Name: two-way valorization of blast furnace slag: synthesis of precipitated calcium carbonate and zeolitic heavy metal adsorbent
Uploaded: 2017-02-21T13:00:00.000+00:00
Duration: 11 min 14 s
Description: Watch this Scientific Journal Video about Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent at JoVE.com

我们承认由谢里登化学与环境实验室的实验室工作人员，特别是Jaspreet恰恩德拉，Nausheen Zehra，迈克OVAS，艾琳萨顿和Daniel廖提供的研究支持。 EG还感谢副院长特里·戴维森和Dave Wackerlin托管在他的谢里登。从特里·戴维森和伊恩·麦克纳布博士，应用科学和技术在谢里丹学院院长的资金支持，也表示赞赏。 ATS科技公司，康塔仪器和马尔文仪器均符合氮吸附和粒度分析协助亲切。

1.高炉矿渣提取钙注意:由于在浸出选择性酸度的不利影响，钙的提取发生在两个步骤的地方，使用将在单一步骤中使用乙酸（CH 3 COOH）的一半摩尔浓度。 <ol><li>使用研钵和研杵研磨高炉炉渣和其筛至粒度低于2毫米。 </li><li>启封该配备有双叶轮搅拌器，一个加热/冷却套，压力计，和热电偶的高压釜反应器中。确保反应器容器的内部，并从反应器头部（搅拌器轴;叶轮;以及热电偶良好，其作为一个挡板）伸出的部件是清洁，无可与钙提取过程干涉的任何杂质。如果不是，彻底清洗。 </li><li>称量100克过筛高炉炉渣的（&lt;2毫米），将其放置在容器中。添加731毫升的CH 3 COOH（2M）至t他容器密封。确保密封反应器正确固定在支架上。 </li><li>放置在适当的位置的加热夹套，使得它覆盖几乎整个容器。设定加热温度至30℃，并开始以1000rpm的浆液混合。等到在反应器内部的温度达到设定点（约15分钟），然后离开淤浆在上述条件下混合60分钟。 </li><li>一旦酸提取时间已经过去时，除去加热套，启封反应器中，并倾从反应器中的淤浆到烧杯中。漏极阀也可使用，但粗固体可能会阻塞通道。 </li><li>真空过滤从残余固体浸出液溶液中分离的浆料;使用滤纸的8微米或更小的孔径。立即（湿滤饼）处理该固体，或将它们在环境温度下加工在稍后的时间进行干燥。 注:渗滤液可以存储在T环境温度，但应优选被进一步处理（纯化和碳酸）不久之后，以避免溶解化合物的不受控制沉淀。 </li><li>洗两个反应器头部，并与去离子水的容器中，以确保没有从酸或炉渣残余物留下。 </li><li>从在容器中的第一个的Ca提取步骤放置干燥，固体残余物，并添加731 CH毫升3 COOH（2M）。重复同样的过程（步骤1.5），以固体用酸（在30℃和1000转，60分钟）混合。 </li><li> 在第二提取步骤的末尾，将萃取后的浆液到离心管中。采用大容量管（ 如 50毫升以上），并按照标准离心的做法，如确保每管相同的权重。 <ol><li>通过离心在2500 xg离心浆液最少10分钟分开浸出液固体。慢慢倒入上清到一个新瓶，而柯eping在管中的固体。 注:因此实现从富醋酸钙的液相中的固体（悬浮的二氧化硅和残余高炉炉渣）的分离。 </li></ol></li><li>在DI水中回收从管和第二提取步骤得到的固体残余物再悬浮它们。执行新一轮离心以去除残留的可溶性乙酸盐。恢复洗净固体，并允许他们在环境条件下干燥。 </li><li>从第一萃取过滤（滤液）和第二提取离心（上清液）结合的解决方案，以获得提取后的浸出液。 </li></ol> 2.拔牙后的渗滤液的理化净化注意:尽管从浸出液溶液（步骤1.9）的固体的分离，将得到的上清液仍包含水溶性或胶态的杂质。最重要的，这些杂质是硅，镁和铝。根据以前发表的工作32，在纯水中的二氧化硅的溶解度成正比的溶液（ 即，通过降低纯水的温度，二氧化硅的溶解度也降低）的温度。虽然渗滤液溶液是不纯净水，它已经发现，对从萃取后的浆液的固-液分离，以冷却在进一步的二氧化硅去除结果上清液（单独相比离心）2。另一方面，镁和铝的杂质存在于乙酸盐的形式上清液。为了显著降低其溶解度，它们必须调节pH值2转化为不溶性金属氢氧化物。 <ol><li>添加浓NaOH溶液（50％W / W）向上清液，使得NaOH在上清液中的最终浓度为1.25米;这将增加pH值至约8.4，从而将所述镁和铝王牌tates到氢氧化物的其显著少可溶形式。加入苛性碱溶液缓慢搅拌的同时并测量pH值。 </li><li>放置该NaOH富集上清液在冰箱和冷却下降到1℃，以使二氧化硅的额外沉淀。 </li><li>一旦冷却，真空过滤用滤纸具有0.45μm的孔径的溶液。该解决方案导致的镁和铝的沉淀杂质的进一步除去硅和微过滤。 </li></ol> 3.净化渗滤液碳化注意:由于在碳化乙酸的再生，使用NaOH作为添加剂来缓冲酸度，从而抑制钙沉淀。为生产更纯的PCC，氢氧化钠应在子等摩尔浓度使用相对于在萃取步骤（2M）中使用的CH 3 COOH的。 <ol><li>倒入纯化渗滤液入高压釜中再演员。检查两个其容器和瓶盖组件，以验证它们是否干净以前用途残留，以免杂质与碳化反应干扰。添加浓NaOH（50％W / W）的容器中，使得在纯化的渗滤液溶液的最终的NaOH浓度是1.7M的，为了在碳酸化过程中和再生的CH 3 COOH。密封反应器，然后小心固定在它的支持。 </li><li>放置在反应器的加热套在适当的位置。调节加热温度至30℃，并开始以1000rpm的浆液混合。等到反应器的内部达到期望的温度（约15分钟）。通过引入到在2巴高纯度（99.5％）的反应器中的 CO 2开始该混合物的碳酸化;运行60分钟。 </li><li>在碳酸化完成后，去除加热夹套，减压和启封反应器中，并倾碳酸浆料到烧杯中。 注意:排水阀也可降压后的固体都很好使用。 </li><li>真空过滤得到的淤浆以分离从溶液中固体沉淀;使用滤纸的8微米或更小的孔径。用去离子水彻底冲洗滤饼真空下除去可溶性钠盐。 注:在漂洗滤液的导电率的显着减少，可用于确认该冲洗终点。 </li><li>烘箱干燥在105℃的固体材料24小时来检索的PCC。 </li></ol> 4.提取固体残留物的水热转化注:对于水热转化，使用由高炉炉渣乙酸萃取钙贫残留固体。每次提取运行（包括这两个步骤），之后初始质量的不到50％（重量）可以被恢复（由于钙提取和胶体二氧化硅的中过滤的部分损失，并根据在滤纸上porosiTY使用）。因此，需要提取的多个批次，以产生在水热转化步骤中使用的固体的质量。 <ol><li>放置60克从钙萃取干，残余固形物的到干净的高压釜反应器中。添加300mL的2M的NaOH溶液。密封反应器并将其固定到其支撑。 </li><li>放置在反应器的加热套在适当的位置。调节加热温度至150℃，并开始以300rpm的浆混合。等待大约45-50分钟，直到反应器的内部达到期望的温度。离开淤浆在上述条件下混合24小时。 </li><li> 在水热转换完成，取出加热夹套，并允许该反应器冷却60分钟，至约35℃。将反应器夹套的冷却回路也可以用于加速冷却。 <ol><li>启封在反应器和倒转换的浆液到烧杯中。 </li></ol></li&gt; <li>真空过滤该浆料，分离从溶液中转化固体;使用滤纸的8微米或更小的孔径。