[Critical Review on Environmental Occurrence and Photochemical Behavior of Substituted Polycyclic Aromatic Hydrocarbons].

Substituted polycyclic aromatic hydrocarbons (SPAHs) are a type of emerging pollutant that widely exist in the environment, which also exhibit carcinogenicity, mutagenicity, and teratogenicity. These pollutants belong to toxic pollutants because of their similar structures to polycyclic aromatic hydrocarbons (PAHs). Their environmental behavior and ecological risk have attracted increasing attention. Based on a literature review, we found a new breakthrough in the source, distribution, behavior, and risk of SPAHs with comparison to traditional pollutants PAHs. This paper reviewed the current research progress on the environmental occurrence and photochemical behavior of SPAHs. Their sources, formation mechanisms, and distribution characteristics in the multimedia environment were highlighted, and the photochemical transformation kinetics, pathways, and affecting factors of SPAHs in water, ice, and other media were discussed. Furthermore, the research prospects about the environmental behavior and risk of SPAHs were proposed.

Fabrication of PAN Electrospun Nanofibers Modified by Tannin for Effective Removal of Trace Cr(III) in Organic Complex from Wastewater.

Removal of chromium ions is significant due to their toxicity and harmfulness, however it is very difficult to remove trace Cr(III) complexed with organics because of their strong stability. Herein, a novel electrospun polyacrylonitrile (PAN) nanofibers (NF) adsorbent was fabricated and modified by tannic acid (TA) by a facile blend electrospinning approach for removal of trace Cr(III) in an organic complex. Utilizing the large specific area of nanofibers in the membrane and the good affinity of tannic acid on the nanofibers for hydrolyzed collagen by hydrophobic and hydrogen bonds, the as-prepared PAN-TA NFM exhibited good adsorption toward Cr(III)-collagen complexes and effective reduction of total organic carbon in tannage wastewater. The maximal adsorption capacity of Cr(III) is 79.48 mg g-1 which was obtained at the pH of 7.0 and initial Cr(III) concentration of 50 mg g-1. Importantly, the batch adsorption could decrease the Cr(III) concentration from 10-20 mg L-1 to under 1.5 mg L-1, which showed great application potential for the disposal of trace metal ions in organic complexes from wastewater.

[Spectroscopic analysis of the crystallization mechanism of synthesized zeolite with XRD and FTIR approaches].

Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used to indicate the crystallization characteristics and mechanism. The zeolite NaP1 was synthesized, and the CEC value reached to the maximum of 135 mmol/100g at 24 h. After the hydrothermal reaction for 12 h, the characteristic peak and metastable crystalline structure of zeolite NaP1 appeared, then the hydroxy sodalite products formed at 48 h. The crystallization process was the result of materials transformation: the elements of fly ash released into the liquid system for the melting effect of alkali solution, and the solid system played the role of skeleton in crystallization process, being the "source" and the "sink" of the reaction, respectively, and the achievements presented the crystallization mechanism of liquid-phase and solid-phase transformation.

[FTIR and XPS analysis of characteristics of synthesized zeolite and removal mechanisms for Cr(III)].

Zeolite products were synthesized from fly ash using one-stage method, and the characteristics of zeolite were analyzed with approaches of XRD, SEM and zeta potential, the removal mechanism for Cr(III) was further investigated by FTIR and XPS. From the pH value of 8 to 12, the negative zeta potential of NaP1 zeolite products decreased from -8.72 to -24.46 mV. The pseudo-second-order kinetics equation and Langmuir isotherm fit better the reaction, the maximum adsorption capacity was 33.557 0 mg x g(-1). Functional groups of -OH and Si-O were important for Cr(III) removal shown from FTIR spectra. The Cr(2p3/2) peak was found at the binding energy of 576.45 eV, indicating the effectiveness of reaction. The binding energy of Si-Si and Si-O increased by 0.25 eV and 0.60 eV, respectively, coordination effect might work between functional groups and Cr(III), and O(1s) binding energy decreased after the adsorption process. The removal for Cr(III) on zeolite was the comprehensive results of physical and chemical adsorption effects.

[Environmental quality assessment of water body and surface sediment in the sea area of Jiaozhou Bay wetland].

