Advanced Materials Research Vols. 1073-1076

Abstract: Two roads (‘Nan Er huan’ abbreviated as R1,and ‘Huan Cheng Nan Lu’ abbreviated as R2) as the sampling area were selected based on Xi 'An traffic condition in China. Soil samples were randomly collected by triple sub sampling technique in each area and digested by mixed solution of FAAS and GFAAS according to the standard methods. The results show that total heavy metal contents of Cu, Cr, Pb and Cd in soil are 30.01±6.27 mg•kg^-1、51.55±24.82 mg•kg^-1、176.13±23.19 mg•kg^-1 and 2.73±1.93 mg•kg^-1, and are 1.15, 0.73, 4.54, and 9.75 times of corresponding heavy metal soil background values in Xi 'an, China. The Nemerow composite index is 12.74, Geoaccumulation index of Cd, Pb, Cu and Cr are 2.7, 0.73, 0.38 and 1.04, Enrichment factors were:10 > Cd > Pb > Cu > Cr > 1. Surface soil is characterized by accumulation of the strength of the Pb, Cd, and Cu, Cr pollution is to a lesser degree.

Abstract: Two different tetrabromobisphenol A (TBBPA) degradation bacteria were isolated from an anaerobic sludge after 100 days of acclimatization, named as NJUST20 and NJUST21. Both of them are able to degrade TBBPA at 30 °C and pH 7.0. The degradation rates of NJUST20 and NJUST21 are 62.85% and 42.28%, respectively, with the initial TBBPA concentration of 10.00 mg/L. According to analysis of the 16S rDNA sequences, NJUST20 should be classified as a species of genus Enterobacter and NJUST21 as a species of genus Serratia, for which the name Enterobacter sp. NJUST20 and Serratia sp.NJUST2 are proposed.

Abstract: through the introduction of the seven functions of city canal, artificial environment construction to find the existence of city canal construction material watertightness, surrounding buildings, excess production and living activities influence, influence city canal causes ecological damage; analysis of the structure characteristics of city ecological system of canals, puts forward the water self-repairing, biological floating island,ecological revetment combining city canal ecological restoration technology; to put forward suggestions for sustainable construction of city canal.

Abstract: In this study, we conducted a series of pot experiments to examine the effect of Chinese medicine residue vermicompost on yield and nutrient content of pakchoi. Vermicompost was proved to be effective in increasing yield and nutrient uptake by the results. The study showed that half vermicompost and half fertilizer works best, 9.86% higher than single fertilizer, with NPK content increased by 3.85%, 7.69% and 11.48%. In addition, the application of vermicompost improved the chlorophyll content of pakchoi. The study indicated that vermicompost, as an environment-friendly fertilizer, has great potential to assure the sustainable development of agriculture.

Abstract: Two parallel biofilm reactors were developed and applied for treating the simulated wastewater. The experimental results showed that compared with a without electric-shocking biofilm, and a mean removal rate of COD increased by 18.82% by shocking of direct current. Which suggested that the electro-shocking can significantly increase the removal rate of COD.

Abstract: Soil organic matter (SOM) is derived from dead biomass of animals and plants, and its formation process in which the precursor materials of SOM are transformed into macro organic molecules through geo-chemical and geo-biological reactions in the subsurface environment is referred to as humification. Carbon content increases, but oxygen content decreases along with marked increased in molecular weight and degree of condensation of SOM during humification. It has been known that humus materials evolve in the order of biopolymer, fulvic acid, humic acid, and humin. Humification process takes place in a geological time scale, but it can be accelerated at extremely high temperatures, which can be achieved by microwave (MW) with hyperthermal catalysts (HTCs). Thus, MW was irradiated to the mixture of soil and HTCs to stimulate humification of SOM and to enhance its binding capacity for recalcitrant organic contaminants in this study. MW irradiation with HTCs was optimized, and the characteristic changes of SOMs before and after the irradiation were assessed to confirm humification. Soils were collected from 4 different forest regions in Seoul, Korea (Konkuk University, Yongma Mountain, Surak Mountain, and Bukhan Mountain), and they were screened by wet-sieving. Each component of SOM was isolated by acid-base extraction/selective exchange resin, which was proposed by the International Humic Substance Society. Total organic carbon (TOC) content, specific ultraviolet absorbance (SUVA), E4/E6 ratio, and Fourier transform-infrared spectroscopy (FT-IR) spectrum of SOM before and after MW irradiation were examined. Soil of Surak Mountain exhibited the highest organic carbon content, but Yongma Mountain contained the highest amount of fulvic acid. Soils of Yongma Mountain and Konkuk University were chosen due to their high fulvic acid content, which supported that these soils are relatively geologically-young soils. Powdered and granulated activated carbon (PAC and GAC), graphite, charcoal, and carbon nanotube (CNT) were selected and screened with regard to their hyperthermal activity under MW irradiation. The temperature changes by MW with HTCs were monitored at various MW irradiation intensity and time. Graphite-and CNT-soil mixtures exhibited the optimum heating capacity at 600 W, resulting in heating HTC-soil mixtures to approximately 1,000oC within 10 min. TOCs, SUVAs, E4/E6 ratios, and FT-IR spectra of SOM supported effective humification of SOM after MW irradiation with HTCs, and notable increase in binding capacity with hydrophobic organic contaminants. The results of this study are expected to provide the fundamental information for developing the performance-efficient and cost-effective treatment process for the removal of persistent organic contaminants based on MW and HTC.

