Xiao Jun Hu

Long-Term Phytoremediation Process of Diesel Oil-Contaminated Soil

Soils contaminated with diesel oil were remediated with alfalfa (Medicago sativa) by outdoor pot experiment over a 5-growth season treatment, with pollutant levels, special microbial inoculators, fungi inoculators, and organic manure as control factors. The dynamics of residual concentrations of mineral oil and PAHs in soil of different phytoremediation treatments during the 5 seasons were determined. Results showed that significant reduction of contaminant concentration was achieved. At the end of the fifth growth season, initial concentrations of mineral oil were reduced by 96.5% to 98.8% in the phytoremediat treatments. Among the four factors, bacterial and fungi inoculators showed no significant effect on the contaminant removal in the process of long-term bioremediation. Effect of organic fertilizer amendments differed depending on the diesel concentration. In the highly contaminated treatments (15000 and 30000 mg/kg dry weight) remarkable stimulation was detected with the increase of fertilizer amendment; however, the trend was just reversed in the lightly contaminated treatments (5000 mg/kg dry weight) with the increase of manure amendment.

Accumulation and Distribution of Heavy Metals in Phragmites australis in the Wetland of Liaohe River Estuary

Phytoextraction has been recognized as an alternative technique for the remediation of wetland contaminated by heavy metals. The objective of this paper is to investigate the characteristics of heavy metal phytoextaction by phragmites australis and the distribution in soils and phragmites australis of 13 sampling points distributed in fields of Zhaoquanhe, Yangjuanzi and Dongguo in Liaohe estuary.The results showed that the content of heavy metal of Cu and Zn is close in the three phragmites australis fields. The content of heavy metal of Pb in Dongguo field is higher than the others. The content of heavy metal of Cd is lowest for all the heavy metals in the three fields. For the content of heavy metal in different layer soils in the three phragmites australis fields, the content of heavy metal of Cu, Pb, Zn in soils of 0-10 cm, 10-20 cm is higher than in other layer soils. for Cd in soils of 0-30 cm is higher than in other layer soils. And the content of heavy metal in siols of 30-40 cm is lowest for all the heavy metals. The transfer and interaction of Cu, Zn, Cd and Pb in the soil- phragmites australis systems in the three fields is studied, the content of heavy metal of Cu, Zn, Cd is that soils>phragmites australis of aerial part>phragmites australis of underground part, and for the content of heavy metal of Pb, soils>phragmites australis of aerial part≈phragmites australis of underground part. The biological concentration factor of heavy metal of Cu, Zn, Cd is low and transfer coefficient is high relatively .

Remediation of Cadmium Contamination in Soil by Washing

Soil washing is a possible remediation technique for contaminant extracting from the soil. Thiacalix[4]arenetetrasulfonate has become an alternative to metal extractants due to its high selectivity and high stability. Batch soil-washing experiments were conducted to investigate the effect of pH on extraction efficiency of Cd from soil by the thiacalix[4]arenete-trasulfonate solution. Results showed that more than 82 percent of cadmium was extracted by the thiacalix[4]arenetetra- sulfonate solution from the artificially contaminated soil with the concentration of 562 mg/kg cadmium at the initial pH value of 11. Thiacalix[4]arenetetrasulfonate could be an attractive alternative in washing remediation of soil contaminated by Cd.

Heavy Metals Accumulation and its Environmental Risk in Sediments of Xihe River, Shenyang City

Heavy metal accumulation in Xihe River sediments was studied, and also its potential environmental risk was evaluated using geoaccumulation index (Igeo). The results showed that mean concentrations of Hg, Cd, Zn, Pb, Ba, Bi, Sn and Sb were 2.73, 18.42, 1066.1, 128.8, 366.9, 7.76, 24.70 and 8.53 mg/kg, respectively. The values of examined heavy metals, except for Ba, were higher than the reference of deep soil. There were different accumulation characteristics for heavy metals at different river sections. Cadmium and Pb concentrations in sediment dropped from upper to lower reaches along river, but Ba was quite the reverse. The potential environmental risk of heavy metals in sediments was in order: Cd > Hg > Bi > Zn > Sb > Sn > Pb > Ba. The river was subjected to a higher potential risk by Hg, Cd, Zn and Bi, a medium-high risk by Sn and Sb, and a lower risk by Pb and Ba.

Seasonal Variations of the Regular Indices of the Surface Water in the Taizi River

The regular indices of the surface water of the Taizi River, Liaoning Province, northeast of China, were investigated. Samples were collected from upstream to downstream locations of the mainstream, and also from the tributaries of the Taizi River in dry season, wet season, and normal season, respectively. The DO values of the surface water ranged from 3.35 mg/L to 18.73 mg/L, 0.09 mg/L to 13.44mg/L, and 3.49 mg/L to 16.9 mg/L, respectively, in the dry season, wet season, and normal season, respectively. The seasonal variations of the pH values of the surface water were in the order of dry season >wet season >normal season.

