不同耕作措施对黑土碳排放和活性碳库的影响

农田耕地土壤碳的动态变化是陆地生态系统碳循环的研究热点,明确人为干预下土壤碳固定及排放的主导途径和因素,可以为制定农田固碳减排管理措施提供理论基础。为探究不同耕作措施下农田土壤碳循环特征,在东北典型黑土区黑龙江省青冈县设置不同耕作措施和秸秆还田方式的玉米种植田间试验,包括深松25 cm(T1),深松25 cm+秸秆粉碎还田(T2),深松35 cm(T3),深松35 cm+秸秆粉碎还田(T4),深松35 cm+秸秆粉碎覆盖还田(T5);对5种处理下土壤呼吸速率及碳累积排放量、土壤活性有机碳库组分和作物产量进行了分析。结果表明,秸秆粉碎还田显著增加了土壤碳排放,并且秸秆粉碎翻埋还田在增加土壤有机碳库和提高作物产量方面的效果优于秸秆粉碎覆盖还田。     

Trihalomethanes Adsorption on Activated Carbon Fiber and Granular Activated Carbon

Isotherms and the effects on activated carbon fiber (ACF), compared with granular activated carbon (GAC), adsorption of trihalomethans (THMs) in water were studied. It was found that the isotherms for ACF or GAC were not agree to Langmuir equation well, but successfully correlated by Freundlich equation, and the coefficients of Freundlich isotherm were given and compared to isotherms reported in the literatures for THMs. ACF and GAC adsorbing THMs was exothermic, isotheric heats of adsorption were calculated and increased with increasing bromine substitution in CHCl₃. The adsorptive capacity of ACF was about two-fold greater than that of GAC, and increased with THMs more hydrophobic or bromine substitution. pH value and temperature had no significant effect on the adsorptive capacity of ACF. The adsorptive capacity of GAC was decreased with temperature slightly. The adsorptive capacities of ACF or GAC was increased with the THMs initial concentration rising. Fixed-bed reactor studies were measured, the amount of THMs adsorbed on ACF column at saturation was much greater than that of GAC at the same operating conditions, and the running time of ACF column was two-fold longer than that of GAC column. The mass transfer zones of ACF column were less than those of GAC column and decreased as the chlorine atoms in CHCl₃ substituted by bromine atoms, while the mass transfer zones of GAC column were quite uniform.     

Adsorption of Nonylphenol onto Granular Activated Carbon

The applicability of granular activated carbon (GAC)filtration for the removal of the xeno-estrogenicmicropollutant nonylphenol (NP) is evaluated using batchadsorption data. From the obtained adsorption data, it wasapparent that with contact times of 4 d and 24 hr and GACdosages of 1 and 0.1 g L^-1 no saturationof the GAC could be obtained with NP total contaminantloadings up to 10 000 μg L^-1.Higher NP concentrations could not be applied due to its lowwater solubility (～5 mg L^-1). The influence of temperature(4 or 28 °C) on NP sorption onto GAC was negligible.The results showed that the sorption capacity of GAC for NPwas at least 100 mg g^-1 GAC. According to thesedata it can be concluded that a full-scale GACfilter unit will be sufficient to remove environmentallyrelevant NP concentrations of 10 μg L^-1.Consequently, the existing GAC treatment technology indrinking water treatment should protect the consumer from theintake of the xeno-estrogenic micropollutant NP via drinkingwater. The sorption capacity of dissolved humic acids (DHA)for NP is considerable at liquid NP concentrations of 10 μgL^-1 and the affinity of DHA for GAC is not significant.These observations suggest that interference on removal of NP onGAC, due to the presence of DHA, can be expected at microgramper liter concentrations of NP. They may warrant the removalof humic substances in treatment steps preceding GAC-filtration.     