用DI水彻底冲洗的固体在真空下以除去过量的苛性碱。 注:在漂洗滤液的导电率的显着降低可用于确认漂洗终点。 </li><li>烘箱干燥在105℃下将过滤材料24小时，以获得水热转换材料。 </li><li>使用研钵和研杵分解的颗粒材料并将所得材料筛到粒度&lt;0.85毫米。 </li></ol> 5.重金属的吸附试验的沸石产品注:镍离子被选择作为重金属进行调查。用不同的初始重金属污染浓度的溶液合成。的2-200毫克/升初始重金属浓度被选择为适合本研究的需要。 <ol><li>为了制备用于该平衡实验的污染溶液，用微量移液器添加1,000 mg / L的分析级的Ni 2+的标准溶液适量到1升的超纯水在容量瓶中，以产生解所需的Ni 2+浓度（2毫克/升，10毫克/升，20毫克/升，100毫克/升和200毫克/升）。 </li><li>在封端的塑料瓶，分散1克来自步骤4.6的100ml各合成制备污染溶液的所得水热转换材料构成。 </li><li>添加浓NaOH（2M在第一和0.5M接近终点）滴加至溶液的pH调节至4-5。连续地搅使用上的搅拌盘磁性搅拌棒以低速的溶液。监测pH值，同时通过在溶液中浸泡过的pH电极添加氢氧化钠。 </li><li>放置瓶在摇床培养箱中，在160转和20℃24小时搅拌它们。 </li><li>混合后，加入浓盐酸（的2M在第一和0.2M接近终点）滴入到该溶液中，以调整pH至4-5。调节过程中，连续搅使用上的搅拌盘磁性搅拌棒以低速的溶液。连续监测pH值，同时通过在溶液中浸泡过的pH电极添加盐酸。 </li><li>放置在离心管的淤浆。通过使用实验室离心机以2,500×g离心5分钟分离，从该溶液中的固体。小心倾上清液到新的瓶子，同时保持固体在离心管中。 </li><li>酸化用HNO 3（2％（重量）硝酸浓度）的溶液，以减少将pH &lt;2。 注:执行该步骤，以确保离子储存期间保留在溶液中（在环境温度）之前，进一步处理和分析。 </li><li>通过使用ICP-OES测定上清液中的调查重金属的平衡浓度。 注意:溶液通过一个稀释的10-100因子使用2重量％的HNO 3的稀释剂，以使得预期的浓度落在校准仪器（0-2毫克/升）的线性范围。钇，以2mg / L时，加入到每个稀释样品作为内部标准。的ICP-OES仪器是根据制造商的金属的废水37的分析建议操作。镍浓度的测定替代技术中的解决方案，例如ICP-MS和AAS，也适用于这一步骤。 </li><li>计算使用下面的公式在平衡（Q E）每克吸附剂的吸附重金属的量: <img alt="方程" src="/files/ftp_upload/55062/55062eq1.jpg" /> 其中，C o为在溶液中的重金属离子的初始浓度（微摩尔/毫升），C e是重金属离子的溶液中的（微摩尔/毫升）的平衡浓度，V是沃受污染的溶液的lume明（mL）中，m是干吸附剂（G）的质量。 </li></ol>

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尽管间接碳化7,8和水热转化9，高炉炉渣10已被广泛研究作为单独的工序，其对PCC和沸石矿物的共生合成耦合最近才提出5，并且该方法是在这里提出详情。的过程中最关键的步骤是Ca的足够（几乎完全）萃取，并从高炉炉渣的二氧化硅和铝的在提取阶段期间的有限浸出。在该浸出液的高量的钙碳化后固定的PCC合成率高并抑制大量不希望的相的产生（ 例如，雪硅钙石，水榴（钙3 的 Al 2（的SiO 4）3-Y（OH）4Y） ）水热转化产品9中。在thê另一方面，Si和Al的在提取后的固体残留物的最大部分的保存是用于沸石矿物的形成工具的重要性。 为此，在文献中研究了几种萃取剂中7，8，10，11，34，35，36，乙酸被选为最适合于本研究的目的。