Visible-light-driven photocatalytic degradation of ibuprofen by Cu-doped tubular C3N4: Mechanisms, degradation pathway and DFT calculation.

The copper-modified tubular carbon nitride (CTCN) with higher specific surface area and pore volume was prepared by a simple in-situ hydrolysis and self-assembly. Increased ∼4.7-fold and ∼2.3-fold degradation rate for a representative refractory water pollutant (Ibuprofen, IBP) were achieved with low-energy light source (LED, 420 ± 10 nm), as compared to graphitic carbon nitride (GCN) and tubular carbon nitride (TCN), respectively. The high efficiency of IBP removal was supported by narrow band gap (2.15 eV), high photocurrent intensity (1.10 µA/cm2) and the high surface -OH group (14.75 µg/cm3) of CTCN. According to analysis of the various reactive species in the degradation, the superoxide radical (•O2-) played a dominant role, followed by •OH and h+, responsible for IBP degradation. Furthermore, Fukui functions were employed to predict the active sites of IBP, and combined with the HPLC-MS/MS results, possible mechanisms and pathways for photocatalytic degradation were indicated. This study will lay an important scientific foundation and a possible new approach for the treatment of emerging aromatic organic pollutants in visible-light-driven heterogeneous catalytic oxidation environment.

Sex-specific impacts of thimerosal on the behaviors and brain monoaminergic systems in zebrafish (Danio rerio).

Thimerosal (THI) is the most widely used form of organic mercury in pharmaceutical and personal care products, and has become a major source of ethylmercury pollution in aquatic ecosystems. However, knowledge about its potential risk to aquatic species is limited. In this study, zebrafish were exposed to THI for 7 days, and variations in their behavioral traits, brain monoaminergic neurotransmitter contents, and related gene expression were investigated. After the 7-day exposure, THI reduced locomotor activity and thigmotaxis in males but not females. Exposure to THI increased the social interaction between females but decreased that between males. The THI exposure also significantly reduced the serotonin (5-HT), 5-hydroxyindoleacetic acid, dopamine (DA), and 3,4-dihydroxyphenylacetic acid contents in the brain of males, but only significantly decreased the DA content in females. Correlation analysis revealed that the neurochemical alterations in the brain of zebrafish play critical roles in the behavioral abnormalities induced by THI exposure. Moreover, THI also significantly altered the expression of some genes associated with the synthesis, metabolism, and receptor binding of 5-HT and DA in the brain of zebrafish. The differences in these gene expressions between female and male zebrafish exposed to THI seem to be an important mechanism underlying their sex-specific responses to this chemical. This is the first report on the sex-specific effects of THI on behaviors and brain monoaminergic neurotransmitter contents in zebrafish, which can further improve our understanding of its toxic effects on teleost.

Study on the performance of a new type of combined packing biofilm reactor treating wastewater.

The present work investigates the performance of a biofilm reactor filled with a new type of combined packing used to treat wastewater and explores a new technology approach for the application of coral sand and waste non-woven fabric. The combined packing was made of coral sand and waste non-woven fabric, which was used as a biofilm carrier to treat sewage. The experimental results showed that the removal efficiencies of COD, NH4+-N and TN in the biofilm reactor containing the combined packing were 92.9%, 72.9% and 63.2%, respectively. The maximum removal efficiencies of COD, NH4+-N and TN in the biofilm reactor containing single packing were 89.0%, 63.4% and 55.2%, respectively. The properties of the combined packing were characterized by Fourier Transform Infrared (FTIR), specific surface area, SEM and dehydrogenase activity. Infrared analysis showed that there were hydroxyl, carboxyl and carbonyl groups on the surface of coral sand and non-woven fabric which were beneficial for biofilm growth and wastewater treatment. The large pores in the interior of coral sand and non-woven fabric could provide a comfortable environment for microbes to grow and reproduce. The dehydrogenase activity of the biofilm on the surface of coral sand in the third biofilm reactor was 49.91 µgTF·g-1·h-1, which was significantly higher than that of the other two biofilm reactors. The new type of combined packing is suitable for biofilm carriers with low cost, which can be applied to actual sewage treatment projects. This study provides a reference for the practical application of the technique.

Property of filler-loaded magnetic ferrite from plastic waste bottle used to treat municipal domestic sewage.

The present work investigates the properties of self-made magnetic filler from plastic waste bottle and explores a new technology approach of waste plastic resource utilization. The magnetic filler was prepared by air plasma modification and loading magnetic ferrite on the plastic strip from waste plastic bottle. The surface properties of magnetic filler were characterized by Atomic Force Microscope (AFM), contact angle system and Fourier Transform Infrared (FTIR). AFM images of original and modified plastic strip showed that low-temperature plasma treatment markedly increased the surface roughness of plastic strip. The mean roughness (Ra) of plastic strip rose from 1.116 to 5.024 nm. FTIR spectra indicated that a lot of polar oxygenic groups were introduced onto the surface of plastic by plasma modification. Modification by low-temperature plasma increased the hydrophilicity of plastic strip surface. When treatment time is 40 s, water contact angle of plastic strip surface reduced from 78.2° of original plastic strip to 25.3°. When used in bioreactor, magnetic filler had very favorable microenvironment for microorganism growth. Magnetic filler was more efficient for removing chemical oxygen demand (COD) and [Formula: see text] in sewage than nonmagnetic filler. The resource utilization of plastic wastes will become reality if the magnetic filler is applied widely.