超声波协同柠檬酸淋洗去除土壤中的重金属

利用超声波协同柠檬酸淋洗技术处理重金属污染土壤,研究淋洗剂浓度、固液比、超声波处理时间、功率密度对重金属淋洗修复效果的影响,采用Tessier连续提取法分析了只施用柠檬酸和超声波协同施用柠檬酸两种处理方式下,淋洗前后重金属的形态变化,并提出采用内梅罗污染综合指数法来评价淋洗试验对污染土壤的修复效果。结果表明,在淋洗过程中,柠檬酸的作用是主要的,超声波起到良好的强化协同作用,不仅能促进去除可交换态、碳酸盐结合态和铁锰氧化物结合态存在的包括Pb、Cd、Cu在内的重金属,而且有助于去除以这些重金属中以有机结合态和残渣态存在组分。经超声处理后,对土壤中重金属Pb、Cd、Cu的有机结合态和残渣态最优去除率可达89. 1%、94. 5%、69. 3%和49. 4%、86. 5%、49. 7%。     

化学淋洗法对铀污染土壤的修复效果研究

采用振荡淋洗方法对三种粒径(+2mm、-2mm+0.15mm、-0.15mm)某尾矿库周边铀污染土壤进行去污试验,选用盐酸、硝酸、柠檬酸、草酸为淋洗剂,通过控制淋洗浓度、液固比、时间、温度、混合淋洗等因素来确定较优的淋洗条件。结果表明:各淋洗剂对铀污染土壤的去污效果为草酸盐酸硝酸柠檬酸;当淋洗浓度大于0.5mol/L、淋洗时间大于8h或液固比大于10∶1时,其淋洗效果都逐渐趋于稳定;提高淋洗温度可显著提升淋洗效果;选用草酸+盐酸和草酸+硝酸两组较优混合淋洗组合对全粒径土壤进行淋洗时,土壤中铀去除率均达50%以上,总含铀量分别降至27.15、24.32mg/kg,均达到土壤修复目标(40mg/kg)。     

化学氧化强化化学淋洗修复汞污染土壤的试验研究

分别采用KI、Na_2S_2O_3、EDTA溶液对汞污染土壤进行淋洗修复,筛选出修复效果最好的淋洗剂,确定了最佳淋洗工艺条件,并研究了化学氧化对化学淋洗修复汞污染土壤的强化作用。结果表明,Na_2S_2O_3溶液对汞的淋洗效果最好,最佳淋洗工艺条件为Na_2S_2O_3浓度0.05 mol/L、固液比1∶6(g/mL)、淋洗时间5 h,在此条件下,土壤中汞的淋洗效率达到62.54%。化学氧化能大大提高土壤汞的淋洗效率,经化学氧化强化化学淋洗处理后,土样汞含量降低到1.65 mg/kg,且淋洗效率达到78.85%。     

镍钼厂砷污染土壤的淋洗修复研究

以镍钼厂砷污染土壤为研究对象开展淋洗修复试验,选用柠檬酸、草酸、磷酸氢二胺、乙酸铵、氢氧化钠和抗坏血酸等淋洗剂对砷污染土壤进行单一及复合淋洗效果研究,针对淋洗次数、pH值和淋洗剂浓度等因素对淋洗效果的影响进行了分析,并根据单一淋洗修复效果开展复合淋洗研究.试验数据表明:在同一浓度下,当淋洗时间为4 h,固液比为1∶10...     

不同淋洗剂对重金属镉污染土壤有效镉的去除

为解决土壤重金属镉污染问题，在实验室条件下研究了EDTA、柠檬酸、乙醇酸、氯化镁、十二烷基硫酸钠(SDS)对某地镉超标土壤的解吸作用，探究以上几种淋洗剂最佳去除浓度及液固比，并探究几种淋洗剂复配对土壤淋洗效果的影响。结果表明，有效镉的去除效果为EDTA(84%)>乙醇酸(71.02%)>氯化镁(59.45%)>柠檬酸(56.69%)>SDS(11.02%)。在液固比3时淋洗剂达到最佳淋洗效果。复配方案中EDTA与乙醇酸混合体积比为1︰2时达到最大值87.48%，与柠檬酸混合体积比为1︰1时达到85.91%，增强了EDTA的效果，与SDS混合则无明显影响。氯化镁与柠檬酸、乙醇酸复配效率分别可以达到81.5%、82.6%，与SDS混合则呈现轻微拮抗的效果。两种酸与SDS的混合淋洗剂虽未提高重金属去除率，但在调节土壤pH、节省酸用量上起到一定作用。综合淋洗效率及对土壤pH、有机质、阳离子交换量的影响，0.13 mol/L EDTA与1 mol/L柠檬酸在液固比3、混合体积比1︰1时达到最佳淋洗效率85.91%。试验结果可为利用柠檬酸与EDTA复配和氯化镁与两种小分子酸复配提高重金属在土壤介质中的解吸率提供参考，为污染土壤的治理提供思路。     

