Baoxin Wang

Detection and analysis of reactive oxygen species (ROS) generated by nano-sized TiO2 powder under ultrasonic irradiation and application in sonocatalytic degradation of organic dyes

Recently, the sonocatalytic technology using various semiconductors combined with ultrasonic irradiation has been received much attention to solve the environmental problems. In this paper, nano-sized titanium dioxide (TiO(2)) powder as a sonocatalyst was irradiated by ultrasound and the generation of reactive oxygen species (ROS) during sonocatalytic reaction process has been estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenylcarbohydrazide (DPCI) can be oxidized by ROS into diphenylcarbonzone (DPCO), which can be extracted by the mixed solution of benzene and carbon tetrachloride and show the great absorbance at 563 nm wavelength. The synergistic effect of TiO(2) and ultrasonic irradiation was estimated and some influencing factors, such as ultrasonic irradiation time and TiO(2) addition amount on the generation of ROS were reviewed. The results indicate that the quantities of generated ROS increase with the increase of ultrasonic irradiation time and TiO(2) addition amount. Moreover, the relationship between quantities of generated ROS and DPCI concentration was also studied. And then, several quenchers were used to determine the kind of the generated ROS. At last, the researches on the sonocatalytic degradation of organic dyes and the corresponding reaction kinetics have also been performed, which is found to follow the pseudo first-order kinetics approximately. This paper may offer some important subjects for broadening the applications of sonocatalytic technology.

Detection and comparison of reactive oxygen species (ROS) generated by chlorophyllin metal (Fe, Mg and Cu) complexes under ultrasonic and visible-light irradiation

In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment.

The investigation of sonocatalytic activity of Er3+:YAlO3/TiO2-ZnO composite in azo dyes degradation

In this work, the emphasis was mainly placed on investigating the sonocatalytic activity of TiO(2)-ZnO mixed with Er(3+):YAlO(3), namely, Er(3+):YAlO(3)/TiO(2)-ZnO composite. It is able to utilize the sonoluminescence light to improve the sonocatalytic degradation of organic dyes. The Er(3+):YAlO(3) as up-conversion luminescence agent was synthesized by sol-gel and auto-combustion method, and then Er(3+):YAlO(3)/TiO(2)-ZnO composite as sonocatalyst were prepared by ultrasonic dispersion and liquids boil method. The prepared up-conversion luminescence agent and composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Acid Red B dye was selected to examine the sonocatalytic activity of Er(3+):YAlO(3)/TiO(2)-ZnO composite. The degradation reaction processes were monitored by UV-vis spectrophotometer and ion chromatogram. The influences on the activity of the Er(3+):YAlO(3)/TiO(2)-ZnO such as Ti/Zn molar ratio, heat-treated temperature and heat-treated time were studied. The results showed that the Er(3+):YAlO(3)/TiO(2)-ZnO composite exhibited a significantly high sonocatalytic activity compared with other catalysts in the degradation of Acid Red B. And the sonocatalyst with 1:1 Ti/Zn molar ratio heat-treated at 550°C for 60min showed the highest sonocatalytic activity. At last, the experiment also indicated that it has a good sonocatalytic activity to degrade other organic dyes.

Improvement of sonocatalytic activity of TiO2 by using Yb, N and F-doped Er3+:Y3Al5O12 for degradation of organic dyes.

In this study, several up-conversion luminescence agents (Er(3+):Y3Al5O12, Er(3+):Yb0.2Y2.79Al5O12, Er(3+):Yb0.2Y2.79Al5N0.01O11.99, Er(3+):Yb0.2Y2.79Al5F0.01O11.99 and Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98) were synthesized using sol-gel method. And then, the corresponding sonocatalyst (Er(3+):Y3Al5O12/TiO2, Er(3+):Yb0.2Y2.79Al5O12/TiO2, Er(3+):Yb0.2Y2.79Al5N0.01O11.99/TiO2, Er(3+):Yb0.2Y2.79Al5F0.01O11.99/TiO2 and Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites) were prepared by sol-gel coating process. The synthesized up-conversion luminescence agents and their coated composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). And that, the sonocatalytic activities were detected through the degradation of Azo Fuchsine (AF) dye in aqueous solution by UV-vis spectroscopy. Some key influences such as heat-treated temperature and heat-treated time on the sonocatalytic activity of Er(3+):YbaY2.99-aNxFyAl5O12-x-y/TiO2 coated composite, as well as ultrasonic irradiation time and initial dye concentration on the sonocatalytic degradation were studied. The results showed that the doping of Yb, N and F into Er(3+):Y3Al5O12/TiO2 significantly enhanced the sonocatalytic activity of Er(3+):Y3Al5O12/TiO2 coated composite in the degradation of organic dyes. Particularly, Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites with 3:7 M ratio heat-treated at 550 °C for 60 min showed the highest sonocatalytic activity. At last, the experiments also indicated that the Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites has a good sonocatalytic activity to degrade other organic dyes under ultrasonic irradiation.

