Yulong Yang,Jiao Feng,Shicui Zhu,Jinshu Zhou,Kejia Zhang,Xiaoyan Ma,Danial Gallagher,Andrea M. Dietrich
Nitrogenous disinfection by-products (N-DBPs) are more genotoxic and cytotoxic than the currently regulated carbonaceous DBPs (i.e., C-DBPs), and it has become a frontier issue of drinking water safety research. In this paper, the effect of granular activated carbon (GAC) on adsorption and its influencing factors was investigated for a typical N-DBP phenylacetonitrile, which is produced during chlorination of phenylalanine precursor during water treatment. The results showed that GAC had a high adsorption capacity (q max = 22.92 mg/g) for phenylacetonitrile, and the adsorption isotherm was fitted to the Langmuir isotherm model. Pseudo-second-order equation can well describe the behavior of phenylacetonitrile adsorption on activated carbon (R 2 > 0.990), and the adsorption rate constant k 2 = 0.7780–14.12 g/(mg h). Analysis of the influencing factors showed that higher phenylacetonitrile concentration improved the adsorption equilibrium capacity and the adsorption rate. Water temperature and pH had little effect on the capacity or rate of adsorption.
The corrosion inhibition performances of Diantipyrylmethane (DAM) for mild steel in 0.5 M H 2 SO 4 were investigated using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electron microscope (SEM) and quantum chemical calculation. The obtained results reveal that DAM acts as a mixed-type inhibitor with a predominantly anodic reaction, and the inhibition efficiency increases with increasing inhibitor concentration whereas decreases with increasing temperature. The adsorption of DAM on steel surface is found to obey Langmuir isotherm, and the adsorption mechanism is mixed physical and chemical adsorption. The results of quantum chemical calculation demonstrate that pyrazolone rings within molecular structure of DAM play a dominant role in corrosion inhibition of mild steel.
Qixuan Song,Hui Wang,Baoshan Yang,Fei Wang,Xinrong Sun
A novel silver nanoparticle-modified magnetic multi-walled carbon nanotube composite (Ag-FMWCNTs) was synthesized by embedding Fe3O4 and assembling Ag nanoparticles in one-step. The properties of the Ag-FMWCNTs composites and magnetic multi-walled carbon nanotubes (FMWCNTs) were studied by scanning electron microscopy, vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy. The adsorption isotherms, adsorption kinetics and the effects of solution pH and ionic strength to adsorb emerging contaminant sulfamethoxazole (SMX) from aqueous solution on different multi-walled carbon nanotubes-based adsorbents were determined. The results showed that the adsorption kinetics could be explained well by means of the pseudo-second-order and intraparticle diffusion models. The pH experiments showed that maximum adsorption occurred at pH 4. Additionally, all adsorbents had a strong adsorption ability to SMX and the Langmuir maximum capacity followed the order: 5% Ag-FMWCNTs (118.58 mg g−1) > 3% Ag-FMWCNTs (86.41 mg g−1) > MWCNTs (73.69 mg g−1) > 1% Ag-FMWCNTs (70.26 mg g−1) > FMWCNTs (45.13 mg g−1). The spent adsorbents were regenerated in methanol. It was also found that after regenerating four times, multi-walled carbon composites retained up to 80% of their original adsorption performance. Therefore, the Ag-FMWCNTs composite could be used as a potential adsorbent for removing sulfamethoxazole from water.
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