维生素B12改性纳米零价镍去除溶液中U(Ⅵ)的性能

采用液相还原法制备了维生素B12改性的纳米零价镍,并用来去除溶液中的U(Ⅵ)。探究了纳米零价镍和维生素B12质量比、溶液pH、固液比、溶液中U(Ⅵ)的初始质量浓度以及温度和时间等对溶液中U(Ⅵ)去除的影响。结果表明：在室温（25 ℃）下,维生素B12与纳米零价镍质量比1︰1,溶液pH为5.0,固液比0.3 g/L,反应时间30 min时,U(Ⅵ)的去除率达到98.54%,去除量达到85.36 mg/g。     

岩棉负载纳米零价铝去除溶液中U(Ⅵ)的性能研究

通过液相还原法制备了岩棉负载纳米零价铝（RW-NZVAl）,利用SEM和XRD对材料进行了表征,探究了纳米零价铝负载量、溶液pH、U(Ⅵ)初始浓度、固液比、温度、反应时间等对RW-NZVAl去除溶液中U(Ⅵ)的影响。结果表明,RW-NZVAl对溶液中U(Ⅵ)有很好的去除效果,当岩棉与纳米零价铝质量比为4︰1、溶液pH＝4.0、U(Ⅵ)初始浓度25 mg/L、固液比0.4 g/L、温度25 ℃、反应时间150 min时,RW-NZVAl对溶液中U(Ⅵ)的去除率为93.21％,去除量为58.26 mg/g。     

玉米淀粉负载型纳米零价铁去除溶液中U(VI)研究

通过液相还原法制备玉米淀粉负载型纳米零价铁(CS-NZVI),利用SEM和XRD对材料进行了表征,并且探究了不同溶液pH、U(Ⅵ)初始浓度、CS-NZVI浓度、温度、反应时间对U(Ⅵ)去除效果的影响。结果表明,CS-NZVI整体分散性较好,相较于NZVI团聚情况明显改善。在溶液pH=6.0、U(Ⅵ)初始浓度10.0 mg/L、CS-NZVI浓度0.4 g/L、温度30 ℃、反应时间140 min时,CS-NZVI材料对溶液中U(Ⅵ)的去除率为95.05%,去除量为24.86 mg/g。     

用改性纳米零价铁去除废水中U(Ⅵ)的性能及机制

为了绿色高效处理含铀废水，研究了用液相还原法制备多硫化钙改性纳米零价铁(CPS@nZVI)材料并用于去除溶液中U(Ⅵ),考察了CPS@nZVI对溶液中U(Ⅵ)的去除效果。并通过SEM-EDS、XPS和XRD对材料的形貌和表面物质组成进行表征。结果表明：在溶液pH=3.5、U(Ⅵ)初始质量浓度10.0 mg/L、固液质量体积比0.5 g/1 L、反应温度25℃、反应时间120 min条件下，CPS@nZVI材料对溶液中U(Ⅵ)去除率为98.13%,去除量为19.53 mg/g; SEM-EDS、XPS、XRD表征结果表明，样品主要由Fe⁰、FeS组成；反应过程符合准二级动力学模型和Langmuir等温吸附模型，该吸附过程受化学吸附控制，为单分子层吸附；还原过程符合伪一级还原动力学，溶液中的U(Ⅵ)以吸附和还原沉淀2种方式去除。     

糯米粉包覆纳米零价铁去除溶液中U(Ⅵ)的试验研究

研究了以糯米粉为载体、采用液相还原法制备包覆型复合材料糯米粉-纳米零价铁(nZVI),并用于去除溶液中以UO_2~(2+)形式存在的U(Ⅵ)。采用扫描电镜(SEM)表征材料的微结构,并考察溶液pH、糯米粉-nZVI用量、温度、反应时间及U(Ⅵ)初始质量浓度等因素对铀去除效果的影响。结果表明:在溶液U(Ⅵ)初始质量浓度为10mg/L、溶液pH=6、温度30℃、材料投加量0.4g/L、反应120min条件下,U(Ⅵ)去除率达96.4%,吸附量为18.73mg/g;U(Ⅵ)初始浓度越高,U(Ⅵ)去除效果越好,糯米粉-nZVI可用于从溶液中吸附去除U(Ⅵ)。     