海泡石辅助含铀土壤化学清洗及对铀富集研究

运用海泡石辅助对铀矿山的含铀土壤进行化学淋洗。研究了铀在不同粒级含铀污染土壤中的含量,通过搅拌淋洗的方法对土壤进行修复研究,探讨了淋洗时间、淋洗剂种类、温度、超声加热等因素对淋洗效果以及海泡石对土壤中铀的富集的影响。结果表明,随着土壤粒径的增大,土壤中的含铀量逐渐减少,即土壤中含铀量与土壤粒径成负相关关系,且除了砂砾外,其他的铀含量均已超过了铀的目标修复值40 mg/kg。在淋洗时间为8 h,淋洗较为充分,淋洗效果达到最佳,成本合适。通过提高温度、超声辅助等方法,既可以使淋洗效果得到明显的提升,对海泡石的富集效果也有很好的促进作用。在淋洗方面,柠檬酸的效果最好,盐酸的效果最差;在海泡石对土壤中铀的富集方面,硫酸淋洗土壤铀的富集倍数最高,柠檬酸淋洗土壤铀的富集倍数最差。通过构建土壤—淋洗液—海泡石的铀迁移路径实现土壤中铀去除并在海泡石中的富集。     

超声与微波辅助柠檬酸对铀污染土壤的淋洗参数研究

选用柠檬酸为淋洗剂，分别在超声和微波辅助下对某铀尾矿附近的污染土壤进行淋洗修复。通过改变柠檬酸浓度、液固比、超声功率和温度、微波功率等参数分析其对土壤中铀去除的影响，得到超声、微波强化淋洗最佳参数。通过构建淋洗动力学模型、金属化学形态分析和XRD分析等手段分析土壤中铀的淋出特性、淋洗前后金属的流动性和稳定性，揭示超声和微波辅助柠檬酸对土壤中铀去除的机理。结果表明，超声、微波强化柠檬酸淋洗铀污染土壤最佳参数为：柠檬酸浓度0.05 mol/L、液固比15 mL/g、超声功率675 W、超声温度40 ℃、超声时间90 min、微波功率300 W、微波时间15 min。两种强化化学淋洗动力学模型基本符合颗粒内扩散模型，与复非均相扩散模型拟合度最高，土壤中铀的扩散类型为复非均相扩散。淋洗过程不仅仅为简单的扩散控制，有可能伴随离子交换作用、络合反应等一系列反应。     

超声辅助柠檬酸化学淋洗复合污染土壤的研究

以某尾矿库周边重金属污染土壤作为研究对象,采用超声辅助淋洗方式,使用柠檬酸作为淋洗剂对Th、Fe、Mn进行去除。通过改变淋洗剂浓度、液固比、温度等条件,比较并分析其对去除量的影响并确定最优条件,结合淋洗动力学模型和热力学参数探究淋洗动力学表征与反应特性。结果表明,柠檬酸超声辅助化学淋洗90 min,适当提高淋洗剂浓度与温度、扩大液固比可提高重金属去除量,最优条件为：浓度0.1 mol/L、液固比为10 mL/g、温度45 ℃。重金属的去除量由大到小依次为Mn>Fe>Th,分别为5 055.09、1 750.98、61.48 mg/kg。三种重金属的淋洗动力学均符合双常数模型,Mn的淋洗动力学同时符合抛物扩散模型。Th和Fe为非均相扩散,Mn为抛物扩散、非均相扩散的混合扩散。Mn平均反应速率最大,为0.82,Th的表观活化能最小,为12.90 kJ/mol,表明Mn与柠檬酸反应更快,Th更易与柠檬酸反应。     

