MIBK removal from aqueous solution by aeration method

In order to develop an effective MIBK removal method of H₂TaF₇ solution in tantalum extraction process, MIBK removal from aqueous solution by the aeration method was investigated by using an aeration column with the dimensions of 78 mm in inner diameter and 1 100 mm in length. The effects of aeration conditions on aerating efficiency were investigated in the ranges of temperature 303–333 K, airflow rate 50–300 L/h, volume of solution 1 600–3 200 mL. Aerating efficiency increases with the increase of temperature and airflow rate. MIBK in aqueous solution can be removed from 0.058 mol/L to 0.002 mol/L at 50°C, airflow rate 200 L/h, volume of solution 2 400 mL and aeration time 1h. The experimental results show that MIBK can be removed effectively from aqueous solution by the aeration method. Biography of the first author: LI Qing-gang, engineer, born in March 1966, majoring in extraction metallurgy of rare metals, application of membrane separation technology to metallurgical process.     

Lead removal from aqueous solution by employing natural brucite

The effect and mechanism of the removal of Pb^2 from an aqueous solution by using brucite as the adsorbent were studied. It was revealed that the increase in pH of brucite suspension, as a result of the release of magnesium hydroxide into the suspension, leads to a sharp rise of the adsorption amount of Pb^2 on brucite. The synergism of buffering and adsorption capacities of brucite is responsible for the removal of Pb^2 from the aqueous solution. The coexistence of Cu^2 with Pb^2 causes a decrease of their adsorption on brucite due to a competition for surface sites and brucite exhibits a higher adsorption capacity for Pb^2 than for Cu^2 . The percentage adsorption of Pb^2 on brucite could reach 96.38%, 97.20% and 94.09% respectively with the initial pH of the suspension pHi= 1,76 (initial Pb^2 concentration [Pb^2 ]i = 20μmol/L), 1.82 ([Pb^2 ]i=100μmol/L ) and 1.84 ([Pb^2 ]i = 500 μmol/L). It was concluded that brucite is a very efficient mineral adsorbent for Pb^2 removal from polluted acidic water.     

Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups

The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as（3-Mercaptopropyl） triethoxysilane（MPTES） and（3-Amincpropyl） trithoxysilane（APTES）. Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared（FI-IR） and X-ray photoelectron spectroscopy（XPS）. The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2＋, Cu2＋, Hg2＋, Cd2＋ and Zn2＋ions in aqueous solutions. The results show that the（3-Mercaptopropyl） triethoxysilane functionalized silica nanoparticles（SiO2-MPTES） play an important role in the selective adsorption of Cu2＋ and Hg2＋, the（3-Amincpropyl） trithoxysilane（APTES） functionalized silica nanoparticles（SiO2-APTES） exhibited maximum removal efficiency towards Pb2＋ and Hg2＋, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2＋ at room temperature, respectively.     

Study on the removal of MIBK from aqueous solution by vacuum membrane distillation

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Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion（Cl-） concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution （pH=3.0） decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.     

Ammonia nitrogen removal from aqueous solution using zeolite modified by microwave-sodium acetate

The characteristics of the zeolite modified by microwave and sodium acetate and its sorption of ammonia-nitrogen from simulated water sample were investigated.The results show that the modified zeolite by microwave-sodium acetate(SMMZ)has a high sorption efficiency and removal performance.The ammonia-nitrogen removal rate of SMMZ reaches 92.90%.The surface of SMMZ becomes loose and some pores appear,the specific surface area,total pore volume and average pore diameter increase after modification.Compared to the natural zeolite,SMMZ has a more concentrated pore size distribution in the range of 0-10 nm.The cation exchange capacity(CEC)of SMMZ is higher than that of the natural zeolite.And the ammonia nitrogen removal rate is consistent with the change of CEC.The SMMZ possesses rapid sorption and slow balance characteristics and ammonia-nitrogen sorption is consistent with both Langmuir adsorption isotherm model and Freundlich adsorption isotherm model.The adsorption kinetics of ammonia-nitrogen follows the pseudo-second order kinetic model.     