玉米淀粉负载型纳米零价铁去除溶液中U（Ⅵ）研究

通过液相还原法制备玉米淀粉负载型纳米零价铁(CS-NZVI),利用SEM和XRD对材料进行了表征,并且探究了不同溶液pH、U(Ⅵ)初始浓度、CS-NZVI浓度、温度、反应时间对U(Ⅵ)去除效果的影响。结果表明,CS-NZVI整体分散性较好,相较于NZVI团聚情况明显改善。在溶液pH=6.0、U(Ⅵ)初始浓度10.0mg/L、CS-NZVI浓度0.4g/L、温度30℃、反应时间140min时,CS-NZVI材料对溶液中U(Ⅵ)的去除率为95.05%,去除量为24.86mg/g。     

纳米铁镍双金属去除溶液中U(VI)的研究

采用同步液相法制备纳米Fe/Ni双金属来去除溶液中的U(VI),通过BET、SEM等方法对双金属材料进行表征分析,用批试验法研究n(Fe)/n(Ni)比、pH、初始铀浓度、反应时间和温度对去除U(VI)的影响。结果表明,铁镍双金属体系去除U(VI)的最佳pH为3.5,反应平衡时间为30 min,25 ℃时的饱和吸附量为161.91 mg/g。     

用负载纳米零价铁的改性沸石从溶液中去除U(Ⅵ)试验研究

研究了用液相还原法制备纳米零价铁,并将其负载于改性沸石表面制备出负载纳米零价铁的改性沸石复合材料(Z-nZVI),用于去除溶液中的U(Ⅵ)。借助X射线衍射法(XRD)对复合材料进行表征,考察了溶液pH、温度、吸附时间对复合材料吸附去除U(Ⅵ)的影响,分析了复合材料吸附U(Ⅵ)的动力学。结果表明:负载纳米零价铁的改性沸石对U(Ⅵ)有很好的去除效果;在溶液pH=4、温度30℃、接触时间60min条件下,U(Ⅵ)去除率和最大吸附量分别为96.72%和48.55mg/g;该复合材料对U(Ⅵ)的吸附过程符合准二级动力学方程和Langmuir等温吸附模型。     

活性炭负载纳米零价铁去除矿山废水中的Cu2+

将纳米零价铁颗粒负载到颗粒活性炭上,能有效地解决纳米零价铁易氧化易团聚的问题,而且还能增大其比表面积和稳定性.采用SEM、比表面积与孔径分析和XPS对材料进行表征.纳米零价铁填充于活性炭的孔隙中,其粒径在50~100 nm之间.使用该材料对50 mg/L 的Cu2+溶液进行去除试验研究,在铁含量为10.99%,投加量为15 mg/L,反应pH=5,反应时间为24 h时,对Cu2+的去除率达到85.06%.实验室的初步试验结果表明该材料对水相中的Cu2+具有较好的去除效果.     

CuInS_2光催化还原溶液中U(Ⅵ)的性能研究

通过溶剂热法制备了CuInS_2可见光响应型材料,借助SEM和XRD对材料进行表征分析。探究了不同溶液pH、反应时间、CuInS_2浓度、U(Ⅵ)初始浓度对CuInS_2光催化还原U(Ⅵ)性能的影响。结果表明,CuInS_2具有良好的光催化性能,在溶液pH=5.5、U(Ⅵ)初始浓度10.0 mg/L、CuInS_2浓度0.8g/L时,CuInS_2材料对溶液中U(Ⅵ)的去除效果最佳,去除率为87.81%,去除量为12.13mg/g。     

