竹叶与餐厨垃圾厌氧共消化工艺

将黄金竹和毛竹的竹叶分别与餐厨垃圾厌氧共消化,通过分析消化过程中的产气量、pH、COD、NH4+-N和VFAs变化,探讨添加不同竹叶对餐厨垃圾厌氧消化效果的影响.实验结果表明,添加毛竹叶显著增强了餐厨垃圾的厌氧消化能力.毛竹叶+餐厨垃圾组的总产气量是餐厨垃圾对照组单独厌氧消化总产气量的3.28倍,甲烷总产量为10.1 L,COD去除率高达83.0％.而添加黄金竹叶对餐厨垃圾厌氧消化的影响则不明显,可能因为黄金竹叶在消化过程中释放了大量挥发性脂肪酸(VFAs),造成体系酸中毒.     

Sorption and photodegradation of chlorpyrifos on riparian and aquatic macrophytes

Surface water bodies may become contaminated via spray drift following pesticide application. In this investigation, the photodegradation and sorption of chlorpyrifos was studied in four riparian macrophytes representative of Mediterranean flora (Phragmites australis, Iris pseudacorus, Equisetum pratense and Typha latifolia). The results of experiments with both the active ingredient and the formulation DURSBAN 48® EC confirm the ability of these species to interact with chemicals such as chlorpyrifos. The maximum sorption of chlorpyrifos at equilibrium was observed in Phragmites australis (22%). And, the maximum instantaneous sorption of chlorpyrifos was observed in the dried biomass of Phragmites australis (49%). The epicuticular waxes present on leaves influence photodegradation processes, resulting in a decrease in chlorpyrifos persistence depending on the nature of the extract. The half-life of chlorpyrifos residues in leaf waxes decreased from 34 to 99 minutes when irradiated.     

Low-heat alkaline pretreatment of biomass for dairy anaerobic codigestion

In this research, low-heat alkaline pretreatment was evaluated to determine the extent to which urban landscape waste (yard waste), corn stover, and switchgrass could be codigested under conditions typical of US farm-based anaerobic digestion (AD). Waste heat from combined heat and power (CHP) units associated with AD could make such pretreatment economical. Short-term batch digestion studies and 8-week continuous-feed studies were used to screen and evaluate various pretreatment conditions. Results indicate that maple and oak leaves did not digest well, even with pretreatment. Pretreatment did improve digestion of corn leaves and stalks as well as switchgrass. However, these materials also digested reasonably well even without pretreatment. No digester operational problems were observed during continuous-feed studies of intermittently stirred bench top digesters, but optimal levels of alkali, temperature, and pretreatment time may be specific to the feedstock, particle size, and digester loading rate. Results suggest that some common lignocellulosic biomass materials, such as corn stover and switchgrass, could be successfully codigested in many existing farm-based digesters. Interestingly, without pretreatment, switchgrass digestion improved over 20-fold when digested with seed culture from a dairy digester compared to seed culture from a municipal digester, suggesting that culture acclimation could be as important as pretreatment in improving digestion of specific lignocellulosic feedstocks.     

Behavior of pyrimethanil,pyraclostrobin, boscalid,cypermethrin and chlorpyrifos residues on raspberry fruit and leaves of Laszka variety

The purpose of the research conducted was to investigate and evaluate the behavior of pyrimethanil, pyraclostrobin, boscalid, cypermethrin and chlorpyrifos, the active ingredients of selected fungicides and insecticides, on ripe fruit and in fully developed leaves of raspberry of the Laszka variety. The field trial was carried out in the period of one month starting from the first fruit picking. The results obtained indicated that residue levels on the day of the first crop picking did not even approximate the corresponding EU-MRLs (http://ec.europa.eu/sanco_pesticides). Individual substances in raspberry fruits and leaves disappeared at a similar rate. As a result of chlorpyrifos application to the soil, its residue in fruits and leaves occurred for the whole period of fruit bearing, though in fruit they dropped successively. To produce raspberries with residues below or equal to 0.01 μg g^?1, the application of pesticides should be stopped at least 2–3 weeks before the first crop picking, and on condition that an appropriate preparation (active in low doses) is applied to the last treatments.     

北京市常见树种叶片吸滞颗粒物能力时间动态研究

目前,以显微镜观察叶片微观结构已被证明是研究叶片吸滞颗粒物机理的有效方法.本文利用颗粒物再悬浮法和原子力显微镜,观察了北京市主要园林树种吸滞颗粒物的能力和叶片的表面特征,并探讨了不同树种吸滞颗粒物能力随时间变化的规律及叶片微观结构对滞尘能力的影响.结果表明:1针叶树种吸滞总悬浮颗粒物(TSP)能力大于阔叶树种,排序为:油松((27.13±0.44)μg·cm~(-2))白皮松((10.74±0.23)μg·cm~(-2))五角枫((8.24±0.18)μg·cm~(-2))柳树((7.71±0.18)μg·cm~(-2))银杏((6.43±0.17)μg·cm~(-2))杨树((6.17±0.19)μg·cm~(-2)),不同时间段树种滞尘能力不一致;2观测期间,针叶树种吸滞TSP和粗颗粒物(PM10)能力随月份呈U型趋势,在8、9和10月最低,随后又逐渐上升,而阔叶树种吸滞颗粒物能力则呈倒U型趋势,在7、8月最高,但不同树种吸滞细颗粒物(PM2.5)能力随时间变化均无明显规律性;3通过对叶片表面原子力显微镜(AFM)结构观测发现,叶片表面粗糙度越大,其吸滞颗粒物能力越强.     

