[Ethanol-induced influence on the structure and arsenate adsorption of resin-based nano-hydrated ferric oxide].

Here the role of ethanol in the synthesis of a new nanocomposite (D201-HFO) was evaluated in terms of its structure variation and arsenate adsorption. Results indicated that the ethanol-induced procedure improved the dispersion of HFO inside the polymer host D201 and increased the HFO sorption capacities towards arsenate by 20%. Also, the ethanol-induced procedure resulted in the increase of pore size, pore volume, and specific surface area of D201-HFO by 52%, 65% and 28%, respectively. Nevertheless, ethanol rinsing did not affect the mechanical strength of D201-HFO and the crystal type of the immobilized HFO. Little effects of the ethanol process was observed on the pH and co-anion dependent adsorption of arsenate. Furthermore, the ethanol step posed insignificant influence on the fix-bed adsorption and the repeated use of the adsorbent. The results showed that the ethanol procedure exerted little influence on the sorption properties of D201-HFO from the viewpoint of practical application and thus, it could not be included.

Influence of pH on the formation of sulfate and hydroxyl radicals in the UV/peroxymonosulfate system.

The influence of pH on the degradation of refractory organics (benzoic acid, BA) in UV(254 nm)/Peroxymonosulfate (UV/PMS) system was investigated. The degradation of BA was significantly enhanced at the pH range of 8-11, which could not be explained only by the generally accepted theory that SO(4)(•-) was converted to HO(•) at higher pH. A hypothesis was proposed that the rate of PMS photolysis into HO(•) and SO(4)(•-) increased with pH. The hypothesis was evidenced by the measured increase of apparent-molar absorption coefficient of PMS (ε(PMS), 13.8-149.5 M(-1)·cm(-1)) and photolysis rate of PMS with pH, and further proved by the increased quasi-stationary concentrations of both HO(•) and SO(4)(•-) at the pH range of 8-10. The formation of HO(•) and SO(4)(•-) in the UV/PMS system was confirmed mainly from the cooperation of the photolysis of PMS, the decay of peroxomonosulfate radical (SO(5)(•-)) and the conversion of SO(4)(•-) to HO(•) by simulation and experimental results. Additionally, the apparent quantum yield for SO(4)(•-) in the UV/PMS system was calculated as 0.52 ± 0.01 at pH 7. The conclusions above as well as the general kinetic expressions given might provide some references for the UV/PMS applications.

[Study on adsorption of bisphenol A from aqueous solution on modified activated Carbons].

A commercial activated carbon (WV A1100) was modified with nitric acid, sodium hydroxide and thermal treatment in an atmosphere of N2. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pH(PZC) and Boehm titration. The results indicated that the specific surface area of the W20 remarkably decreased after oxidized by nitric acid. But the amount of surface acidic oxygen-containing functional groups of the oxidized sample increased compared to the W20 and resulting in the points of zero charge (pH(PZC)) changed from 4.95 to 1.50. The changes of surface chemical properties of thermal treatment and sodium hydroxide treatment were opposite to the oxidized sample, as a result, the pH(PZC) of them was changed to near pH 7.0. However, a 43.81% surface area of W20 was also diminished by thermal treatment. Furthermore, the results of BPA adsorption indicated that the oligomerization of BPA on the surface of activated carbon could not be formed through oxidative coupling reactions in the presence of dissolved oxygen. And the data of BPA adsorption on original sample, thermal and sodium hydroxide treatment sample were fitted to the Langmuir isotherm model well. Whereas the Freundlich isotherm model described the adsorptive behavior of the oxidized sample better. In addition, the adsorption capacity of thermal treatment sample was the highest and its saturated adsorption capacity reached 526.32 mg/g. The value was three times higher than that of the oxidized sample. Combined with the results of characterization, it was found that the hydrophobic nature and zero of net charge density of carbon surface were the main factors to affect the BPA adsorption on activated carbons and the adsorption is based on pi-pi theory.

[Isolation, identification and biodegradation characteristics of A bacterial strain able to degrade nonylphenol].

A bacteria strain F-10 was isolated from activated carbon, which was processed with sand filtered water from Songhua River for a long time, pre-oxidized with ozone, PPC and ferrate. The bacterial strain was capable of utilizing nonylphenol (NP) as sole carbon source and identified as Rhodococcus erythropolis with the Sherlock Microbial Identification System (MIS) from the MIDI Corporation. The optimal conditions for NP biodegradation in the shaking flasks were at 30 degrees C and pH 6.0. Under those conditions, NP at concentration of 1 mg/L was biodegraded by 62% with 2% of inoculum amount. The biodegradation reaction fitted well with first-order kinetic model, with a degradation rate constants (k) of 0.0865 d(-1) and half-lives (t1/2) of 8.0 d. Aerobic degradation rate for NP was enhanced by increased level of NH4+, Mn2+, Mg2+, and NaCl, and by addition of glucose, NaAc, and yeast extract as well as by reduced level of Ca2+, Cu2+, Fe2+, and phosphate, while no apparent effect of original NP concentration was observed. The combination of F-10 with other 27 bacterial strains which were also isolated from activated carbon expressed better biodegradation effectiveness.

[Ozonation of representative endocrine disruptors (EDs) in water].

The effects of ozone dose, bicarbonate concentration and pH on endocrine disruptors(EDs) removal, such as E1, E2, EE2, DES and 4-n-NP, were investigated through batch experiment. The results indicated that the removal rates were enhanced by increasing ozone dose, and O3 exposures of only 63.6 microg/L were calculated to achieve > or = 92.0% EDs removal efficiency. The presence of bicarbonate (0 - 100 mg/L) inhibited EDs ozonation. Furthermore, the EDs removal rates increased significantly as pH increased. The five apparent rate constants (20 degrees C +/- 0.5 degrees C) of ozone with the five EDs were in the range of (1.67 - 3.89) x 10(6)L (mol s) (-1) at neutral pH (pH approximately 7.0) and (0.93 approximately 1.75) x 10(9) L (mol s)(-1) at basic pH (pH > 10.6). It was indicated that the five EDs were removed rapidly by O3 in water. At the same time, the elementary reaction ozone rate constants (20 degrees C +/- 0.5 degrees C) were calculated, and the reactivity of ozone with ionized EDs [i.e. 1.21 x 10(9) - 3.81 x 10(9) L (mol s)(-1)] was 10(3) - 10(4) times higher than with neutral EDs [i.e. 7.62 x 10(5) - 2.55 x 10(6) L (mol s)(-1)]. The comparative test of EDs ozonation under different water quality conditions indicated that the removal rates of EDs in filtrated water and river water were reduced 26.5% - 50.3% and 57.3% - 72.0% respectively compared with the case using ultrapurified water as the background. It showed that organics in real water would compete with EDs for ozonation.