钢渣负载羟基磷灰石复合材料对水溶液中铀的去除性能

采用溶胶—凝胶法制备出钢渣负载羟基磷灰石复合材料,并通过静态试验方法探讨pH、复合材料投加量、反应时间及铀初始浓度对复合材料吸附水溶液中U(Ⅵ)的影响。结果表明,复合材料对U(Ⅵ)具有较好的去除性能,在pH=4、投加量0.4g、反应时间120min的条件下,对初始浓度5mg/L的水溶液中U(Ⅵ)的去除接近完全,对应吸附量为1.25mg/g。复合材料对U(Ⅵ)的吸附过程为化学吸附,符合准二级动力学模型(R~2=0.996 9);Langmuir吸附等温线模型拟合(R~2=0.999 1)表明,吸附过程为吸附剂表面上的单层吸附;且通过R_L(R_L 0.063)的计算表明,复合材料对U(Ⅵ)的吸附极其接近不可逆吸附。     

生物聚合硫酸铁去除U(VI)的絮凝试验

采用生物聚合硫酸铁絮凝剂对低浓度含铀废水进行絮凝试验研究,考察U(VI)溶液pH、絮凝剂投加量以及U(VI)初始浓度对絮凝效果的影响。结果表明,反应最佳pH范围在5~7,反应平衡时间为5 min,其絮凝过程符合Lagergren准二级反应动力学模型。含铀废水经生物聚合硫酸铁絮凝处理过后,残余铀浓度低于《铀加工与燃料制造设施辐射防护规定》（EJ 1056-2005）中的排放限值（0.05 mg/L）。     

碳酸钠溶液堆浸-硫酸亚铁还原联合解毒铬渣

以碳酸钠溶液作浸出剂、硫酸亚铁作还原剂,对循环碳酸钠溶液堆浸—硫酸亚铁还原联合解毒铬渣新工艺进行研究。结果表明,在整个解毒过程中,浸出液pH在10～12变化,浸出液经还原后溶液中Cr(VI)的实际浓度略高于其理论值;第一次浸出后,铬渣中钙铁石或水榴石中的Cr(VI)被大量浸出,浸出液中碳酸钠浓度由浸出前的9.3g/L下降至7.98g/L,Cr(VI)浸出率为62.67%;在此后的循环解毒过程中,浸出液中碳酸钠浓度均维持在8g/L左右,Cr(VI)浸出率增加缓慢;循环处理12次后,铬渣中Cr(VI)浸出率达85%,最终解毒渣中残留Cr(VI)主要存在于水滑石中;铬渣粒度显著影响其解毒效果,当粒度小于0.15mm时,最终解毒渣的毒性浸出液中Cr(VI)和总Cr浓度分别为1.98mg/L和2.45mg/L,达到一般工业固体废物填埋的标准。     

纳米零价铁对溶液中铅镉铬砷的去除性能研究

通过液相还原法,采用KBH4还原Fe2+成功制备了平均粒径40~80nm、比表面积19.713 4m2/g、有较好表面活性的纳米零价铁(NZVI),NZVI在含铅、砷、铬、镉初始浓度为100mg/L的pH分别为2、7、12的溶液中进行去除试验。结果表明,在pH=2与pH=7的条件下NZVI对铅、砷、铬的去除效果较好,去除速率在前30min较快;在pH=12条件下对镉的去除效果明显,去除速率在前40min较快;不同pH条件下各离子的去除率差异较大,这主要与各离子在不同pH条件下的存在形态有关。NVZI去除溶液中的铅、砷、铬、镉,不仅效率高,而且绿色环保,不会对环境造成二次污染。     

硫酸锌溶液离子交换脱氟氯

以含氟氯硫酸锌溶液为原料,采用离子交换法研究氟氯离子的脱除。试验筛选出D201树脂对氟氯离子有较好的吸附和解吸性能。多级动态试验结果表明,经D201树脂处理,将Cl-浓度由原液497.61mg/L降至58.77mg/L,Cl-脱除率88.19%;F-浓度由原液201.17 mg/L降至178.64mg/L,F-脱除率11.98%。动态吸附后的载氟氯D201树脂,用4mol/L硫酸液可将氟氯解吸,氟解吸率高于95%,氯解吸率高于99%。     

