制备方法对MnO_x-TiO_2吸附剂脱汞性能的影响

针对燃煤烟气中单质汞不溶于水,难以脱除的问题,采用水热合成法(HT)和沉积-沉淀法(DP)制备了Mn Ox-Ti O2单质汞(Hg0)吸附剂,在固定床实验台架上考察2种吸附剂(Mn Ti-HT和Mn Ti-DP)的脱汞性能;利用N2吸附/脱附、透射电子显微镜(TEM)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)和X射线光电子能谱(XPS)等技术对吸附剂进行物化表征。结果表明:物理吸附不是吸附剂脱汞的主要因素。Mn Ti-DP对Hg0的吸附剂量为620μg/g,远高于Mn Ti-HT的236μg/g,说明制备方法对吸附剂的脱汞性能有较大影响。Mn Ti-DP吸附剂中Mn含量较高,Mn4+含量约为34%,远高于Mn Ti-HT的Mn4+(22%);Mn Ti-DP中化学吸附态氧和晶格氧的强度均高于MnTi-HT,表明Mn Ti-DP中化学吸附态氧的总体含量高于Mn Ti-HT,有利于增强Mn Ti-DP还原特性,提高脱汞能力。     

MnO2的制备及其在电化学电容器中的应用

在不同的pH值下,以KMnO4氧化Mn(NO3)2分别合成2种化学MnO2. 晶体结构和晶型经X射线衍射仪和X射线扫描电镜检测,表明pH值对晶体形成有一定的影响. 在-0.3~0.6 V(相对Hg/HgO电极电位)范围用循环伏安法研究两种材料的电化学性能,结果显示它们具有静电电容特征. 活性炭作为对电极组成混合型电化学电容器与MnO2相同电极对称型电化学电容器相比,工作电压窗口和比电容都得到了提高. 恒流充放电显示,对称结构电极比电容分别为262和302 F/g;不对称结构电极比电容为348和342 F/g,具有较好的大电流放电能力和循环寿命.     

KTA-2型脱砷剂在炼厂丙烯精制中的工业应用

介绍了锦西石化公司15万t/a聚丙烯装置丙烯脱砷流程,结合KTA-2型脱砷剂的实际应用过程及生产运行数据,对KTA-2型丙烯脱砷剂在炼厂丙烯精制中的工业应用进行了总结。工业应用表明:KTA-2型脱砷剂具有较好的脱砷活性,精制丙烯中含砷化合物的质量分数小于20×10-9,脱砷率达99.1%以上,满足高效催化剂对丙烯中砷含量要求;KTA-2型脱砷剂具有较高的砷容,穿透砷容(w)可达10%。     

Ozone Application for Arsenic and Manganese Treatment at the City of White Rock,BC, Canada

The City of White Rock purchased the water utility on October 30, 2015, from EPCOR Utilities Inc. The City of White Rock‘s water utility provides safe and clean drinking water to its residents. The drinking water is obtained from the Sunnyside Uplands Aquifer. To ensure water supplied is of the highest quality, the City collaborated with the RES‘EAU-WaterNET, to conduct research to evaluate and identify technologies that are capable of providing a significant reduction of arsenic and manganese, to improve water quality. The City submitted a grant application to the Clean Water and Wastewater Fund (CWWF) for the construction of a water treatment plant to reduce arsenic and manganese in drinking water. The Government of Canada and the Province of British Columbia provided funding from the Clean Water and Wastewater Fund (CWWF) to the City of White Rock for the “Arsenic and Manganese Water Treatment Project. The City awarded a contract for the Design Build for a Water Treatment Plant to provide a major reduction in arsenic and manganese in drinking water. The Design Build project utilized the scientific findings from the research conducted. The construction of the plant started in March 2018, and the project is expected to be completed by March 2019.     