新型磁性Fe/Mn纳米复合材料对水中铅离子的去除

为了有效去除水中的铅离子,实验制备以MnO₂为吸附表面的磁性Fe/Mn纳米复合吸附剂,并进行了吸附实验研究,分析pH、温度等参数对吸附的影响．结果发现,从298 K Langmuir等温吸附曲线可以计算出Fe/Mn复合吸附剂对Pb2+的饱和吸附量(Q₀=118.06 mg/L)．复合吸附剂对Pb2+的吸附总量正比于pH(1.5～5)和温度(303～323 K)．在研究纳米复合材料对铅离子的吸附动力学实验中发现,纳米复合材料和铅离子之间的吸附动力学符合假二级模型,通过相关热力学研究计算得到纳米材料和铅离子之间为吸热反应．     

蔗渣木质素对溶液中重金属离子的吸附性能

研究了蔗渣木质素在不同的吸附时间、pH值、溶液浓度、木质素用量等条件下对Pb2+、Cd2+、Hg2+3种重金属离子的吸附作用,探讨了蔗渣木质素的等温吸附规律及吸附性能。实验结果表明:木质素吸附平衡时间约为15 min;溶液pH值是影响木质素对重金属吸附能力的主要因素,吸附量随pH值升高而增加;木质素对3种重金属离子皆有一定的吸附作用,吸附量次序为Pb2+(21.62 mg/g)Hg2+(7.65mg/g)Cd2+(3.32 mg/g)。Redlich-Peterson与Langmiur等温吸附模型可以较好的描述蔗渣木质素对3种重金属离子的吸附特性,其吸附过程属于优惠吸附。本结果可为用蔗渣木质素开发吸附重金属食品添加剂提供科学依据。     

Preparation and Properties of A Novel Adsorbent for Selective Removal of Anions from Aqueous Solution

Zeolite modified by lanthanum compounds would be an excellent wnter purification agent that can simultaneously remove both cations and anions in aqtwous solution. For this purpose, a novel adsorbent was prepared by loading lanthanide on the zeolite, and the optimum manufacturing conditions were achieved. The concentration of the modifying solution was 0.5M, in which zeolites .should be kept for 2 hours. The applicable solid/ liquor ratio was 1：25 nt pH10, and the sample was sintered at 600 ℃ for an hour. In addition, the adsorption capacity of modified zeolite for removing different anions from aqueous solution and its regeneration were ulso investigated. The results indicate that high performances uf the novel adsorbent make it possible to be manufactured in industy .     

Comparison of heavy metal removal efficiencies in four activated sludge processes

The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.     

巴氏芽孢杆菌生物修复重金属污染溶液试验研究

垃圾填埋场中重金属污染问题严峻,亟待高效的修复技术予以处理.近年来,MICP技术修复重金属污染土体/水体的潜力被广泛探究.在众多土著微生物中,巴氏芽孢杆菌脲酶活性和重金属耐受性更佳,但少有研究探究巴氏芽孢杆菌对高浓度重金属的固定/去除潜力,且仅利用MICP理论难以解释巴氏芽孢杆菌对不同重金属的固定/去除机理,此外,常见...     

泡沫分离水溶液中硫酸铜和曙红Y色素工艺研究

对泡沫分离法除去水溶液中微量硫酸铜及曙红Y的工艺进行研究,以十二烷基苯磺酸(DBSA)和十六烷基三甲基氢氧化铵(CTAOH)作为表面活性物质研究除去水溶液中的硫酸铜及色素曙红Y,将脱盐和脱色有机的结合在一起.考察了表面活性剂浓度、pH、气速和装液量对分离效果的影响.确定了最佳操作工艺,在DBSA浓度0.23g/L,CT...     

