Effects of antibiotics on enhanced biological phosphorus removal and its mechanisms

Method to characterize color of biochar and its prediction with biochar yield as model property

Adsorption of sulfonamides on biochars derived from waste residues and its mechanism

Relation of tributyltin and triphenyltin equilibrium sorption and kinetic accumulation in carp and Ceratophyllum demersum

Uptake and elimination of butyl- and phenyltins by Ceratophyllum demersum L.

Dissipation of Sulfonamides in Soil Emphasizing Taxonomy and Function of Microbiomes by Metagenomic Analysis

Mixture toxicity of zinc oxide nanoparticle and chemicals with different mode of action upon Vibrio fischeri

Abstract Background: Zinc oxide nanoparticle (nZnO) and chemicals with different mode of action (MOA, i.e., narcotic and reactive) were frequently detected in the Yangtze River. Organisms are typically exposed to mixtures of nZnO and other chemicals rather than individual nZnO. Toxicity of nZnO is caused by the dissolution of Zn2+, which has been proved in the field of single toxicity. However, it is still unclear whether the released Zn2+ plays a critical role in the nZnO toxicity of nZnO-chemicals mixtures. In the present study, the binary mixture toxicity of nZnO/Zn2+ and chemicals with different MOA was investigated in acute (15 min) and chronic (12 h) toxicity test upon Vibrio fischeri (V. fischeri). The joint effects of nZnO and tested chemicals were explored. Moreover, two classic models, concentration addition (CA) and independent action (IA) were applied to predict the toxicity of mixtures. Results: The difference of toxicity unit (TU) values between the mixtures of Zn2+-chemicals with those of nZnO-chemicals was not significant (P> 0.05), not only in acute toxicity test but also in chronic toxicity test. The antagonistic or additive effects for nZnO-chemicals can be observed in most mixtures, with the TU values ranging from 0.75-1.77 and 0.47-2.45 in acute toxicity test and chronic test, respectively. We also observed that the prediction accuracy of CA and IA models was not very well in the mixtures where the difference between the toxicity ratios of the components was small (less than about 10), with the mean absolute percentage error (MAPE) values ranging from 0.14-0.67 for CA model and 0.17-0.51 for IA model, respectively.Conclusion: We found that the dissolved Zn2+ mainly accounted for the nZnO toxicity in the mixtures of nZnO-chemicals, and the joint effects of these mixtures were mostly antagonism and additivity. CA and IA models were unsuitable for predicting the mixture toxicity of nZnO-chemicals at their equitoxic ratios.

The mixture toxicity of heavy metals on Photobacterium phosphoreum and its modeling by ion characteristics-based QSAR

Effects of soil acidification on the toxicity of organophosphorus pesticide on Eisenia fetida and its mechanism

Hormetic effects of metal ions upon V. fischeri and the application of a new parameter for the quantitative assessment of hormesis

Mechanistic model for interpreting the toxic effects of sulfonamides on nitrification

Mechanistic QSAR models for interpreting degradation rates of sulfonamides in UV-photocatalysis systems

Novel application of bamboo-based fibers in a biological contact oxidation process

Generally, biofilm-supporting carriers in biological contact oxidation processes are made from thermoplastic polymers, which cause potential ecological damage because of the low biodegradation and high accumulation in organisms. Thus, four bamboo-based fibers, bamboo primitive fiber, bamboo fiber, bamboo charcoal fiber (BBF) and bamboo charcoal–cotton blending fiber (BCBF), were used as carriers and compared with two commercial carriers (vinylon (VY) and polypropylene (PP)) in a biological contact oxidation process system with the goal to develop a biodegradable and sustainable biofilm medium. Under steady state conditions, pollutants (chemical oxygen demand and NH4+-N) in stage 1 (days 1–29, hydraulic retention time (HRT) = 12 h) were efficiently removed with a removal efficiency ranging from 85 to 95%. In stage 2 (days 30–53, HRT = 4–12 h), the pollutant-removal efficiency of four reactors (BBF, BCBF, VY and PP) were nearly indistinguishable and were higher than the two other reactors, especially when the HRT was set at 4 h (days 46–53). Consequently, two optimized bamboo-based fibers (BBF and BCBF) can be developed as biofilm carriers for wastewater treatment in the future. Furthermore, studies demonstrated that the biofilm development difference showed good correlation with their specific area and relative oxygen content but not with their tenacity and antimicrobial activity.

A novel application of modified bamboo charcoal to treat oil-containing wastewater and its modified mechanism

Three conventional coalescence filters including walnut shells (WS), polystyrene resin particles (PR), and quartz sand (QS) were compared with bamboo charcoal (BC) to treat oily wastewater in a coalescence system process. The results showed the order of oil removal efficiency was QS>BC>WS>PR. To improve the oil removal efficiency of BC further, six types of modified BC were prepared. The results showed that the modified BC using silane coupling agent (SCA) significantly increased oil removal efficiency, but the other types (including the use of NaOH, HNO3, H2O2, FeCl3 and ultrasound) of modified BC exhibited nearly the same level of efficiency as that of pure BC. Infra-red, X-ray diffraction, scanning electron microscopy, and the contact angle for modified BC were measured to reveal the modified mechanism. It was found that the higher oil removal efficiency of the SCA-modified BC occurred due to the changed crystal structure of the BC and the increase in its surface hydrophobicity, which resulted in higher oil removal efficiency. Therefore, modified bamboo charcoal is an attractive filter candidate for oil removal in a coalescence system process.

Novel approach to predicting hormetic effects of antibiotic mixtures on Vibrio fischeri

The joint effects of sulfonamides and their potentiator on Photobacterium phosphoreum: Differences between the acute and chronic mixture toxicity mechanisms

A docking-based receptor library of antibiotics and its novel application in predicting chronic mixture toxicity for environmental risk assessment