Potential of MnO2-based composite and numerous morphological for enhancing supercapacitors performance

The development of materials and electrochemical energy storage (EES) technologies are currently taking the lead and showing excellent performance in the global effort to tackle the issues of sustainable energy supply. Supercapacitors have been widely studied among the EES technologies as they exhibit quick charging rates under high-power conditions. Manganese dioxide (MnO₂) has attracted renewed interest as a promising material due to its high theoretical capacitance and high energy density. However, the widespread application is immediately impacted by low conductivity. Hence, combining nanomaterials and various morphologies of MnO₂ can improve the electrochemical performance of supercapacitors. This paper presents a review based on the composites of nanomaterials/MnO₂ with various morphologies. Their mechanism and practical applications in supercapacitors are introduced in detail. Finally, the challenges and next steps in developing MnO₂ electrode materials are proposed.     

氨-硫酸铵法生产饲料级氧化锌中除砷工艺研究

以锌焙砂和氨-硫酸铵溶液为原料生产饲料级高纯氧化锌,对除砷进行了重点研究.采用沉淀混凝吸附法,先用氧化剂氧化砷(Ⅲ)成砷(Ⅴ),再用沉淀吸附剂沉淀砷(Ⅴ).结果表明,温度为60℃,砷与氧化剂及沉淀吸附剂的物质的量比为1,0:1.2:1.2,搅拌浸出2 h,静置1 h,除砷效果最好.通过除砷所得氧化锌产品各项指标都符合HG 2792-1996标准.革新了氨法生产氧化锌的除砷工艺.     

Solar‐light assisted removal of arsenic from natural waters: effect of iron and citrate concentrations

The optimal conditions to remove arsenic(III) from a solution were fitted using a factorial experimental design in a reaction catalysed by visible light (black light, 360 nm) and an iron‐citrate complex. Experiments were performed by simultaneously modifying the two variables affecting the removal of arsenic, i.e. iron and citrate concentrations. The single polynomial function obtained with the factorial design methodology indicates that the iron concentration was the most critical parameter in the removal of arsenic by precipitation. Mathematically, it was determined that the optimum molar ratio for arsenic, citrate and iron was 1:4.5:18.7, respectively, over 90% of arsenic being eliminated after 4 h of irradiation. The comparison between the As(III) and As(V) co‐precipitation rates indicates that almost 80% of As(III) was removed after 1 h of irradiation with black light, while As(V) required 4 h of irradiation to reach the same value. When natural water containing approximately 1 mg L⁻¹ of arsenic, only as As(V), was irradiated with solar light under optimised conditions, approximately 95% of the arsenic was removed after 1 h of irradiation. Copyright © 2006 Society of Chemical Industry     

二氧化硅制备、改性、应用进展

综述了近几年二氧化硅表面改性技术的新进展。介绍了制备高性能二氧化硅的新工艺以及二氧化硅在橡胶制品、塑料制品、粘合剂、涂料等工业中的应用。     

Kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite

This paper describes a study of the kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite through leaching and electrochemical parameters. Manganese(iv) was found to dissolve mainly through reduction by the ferrous ion generated during oxidation of pyrite by the ferric ion. The oxidation which is slower and rate controlling may proceed through two different reactions, one producing S0 and the other SO42–. Manganese dissolution runs at the same rate as that of pyrite oxidation by maintaining ferrous ion concentration at a much lower level than that of ferric. Kinetic equations based on corrosion coupling principles are developed to explain the observed leaching behaviour.     

超声辅助碱浸铜冶炼烟灰中铜砷分离

采用超声辅助Na₂S-NaOH浸取体系对铜冶炼烟灰进行研究,在NaOH、Na₂S与烟灰质量比0.4：1,液固比20：1,反应温度75℃,反应时间5 min,超声功率80 W,搅拌速率400 r·min^-1条件下,As浸出率为88.81%,Cu浸出率为0.025%,实现了Cu和As的有效分离。采用该方法处理后,与单独碱浸相比,As浸出率提高9.21%,烟灰中As含量由0.85%降至0.58%,Cu含量由2.21%增至2.30%,且As浸出毒性浓度由12.66 mg·L^-1降至2.84 mg·L^-1,为烟灰的资源化利用创造了条件。超声辅助碱浸除砷动力学满足收缩核混合反应控制模型,表观活化能0.114 kJ·mol^-1。XRD、XPS和重金属形态分析结果表明,超声空化作用可使As（Ⅲ）氧化为As（Ⅴ）,有利于As浸出,故超声过程强化有利于Cu和As在碱浸体系中的选择性分离。     