A New Approach to Fluorescent Chemosensor of Cu2+ Ion

According to the principle of dynamic quenching a new ON-OFF fluorescent chemosensor for Cu2+ ions was designed, this chemosensor was composed of p-tert-butylthiacalix [arene (TCA),sodium dodecyl sulfate (SDS) and perylene through the form of self-assembly in aqueous solution. Addition of Cu2+ ions could result in a quenching of the fluorescence emission of perylene inside micelles, which due to intramicellar complex-fluorophore electron-transfer or energy-transfer effects induced by the complexation of TCA with the Cu2+ ions.The experimental results indicated that: Under the condition of TCA/perylene was 800/1, SDS concentration was 150mmol/L and pH value above 9, according to the fluorescence quenching ,within a certain range of the concentration of Cu2+ ion can be linearly determined.

Preparation and Properties of Organosilicon-Modified Acrylate Resin

Organosilicon-modified acrylate resin was successfully prepared by solution polymerization and the effect of content of silica sol and silane coupling agent (KH570) on the resistance to water, acid, alkali and aging, the polymerization mechanism, structure were studied,respectively. The results showed that: compared with the properties of resistance to water, acid, alkali and aging of pure acrylate resin, to some extent, those of organosilicon-modified acrylate resin had been improved a lot. The properties of resistance to water, acid, alkali and aging increased at first and then decreased with the increase of the content of organosilicon. Especially, the comprehensive performance of composite resin was relatively excellent when the content of silica sol and KH570 was 5% and 5.1%, respectively.

Spatial Distribution and Seasonal Variations of Heavy Metals in Surface Water of the Taizi River

The contamination levels and distribution of heavy metals in surface water of the Taizi River were investigated. Samples of water were collected from upstream to downstream locations, and also from the main tributaries of the Taizi River. All samples were analyzed for arsenic, mercury, and chromium (Ⅵ). Results indicated that the metal levels of upriver sites were lower than downriver sites. The total concentrations of Cr6+ and As in dry season was higher than that in flood season. While heavy metal Hg represents the highest concentration in flood season. Compared with the permissible levels of surface water environmental quality standards (GB3838-2002), the levels of Cr6+ and As attained the first and second level, but Hg attained the fifth level. This indicated that most sites of the Taizi River have a high risk of Hg pollution in flood period.

Study on the Contamination of NH3-N and Total Phosphorus in the Seasonal River

Water samples were collected from the upstream to the downstream of a seasonal river, the Taizi River, and its main tributaries in dry season, normal season, and wet season. The variations of NH3-N, and total phosphorus (TP) within a hydrological year were analyzed, aimed to study the pollution characteristics and sources of the water bodies. It was found that the tributaries of the Taizi River were heavily contaminated by NH3-N, with 83.8%, 100% and 100% of the sampling sites exceeding the fifth level in the dry season, wet season and normal season, respectively. The concentration of TP in the dry season fluctuated wildly, which was much higher than those in the wet and normal season. Compared with the permissible levels set by the environmental quality standards for surface water standard (GB3838-2002) of China, 57.1% of the sampling sites in the main stream and tributaries of the Taizi River belong to the fifth level or exceed the fifth level in the dry season, and only 7.1% of the sampling sites were belonging to the fifth level or exceed the fifth level in the wet and normal season. Overall, the waterbody of Taizi River was more seriously polluted by urban domestic sewage and point source of industrial wastewater.

Removal of Dichloroethylene in Water Using a Novel TCAS-Loaded Resin

Through the method of the static tests, the removal rate of aqueous dichloroethylene onto a new TCAS-loaded resin was researched. This TCAS-loaded resin was made of a novel supramolecular acceptor compound named thiacalix[4]arenetetrasulfonate(TCAS) and anion exchange resin, and the adsorption mechanism was discussed preliminarily. The results of adsorption indicated that the pH value was an important factor for the removal of dichloroethylene and it would be better for the adsorption if the pH value was greater than 6. The operating temperature should be controlled in 5 to 15°C for the adsorption of dichloroethylene onto TCAS-loaded resin while the removal rate decreased with the temperature increasing and the best time for reaction was 40min. The removal rate of dichloroethylene in aqueous solution was better when 25mL aqueous solution of dichloroethylene (1.0mg/L) was adsorbed by 0.5g TCAS-loaded resin. The dichloroethylene can be resolving and TCAS-loaded resin can be reused.