Inhibitory interaction of flavonoids with organic anion transporter 3 and their structure-activity relationships for predicting nephroprotective effects.

The organic anion transporter 3 (OAT3), an important renal uptake transporter, is associated with drug-induced acute kidney injury (AKI). Screening and identifying potent OAT3 inhibitors with little toxicity in natural products, especially flavonoids, in reducing OAT3-mediated AKI is of great value. The five strongest OAT3 inhibitors from the 97 flavonoids markedly decreased aristolochic acid I-induced cytotoxicity and alleviated methotrexate-induced nephrotoxicity. The pharmacophore model clarified hydrogen bond acceptors and hydrophobic groups are the critical pharmacophores. These findings would provide valuable information in predicting the potential risks of flavonoid-containing food/herb-drug interactions and optimizing flavonoid structure to alleviate OAT3-related AKI.

Multifold enhanced synergistic removal of nickel and phosphate by a (N,Fe)-dual-functional bio-sorbent: Mechanism and application.

A novel (N,Fe)-dual-functional biosorbent (N/Fe-DB) capable of efficient synergistic removal of Ni(II) and H2PO4- from aqueous solution was synthesized. The adsorption capacities of Ni(II) and H2PO4- were both remarkably enhanced over 3 times compared with those in single systems. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that complexation of amino groups and ligand exchange of hydrous ferric oxide in N/Fe-DB played dominant roles. The electric double layer compressing and chelating ligand of deprotonated H2PO4- accounted for the enhanced removal of Ni(II) in binary system, while cation bridge interaction promoted uptake of H2PO4-. Furthermore, the coadsorbates were sequentially recovered, with the ratios of more than 99.0%. Besides, the recovered N/Fe-DB remained stable and applicable to the treatment of real electroplating wastewater even after six adsorption-regeneration cycles. Since the electroplating industry is springing up, effective control of heavy metals and phosphate has attracted global concerns. Based on the enhanced coremoval properties and superb regenerability, N/Fe-DB is potentially applicable to practical production.

A Rhodamine-based Dual Chemosensor for the Simultaneous Detection of Fe3+ and Cu2.

A Rhodamine-based dual chemosensor L1 for simultaneously detecting Fe3+ and Cu2+ was designed and synthesized. The spectroscopic properties of L1 were analyzed, and its recognition mechanism was speculated. We found that the addition of Fe3+ induced a great fluorescence enhancement, while Cu2+ induced a strong UV-Vis absorption enhancement. The results revealed that L1 was highly selective for recognizing Fe3+ and Cu2+ in UV-Vis spectroscopy in CH3OH-H2O (1/1, v/v, pH 7.2) with the interference of other metal ions. A good linear relationship between the fluorescence intensities of L1 and the concentration of Fe3+, as well as the UV-Vis absorption intensities of L1 and the concentration of Cu2+ was observed, respectively. The detection limit was 9.2 × 10-8 M (5.5 µg/L) for Fe3+ and 3.8 × 10-8 M (2.4 µg/L) for Cu2+, respectively. The detection capacity for targeted metal ions of Fe3+ and Cu2+ were studied, which are less than 5 min. Job's plot method for L1 with Fe3+ and ESI-MS for L1 with Cu2+ indicated a 1:1 stoichiometry in the complex. The results may provide an effective strategy for the design of new dual chemosensors for the rapid detection of targeted metal ions.

[Photodegradation of Ciprofloxacin Hydrochloride in the Aqueous Solution Under UV].

Effects of ciprofloxacin hydrochloride (CIP) initial concentration, Pb (NO3) 2, Cd (NO3) 2, PbCl2 and CdCl2 on the photodegradation of CIP using UV irradiation were investigated. The experiments results showed that UV irradiation could lead to effective removal of CIP, but there was no CIP degradation in dark. The photodegradation rate of CIP reduced with increasing initial concentration under UV irradiation. Pb(NO3)2 and Cd(NO3)2 (except for the experiment group of 0.006 mmol x L(-1)) could enhance CIP photodegradation, and the half-life of CIP gradually increased with increasing molar ratio between heavy metal and CIP ( with the decreasing concentration of nitrate). With increasing molar ratio (with the decreasing concentration of chlorate), PbCl2 and CdCl2 first promoted and then inhibited the CIP photodegradation.