Supercritical carbon dioxide combined with high power ultrasound: An effective method for the pasteurization of coconut water

Industrially, thermal treatments are extensively used to inactivate microorganisms in foods. However, the demand for new pasteurization methods with reduced impact on the nutritional content and overall food quality is increasing. In this context, this study investigated and compared the effect of supercritical carbon dioxide (SC-CO₂) alone or in combination with high power ultrasound (HPU) on both the natural microbial flora (mesophilic, lactic acid bacteria and yeast and molds) of coconut water and the pathogenic Gram-negative bacteria Salmonella enterica inoculated in the product. Inactivation kinetics were obtained at 12 MPa, by means of batch apparatuses, at different times (from 1 up to 60 min) and temperature conditions (from 25 up to 45 °C). The synergistic effect of SC-CO₂ + HPU was evident and a higher microbial reduction was achieved compared to SC-CO₂ alone: at 12 MPa and 40 °C about 5 log reductions were achieved for natural microbial flora in about 15 min while about 30 min were needed for SC-CO₂ treatment. The storage study highlighted that SC-CO₂ treated coconut water resulted microbiologically unstable and showed heavy regrowth phenomena during the storage, while, a full shelf life of 4 weeks was assured for SC-CO₂ + HPU treated samples.     

Photochemical and acoustic interactions of biochar with CO2 and H2O: Applications in power generation and CO2 capture

A critical literature review suggests that carbonaceous compounds react with (CO₂ +H₂O) mixture through thermal, photochemical, and sonochemical/sonophysical routes. A biochar was selected for studying these effects at 60°C and 1 atm for its potential benefits on power generation and CO₂ capture. All treatments remove sizable minerals (K, Na, and Si) detrimental in power generation, and introduce carbon (up to 16% of original carbon in biochar) into the biochar matrix. Most treatments show increased hydrogen (up to 24%). Treatments lead to notable increased heating value of biochar (up to 50%). Treated biochars show increase (up to 19 fold) in internal surface area. The ultrasound energy output is a fraction of the increased heating value. Thus, pretreatment is potentially attractive for increasing the energy efficiency in combustion and gasification. Moreover, better understandings of the salient reactions of these processes will be advantageous for the development of advanced adsorbents for CO₂ capture. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1054–1065, 2014     

NH4Cl辅助热解制备镍-氮-碳纳米管催化剂及其电还原CO2性能

二氧化碳（CO₂）的资源化利用是实现“碳达峰,碳中和”的重要手段。在众多CO₂转化技术当中,电催化CO₂还原反应因反应条件温和、工艺过程简单等优点,被认为是极具应用前景的减碳技术之一,其关键在于高效、高稳定性电催化剂的开发。过渡金属-氮-碳（M-N-C）材料是电还原CO₂生成CO的有效催化剂,针对其高温热解制备过程中活性金属原子容易聚集且氮原子流失严重,进而使得活性位密度降低,催化性能下降等问题,本文提出以双氰胺（DCDA）为碳源和氮源,以乙酰丙酮镍（Ni（acac）₂）为金属源,以氯化铵（NH₄Cl）为第二氮源和造孔剂,采用简单的NH₄Cl辅助热解-酸刻蚀的方法制备得到镍-氮-碳纳米管（Ni-N-CNTs）电还原CO₂催化剂,并详细考察NH₄Cl添加量对催化剂结构和催化性能的影响。表征结果表明：NH₄Cl的加入有利于催化剂纳米管状形貌和多级孔结构的生成,同时有利于催化剂中Ni-Nx （1.6%,摩尔分数）和pyridinic-N （1.75%,摩尔分数）物种含量的增加。一系列性能测试结果表明：催化剂的活性中心为Ni-Nx,同时pyridinic-N的存在也有利于催化性能的提高,当前体中NH₄Cl加入量与氮源和金属源总质量比为1∶1时,所得Ni-N-CNTs-1催化剂催化性能最好,在电压为-0.65 V （vs RHE）时,CO法拉第效率最高达92%,此时CO部分电流密度为8 mA·cm^-2。此外,该催化剂还表现出良好的催化稳定性,连续恒电位电解12 h,催化性能基本不变。该催化剂制备工艺简单,制备条件可控,研究结果可为高效M-N-C电还原CO₂催化剂的设计和制备提供一种切实有效的研究思路和方法。     

