Distribution of Al-, Fe- and Mn-pools and their correlation in soils from two acid deposition small catchments in Hunan, China

Distribution of Al-, Fe- and Mn-pools was investigated in five forest soil profiles (consisting of four horizons) in each of two Hunan catchments (BLT and LKS) where acid deposition has been considered critical. Al- and Fe-pools were higher in BLT than those in LKS, but Mn-pools much lower in BLT. Mn-pools vary from topsoils to bottom soils, but there are different trends for different Mn speciation. Al- and Fe-pools, except amorphous Fe_ox, were positively correlated to contents of soil organic matter (OM) showed by the loss on ignition in the two catchments. Accumulation of Al- and Fe-pools may occur in the area where soil organic matter was enriched (e.g. in top soil and rhizosphere soil). However, no direct correlation is observed between Mn and OM. Acidic atmospheric deposition may affect transforming among speciations of Al-, Fe- and Mn-pools and leaching of soil Al, Fe and Mn through formation of soluble organo-metal dissolved Al which was potentially toxic, increased. There were significant correlations between Al-pools complexes or change of oxidation–reduction conditions. Mn_ex (exchangeable Mn) and Mn_ox (amorphous and organic Mn) were highly linearly correlation with soil pH values at LKS but at BLT. Under acid deposition, the availability of the nutrient Fe increased with the amount of dissolved Al, which was potentially toxic, in the two catchments. There are no significant correlations between Al_ex (exchangeable Al) and Mn_ex, Fe_ex (exchangeable Fe) and Mn_ex in this work, indicating potentially toxic Mn increase seldom accompanying with Al increase in the two catchments.     

Removal of SO2 from O2-containing flue gas by activated carbon fiber (ACF) impregnated with NH3

Adsorption of SO(2) from the O(2)-containing flue gas by granular activated carbons (GACs) and activated carbon fibers (ACFs) impregnated with NH(3) was studied in this technical note. Experimental results showed that the ACFs were high-quality adsorbents due to their unique textural properties. In the presence of moisture, the desulphurization efficiency for the ACFs was improved significantly due to the formation of sulfuric acid. After NH(3) impregnation of ACF samples, nitrogen-containing functional groups (pyridyl C(5)H(4)N- and pyrrolyl C(4)H(4)N-) were detected on the sample surface by using an X-ray photoelectron spectrometer. These functional groups accounted for the enhanced SO(2) adsorption via chemisorption and/or catalytic oxidization.     

Cu and Zn adsorption onto non-residual and residual components in the natural surface coatings samples (NSCSs) in the Songhua River, China

Natural surface coatings samples (NSCSs) from the surface of river shingles were employed to investigate the roles of non-residual and residual components of the NSCSs in controlling Cu and Zn adsorption via the selective extraction techniques and statistical analysis. The results indicate that the greatest contribution to metals adsorption on a molar basis was from Mn oxides in the non-residual fraction. Metals adsorption capacities of Mn oxides exceeded those of Fe oxides by one order of magnitude, fewer roles were found attributing to adsorption by organic materials (OM), and the estimated contribution of the residual fraction to metals adsorption was insignificant. These results implied that Mn oxides were the most important component in controlling heavy metals in aquatic environments. Experiments with Cu and Zn adsorption measured together showed that Cu severely interfered with Zn adsorption to the NSCSs and vice versa under the conditions of the two coexisted ions adsorption.     

以pH和ORP作为脉冲SBR工艺的实时控制参数

为了实现脉冲SBR深度脱氮的实时控制,以某污水处理厂市政污水为处理对象,考察了脉冲SBR在深度脱氮过程中pH及ORP的变化规律.试验结果表明,pH及ORP的变化规律与脉冲SBR有机物去除、硝化与反硝化过程存在较好的相关关系.可以根据pH和ORP变化曲线上的特征点对脉冲SBR进行实时控制.并考察了污水C/N(COD/NH4 -N)对pH及ORP的变化规律的影响.在硝化过程中,C/N对pH及ORP曲线变化点的出现没有影响;在反硝化过程中,应结合pH值"硝酸盐峰"和ORP"硝酸盐膝"来判断低C/N污水反硝化的终点.在该试验中,出水TN低于2 mg/L,TN去除率可达到96%以上.     

Distribution and migration of 95Zr in a tea plant/soil system

(95)Zr is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of (95)Zr is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of (95)Zr in a tea plant/soil system. (95)Zr was accumulated primarily in the trunk of tea plants after being taken up from the soil. The radioactivity concentration of (95)Zr in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of (95)Zr in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that (95)Zr was not readily translocated in the tea plant. About 98.9% of applied (95)Zr was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that (95)Zr could not readily move downwards with percolating water due to strong adsorption to surface soil.     

A sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for chlorpyrifos residue determination in Chinese agricultural samples

A monoclonal antibody-based competitive antibody-coated enzyme-linked immunosorbent assay (ELISA) was developed and optimized for determining chlorpyrifos residue in agricultural products. The IC₅₀ and IC₁₀ of this ELISA were 3.3 ng/mL and 0.1 ng/mL respectively. The average recoveries in six agricultural products were between 79.5% and 118.0%, with the intra-assay coefficient of variation being less than 8 %. The limit of detection for all tested products was 30 ng/g. To the best of our knowledge, this assay has the best specificity among all the published research on ELISAs for chlorpyrifos.     

空心壳聚糖微球对二甲酚橙的吸附性能研究

以生物可降解的壳聚糖为原料,采用反相悬浮交联法制备了具有空壳结构的壳聚糖微球,通过控制反应条件得到单分散性的微米级微球.通过分光光度法探讨了溶液初始pH、吸附时间、二甲酚橙初始浓度、壳聚糖微球用量及其直径对壳聚糖微球吸附二甲酚橙的影响.结果表明,常温下壳聚糖微球对二甲酚橙的最佳吸附条件为:溶液初始pH为5,吸附时间为2.0 h,二甲酚橙初始质量浓度为32 mg/L,壳聚糖微球用量为0.3 g/L(以每升二甲酚橙溶液计),壳聚糖微球直径为74 靘;在此最佳吸附条件下,采用分光光度法对二甲酚橙模拟废水进行测定,相应的回收率误差均在-1%～1%.     

Distribution and variation of mercury in frozen soils of a high-altitude permafrost region on the northeastern margin of the Tibetan Plateau

Environmental Science and Pollution Research - The Tibetan Plateau (TP) is home to the largest permafrost bodies at low- and mid-latitudes, yet little is known about the distribution and variation...