助剂作用下超声浸取电解锰渣

用8-羟基喹啉、黄原酸钾、十六烷基三甲基溴化铵、磷酸三丁酯、柠檬酸5种物质作浸取助剂,考察了助剂作用下超声辅助浸取法从电解锰渣中提取锰的工艺条件。实验结果表明：用1%（质量分数）柠檬酸作浸取助剂,在固液比（g/mL）为1∶4、酸矿比（mL/g）为0.3∶1、浸取温度为70℃的条件下,超声浸取15min,锰浸出率平均可达57.28%,是加热酸浸法锰浸出率的2.72倍,是无助剂超声辅助浸取法锰浸出率的1.52倍。     

厌氧-好氧生物反应器填埋工艺特性研究

基于生物反应器填埋技术,研究1种填埋场地循环操作的厌氧-好氧生物反应器填埋工艺,设计了该工艺模拟装置并研究了其运行工艺特性.厌氧阶段主要通过渗滤液回灌控制反应器工艺条件,主要试验结果为,pH值,R1在 6周后可上升至6.7～7.8,R2在17周内一直低于6.8;渗滤液COD浓度,R1在13周时下降至10?617 mg/L,R2在5周后上升至60?000 mg/L后长期趋于稳定;填埋气累计产量,R1在8周达到44%,R2几乎不产气.衡量稳定化可以分别采用渗滤液pH、COD浓度及BOD₅/COD的减少率、填埋气的累计产率等指标来判断,并据此转换为好氧填埋运行.好氧阶段主要是通过强制通风来减少恶臭和水分,主要试验结果为,通风19d氨气浓度降为1.16 mg/m³,通风23d后恶臭浓度降为19;通风14d后含水率降为26%.完成此阶段的工艺指标值可依据矿化垃圾开采的最终用途确定.对主要试验数据进行了数值模拟.厌氧-好氧填埋过程的微生物演替经RISA分析,有4个优势菌群,一些兼性菌群在厌氧-好氧阶段起着重要的承前启后作用.     

水葫芦厌氧发酵工程化应用研究

在实验室进行了接种率、破碎程度和温度等对水葫芦厌氧发酵产气率的影响研究.结果表明:水葫芦在中温35℃下,水葫芦和接种污泥的最佳接种率为1:1(总固体物质比),经简单切分后产气率最高,原料产气率为0.540 m3/d(以每千克固体含量计,下同);高温消化与中温消化相比,产气率无明显优势.在实验室研究基础上,对中国农村地区原有的沼气发酵工艺进行适当的改进,设计构建了5 m3 15 m3(酸化池 产气池)两级反应池,该反应池在夏季常温条件下运行良好,80 d的平均原料产气率达0.305 m3/d.     

鲢鱼放养控制北京城市河湖水华试验研究

介绍了利用鲢鱼控制北京城市河湖水华的试验研究,通过不同放养密度(0、17、51和103 g/m3)的现场围隔试验,对鲢鱼放养对水体水质和浮游生物的影响进行了分析.研究结果表明,鲢鱼放养使有鱼围隔中浮游生物量极低,从而使浮游植物基本不受浮游动物影响,而直接受鱼类影响;同时,中等密度(51 g/m3)的鲢鱼放养使水华蓝藻和微小藻的生长均得到了有效抑制,使藻类生物量最低.     

A study on oxidative degradation of polyacrylamide in wastewater with UV/FENTON/C4H4O62−

The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C₄H₄O₆^2? system. The factors such as molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C₄H₄O₆^2? system were investigated. The experimental results showed that adding C₄H₄O₆^2? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H₂O₂, Fe²⁺, and C₄H₄O₆^2? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2? was 10:1:1), the pH value was 3.0.     

Steam reforming of glycerol for syngas generation under cold plasma conditions: A DFT study

Density functional theory (DFT) has been used to investigate the reaction pathways with steam reforming of glycerol under cold plasma conditions. Total energies, energy barriers, and reaction enthalpies at 298.15 K have been calculated at the GGA/PW91/DNP level. The calculation shows that, with the presence of steam, the energy barrier of glycerol conversion is reduced and the conversion from glycerol to H₂ and CO is promoted under cold plasma conditions. The formation of syngas was through a multi-step pathway via the conversion of OHCH₂CHOH, CH₂OH, CH₂O, HCO,·and CH₃, while the recombination of H generated extra H₂. The synthesis of hydrocarbons are from the recombination of·CH₃,·CH₂, and·CH, which could be primarily generated through glycerol dissociation. The structure of glycerol anion was also studied in this work, and it was less stable than the neutral molecule. The route for the formation of OHCH₂CHOH·and CH₂OH·from glycerol anion is thermodynamically favorable.     