的特定萃取剂导致的大量从熔渣到溶液的钙的释放，同时确保Si和Al在所得残留物的最大的部分的停留时间。这促进了PCC和沸石的并联形成。在每次萃取步骤中使用的乙酸对钙的摩尔比为2:1（基于熔渣，炉渣中的钙含量，和第质量的醋酸溶液E体积），这意味着在两个提取步骤的总比例为4:1。自醋酸钙具有2醋酸对钙的比例:1，加倍使用了化学计算量，如通过Chiang 等发现有必要。 五 为了限制在所生成的PCC不希望的杂质的存在，该浸出液溶液应当是碳酸前进行进一步纯化;这是所提出的共生方法的另一个新颖性。在先前的工作中，PCC质量（化学纯度，矿物组成，颗粒大小和形状）通过杂质被负面影响。对合成PCC有资格做造纸填料，某些条件必须得到满足。所产生的PCC应由高的化学纯度（最小98％（重量）的Ca）的，均匀的矿物学结构，平均粒径小，且粒度分布窄6来表征。正如代表提交的结果截口，所提出的方法得到这些特征。沉淀的碳酸盐是高纯度的，并且具有98.1％（重量）（ 图2a），钙含量。 水热转化过程的优化导致产生与充当重金属的吸附剂的能力的材料制成。优化是通过发现温度，氢氧化钠浓度和反应时间的最合适的组合制成。雪硅钙石是不希望的矿物相，可以形成中的一个;其分层晶体结构导致降低比表面积39，性状为吸附剂重要，尽管已经报道了雪硅钙石可以作为通过离子交换机构40的吸附剂起作用。然而，占主导地位的转换后的材料在这项研究中的矿物相，在最佳条件下，是方沸石（ 图3b）的。这是已报道的沸石有一个显着的重金属的吸附能力41，42和可因此被用于从废水中除去有毒污染物的，如本文所示。 这种材料作为吸附剂的潜在用途进行了研究用于从水中除去镍。镍离子的合成制备污染溶液的pH值在测试过程中控制在4-5中，首先，以防止材料的溶解在合成溶液的初始酸性环境，并且，第二，以调节pH至水平通常在重金属修复条件43中。三种不同的等温线模型，即朗缪尔，Freundlich吸附和的Temkin，以表征所述吸附方法（ 图4和5），Langmuir模型证明是最合适的被应用。应当注意的是，对D M值ATTRIB布式的未经调整的平衡吸附剂吸附的解决方案比对应调整后的均衡解高。这是通过在pH值的上升，在在溶液中发生，直到它到达它的平衡吸附反应发生说明。较高的pH（&gt; 5）导致镍沉淀为镍（OH）2，根据地球化学建模和由Santos 等的实验研究。 44，这反过来又膨胀为D m值的 。这种类型的重金属的不应该被考虑为试验材料的实际吸附能力。在努力避免这种偏置测量，平衡吸附剂吸附溶液的pH值通过加入浓盐酸滴重新调节至〜5.0。在较低的Që值（ 图4a），因此，在调节pH的溶液的更保守的Ni吸附的估计，因此可以为Obtained。 本文描述的技术有潜力适于开发的其它材料作为用于PCC和沸石的合成的Ca，Al和硅的来源。比高炉矿渣等可以包括炼钢炉渣，焚化灰，采矿和选矿尾矿，建筑垃圾，天然矿物质等潜在的材料并非所有这些材料都含有钙，铝，和Si的相同比例高炉渣（这是什么使高炉炉渣特别有吸引力的），但尽管如此，它们仍然可以用于生产轻质碳酸钙，沸石，或其它矿物衍生的产品（ 例如，聚集体45或火山灰材料）通过类似的处理技术（提取的一些组合，沉淀和/或化学转换）。此外，从高炉渣或其他矿物质产生的沸石材料应为其他废水或调整应用程序进行测试，因为他们可能有ADSOrption能力等重金属，如镉，铅，和锌46。经济学（需支付原生材料与处置费避免的废弃物，或者利用产品的较高或低价值应用的财务回报）应在适当的矿物原料的识别发挥作用。通过成本更低或更易于可收回替代其他过程输入置换（乙酸，氢氧化钠，并浓缩的 CO 2），也应考虑到提高加工成本。