Efficiency of removal of cadmium from aqueous solutions by plant leaves and the effects of interaction of combinations of leaves on their removal efficiency

Removal of cadmium from aqueous solutions using 20 species of plant leaves and combinations of these leaves have been studied. Several factors affecting the removal efficiency have been studied. The most efficient types of plant leaves for the removal of cadmium are those of styrax, plum, pomegranate and walnut. The interaction effect of the combined leaf samples on the efficiency of removal of cadmium has been found to be additive in combinations involving styrax plant leaves but seems to be antagonistic in all other combinations. The optimum experimental conditions for removal of cadmium have been found to be at pH 4.1, using high concentrations of naturally dried plant leaves, using ground leaves and to remove cadmium from agitated aqueous solutions. The percentage of metal removed at an initial cadmium concentration of 10mg/l by the most efficient types of leaves have been found to be 85% for styrax leaves, 85% for plum leaves, 80% for pomegranate leaves, 78% for walnut leaves and 77% for meddler leaves. The presence of foreign ions or complexing agents has been found to reduce the efficiency of removal of cadmium by plant leaves. About 80-85% of the cadmium in charged plant leaves has been released under the influence of changing the pH of the solution, addition of competing ions and the addition of EDTA. The results of removal of cadmium by plant leaves have been found to follow the Freundlich adsorption isotherm, first-order reaction with respect to cadmium and to have intra-pore diffusion as the rate-limiting step.     

Groundwater-soil-crop relationship with respect to arsenic contamination in farming villages of Bangladesh--a preliminary study

To clarify the groundwater-soil-crop relationship with respect to arsenic (As) contamination, As concentration was measured in tubewell (TW) water, surface soil from farmyards and paddy fields, and fresh taro (Colocasia esculenta) leaves from farmyards in the farming villages of Bangladesh. The As concentration in TW water from farmyards was at least four times higher than the Bangladesh drinking water standard, and the concentration in fresh taro leaves was equal to or higher than those reported previously for leafy vegetables in Bangladesh. As concentration of surface soils in both farmyards and paddy fields was positively correlated with that of the TW water. Further, the concentration in surface soil was positively correlated with levels in fresh taro leaves in the farmyard. This study, therefore, clarified the groundwater-soil-crop relationship in farmyards and the relationship between groundwater-soil in paddy fields to assess the extent of As contamination in Bangladeshi villages.     

榕树叶对铀吸附的研究

为探讨榕树叶对铀的吸附特性 ,考察 pH、吸附时间、含重金属溶液浓度对吸附能力的影响 ,绘制出吸附等温线 ,并求出Langmuir曲线和Freundlich曲线相应方程 .结果表明 :榕树叶在pH =3 ,吸附时间t=2 0min时吸附铀的能力最高 .重金属离子浓度越高 ,榕树叶的吸附量越高。     

北京9个树种叶片滞尘量及叶面微形态解释

不同树种叶片对PM(颗粒物)的滞留能力存在较大差别,并与其表面特性密切相关. 在北京市选择空气相对清洁的植物园和污染严重的国贸桥2个地点,测定了9个常见绿化树种——白蜡、大叶黄杨、垂柳、国槐、毛白杨、玉兰、紫叶李、元宝枫和银杏的单位叶面积滞尘量及其粒径组成,并观测了各树种叶面微形态结构. 结果表明,国贸桥和北京植物园9个树种PM、PM>10、PM_2.5~10和PM_2.5平均滞留量之比分别为1.64、1.60、1.89和2.50,该比值随PM粒径减小呈增大的趋势. 环境污染会改变树木叶片表面结构与性质,从而改变其滞尘能力. 叶面沟槽深且间距大、润湿性好、气孔密度(>189 N/mm2)(以单位面积气孔数计)较大有利于滞尘;气孔密度(>217 N/mm2)更大的叶片有利于滞留PM_2.5~10. 此外,叶面绒毛数量直接影响PM_2.5滞留量,在不同污染程度下均表现为有绒毛树叶的PM_2.5滞留能力更强.      

Optimization of methyl orange removal from aqueous solution by response surface methodology using spent tea leaves as adsorbent

The effective disposal of redundant tea waste is crucial to environmental protection and comprehensive utilization of trash resources. In this work, the removal of methyl orange （MO） from aqueous solution using spent tea leaves as the sorbent was investigated in a batch experiment. First, the effects of various parameters such as temperature, adsorption time, dose of spent tea leaves, and initial concentration of MO were investigated. Then, the response surface methodology （RSM）, based on Box- Behnken design, was employed to obtain the optimum adsorption conditions. The optimal conditions could be obtained at an initial concentration of MO of 9.75 mg·L-1, temperature of 35.3℃, contact time of 63.8 min, and an adsorbent dosage 3.90 g· L-1. Under the optimized condi- tions, the maximal removal of MO was 58.2%. The results indicate that spent tea leaves could be used as an effective and economical adsorbent in the removal of MO from aqueous solution.