Search

The effect of ion-doping on TiO2 nanotubes were investigated to obtain the optimal TiO2 nanotubes for the effective decomposition of humic acids (HA) through O3/UV/ion-doped TiO2 process. The experimental results show that changing the calcination temperature, which changed the weight fractions of the anatase phase, the average crystallite sizes, the Brunauer-Emmett-Teller surface area, and the energy band gap of the catalyst, affected the photocatalytic activity of the catalyst. The ionic radius, valence state, and configuration of the dopant also affected the photocatalytic activity. The photocatalytic activities of the catalysts on HA removal increased when Ag+, Al3+, Cu2+, Fe3+, V5+, and Zn2+ were doped into the TiO2 nanotubes, whereas such activities decreased as a result of Mn2+- and Ni2+-doping. In the presence of 1.0 at.% Fe3+- doped TiO2 nanotubes calcined at 550°C, the removal efficiency of HA was 80% with a pseudo-first-order rate constant of 0.158 min–1. Fe3+ in TiO2 could increase the generation of •OH, which could remove HA. However, Fe3+ in water cannot function as a shallow trapping site for electrons or holes.

One of the most common taste and odour compounds (TOCs) in drinking water is 2-methylisoborneol (2-MIB) which cannot be readily removed by conventional water treatments. Four bacterial strains for degrading 2-MIB were isolated from the surface of a biological activated carbon filter, and were characterized as Micrococcus spp., Flavobacterium spp., Brevibacterium spp. and Pseudomonas spp. based on 16S rRNA analysis. The removal efficiencies of 2-MIB with initial concentrations of 515 ng·L−1 were 98.4%, 96.3%, 95.0%, and 92.8% for Micrococcus spp., Flavobacterium spp., Brevibacterium spp. and Pseudomonas spp., respectively. These removal efficiencies were slightly higher than those with initial concentration at 4.2 mg·L−1 (86.1%, 84.4%, 86.7% and 86.0%, respectively). The kinetic model showed that biodegradation of 2-MIB at an initial dose of 4.2 mg·L−1 was a pseudo-first-order reaction, with rate constants of 0.287, 0.277, 0.281, and 0.294 d−1, respectively. These degraders decomposed 2-MIB to form 2-methylenebornane and 2-methyl-2-bornane as the products.

Sulfide and vanadium (V) are pollutants commonly found in wastewaters. A novel approach has been investigated using microbial fuel cell (MFC) technologies by employing sulfide and V(V) as electron donor and acceptor, respectively. This results in oxidizing sulfide and deoxidizing V(V) simultaneously. A series of operating parameters as initial concentration, conductivity, pH, external resistance were carefully examined. The results showed that these factors greatly affected the performance of the MFCs. The average removal rates of about 82.2 and 26.1% were achieved within 72 h operation for sulfide and V(V), respectively, which were accompanied by the maximum power density of about 614.1 mW m(-2) under all tested conditions. The products generated during MFC operation could be deposited, resulting in removing sulfide and V(V) from wastewaters thoroughly.

Background Selenoprotein S (SelS) is an important endoplasmic reticulum and plasma membrane-located selenoprotein implicated in inflammatory responses and insulin resistance. However, the effects of SelS on endothelial cells (ECs) have not been reported. In the present study, the role of SelS in oxidative stress and the underlying mechanism were investigated in human ECs. Methods A SelS over-expression plasmid (pc-SelS) and a SelS-siRNA plasmid were transfected into human umbilical vein endothelial cells (American Type Culture Collection, USA). The cells were divided into four groups: control, SelS over-expression (transfected with pc-SelS), vector control, and SelS knockdown (transfected with siRNA-SelS). After treating the cells with H2O2, the effects of oxidative stress and the expression of caveolin-1 (Cav-1) and protein kinase Cα (PKCα) were investigated. Results Following treatment with H2O2, over-expression of SelS significantly increased cell viability and superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) production and Cav-1 gene and protein expression. However, no effects on PKCα were observed. In contrast, knockdown of SelS significantly decreased cell viability, SOD activity, and PKCα gene and protein expression, and increased MDA production and Cav-1 gene and protein expression. Conclusions SelS protects ECs from oxidative stress by inhibiting the expression of Cav-1 and PKCα.