Abstract: 4-Chlorophenol is well-known as an extensively used antiseptic, and it may cause severe damage to the environment and human health. 4-Chlorophenol can be biologically degraded by Arthrobacter chlorophenolicus A6, which can be attributed to the cphC-I and cphB genes of the microorganism that encode for a two-component flavin-diffusible monooxygenase (TC-FDM), composed of oxygenase and reductase components. This study reports the cloning, overexpression, purification, and function analysis of the oxygenase and reductase components from the genes cphC-I and cphB. The genes were cloned into vector pET-24a, and 4 different strains of Escherichia coli were transformed with these recombinant genes. The optimization of expression conditions indicated that cphC-I is best overexpressed in E. coli BL21(DE3) incubated for 24 hours at 15°C with 0.5 mM of isopropyl-β-D-1-thiogalactopyranoside. However, cphB was not expressed into soluble form enzyme in any of the conditions, and therefore fre of E. coli was used instead to analyze the function of CphC-I. CphC-I was able to degrade approximately 13.86% of 4-chlorophenol, indicating that it is indeed a reduced flavin-dependent monooxygenase and utilizes 4-chlorophenol as a substrate. The results of this study are expected to establish the basic understanding of TC-FDM for its application to enzymatic bioremediation of phenol-contaminated environment.

Abstract: In this study, an efficient soil flushing process was developed for the remediation of soil complex contaminated with heavy petroleum oils (HPOs) and heavy metals. In most cases, remediation of contaminated soil is carried out after all industrial activity is suspended and removal of facilities. Therefore, in-situ remediation becomes more favored over ex-situ technologies albeit relatively long remediation periods are needed. In particular, soil flushing has been employed as an efficient in-situ technology most frequently in many railroad and industrial sites still in business. The objective of this study was to develop an in-situ soil flushing method using horizontal injection/suction channels. A pilot-scale box reactor (1 m × 0.6 m × 0.7 m) was employed to evaluate desorption of complex contaminants from complex contaminated soils by flushing agents. Since HPOs and heavy metals can be removed by different mechanisms, various flushing agents were required for the treatment of HPOs and heavy metals. Hydrogen peroxide (H₂O₂) and citric acid were selected and injected sequentially as flushing agents for HPOs and heavy metals, respectively. Soils complex contaminated with HPOs, Zn, and Pb were collected from a railroad site, Seoul, Korea, and they were packed into the pilot-scaled reactor. Two horizontal channels were installed: injection channel was placed 10 cm below the top of soil surface and suction channel was placed 10 cm above the bottom of the reactor. Flushing agents were injected at a flow rate of 3.86 mL/min for 1 month. After flushing, soil samples were collected separately from various points of the reactor (divided into 5 vertical layers and 15 horizontal sections), and then each soil sample was analyzed for the soil flushing efficiency. The initial concentrations of HPOs, Zn and Pb were 4685.5±374.4 mg/kg, 204.9±60 mg/kg, and 139.8 mg/kg (n = 3). After soil flushing, the concentrations were decreased to 1448.4±166.7 mg/kg, 143.4 mg/kg, and 99.5 mg/kg (total removal rates = 69%, 30% and 28.9%, for HPOs, Zn, and Pb, respectively). Hence, it was confirmed in this pilot-scale study that sequential soil flushing by combination of flushing agents was effective for soils complex contaminated with HPOs and heavy metals. These results must be useful for field-scale application of soil flushing remediation for the complex contaminated soils.

Abstract: The surface properties and performance of activated carbon (AC) used for catalytic ozonation were investigated after nitric acid modification (N-AC) and Cu (II)-loaded (N-Cu-AC). The results showed that the nitric acid modification could increase the amount of surface functional groups of AC. As a result, the adsorption capacity and catalytic activity of AC could be improved. The surface functional groups and Cu (II)-loaded of N-Cu-AC showed a synergistic effect on catalytic ozonation, where the catalytic activity of Cu (II)-loaded was more stable. N-Cu-AC was an effective and reusable catalyst for catalytic ozonation. The highest TOC removal efficiency of 58.0% could be achieved when N-Cu-AC was used for 60 min-catalytic ozonation treatment of acid red 3R.

Abstract: Subsurface wastewater infiltration system (SWIS) is considered to be an efficient and economic ecological process for decentralized domestic wastewater treatment. The process structure determines the performance and removal efficiency of the pollutants. This paper introduces several kinds of commonly used structure and their applications, and it proposes that it is essential to make the structure type diversified and broaden the application space of the SWIS.