NH4Cl辅助热解制备镍-氮-碳纳米管催化剂及其电还原CO2性能

二氧化碳（CO₂）的资源化利用是实现“碳达峰,碳中和”的重要手段。在众多CO₂转化技术当中,电催化CO₂还原反应因反应条件温和、工艺过程简单等优点,被认为是极具应用前景的减碳技术之一,其关键在于高效、高稳定性电催化剂的开发。过渡金属-氮-碳（M-N-C）材料是电还原CO₂生成CO的有效催化剂,针对其高温热解制备过程中活性金属原子容易聚集且氮原子流失严重,进而使得活性位密度降低,催化性能下降等问题,本文提出以双氰胺（DCDA）为碳源和氮源,以乙酰丙酮镍（Ni（acac）₂）为金属源,以氯化铵（NH₄Cl）为第二氮源和造孔剂,采用简单的NH₄Cl辅助热解-酸刻蚀的方法制备得到镍-氮-碳纳米管（Ni-N-CNTs）电还原CO₂催化剂,并详细考察NH₄Cl添加量对催化剂结构和催化性能的影响。表征结果表明：NH₄Cl的加入有利于催化剂纳米管状形貌和多级孔结构的生成,同时有利于催化剂中Ni-Nx （1.6%,摩尔分数）和pyridinic-N （1.75%,摩尔分数）物种含量的增加。一系列性能测试结果表明：催化剂的活性中心为Ni-Nx,同时pyridinic-N的存在也有利于催化性能的提高,当前体中NH₄Cl加入量与氮源和金属源总质量比为1∶1时,所得Ni-N-CNTs-1催化剂催化性能最好,在电压为-0.65 V （vs RHE）时,CO法拉第效率最高达92%,此时CO部分电流密度为8 mA·cm^-2。此外,该催化剂还表现出良好的催化稳定性,连续恒电位电解12 h,催化性能基本不变。该催化剂制备工艺简单,制备条件可控,研究结果可为高效M-N-C电还原CO₂催化剂的设计和制备提供一种切实有效的研究思路和方法。     

辉光放电等离子体辅助碱浸铜冶炼烟灰中铜砷分离

采用辉光放电等离子体辅助Na₂S-NaOH浸取体系对铜冶炼烟灰（简称“烟灰”）进行研究,在放电时间10 min、放电功率500 W、放电压强150 Pa、极板间距0.9 cm的条件下,砷的浸出率为92.52%,铜的浸出率为7.76%,实现了砷和铜的有效分离。采用该方法处理后烟灰中的砷从7.11%降到0.45%,铜从2.62%变为2.42%,为烟灰的进一步利用创造了条件。XPS、XRD和重金属形态分析的综合分析结果表明,辉光能将As（Ⅲ）氧化为As（Ⅴ）、Cu（Ⅰ）氧化为Cu（Ⅱ）,且在碱性条件下As（Ⅴ）比As（Ⅲ）更易浸出。因此,辉光放电预氧化有利于砷和铜在碱浸体系中选择性分离。     

TiO2-coated glass hollow fiber membranes: preparation and application for photocatalytic methylene blue removal

A glass hollow fiber membrane coated with TiO₂ was successfully synthesized by dip-coating and calcination. In addition, the effects of the calcination temperature, number of coating layers, and treatment method on the photocatalytic removal of methylene blue from wastewater by the membrane were investigated. The results showed that the TiO₂-coated membrane calcined at 550 °C was uniform. It showed good photocatalytic and anti-fouling properties. As compared to the basement membrane, the TiO₂-coated membrane showed significantly improved photocatalytic removal of methylene blue. It showed a methylene blue removal degree as high as 97.2% and could be recycled multiple times by a simple treatment. The methylene blue removal degree of the membrane remained 92.3-93.6% after five recycling operations. Therefore, the membrane prepared via the simple method proposed in this study could be used as an efficient photocatalyst to remove methylene blue from wastewater.     