高酸度芦苇活性炭的制备及其吸附性能

为实现湿地植物资源化,解决重金属废水难处理问题,本文采用青贮活化法制备高酸度湿地植物质活性炭作为吸附材料去除废水中重金属离子镍Ni(Ⅱ)和镉Cd(Ⅱ),通过XRD、N2吸附/脱附、Boehm滴定和元素分析等表征方法,探究湿地植物在青贮过程中结构变化,以及高酸度活性炭比表面积、孔径结构、官能团数量及表面元素。通过批次实验,研究活性炭对重金属离子镍和镉吸附特性,用Langmuir和Freundlich模型对实验数据进行拟合。结果表明:青贮活化法能够有效地提高活性炭的表面酸度,从而提升对重金属离子的吸附能力。通过吸附实验,高酸度活性炭对Ni(Ⅱ)和Cd(Ⅱ)的吸附过程可以用Langmuir模型进行很好的描述,并且活性炭对重金属离子的吸附过程主要由化学吸附控制。     

Bacteriological Changes Associated with Granular Activated Carbon in a Pilot Water Treatment Plant

Bacteriological analysis were performed on collected water samples from a conventional water treatment pilot plant in Cincinnati, Ohio in which granular activated carbon (GAC) has been used as the final process to assess the impact of GAC on the bacteriological quality and incidence of antibiotic resistant bacteria in water produced. Heterotrophic bacterial counts (HPC) at 20 °C was stabilized at 10² to 19⁴ cfu mL^-1 and did not markedly differ at different water treatment processes. On the other hand, slight reduction in HPC was observed for the effluent produced from sand filter and GAC contactors. Effluents produced from both the sand filter and GAC contactors showed 2 log reduction in coliforms count. Fecal coliform showed the same rate of reduction as a result of sand filtration, while it reached undetectable numbers in the effluent of GAC contactors. Subculturing the isolated strains in tryptic soy broth revealed that 61.3, 61.5, 12.6 and 8.5% of HPC at 28 °C, total coliforms and fecal coliform, respectively were non-culturable. In this case, R2A or R3A broth was used as subculturing media. The incidence of coliform resistant strains among isolates varied significantly according to the source of water samples. Multiple antibiotic resistance (MAR) was not always high in the same samples in which the overall resistance was high. The species composition varied considerably in different water samples. Selection for bacteria exhibiting resistance to antibiotic or antibiotics was observed under some experimental conditions using different doses of chlorine. The antibiotic resistance character was mostly transferable. As a conclusion, the use of GAC has no observable adverse effect on the bacteriological quality of the water produced from the pilot plant under investigation.     

土壤无机离子对CO2封存泄漏的响应

[目的]旨在研究土壤中无机离子含量对CO2封存泄漏的响应。[方法]在CO2人工气候箱中分别种植绿豆、荞麦两种作物,模拟10 000,20 000,40 000和80 000μl/L这4个浓度梯度,外加一个空白浓度对照组,观测土壤无机离子含量变化及作物生长情况。[结果]随着大气中CO2浓度升高,土壤中的Cl-,K+,Ca2+含量基本先降后升,SO2-4呈现先升后降再升再降的M型变化趋势,Na+,Mg2+,HCO-3变化不显著,而CO2-3始终未检出。绿豆、荞麦的光合速率及生物量均在CO2浓度10 000μl/L时达到最大。[结论]大气中CO2浓度升高一方面会直接影响土壤溶液酸碱度、碳平衡,发生离子沉淀;另一方面还会影响作物和微生物生长,改变其对土壤离子的吸收和代谢。     

稻草秸秆活性炭的制备及其表征

利用廉价的农业废弃物稻草秸秆,选择磷酸氢二铵为活化剂在不同的活化温度和预氧化条件下来制备活性炭。应用N2吸附－脱附等温曲线对产品表面孔结构进行表征,采用热重分析来研究稻草秸秆的活化过程。结果表明,同其他处理方法相比,先浸泡后预氧化处理并在700℃下活化制得的样品不但有最大的比表面积（1078．21m^2·g^-1）,其得率和碘吸附值也最大,分别为39．75％和636mg·g^-1热重分析表明磷酸氧二铵的浸泡可以增加稻草秸秆的热稳定性。不论是否经过预氧化,制得的样品平均孔径在2-3nm。（NH4）2HPO4的浸泡可以明显地增加样品的比表面积从而增加其吸附性能。     

Changes in Rainwater pH associated with Increasing Atmospheric Carbon Dioxide after the Industrial Revolution

Water, Air, & Soil Pollution - This paper examines the historical change in the pH of natural rainwater due to increased atmospheric CO2 from 1800 until 2007, giving predicted change in 2100....     