Competitive time-resolved immunofluorometric assay for quantifying carbonic anhydrase VI in saliva

A competitive time-resolved immunofluorometric assay sensitive and robust enough for quantifying human salivary carbonic anhydrase isoenzyme VI (HCA VI) was developed. The solid-phase immunoassay is based on competition between Eu(3+)-labeled HCA VI and salivary HCA VI for polyclonal rabbit anti-HCA VI antibodies that are attached to microtiter plate wells precoated with sheep anti-rabbit IgG. The subsequent immunoassay including the separation of free and bound HCA VI requires only one incubation step, after which the Eu3+ of the bound labeled antigen is released into an enhancement solution. The highly fluorescent Eu chelates formed in this solution are then quantified by time-resolved fluorometry (Delfia). The time-resolution principle effectively obviates possible interferences from complex biological material such as saliva. The assay detection limit was 1.5 micrograms/L. Intra- and interassay imprecisions (CVs) were 5.1% and 5.3%, respectively. The mean analytical recovery was 93%. The mean +/- SD concentration of HCA VI in paraffin-stimulated saliva was 6.8 +/- 4.3 mg/L (n = 30) and the secretion rate was 10.2 +/- 7.9 micrograms/min. The method was useful for further investigations of the role of HCA VI in difficult matrices, e.g., saliva.     

二苯碳酰二肼分光光度法测定氮化硅铁中铬

氮化硅铁是一种重要的耐火材料,实验研究了应用二苯碳酰二肼分光光度法测定氮化硅铁中铬元素含量的分析方法。针对试样分解方法、氧化条件、显色条件、干扰消除等进行了试验研究,确定了最佳分析条件。试样于镍坩埚中以2 g氢氧化钠作为熔剂在650 ℃熔融10 min分解,在热水中浸取熔块后,以氢氟酸、高氯酸冒烟除去试样中的硅元素。用硫酸(1+9)溶解盐类后,在硫酸介质中以2.0 mL 10 g/L高锰酸钾溶液氧化铬至正六价,再加入过量的200 g/L碳酸钠溶液沉淀分离铁、镍等共存元素,最后在0.05～0.2 mol/L硫酸中利用铬与二苯碳酰二肼反应显色对其进行了测定。应用实验方法对氮化硅铁样品进行测定,测定值与电感耦合等离子体原子发射光谱法(ICP-AES)测定值一致,测定结果的相对标准偏差(RSD,n=11)小于2%;加标回收试验结果表明回收率为101%。     

In situ reduction of hexavalent chromium in alkaline soils enriched with chromite ore processing residue

In investigating chromium sites in New Jersey, it has been observed that an organic-rich 0.5- to 4-foot-thick layer of decayed vegetation (locally known as "meadowmat") underlying the chromium-containing material acts as a natural barrier to the migration of Cr(VI). The groundwater in a sand layer directly beneath the meadowmat has been shown to contain low or nondetectable levels of chromium. The meadowmat is under highly reduced conditions due to bacterial activity associated with the organic material. Based on the observed ability of the meadowmat to reduce Cr(VI) to Cr(III), the feasibility of in situ reduction of Cr(VI) to Cr(III) at chromite ore processing residue (COPR) sites was investigated in biologically-active, laboratory-scale test columns. COPR typically has a high pH (in excess of 12) and may contain total chromium concentrations as high as 70,000 mg/kg. Experimental results demonstrated that the addition of a mineral acid (to lower the pH to between 7.0 and 9.5) and a bacteria-rich organic substrate (fresh manure) resulted in the reduction of Cr(VI) to the less toxic and less mobile trivalent form. Pore water Cr(VI) was reduced from approximately 800 mg/L to less than 0.05 mg/L over a period of eight months. This is less than the U.S. Environmental Protection Agency's (EPA) Maximum Contaminant Level (MCL) for chromium in drinking water of 0.1 mg/L. Solid phase Cr(VI) concentrations decreased from approximately 2,000 mg/kg to less than 10 mg/kg in the columns over a period of 11 months while the total chromium concentrations remained unchanged. Toxicity Characteristic Leaching Procedure (TCLP) extract from the treated columns met the regulatory limit of 5 mg/L of Cr, whereas the untreated samples had TCLP extract concentrations greater than 40 mg/L. This study demonstrated the potential applicability of in situ reduction to soils contaminated with Cr(VI) by adjusting the pH to between 7.0 and 9.5 and mixing in a bacteria-rich organic substrate.     