Based on the investigation data from 48 sampling stations in the sea area of Jiaozhou Bay wetland in 2009, and by using Nemerow index, eutrophication index (EI), and Hakanson potential ecological risk index, an assessment was conducted on the environmental quality of water body and surface sediment in the sea area. According to the assessment on the 16 indicators including pH, dissolved oxygen (DO), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorous (DIP), chemical oxygen demand (COD(Mn)), petroleum hydrocarbons, Cu, Zn, Pb, Cd, Hg, As, hexachlorocyolohexane (HCH), dichlorodiphenyltrichloroethane (DDT), coliform, and faecal coliform, the water quality was at moderate and serious pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at slight pollution level in the shallow sea. The eutrophication level differed markedly with the regions, being very serious in the tidal reach of Dagu River (EI value 58.13-327.89), serious in the intertidal zone (EI value 1.34-19.96), and slight in the shallow sea (EI value 0.65-2.10). The surface sediments in the sea area were basically at slight pollution level. The sediment quality was at slight pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at cleaner and slight pollution level in the shallow sea. The pollution parameter (C(f)(i)) and contamination index (Cd) of the heavy metals in the surface sediments were low, suggesting that the pollution degree was at a lower level. The Cu and Zn were the primary pollution factors in the sediments. The potential ecological risk parameter (E(r)(i)) and risk index (RI) of the heavy metals in the surface sediments were lower, indicating a slight ecological risk of heavy metals pollution.

[Study on the prediction of soil heavy metal elements content based on mid-infrared diffuse reflectance spectra].

The present paper analyzed the possibility of mid-infrared diffuse reflectance spectra for quick assessment of heavy metal element content in soil quickly. Soil samples were collected from Jiangning District and Baguazhou Island, and the numbers of sample were 103 and 58 separately. Jiangning District samples were used as calibration set while Baguazhou Island samples as validation set. To assess the utility of different pre-treatment process of MIR spectroscopy for soil heavy metal element content analysis, we used PLSR method to develop the calibration between spectral data and soil elements content. Three spectral pretreating techniques such as smooth, log(1/N), baseline correction, multiplicative scatter correction were used for promotion of predicting performance. The result showed that the progress of (log-BC-MSC) in turn achieved optimal calibration of MIR spectra and better prediction for ex-situ soils. Though the calibration data were treated by different pre-treating schema, the R2 of the 8 elements followed the same law: Ni > 0.8 > Cr, Cu, Zn, Pb, Hg > 0.6 > As, Cd. When we applied these calibrations to Baguazhou Island soils, (log-BC-MSC) treated data results in the smallest RMSEp-BGZ. We used the same calibration method to compare the predictive ability of MIR spectra to VNIR spectra. The R2 of 8 elements developed by VNIR spectral calibration are sometime larger than MIR's, but after we applied these calibrations to validation set, the RSME of MIR data for prediction of BGZ soil samples is 21% to 73% of VNIR's. This result showed us that for predicting ex-situ soils, MIR analysis substantially outperformed VNIR These results indicated that MIR spectra can be used to predict soil heavy metal content quickly and non-destructively.

[Effect of bio-charcoal on the trans of polycyclic aromatic hydrocarbons in soil-plant system with composted sludge application].

The effects of bio-charcoal acted as sludge-composting additive on soil characteristics and plant growth were studied. Compared with the treatment of composted sludge without bio-charcoal, soil cation exchange capacity in treatment of composted sludge with bio-charcoal increased over 5% and 10% respectively and soil nitrogen content increased 13% and 18% respectively for two kind soils. The composted sludge with bio-charcoal also resulted in 23% higher enhancement on ryegrass biomass and 8%-10% higher enhancement on ryegrass chlorophyll content. In addition, with the amendment of bio-charcoal, the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in composted sludge was decreased, which resulted in the lower absorption and accumulation of ryegrass to PAHs. Compared with the control, the PAHs concentration in ryegrass amended composted sludge with bio-charcoal decreased 27%-34%. The results indicated that composted sludge with bio-charcoal resulted in much more improvement on the plant growth as well as less negative effect on environment. Therefore, biocharcoal was in favor of the safe land application of sewage sludge.