白云石与氟磷灰石的浸出过程热力学

根据化学位图绘制基本原理和方法,分析了Mg2+-Ca2+-H2CO3-H2O、CaCO3·MgCO3-SO2-4-H2O、Ca2+-F--H3PO4-H2O、Ca5(PO4)3F -SO2-4-H2O和Mg2+-H3PO4-H2O体系在常温下的热力学平衡,研究了Ca-Mg-P-H2SO4体系在常温下的溶液-矿物溶解、沉积条件,形象、直观地描述了该溶液体系化学平衡条件及反应进行的限度,为磷矿选矿和湿法浸出过程提供理论依据.结果表明:硫酸可以促进白云石和氟磷灰石的溶解,溶解产物主要是Mg2+、H3PO4,其次是H2PO-4,固相产物主要是硫酸钙晶体;氟磷灰石溶解过程中产生的磷酸在酸性条件下不与溶出的Mg2+反应形成Mg3(PO4)2.     

铬污染场地修复淋洗工艺应用

针对某铬污染场地土壤中六价铬污染严重的问题,通过实验室测试硫酸亚铁、柠檬酸、复合淋洗剂、水等不同淋洗剂的淋洗效果,选用某公司研发的淋洗剂A进行修复,探讨了浓度、淋洗时间等对淋洗效果的影响,并根据试验结果应用于生产实践。实践表明,修复后,铬污染场地土壤中的铬、砷、锌、汞、镍等污染因子均达到标准管制值,各项污染因子去除率均在60%以上,修复效果良好。     

Treatment of Fuel-Oil Contaminated Soils by Biodegradable Surfactant Washing Followed by Fenton-Like Oxidation

Among petroleum-hydrocarbon pollutants, fuel-oil is more difficult to treat compared to gasoline and diesel fuel. The objectives of this bench-scale study were to: (1) develop a two-stage remedial system consisting of surfactant washing followed by Fenton-like oxidation process to remediate fuel-oil contaminated soils; (2) evaluate the effects of residual surfactant and soil organic matter (SOM) on the efficiency of Fenton-like oxidation; (3) evaluate the effect of potassium dihydrogen phosphate (KH2PO4) addition on the stability of H2O2 and oxidation efficiency; and (4) evaluate the possible oxidation products after the oxidation process. In the surfactant washing stage, biodegradable surfactant, Simple Green (SG) (50?g?L?1), was applied to flush fuel-oil contaminated soils with initial total petroleum-hydrocarbons (TPHs) concentration of 50,000?mg?kg?1. Results show that approximately 90% of TPH could be removed after washing with 45 pore volumes (PVs) of SG followed by 25 PVs of deionized water, while the soil TPH concentration dropped from 50,000 to 4,950?mg?kg?1. In the Fenton-like oxidation stage with initial soil TPH concentration was approximately 4,950?mg?kg?1, TPH removal efficiency can be significantly increased with increased H2O2 concentrations. Results also reveal that residual SG and SOM would compete with TPH for oxidants and cause the decrease in oxidation efficiency. An “oxidation-sorption-desorption-oxidation” scheme for soil TPH was observed in this experiment due to the initial sorption of TPH on SOM. Results show that an addition of 2.2 mM of KH2PO4 could increase the stability and half-life of H2O2, but caused the decrease in TPH removal efficiency. The oxidation potential of Fenton-like process was not capable of completely oxidizing fuel-oil to nontoxic end products. The observed by-products after oxidation process contained carboxyl groups with molecular weights similar to their parent compounds. Results from this study indicate that the two-stage remedial system is a promising technology for fuel-oil contaminated soil treatment.     