Drought-tolerant <Emphasis Type="Italic">Streptomyces pactum</Emphasis> Act12 assist phytoremediation of cadmium-contaminated soil by <Emphasis Type="Italic">Amaranthus hypochondriacus</Emphasis>: great potential application in arid/semi-arid areas

Microbe-assisted phytoremediation provides an effective approach to clean up heavy metal-contaminated soils. However, severe drought may affect the function of microbes in arid/semi-arid areas. Streptomyces pactum Act12 is a drought-tolerant soil actinomycete strain isolated from an extreme environment on the Qinghai-Tibet Plateau, China. In this study, pot experiments were conducted to assess the effect of Act12 on Cd tolerance, uptake, and accumulation in amaranth (Amaranthus hypochondriacus) under water deficit. Inoculated plants had higher Cd concentrations (root 8.7–33.9 %; shoot 53.2–102.1 %) and uptake (root 19.9–95.3 %; shoot 110.6–170.1 %) than non-inoculated controls in Cd-treated soil. The translocation factor of Cd from roots to shoots was increased by 14.2–75 % in inoculated plants, while the bioconcentration factor of Cd in roots and shoots was increased by 10.2–64.4 and 53.9–114.8 %, respectively. Moreover, inoculation with Act12 increased plant height, root length, and shoot biomass of amaranth in Cd-treated soil compared to non-inoculated controls. Physiochemical analysis revealed that Act12 enhanced Cd tolerance in the plants by increasing glutathione, elevating superoxide dismutase and catalase activities, as well as reducing malondialdehyde content in the leaves. The drought-tolerant actinomycete strain Act12 can enhance the phytoremediation efficiency of amaranth for Cd-contaminated soils under water deficit, exhibiting potential for application in arid and semi-arid areas.     

Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an,China

TSP and PM_2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, F^?, Cl^?, NO₃^?, and SO₄^2?). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH₄⁺, K⁺, F^?, Cl^?, NO₃^?, and SO₄^2? were more abundant in PM_2.5 than TSP but the opposite was true for Mg²⁺ and Ca²⁺. PM collected on hazy days was enriched with secondary species (NH₄⁺, NO₃^?, and SO₄²) while PM from straw combustion showed high K⁺ and Cl^?. Firework displays caused increases in K⁺ and also enrichments of NO₃^? relative to SO₄^2?. During DSs, the concentrations of secondary aerosol components were low, but Ca²⁺ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO₄^2?/K⁺, NO₃^?/SO₄^2?, and Cl^?/K⁺) proved effective as indicators for different pollution episodes.     

Concentrations,seasonal variations,and transport of carbonaceous aerosols at a remote Mountainous region in western China

Carbonaceous aerosol concentrations were determined for total suspended particle samples collected from Muztagh Ata Mountain in western China from December 2003 to February 2006. Elemental carbon (EC) varied from 0.004 to 0.174 μg m^?3 (average = 0.055 μg m^?3) while organic carbon (OC) ranged from 0.12 to 2.17 μg m^?3 and carbonate carbon (CC) from below detection to 3.57 μg m^?3. Overall, EC was the least abundant fraction of carbonaceous species, and the EC concentrations approached those in some remote polar areas, possibly representing a regional background. Low EC and OC concentrations occurred in winter and spring while high CC in spring and summer was presumably due to dust from the Taklimakan desert, China. OC/EC ratios averaged 10.0, and strong correlations between OC and EC in spring–winter suggest their cycles are coupled, but lower correlations in summer–autumn suggest influences from biogenic OC emissions and secondary OC formation. Trajectory analyses indicate that air transported from outside of China brings ～0.05 μg m^?3 EC, ～0.42 μg m^?3 OC, and ～0.10 μg m^?3 CC to the site, with higher levels coming from inside China. The observed EC was within the range of loadings estimated from a glacial ice core, and implications of EC-induced warming for regional climate and glacial ice dynamics are discussed.     

化学溶胀法分离废弃线路板中金属与基板

废弃线路板的粉碎和所含金属组分的高效解离是后续分选回收的前提条件。本研究分别使用乙二胺等10种溶剂浸泡废弃线路板,比较对线路板中铜箔与基板间剥离强度的影响,从而筛选出4种有代表性的溶剂,即溶剂D、溶剂F、丙酮和水, 比较废弃线路板经化学溶胀后的单体解离度和获得一定粒径分布的颗粒所需的破碎时间。研究结果表明,化学溶胀后破碎能大幅提高金属的单体解离度,浸泡效果的优良排序为：溶剂D>溶剂F>丙酮>水;浸泡时间越长,浸泡温度越高,对剥离强度的降低越有利;使用溶剂D在150℃、3 h或140℃、5 h的工艺下浸泡废弃线路板,可以使铜箔与基板自动脱落。研究结果为后续的分选提供了便利的条件。