Biosorption Characteristics of Indigenous Plant Material for Trivalent Arsenic Removal from Groundwater: Equilibrium and Kinetic Studies

A biomass derived from plant A. nilotica (leave) has been used for efficient removal of trivalent arsenic (As(III)) from aqueous media. The experiments were carried out to study the effects of different parameters i.e., biomass dosage, As(III) concentration, pH, temperature, and contact time. The equilibrium biosorption data were analyzed by the Langmuir and Freundlich isotherm models and satisfactorily both isotherm models could be fitted well. The biosorption mean free energy based on the D-R isotherm model was calculated in the range of 7.50–8.21 kJ mol^?1. The data of thermodynamic parameters [enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°)] were identified that biosorption of As(III) onto studied biomass was spontaneous, feasible, and exothermic under the optimum experimental conditions. Kinetic estimations based on the experimental data demonstrated that the biosorption of As(III) followed the pseudo-second-order kinetics. The studied biomass was successfully applied for the removal of As(III) from contaminated groundwater samples of Jamshoro district.     

工业废液吸收低浓度CO2：可行性及应用

化工燃料在提供能源过程中产生的低浓度CO₂废气可以被工业废液吸收。结合当前研究现状,介绍了用工业废液吸收低浓度CO₂废气的研究进展,并开展了可行性分析;归纳了CO₂废气与工业废液的反应原理,将其大致分为中和反应、复分解反应、微生物转化等反应类型,并讨论了其吸收动力学;总结了工业废液吸收低浓度CO₂废气的工艺装置与流程。在废液吸收废气的处理模式中,CO₂的吸收对降低碱液的pH、脱除废液中有害物质效果良好,同时还可以副产微纳米碳酸钙、生物柴油等高附加值产品,实现废弃资源的深度循环利用。此外,分析了工业废液吸收CO₂废气的生命周期评价,通过对能耗、碳排放和成本评估,进一步讨论了工业废液吸收CO₂废气对环境的影响及经济可行性。结合CO₂减排的前景,从工业应用的角度探讨了工业废液用作低浓度CO₂吸收剂面临的挑战,并对其未来产业化发展进行了展望。     

Preparation and application of supported demulsifier PPA@SiO2 for oil removal of oil-in-water emulsion

ABSTRACT

To improve the separation efficiency of oil-in-water emulsion of produced water from ASP (Alkaline/Surfactant/Polymer) flooding, a modified silica gel-supported polyether polyquaternium (PPA@SiO₂) was developed as a demulsifier for separating oil-in-water emulsion. The performance of oil removal using PPA@SiO₂ is achieved under combined demulsification and adsorption, the polyether polyquaternium (PPA) was functionalized by displacement and charge neutralization as demulsifier, the modified silica gel (MPS-SiO₂) was functionalized by adsorbing oil droplets as adsorbent. PPA@SiO₂ was synthesized and characterized using FTIR, XPS, SEM, and N₂ sorption analysis. PPA@SiO₂ was applied for the treatment of oil-in-water emulsion of produced water from ASP flooding. A 92.31% of oil removal is obtained under conditions as following: a 500 mg/L of initial oil concentration, a 1.5 g of PPA@SiO₂, a 30°C of demulsifying temperature and a 60 min of demulsifying time. MPS-SiO₂ particles after demulsifying exhibited a high adsorption capacity of 303.6 mg/g. This work not only provides a promising demulsification to demulsify the oil-in-water emulsion of produced water from ASP flooding but also gives a demulsify method combined demulsify and adsorb.