Osteoid osteoma of the proximal humerus: two misleading cases

OBJECTIVES: To investigate how often the ED ordering of stat serum calcium (Ca+2), magnesium (Mg+2), and phosphorus (PO4(-3)) levels affected clinical treatment; to define the diagnoses of patients for whom Ca+2, Mg+2, and PO4(-3) measurements did affect clinical therapy; and to suggest guidelines for more appropriate ordering of these laboratory tests. METHODS: A retrospective chart review was performed in an academic teaching hospital. All adult ED patients who had Ca+2, Mg+2, or PO4(-3) laboratory testing during the 9-month study period were included and evaluated for potential clinical impact of an abnormal Ca+2, Mg+2, or PO4(-3) laboratory test. RESULTS: 1.477 patients had Ca+2, Mg+2, or PO4(-3) measured while in the ED during the study period. Of these, 260 patients (17.6%) had a total of 312 abnormal Ca+2, Mg+2, or PO4(-3) values as defined by results exceeding +/- 15% of normal reference values. Of these, only 5 patients (0.3%) received treatment for abnormal values in the ED, while 75 patients (5.1%) were treated once admitted to the hospital. In this study, the only diagnostic groups to whom significant treatment was administered were diabetic patients (Ca+2 and PO4(-3); alcoholic patients (Mg+2); and renal failure patients (Ca+2, Mg+2, and PO4(-3). CONCLUSION: These results suggest that stat Ca+2, Mg+2, and PO4(-3) levels seldom affect clinical treatment in the ED. The frequency of ordering these tests may be reduced by obtaining Ca+2, Mg+2, or PO4(-3) measurements only for patients known to be at risk for such abnormalities, based on their existing or suspected diagnoses. The authors suggest obtaining these tests, when indicated, on a "non-stat" basis, with the subsequent laboratory results becoming available in-hospital, where treatment is more likely to occur.     

Endaural reflex diagnosis of cochleovestibular dysfunctions in patients with vascular brain diseases

Results obtained prove that respiration stimulation of mitochondria Ca2+, Sr2+, Mn2+ is determined by transport of these cations to the indicated subcellular structures with participation of Ca2(+)-uniporter. Effect of Cd2+ on respiration of mitochondria is of two-phase character. Concentration of Cd2+ being above 100 microM the stimulation phase is accompanied by the further inhibition of mitochondria respiration. La3+ inhibits respiration of mitochondria. However La3+ and Cd2+ stimulate H+ production by mitochondria, that is not blocked by ruthenium red (10 microM). Probably, the effect of La3+ and Cd2+ on respiration of mitochondria is determined by the change of proton conductivity of mitochondrion membrane. Direct inhibiting effect of Cd2+ on the respiration chain of mitochondria has been established.     

异位固化/稳定化技术修复重金属污染土壤研究

采用异位固化/稳定化技术对某工业园废弃遗留地块重金属污染土壤进行土壤重金属修复。具体工艺为“废渣/土壤+水泥+石灰+稳定剂（氯化铁）”。污染土壤修复流程为：拆除修复地块硬化地坪；清挖污染土壤，转运至地块内遗留车间进行暂存及修复，分批次进行固化/稳定化处理；利用修复土壤，通过养护、检验等手段将处理达标的土壤外运用于工业用地或路基填埋。修复后土壤样品的浸出液pH检测最大值为8.56，Cu、Pb、Zn、Cd、As、Ni、Be、Sb、Co检测最大值分别0.004 4、0.009 0、0.998 9、0.003 4、0.032 0、0.005 2、0.000 4、0.009 0、0.020 9 mg/L，达到各重金属修复标准限值。     

Hypoxia enhances [3H]noradrenaline release evoked by nicotinic receptor activation from the human neuroblastoma SH-SY5Y

We have used the human sympathetic neuronal line SH-SY5Y to investigate the effects of hypoxia on noradrenaline (NA) release evoked by either raised [K+]o (100 mM) or the nicotinic acetylcholine receptor (nAChR) agonist dimethylphenylpiperazinium iodide (DMPP). NA release was monitored by loading cells with [3H]NA and collecting effluent fractions from perfused cells kept in a sealed perifusion chamber. Cells were challenged twice with either stimulus and release was expressed as that evoked by the second challenge as a fraction of that evoked by the first. K+-evoked release was unaffected by hypoxia (PO2 approximately 30-38 mm Hg), but release evoked by DMPP was significantly increased. For both stimuli, replacement of Ca2+o with 1 mM EGTA abolished NA release. K+-evoked release was also dramatically reduced in the presence of 200 microM Cd2+ to block voltage-gated Ca2+ channels, but DMPP-evoked release was less affected. In hypoxia, DMPP-evoked Cd2+-resistant NA release was dramatically increased. Our findings indicate that hypoxia increases NA release evoked from SH-SY5Y cells in response to nAChR activation by increasing Ca2+ influx through the nAChR pore, or by activating an unidentified Cd2+-resistant Ca2+-influx pathway. As acetylcholine is the endogenous transmitter at sympathetic ganglia, these findings may have important implications for sympathetic activity under hypoxic conditions.     