Spectroscopic analyses on ROS generation catalyzed by TiO2, CeO2/TiO2 and Fe2O3/TiO2 under ultrasonic and visible-light irradiation.

In this work, the TiO2, CeO2/TiO2 and Fe2O3/TiO2 powders were irradiated, respectively, by ultrasound and visible-light, and the generation of reactive oxygen species (ROS) were estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenyl carbazide (DPCI) can be oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed solvent of benzene and carbon tetrachloride. The DPCO extract liquor displays an obvious absorbance at 563 nm wavelength. In addition, some influencing factors, such as (ultrasonic or visible-light) irradiation time, catalyst addition amount and DPCI concentration, on the generation of ROS were also reviewed. The results indicated that the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and catalyst addition amount. Moreover, the displayed quantities of ROS are also related with DPCI concentration. And then, several radical scavengers were used to determine the kinds of the generated ROS. At last, the researches on the sonocatalytic and photocatalytic degradation of several organic dyes have also been performed. It is wished that this paper might offer some important subjects for broadening the applications of sonocatalytic and photocatalytic technologies in future environment treatment.

Spectroscopic investigation on assisted sonocatalytic damage of bovine serum albumin (BSA) by metronidazole (MTZ) under ultrasonic irradiation combined with nano-sized ZnO

The previous work proved that the bovine serum albumin (BSA) could be damaged under the combined action of ultrasonic irradiation and ZnO. In this work, the assisted sonocatalytic damage of BSA using metronidazole (MTZ) as a sensitizer was further investigated by means of UV-vis and fluorescence spectra. The results indicated that the adding of MTZ could obviously promote the sonocatalytic damage of BSA under ultrasonic irradiation in the presence of nano-sized ZnO powder. Furthermore, it was found that the damage degree of BSA was aggravated by some influencing factors except ionic kind and strength. In addition, the damage site of BSA was also studied with synchronous fluorescence technology. It was found that the damage site was mainly at tryptophan (Trp) residue.

Syntheses, structural determination, and binding studies of nine-coordinate mononuclear complexes (EnH2)3[EuIII(Etha)]2 · 11H2O and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O

Two novel ethylenediaminium salt of europium complexes with aminopolycarboxylic acid ligands, (EnH2)3[EuIII(Ttha)]2 · 11H2O (I) (En is ethylenediamine, H6Ttha is triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O (II) (H4Egta is ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) complexes were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction techniques. Both of the two complexes adopt nine-coordinate structures with the pseudo-monocapped square antiprism and crystallize in the monoclinic crystal system with the P21/n space group. The crystal data for complex I are as follows: a = 17.8262(8), b = 19.3137(5), c = 20.6233(8) Å, β = 111.301(2)°, V = 6615.3(4) Å3, Z = 8, ρc = 1.677 mg/m3, μ = 1.981 mm−1, F(000) = 3432, R = 0.0308, and wR = 0.0737 for 43622 observed reflections with I ≥ 2σ(I). The crystal data for complex II are as follows: a = 12.952(3), b = 12.618(2), c = 14.809(3) Å, β = 105.695(2)°, V = 2330.0(8) Å3, Z = 4, ρc = 1.800 mg/m3, μ = 2.765 mm−1, F(000) = 1276, R = 0.0297, and wR = 0.0638 for 18416 observed reflections with I ≥ 2σ(I). One remarkable feature of the two complexes is that the protonated [EnH22+] cations conjugating to [EuIII(Ttha)]26− and [EuIII(Egta)(H2O)]22− complex anions are reviewed, respectively, which open the path for the EuIII complexes conjugating with other various biomolecules.

