) and ACC (with carboxyl). The isotherm data were fitted well by Langmuir isotherm model. The adsorption capacities of ACA, ACB, and ACC for MB were 454.7 mg/g, 337.7 mg/g, and 414.0 mg/g, respectively. As phenol and carboxyl content of the surface on activated carbon increased, MB adsorption capacity was increased. Although ACA had a smaller specific surface area than ACC, the content of phenol and carboxyl group was abundant, so MB adsorption capacity was found to be higher than ACC.

The adsorption ability of wood-based activated carbon to adsorb methylene blue (MB) and crystal violet (CV) from aqueous solution has been investigated. Adsorption studies were carried out on the batch experiment at different initial MB and CV concentrations (MB=150 mg/L～400 mg/L, CV=50 mg/L～350 mg/L), contact time, and temperature. The results showed that the MB and CV adsorption process followed the pseudo-second-order kinetic and intraparticle diffusion was the rate-limiting step. Adsorption equilibrium data of the adsorption process fitted very well to both Langmuir and Freundlich model. The maximum adsorption capacity (qm) by Langmuir constant was 416.7 mg/g for MB and 462.4 mg/g for CV. The thermodynamic parameters such as ΔH°, ΔS° and ΔG° were evaluated. The MB and CV adsorption process was found to be endothermic for the two dyes.

The efficiency of coal-based activated carbon in removing methylene blue (MB) and phenol from aqueous solution was investigated in batch experiments. The batch adsorption kinetics were described by applying pseudo-first-order, pseudo-second-order, and first order reversible reaction. The results showed that the adsorption of MB and phenol occurs complexed process including external mass transfer and intraparticle diffusion. The maximum adsorption capacity obtained from Langmuir isotherm was 461.0 mg/g for MB and 194.6 mg/g for phenol, respectively. The values of activation parameters such as free energy (△G˚), enthalpy (△H˚), and entropy (△S˚) were also determined as -19.0∼-14.9 kJ/mol, 25.4 kJ/mol, and 135.2 J/mol K for MB and 51.8∼54.1 kJ/mol, -29.0 kJ/mol, and -76.4 kJ/mol K for phenol, respectively. The MB adsorption was found to be endothermic and spontaneous process. However, the CV adsorption was found to be exothermic and non-spontaneous process.

Ti-SBA-15 catalysts doped with samarium ion were synthesized using conventional hydrothermal method. The physical properties of Sm/Ti-SBA-15 catalysts have been characterized by XRD, FT-IR, DRS and PL. In addition, we have also examined the activity of these materials on the photocatalytic decomposition of methylene blue. The Sm/ Ti-SBA-15 was shown to have the mesoporous structure regardless of Sm ion doping. With doping amount of 1% lanthanide ion, the pore size and pore volume of Sm(Er, Cs)/Ti-SBA-15 decreased and the surface area increased. For the purpose of vibration characteristics on the Ti-SBA-15 and Sm/Ti-SBA-15 photocatalysts, the IR absorption at 960 cm-1 commonly accepted the characteristic vibration of Ti-O-Si bond. 1% of Sm/Ti-SBA-15 had the highest photocatalytic activity on the decomposition of methylene blue but the catalysts doped with Er ions had lower activity in comparison with pure Ti-SBA-15 catalyst.