钙铁基磷酸盐作为PRB反应介质修复锰污染地下水试验

采用溶胶—凝胶法制备了一种新型的钙铁基磷酸盐复合材料(CIP),并采用静态吸附试验法探究了pH、反应时间、锰初始浓度及反应温度等因素对其吸附水溶液中Mn(Ⅱ)的影响。结果表明,CIP吸附水溶液中锰的最佳pH为5,CIP对水溶液中Mn(Ⅱ)具有良好的吸附性能,可作为去除水溶液中锰的PRB反应介质。CIP对水溶液中Mn(Ⅱ)的吸附行为符合Langmuir吸附等温线模型和准二级动力学模型,最大理论吸附量为66.22mg/g。热力学分析结果表明,CIP对Mn(Ⅱ)的吸附是一个自发、吸热和熵增的过程。     

Recovery of nickel and cobalt from laterite leach solutions using direct solvent extraction: Part 2: Semi- and fully-continuous tests

In Part 1 of this paper, two synergistic solvent extraction systems consisting of Versatic 10/LIX63/TBP and Versatic 10/4PC were assessed in batch tests for the separation and purification of nickel and cobalt from synthetic laterite leach solution after iron removal. In Part 2, semi- and fully-continuous tests are reported for the Versatic 10/LIX63/TBP system, with conditions optimised for separating nickel and cobalt from manganese, magnesium and calcium.Semi-continuous extraction tests were conducted using the synergistic organic system consisting of 0.50 M Versatic 10, 0.45 M LIX63 and 1.0 M TBP in Shellsol D70. With a pH profile of 5.5/6.1/6.5 for the three stages EX1/EX2/EX3 at 40 °C, the nickel and cobalt extractions were 99.9% with only 5 mg/L nickel and < 1 mg/L cobalt left in the raffinate. With two stages of scrubbing and a pH profile of 5.4/5.0 at 40 °C, about 2 mg/L manganese and less than 1 mg/L magnesium and calcium were left in the scrubbed organic solution. With two stripping stages and an O/A ratio of 10 at 40 °C using 50 g/L H₂SO₄ as strip solution, the stripping efficiencies of nickel and cobalt were over 95%.A fully-continuous pilot plant was operated for 280 h. With an O/A ratio of about 2 and a pH profile of 5.5/5.8/6.0/6.3 for the four stages EX1/EX2/EX3/EX4 at 40 °C, both nickel and cobalt were almost completely extracted. The nickel and cobalt concentration in the raffinate was lower than detection limit of 0.2 mg/L. The manganese, magnesium and calcium concentrations in the loaded organic solution were 34, 8 and 1 mg/L, respectively. Using a pH profile of 5.4/5.0 for SC1/SC2 at an O/A ratio of 10 and 40 °C, the manganese scrubbing efficiency was over 96% and the concentrations of manganese and magnesium in the scrubbed organic solution were < 5 mg/L and that of calcium 1 mg/L. Using three strip stages and a strip solution containing 50 g/L H₂SO₄ and 55 g/L Ni at an O/A ratio of 10 and 40 °C, over 98% Ni and 99% Co were stripped with only 64 mg/L Ni in the stripped organic solution. The nickel concentration in the loaded strip liquor was 86 g/L, giving a ΔNi of 31 g/L. The loaded strip liquor contained less than 1 g/L acid.