Syntheses, structural determination, and binding studies of nine-coordinate (enH2)3[TbIII(ttha)]2·11H2O and eight- coordinate (enH2)[TbIII(pdta)(H2O)]2·8H2O

Two complexes, (enH2)3[TbIII(ttha)]2 · 11H2O (1) (en = ethylenediamine and H6ttha = triethylenetetramine-N, N, N ′, N ″, N ′′′, N ′′′-hexaacetic acid) and (enH2)[TbIII(pdta)(H2O)]2 · 8H2O (2) (H4pdta = propylenediamine-N, N, N ′, N ′-tetraacetic acid), were synthesized and characterized by elemental analysis, infrared spectrum, UV-Vis spectrum, fluorescence spectrum, and single-crystal X-ray diffraction. The central TbIII of 1 is nine-coordinate, pseudo-monocapped square antiprism with four nitrogens and five oxygens from one ttha, and crystallizing in the monoclinic crystal system with P21/n space group. There is a free (non-coordinate) carboxylate (–CH2COO−) in the . The central TbIII of 2 is eight-coordinate in a standard square antiprism with two nitrogens and four oxygens of one pdta, one oxygen from a carboxylate of an adjacent pdta, and one oxygen from water, crystallizing in the monoclinic crystal system with C2/c space group. Binding between the with or [TbIII(pdta)(H2O)]− is reviewed, providing the basis for interaction of TbIII complexes with biomolecules.

Spectroscopic investigation on interaction and sonodynamic damage of Riboflavin to DNA under ultrasonic irradiation by using Methylene Blue as fluorescent probe

In this paper, the Riboflavin (RF) as a sonosensitizer and Methylene Blue (MB) as a fluorescent probe were used to study the interaction and sonodynamic damage to Deoxyribonucleic Acid (DNA) by fluorescence and UV-vis spectroscopy. The results showed that the RF could efficiently bind to DNA in aqueous solution and exchange with the MB through competing reaction. And then, under ultrasonic irradiation, the RF could obviously damage the DNA. In addition, the influencing factors such as ultrasonic irradiation time and RF concentration on the sonodynamic damage to DNA were also considered. The experimental results showed that the sonodynamic damage degree increase with the increase of ultrasonic irradiation time and RF concentration. Perhaps, this paper may offer some important subjects for broadening the application of RF in sonodynamic therapy (SDT) technologies for tumor treatment.

Syntheses, structural determination and binding studies of nine-coordinate mononuclear (EnH2)1.5 [ErIII(Ttha)] · 3H2O and (EnH2)[ErIII(Egta)(H2O)]2 · 6H2O

In this work, the title complexes, (EnH2)1.5[ErIII(Ttha)] · 3H2O (I) and (EnH2)[ErIII(Egta)(H2O)]2 · 6H2O (II), where En = ethylenediamine, H6Ttha = triethylenetetramine-N,N,N′,N″,N″’,N″′-hexaacetic acid, H4Egta = ethyleneglycol-bis-(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, have been successfully synthesized. Their structures have been characterized by IR spectroscopy and single-crystal X-ray diffraction techniques. The X-ray diffraction reveals that I is nine-coordinated and crystallizes in the monoclinic crystal space group P2/n with cell dimensions a = 17.6058(16), b = 9.6249(9), c = 20.560(2) Å, β = 109.7440(10)°, and V = 3279.1(5) Å3. Compound II is also nine-coordinated and crystallizes in the monoclinic crystal space group P21/n with the cell dimensions a = 12.938(6), b = 12.651(5), c = 14.943(6) Å, β = 105.441(5)°, and V = 2357.5(17) Å3. In I, each EnH22+ cation connects three adjacent [ErIII(Egta)(H2O)]− complex anions through hydrogen bonds, while in I, there are two types of EnH22+ anions. One is highly symmetrical, forming hydrogen bonds with two neighboring [ErIII(Ttha)]3− complex anions. The other anion connects three adjacent [ErIII(Ttha)]3− complex anions through hydrogen bonds. These hydrogen bonds lead to the formation of 2D ladder-like layer structure.