废弃铬渣厂土壤理化性质对微生物多样性的影响

以废弃铬渣厂及其周边表层土壤为研究对象,采集5个区域土壤样品,运用高通量测序技术,揭示了表层土壤微生物多样性及其环境主要影响因素之间的关系。结果表明,有机质（SOM）、总磷（TP）、速效磷（AP）、速效氮（AN）和铵态氮（NH4+-N）含量均在下游最高、车间最低。门水平上,Actinobacteria、Proteobacteria、Acidobacteria和Chloroflexi为优势菌种;纲水平上,Alphaproteobacteria、Actinobacteria、Vicinamibacteria、Gemmaproteobacteria和Chloroflexi为优势菌种。总体来看,在重金属与土壤环境因子共同作用下,微生物丰度更倾向于受土壤环境因子的影响,其中TP、硝态氮（NO3+-N）和大多数重金属元素是微生物变化的主要影响因素;Actinobacteria与大多数重金属具有趋同性,对重金属耐受能力最强;金属元素Pb对细菌的生长繁衍存在一定的选择性,即金属元素的不同对土壤细菌类群的影响有差异。综上,废弃厂区修复治理过程中应考虑营养元素的投入与优势菌种的选择。本文研究加深了对重金属污染土壤微生物的变化及其驱动因子的了解,为废弃铬渣厂受污染的土壤修复提供理论依据。     

Fractions and Bioavailability of Soil Inorganic Phosphorus in the Loess Plateau of China under Different Vegetations

Plants play an important role in soil phosphorus nutrition. However, the effect of plants on phosphorus nutrition in soils of the Loess Plateau of China is not well understood. This study was conducted to reveal the relationships between plants and phosphorus' fractions and availability in the Loess Plateau of China. Twenty-two plant communities were surveyed and soil samples under different plant canopies were collected for the determination of soil properties and inorganic phosphorus fractionation. The results showed that Leguminosae and Lilaceae reduced pH and increased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies, while Labiatae and Rosaceae increased pH and decreased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies. The contents of Ca2P, CasP, AI-P and Fe-P were highly related with soil Olsen phosphorus. They were all higher in soils under Leguminosae and Lilaceae and lower in soils under Labiatae and Rosaceae. The results of this study indicate that Leguminosae and Lilaceae improved phosphorus nutrition in soils, yet Labiatae and Rosaceae impeded the improvement of phosphorus nutrition in soils under their canopies, which will be of more help to instruct vegetation restoration in the region and provide information for soil development.     

Effect of change of slag phase on dephosphorization of ��double- slag+slag- remaining�� steelmaking technology

The microstructure and phase constituent of dephosphorization slag of ??double- slag+slag- remaining?? steelmaking technology were observed and analyzed by SEM, part of the slag were heat treatment, and the effect of the change of slag phase on dephosphorization was studied. The research results show that the phase of dephosphorization slag A1-A3 with high dephosphorization rate are composed of calcium ferrite, complex liquid silicate phase (Ca3TiFeSi3O12, Ca54MgAl2Si16O9) and 2CaO??SiO2(C2S) solid phase solution with calcium phosphate (2Ca2SiO4??Ca3(PO4)2, Ca7(PO)4(SiO4)2), the main phase of dephosphorization slag A4 with low dephosphorization rate is liquid phase, the main phases of dephosphorization slag A5 are MnFe2O4, MnV2O4, Ca12Al14O33, little phosphorus rich calcium silicate solid phase is found in both dephosphorization slag A4 and A5; the phase of dephosphorization slag A3 changes little before and after heat treatment, but the phase of dephosphorization slag A4 changes greatly after heat treatment, which changing to liquid phase and white branches like RO phase; the dephosphorization slag of ??double- slag+slag- remaining?? steelmaking technology contain many un- dissolved CaO, but little is found in decarburization slag, the formation of C2S solid phase in dephosphorization slag plays an important role to accelerate the dephosphorization reaction.