A comparative study on the heavy metal solidification/stabilization performance of four chemical solidifying agents in municipal solid waste incineration fly ash.

Investigated in this paper were the content, specification distribution, and risk assessment code (RAC) determination of six targeted heavy metals and potentially toxic metals in fly ashes from a municipal solid waste incinerator in China. Contained in it is a comparison of the solidification/stabilization performance of two novel solidifying agents of sixthio guanidine acid (SGA) and tetrathio bicarbamic acid (TBA) with sodium dimethyldithiocarbamate (SDD) and Na2S, and analysis of their leachability in accordance with TCLP 1311 of the US EPA and the extraction procedures of China (HJ/T 299-2007 and HJ/T300-2007). The total concentration of Zn, Cu, Ni, Pb, Cr, Cd is 37383.47, 3080.77, 1583.92, 1356.43, 566.15, and 77.83 mg/kg, respectively. Cr (3.7%) and Pb (7.50%) pose low risk; and Ni (12.93%) and Zn (15.45%) have a medium risk; while Cu (69.84%) and Cd (82.5%) have a very high risk according to their RAC score. Compared with SDD and Na2S, SGA and TBA show an excellent overall solidifying performance due to their multiply hydrosulfide groups that bind with heavy metals very efficiently. The obtained results indicate that the leaching content of Cd, Ni, Pb and Zn is higher than the thresholds prescribed in GB5085.3-2007, and the excessive acetic acid makes its binding capacity stronger in HJ/T 300-2007 than in TCLP 1311.

[Natural attenuation of tetracycline in the water of Taihu Lake under different environmental conditions].

Tetracycline (TC) has been widely used in veterinary medicines and disease treatments, and has been discharged into nature system due to manure application. To know the harmfulness of TC residues, and to investigate the natural attenuation of TC under different environmental conditions, simulated attenuation experiments in the presence of light, sediment, Cd (NO3) 2 and Pb(NO3)2 were performed. Results showed that the natural attenuation of TC was not obvious under the sunlight, and the natural attenuation rate of TC in water with unsterilized sediment was greater than that with sterilized sediment. The natural attenuation of TC in water with Pb(NO3)2 was slow at the first stage of the experiment, and progressively speeded up as time went on. However, the natural attenuation of TC in water with Cd(NO3)2 was more rapid at the beginning, and significantly faster than that of Pb(NO3)2. The natural attenuation rates of 0.08 mmol x L(-1) TC under different conditions follow the sequence: unsterilized sediment (87.2%) > sterilized sediment (70.37%) > Cd(NO3)2 (64.2%) > Pb(NO3)2 (32.3%) > blank (6.6%), suggesting that all these factors can promote the natural attenuation of TC. Though the natural attenuation trend under different conditions in the dark is similar to that under the sunlight, the natural attenuation rate is less than that under the sunlight, which implicates that sunlight may promote the natural attenuation of TC.

[Adsorption characteristics of the antibiotic sulfanilamide onto rice husk ash].