Remediation of Organochlorine Pesticide-Contaminated Soils by Surfactant-Enhanced Washing Combined with Activated Carbon Selective Adsorption

Remediation of organochlorine pesticide (OCP)-contaminated soils is urgently required especially in China. The present study investigated the removal of OCPs from two soils by triton X-100 (TX-100)-enhanced washing coupled with powdered activated carbon (PAC) adsorption treatment of the solution. Two contaminated soils, including a silt clay contaminated with chlordene, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethanes (DDDs), and dichlorodiphenyltrichloroethane (DDT) and a sandy loam containing chlordanes and mirex, were selected. Effects of varied operating parameters, including TX-100 dosage, liquid/soil (L/S) ratio, and extraction time, on the contaminant removal were examined. For both soils, OCP removal was clearly enhanced with increasing TX-100 in extraction solution and L/S ratio. Meanwhile, the removal efficacy was also impacted by soil texture and characteristics and contents of the contaminants. Moreover, by using PAC as an absorbent, a significant decrease in the contaminants in the extraction solutions was detected, and TX-100 could be further reused. Our investigation suggests that surfactant-enhanced washing combined with activated carbon selective adsorption would be an alternative to remediate OCP-contaminated soils.     

Carbon Dioxide Flux in a Subtropical Agricultural Soil of China

Red soils, one of the typical agricultural soils in subtropical China, play important roles in the global carbon budget due to their large potential to sequester C and replenish atmospheric C through soil CO₂ flux. Soil CO₂ emission was measured using a closed chamber method to quantify year-round soil flux and to determine the contribution of soil temperature, dissolved organic carbon (DOC) and soil moisture content to soil CO₂ flux. Soil flux was determined every 10 d during the experiment from August 1999 to July 2000, at the Ecological Station of Red Soil (the Chinese Academy of Sciences). In addition, diurnal flux measurements for 24 hr were made on August 5 and November 5, 1999 during this experiment. The average soil fluxes from 2 hr measurements between 9:00 and 11:00 can be regarded as the representative of daily averages. Soil CO₂ fluxes were generally higher in summer and autumn than in winter and spring, averaged 7.16 and 0.86 g CO₂ m^-2 d^-1 for the former and latter two seasons, and had a seasonal pattern more similar to soil temperature and DOC than soil moisture. The annual soil CO₂ flux was estimated as 1.65 kg CO₂ m^-2 yr^-1. Regressed separately, the reasons for soil flux variability were 86.6% from soil temperature, 58.8% from DOC, and 26.3% from soil moisture, respectively. Regressed jointly, a multiple equation was developed by the above three variables that explained 85.2% of the flux variance, but only soil temperature was the dominant factor affectingsoil flux, with significant partial correlation coefficient (r² = 0.804, p ≤ 0.05), through stepwise regression analysis. Based on the exponential equation using soil temperature, the predicted fluxes were calculated and were essentially equal to the measured ones throughout the experiment. No significant difference was detected between the predicted average and the measured one. The exponential relationship describing the response of soil CO₂ flux to the changes in soil temperature should accurately predict soil CO₂ flux from red soils in subtropical China.     

Adsorption of Dioxin by Bag Filter + Powdered Activated Carbon

A novel bag filter + powdered activated carbon technique is here proposed to address the low utilization rate of powdered activated carbon and the low dioxin removal rate associated with the conventional activated carbon injection + bag filter technique, better known as the fly ash + activated carbon + bag technique. In this method, dibenzofuran serves as a dioxin simulant. The effect of the adsorption temperature and dibenzofuran inlet concentration on the adsorption performance of activated carbon was studied using a filter cloth adsorption device with an inner diameter of 25 mm, and the adsorption performances of fly ash, activated carbon, and fly ash +5% activated carbon were compared. The results showed that activated carbon exhibited a higher adsorption efficiency and remained highly efficient longer than fly ash +5% activated carbon. When the dibenzofuran inlet concentration was 0.0956 g/m³ (about one million times the concentration of dioxin in the flue gas of incinerated waste), the duration of the high-efficiency (>90%) adsorption of the powdered activated carbon (thickness 1.2 mm) on the filter cloth was over 7 h. These results prove that the replacement of fly ash + activated carbon + filter bag with powdered activated carbon + bag filter can significantly improve the removal efficiency of the dioxin in waste incineration flue gas and the utilization rate of activated carbon.     

