超声波-铁粉协同降解五氯酚

通过超声波-铁粉联合体系协同降解废水中的五氯酚(PCP).实验结果表明:降解120 min后,PCP去除率可达90.4％；在该体系中铁粉被逐渐腐蚀成Fe2+,随降解时间的延长,Fe2+浓度逐渐增加；体系中的Fe2+可以促进·OH的产生,并且可以与超声空化作用下产生的H2O2发生Fenton试剂氧化反应降解PCP；超声波...     

甲苯在两相厌氧系统中降解及其抑制作用

运用两相厌氧工艺处理含甲苯废水,甲苯浓度的提升对两相厌氧系统的高效性和稳定性影响较小。在提升进水中甲苯浓度的初期,即甲苯浓度≤20 mg/L时,产酸相COD去除率及酸化度下降,驯化一段时间后可恢复正常。当浓度高于150 mg/L时,甲苯将对产甲烷相微生物产生抑制作用,系统COD去除率开始下降。但进水甲苯浓度提高至200mg/L,两相厌氧系统对甲苯的去除率仍可达99%以上。在高浓度甲苯影响下,出水中高分子量物质增多,推测高浓度甲苯刺激微生物代谢分泌大分子物质。     

Phytotoxic activity of crop residues from Burdock and an active substance

Abstract

Problems related to weed management such as outbreaks of herbicide-resistant weeds have recently increased. An interesting approach to such problems is to use plant materials with phytotoxic activity. Burdock (Arctium lappa L.) is a biennial herb belonging to Asteraceae and is cultivated in several countries. The present study investigated the phytotoxic activity of burdock and its active substances. Extracts of both burdock leaves and roots inhibited the shoot and root growth of cress and barnyard grass, where the level of inhibition increased with increasing extract concentration. The leaf extracts had 2.0–2.5 times higher activity than the root extracts. Bioassay-guided separations of the leaf extracts led to isolation of a phytotoxic substance, onopordopicrin. Onopordopicrin significantly inhibited the shoot and root growth of cress and barnyard grass. The concentrations of the substance required for 50% growth inhibition were 0.27 and 0.26?mM for cress shoots and roots, respectively, and 1.86 and 0.35?mM for barnyard grass shoots and roots, respectively. The present results suggest that burdock leaves have high phytotoxic activity and onopordopicrin may play a major role in the activity. Burdock leaves may be a good resource for weed management.     

Research of Toxic Mechanism on Anaerobic Digestion by Lead

The paper analyzes the influence of lead toxicity by anaerobic granule sludge inhibition and recovering experiments. The result shows that there are different inhibition types at different lead contents. Higher lead content leads to more inhibition granular sludge, and at the same time, the time of gas recovery is different. Lower lead content per microorganism results in sooner sludge recovery. Microorganisms have a good ability to resist lead toxicity.     

Physicochemical substance properties as indicators for unreliable exposure in microplate-based bioassays

In the last years many efforts were made to transform standardized algal test protocols into low-cost microplate assays. While advantages were pointed out frequently, limitations are not systematically addressed, thus hindering a widespread utilisation. In this study a group of organic substances with a wide distribution of volatility (log K_AW from −6.53 to −2.13) and lipophilicity (log K_OW from 1.26 to 4.92) was investigated with respect to the influence of these physicochemical properties on their algal toxicity in different assays. Therefore the EC₅₀ values were determined with a microplate assay based on ISO 8692 protocol and the results were compared with those of an established algal growth inhibition test conducted in air tight glass vessels. Using the ratio of the EC₅₀ values, a clear connection between biological response and volatility as well as lipophilicity of test substances could be detected. Chemicals with a log K_OW higher than 3 or a Henry coefficient log K_AW higher than −4 were identified as less effective in the microplate assay than in the comparative assay. The loss in nominal concentration due to physicochemical properties could be shown to contribute to this using HPLC analysis. Consequently, when using microplate assay’s one should be aware that lipophilic and volatile chemicals might be underestimated in their toxicity, which could be indicated from evaluating related physicochemical properties modelled from structural information prior to an experimental investigation.     

Cu^2＋、Zn^2＋对生物脱氮系统的影响

Cu^2＋和Zn^2＋是污水处理工艺中经常遇到的金属离子。在驯化好的活性污泥系统中，研究了金属离子Cu^2＋和Zn^2＋在0～100mg／L浓度下对活性污泥生物脱氮系统的影响。试验发现Cu^2＋＞5mg／L、Zn^2＋＞30mg／L时，对硝化过程具有明显的抑制作用，在同样浓度的试验条件下cu“对硝化过程的抑制作用比Zn^2＋大。Cu^2＋≤0．5mg／L时对反硝化过程具有一定的促进作用，有助于提高TN的去除效果；Cu^2＋＞0．5mg／L时，对反硝化产生抑制作用，随着浓度的增加，TN去除率逐渐下降。Zn^2＋不影响反硝化过程，仅在大于30mg／L时，对硝化过程产生抑制作用。重金属Cu^2＋对生物脱氮系统的影响明显强于Zn^2＋。     

基于社会网络分析的江西各地市公路行业碳排放的关联与分异特征研究

针对各地公路碳排放的空间差异与关联特征，制定合理的低碳策略，实现各地协同碳减排，是行业可持续发展的热点问题。以江西省为研究对象，采用空间自相关、社会网络分析和引力模型等分析11地市公路行业碳排放的空间差异与关联，识别社会网络的结构特征及其演变趋势，明确不同地市在网络中的地位和作用，结果显示：（1）公路货运是公路行业碳排放的最主要来源；（2）江西省公路行业碳排放整体上呈现空间随机分布，不存在全局的空间聚集性，且局部空间聚集特征不断变化；（3）公路行业碳排放网络逐渐从南昌、新余双中心结构演变为南昌为主的单中心结构，网络的协同作用整体呈减弱趋势，核心地市对外围地市的影响力和带动作用不足。     

Dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities

The dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities were investigated. The results revealed that carbendazim dissipation was little affected by chloramphenicol, whereas chloramphenicol dissipation was found to be retarded significantly by the presence of carbendazim. The inhibitory effect of carbendazim on the fungal:bacterial ratios was increased by the presence of chloramphenicol, and the inhibitory effect of chloramphenicol on neutral phosphatase was increased by the presence of carbendazim. Carbendazim increased soil catalase and urease activities, but this increase was partially diminished by the presence of chloramphenicol. Little interaction was observed between carbendazim and chloramphenicol with regard to their influence on soil invertase. The results obtained in this study suggest that combinations of fungicides and antibiotics may alter the compounds’ individual behaviors in soil and their effects on soil enzymes.     

Effect of six kinds of scale inhibitors on calcium carbonate precipitation in high salinity wastewater at high temperatures

Precipitation of calcium carbonate(Ca CO3) scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one(scale inhibitor SQ-1211) to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and p H on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca2+was 1600 mg/L, the scale inhibition rate could reach 90.7% at 80°C at p H 8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of Ca CO3 changed from calcite to aragonite.