逆流萃取抽提水溶液中糠醛

选择四氯化碳为糠醛和水萃取分离的溶剂 ,采用逆流萃取法进行模拟计算 ,并进行萃取试验 ,为进一步逆流萃取中试试验提供可行性依据     

含铁废水中重金属离子的比浊法分析

研究了铁离子废水中重金属离子(以铅离子含量为标准)的分光光度测定法.采用不同的稳定剂将沉淀稳定在体系中,实验结果表明:在波长为450 nm处,无水乙醇的稳定效果最好,Pb2+与Fe2+含量与吸光度都成良好的线性关系,测定的Pb2+和Fe2+的质量浓度范围分别为0.25~1.25 ug/mL和1~5 ug/mL.通过各曲线得出含铁废水中重金属离子的含量,其结果与火焰原子吸收光谱法测得的结果基本一致;还研究了稳定剂的影响,测定了Pb2+回收率,验证了本实验方法的可靠性.     

Electrically driven chip cooling device using hybrid coolants of liquid metal and aqueous solution

Heat dissipation of electronic devices keeps as a tough issue for decades. As the most classical coolant in a convective heat transfer process, water has been widely adopted which however inherits with limited thermal conductivity and relies heavily on mechanical pump. As an alternative, the room temperature liquid metal was increasingly emerging as an important coolant to realize much stronger enhanced heat transfer. However, its thermal capacity is somewhat lower than that of water, which may restrict the overall cooling performance. In addition, the high cost by taking too much amount of liquid metal into the device also turns out to be a big concern for practical purpose. Here, through combining the individual merits from both the liquid metal with high conductivity and water with large heat capacity, we proposed and demonstrated a new conceptual cooling device that integrated hybrid coolants, radiator and annular channel together for chip thermal management. Particularly, the electrically induced actuation effect of liquid metal was introduced as the only flow driving strategy, which significantly simplified the whole system design. This enables the liquid metal sphere and its surrounding aqueous solution to be quickly accelerated to a large speed under only a very low electric voltage. Further experiments demonstrated that the cooling device could effectively maintain the temperature of a hotpot (3.15 W/cm²) below 55ºC with an extremely small power consumption rate (0.8 W). Several situations to simulate the practical working of the device were experimentally explored and a theoretical thermal resistance model was established to evaluate its heat transfer performance. The present work suggests an important way to make highly compact chip cooling device, which can be flexibly extended into a wide variety of engineering areas.     

Highly oriented ZnO rod arrays on Si substrates from aqueous solution

Ordered zinc oxide （ZnO） rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers （SAMs）. In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the ＂coin-like＂ SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.     

厌氧生物反应器对农村垃圾滤液重金属去除效果研究

以江苏省徐州市铜山区某街道办事处的3个行政村生活垃圾为对象,设计了厌氧型垃圾生物反应器,研究了农村生活垃圾在反应器中的变化情况.研究表明:3个行政村生活垃圾中的重金属含量在初期含量都较高,随着反应时间进入产甲烷期,其含量迅速降低,设备通过对渗滤液的回流处理,使得渗滤液中Cr、Mn、Cd、Cu浓度在中后期下降明显.其中两个行政村生活垃圾中含有大量的水分和蛋白质,促进了厌氧微生物的生长繁殖,推动甲烷气的产生,使渗滤液pH值迅速上升,30周pH达到最高点8.24和8.33.而另外一个行政村生活垃圾由于渗滤液的大量流失,由于酸化水解阶段微生物对大量有机酸分解缓慢,造成反应器长时间处于低pH值域范围.     

渭河沉积物中重金属释放的粒度效应

相同污染浓度条件下，粗颗粒沉积物中重金属具有较高的初期释放量和释放强度；平衡释放浓度随粒度减小略有增大，考虑到沉簌 物吸附重金属的粒度效应，重金属释放的粒度效应会更加明显。渭河沉积物中构成重金属释放的结合形态主要为离子可交换态和碳酸盐结合态，重金属结合形态相互转化的结果是以水相中重金属释放浓度变化的动力学过程来体现的。     

重金属污染土壤对农业生产的影响及其可持续利用的措施

概述了土壤重金属污染的现状、来源以及对土壤和农作物产生的不利影响。通过改变耕作方法和管理制度，减轻对土壤造成的污染。结合实际提出了污染土壤的生物修复技术和有效的工程治理措施。