高锰酸钾复合药剂与粉末活性炭联用组合对微污染源水的强化混凝效能

通过对高锰酸钾复合药剂、粉末活性炭、预氯化工艺的对比及它们之间的联用组合工艺的试验研究，证明高锰酸钾复合药剂与粉末活性炭联用组合对微污染水的除色、除味、降低出水浊度效果明显。从而为老水厂寻找了一种简便易行、经济有效的去污染手段。     

高锰酸钾复合药剂与粉末活性炭联用组合对微污染源水的强化混凝效能

通过对高锰酸钾复合药剂、粉末活性炭、预氯化工艺的对比及它们之间的联用组合工艺的试验研究 ,证明高锰酸钾复合药剂与粉末活性炭联用组合对微污染水的除色、除味、降低出水浊度效果明显。从而为老水厂寻找了一种简便易行、经济有效的去污染手段。     

超临界二氧化碳萃取红辣椒的夹带剂筛选

研究了夹带剂：水、乙醇和丙酮对超临界二氧化碳萃取及分离红辣椒中辣素和红色素的影响。提出了定量评价夹带剂效应的两个参数：增大系数和选择性。研究表明,三种夹带剂对辣素和红色素都有不同程度的夹带增大效应。水为夹带剂能提高辣素的选择性,有利于分离;而乙醇和丙酮的添加,不利于分离。以水为夹带剂,采用一级萃取二级分离流程。在１９～２０ＭＰａ的压力下萃取,把辣素和红色素一起萃取出来;然后减压到中间压力,实施第一级分离,色素单独沉淀析出,获得纯净红色素产品;最后把流体降至低压,第二级分离,使溶解的辣素沉淀,第二级分离的萃取物中,以辣素为主而带有少量红色素。     

活性炭纤维对水中3，4-二氯苯胺的吸附行为

通过静态吸附实验和动态吸附实验,研究了pH值、电解质（NaCl）、活性炭纤维用量等因素对用棉花秸秆制备的活性炭纤维吸附水中3,4-二氯苯胺的影响,同时从动力学和热力学角度考察了活性炭纤维对3,4-二氯苯胺的吸附行为。结果表明,棉花秸秆制备的活性炭纤维可以有效地吸附3,4-二氯苯胺,电解质（NaCl）的存在对吸附有抑制作用;准二级动力学模型能够很好地描述3,4-二氯苯胺在活性炭纤维上的吸附行为;吸附等温线符合Langmuir方程,吸附行为是一个自发放热的物理吸附过程。     

Activated Carbon Adsorption of Fuel Oxygenates MTBE and ETBE from Water

In order to assess as to whether treated textile effluent could be safely used to irrigate some winter vegetables, growth room experiments were conducted. Varying levels of treated and untreated textile effluents were applied to germinating seeds of some winter vegetables and their effect was evaluated on germination and early growth stage using seed germination, growth, and biochemical attributes. From the results, it was obvious that textile effluent reduced seed germination and early growth of all vegetables. However, this effect was more pronounced at the highest concentration of textile effluent. Furthermore, treated textile effluent did not show any inhibitory effect on seed germination of all vegetables. Photosynthetic pigments such as chlorophyll a and b, and protein contents were higher in the leaves of all vegetable plants irrigated with treated textile effluent than those of supplied with untreated textile effluents. It has been observed that heavy metals were lower in concentration in treated textile effluent as compared with untreated textile effluent. However, germination and growth responses of all three vegetables were different to treated or untreated textile effluents. Furthermore, the Raphanus sativus ranked as tolerant followed by Brassica campastris and Brassica napus based on germination and growth responses. In conclusion, in view of shortage of water, textile effluent could safely be used for irrigation to vegetables after proper processing.