Under different conditions of initial rice husk ash (RHA) dosage, oscillating temperature, oscillating frequency and solution pH, the adsorption characteristics of sulfanilamide on RHA with the change of time and its adsorption kinetics were investigated. RHA was characterized by SEM and FTIR before and after sulfanilamide adsorption. The results indicated that the adsorption characteristics of sulfanilamide on RHA was influenced by RHA dosage, oscillating temperature, oscillating frequency and solution pH. Within the RHA dosing range (0. 1-2.0 g.L-1) in this experiment, the optimal temperature for the adsorption was 25C , and with the increase of RHA dosage, the removal efficiency of sulfanilamide increased, the time required to reach adsorption equilibrium was shortened and the adsorptive quantity of sulfanilamide by per unit mass of RHA decreased. A high oscillating frequency was used to ensure the adsorption effect when the RHA concentration was high. Strong acidic and strong alkaline conditions were conducive to the adsorption of sulfanilamide. The analysis of adsorption dynamics showed that for the adsorption process with high RHA dosage ( >or= 1.0 g.L-1), the pseudo-second-order model fitted the adsorption behavior well, and the process was controlled by physical and chemical adsorption. Intraparticle diffusion model showed that the adsorption process was controlled by both membrane diffusion and internal diffusion, and the influence of the former became more obvious with the increase of the adsorbent concentration. Both the SEM and FTIR spectra proved the effective adsorption of sulfanilamide by RHA.

Synthesis of heavy metal chelating agent with four chelating groups of N1,N2,N4,N5-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide (TMBTCA) and its application for Cu-containing wastewater.

A novel heavy metal chelating agent, N(1),N(2),N(4),N(5)-tetrakis(2-mercaptoethyl) benzene-1,2,4,5-tetracarboxamide (TMBTCA), was designed with four chelating groups, and a facile one-step synthetic procedure was developed with pyromellitic dianhydride (PMDA) and cysteamine hydrochloride (CHC) as raw materials by aqueous acylation. The effects of mole ratio of reactants (CHC/PMDA), reaction temperature, and reaction time on the yield of TMBTCA were studied. Its application for Cu-containing wastewater was investigated. The experimental results showed that the maximum yield of TMBTCA was 75.92%, as the mole ratio of CHC/PMDA reached 4.8, reaction temperature was 5°C, and reaction time was 6h. It was observed that TMBTCA could effectively remove Cu(2+) and CuEDTA to much lower than 0.5 mg/L (the discharge limit of copper ions in China). Furthermore, TMBTCA showed more affinity for cadmium and copper than some traditional commercial precipitants, such as DTC, TBA and TMT, via comparison of their ability for heavy metal removal, and the precipitates of Cu-TMBTCA and Cd-TMBTCA presented good stability in leaching tests. The results can provide a reference for design and further research on new kind of heavy metal chelating agent with more bonding sites, especially for heavy metal precipitation in PCB wastewater treatment.

[Effect of different aeration ways on migration and transformation of nitrogen in heavily polluted urban river].

Water and sediment samples were collected from a heavily polluted urban river in the Xianlin University Town of Nanjing. We examined the effects of different aeration ways (aerating to sediments, aerating to water) on migration and transformation of nitrogen, using the indoor experimental method. The results showed that: nitrogen release from sediments in the form of NH4(+) -N that will accumulate under anaerobic conditions with increasing temperature; the maximum accumulation of NH4(+) -N in overlying water showed that aerating to water group < aerating to sediment group < control group and the maximum concentrations reached 9.40 mg x L(-1), 11.24 mg x L(-1) and 19.30 mg x L(-1), respectively; nitrogen compounds were generally eliminated from experiment system by a process of ammonia volatilization and a combination of two processes, i. e. nitrification and denitrification under aerating conditions; aerating to sediment was more effective for nitrogen removal than aerating to water, which was removed from overlying water, pore water and sediment; at the experimental endpoint, the concentrations of NH4(+) -N in pore water and sediment were significantly decreased by 64.36% and 58.73% respectively compared with those before aeration in aerating to sediment group and that were decreased by 39.53% and 38.78% respectively in aerating to water group; during nitrogen transformation process in overlying water, start-up of nitrification was slowly under aerating conditions; it took 9 days to realize nitrification under aerating to water conditions and 16 days under sediment aeration conditions; the NO2(-) -N accumulation took place in overlying water under the condition of aeration; the sustain time of NO2(-) -N accumulating was 17 days in aerating to water group and that was 14 days in aerating to sediment group.