工业废渣富含碱金属的间接碳化已被广泛研究作为碳捕获和储存（CCS）技术1，2，3，4的部分。 CO 2的一定量的能有效地被存储，永久和的方式，是良性到大气中。然而，虽然形成有价值的材料，存在着保持充分探讨的技术中的一个组成部分。在间接碳化过程中，钙选择性地从材料中提取，并随后在受控条件下进行碳化。然而，废物的物价稳定措施方法产生从材料的固体残渣;这些残基不进一步处理或钙提取阶段后利用。处理减少生产这种残基的，或者甚至是消除它们的路线，应该找到。本端，最近，出现了开发和优化过程，其中，通过使用高炉（BF）炉渣作为原料，碳的零废矿物封存，伴随有用矿物的形成，可以是一个努力取得5,6。 一些废料有资格作为二氧化碳矿化反应效率。其中，炼铁和炼钢炉渣提出相当高的实验CO比所有其他工业废料4 2摄取。高炉炉渣为废物物价稳定措施的吸引力在于它的品质（化学，矿物，和形态性质）和材料5的潜在应用。它是炼铁过程，其中，从铁矿石杂质在火法冶金工艺被除去的副产物。根据该方式，它是从molte其分离之后冷却Ñ铁，会产生四种不同类型的炉渣的:（ⅰ）风冷（即晶体），（ⅱ）造粒（ 即，玻璃化），（ⅲ）膨胀（ 即发泡），和（iv）颗粒化。 虽然使用高炉炉渣的间接碳化生产沉淀碳酸钙（PCC）的是，已设法不起眼7,8的方法，炉渣用于生产沸石矿物的水热转化是已经研究了一种技术和仅在最近几年9开发，10，11。然而，在没有的情况下，已它被认为是可能的组合，以实现PCC和沸石的共生形成用于与高炉矿渣的间接碳化的技术。按照本文的双向物价稳定措施方法中所述，这两种技术被耦合到完成的 CO 2的足够螯合同时还获得沸石矿物和消除任何可能的固体残渣。根据此过程，CO 2被存储在被从炉渣通过酸浸经由矿物碳酸化反应5萃取钙。以实现为在造纸（矿物学，粒径分布，和颗粒形态）应用程序的合适的PCC产品性质，从提取阶段浸出液是第一物理化学纯化的6。平行，形成在通过从钙提取阶段5所得的固体残留物的水热转化苛性溶液沸石矿物。 沸石是一种硅铝酸盐矿物。天然存在的，但它也可以在大规模地工业生产。众多独特沸石框架已经确定，导致各种应用程ations的材料。例如，它们可以在几个工业部门12，13被用作催化剂;它们在洗涤剂和建筑材料如沥青添加剂发现，混凝土14，15，和波特兰水泥16，17;他们也有在医疗18，19，20和农业21，22，23结构域的应用程序。此外，由于它们的大的比表面积和其阳离子交换容量，沸石也可以用作为吸附剂24，25，26，27。这些特定的吸附剂还可以用于吨Ø直接处理重金属载货流，如污水或污染的地下水28，29，30，31。在这项研究中，通过双向的物价稳定措施方法从高炉熔渣制造的沸石材料，对于第一次，测试作为用于重金属，即，镍的吸附剂。 对于所提出的共生过程中，提取剂可亲到PCC和沸石形成都应该被使用。因此，一个合适的萃取剂的选择是至关重要的。间在以前的研究应用在两个间接碳化7,8和水热转化10，高炉炉渣11几个浸出剂，乙酸被选为最有前途的。上都·盐酸10呈现不利影响PCC的和浸出选择性eneration，引起Si和Al的量显著损失渗滤液溶液。另一方面，甲酸11已被证明是有效的，因为它管理而呈现显着浸出选择性，留下两个硅和Al不受干扰有效地从熔渣除去钙和镁。但是，它呈现较低的酸解离比乙酸33恒定，这表明碳酸钙的沉淀应该雇佣醋酸溶液作为提取剂后更容易实现的。还已经表明，在一些情况下，如与使用琥珀酸盐34和草酸盐35，非碳酸盐沉淀代替PCC的形式。 Eloneva 等 。 36，用于从炼钢炉渣去除钙并发现乙酸相比16萃取是最有效的（最好0.5 M和2M的萃取剂浓度之间的性能）和最成功的（最高钙回收率在约100％）。 以下方案详细描述了实验室规模的试验过程中，导致高纯度的PCC的形成和沸石材料，具有潜在的用途分别作为纸张填料和重金属的吸附剂。高炉炉渣是起始材料。施加用于将合成沸石材料作为适当的重金属的吸附剂的评估测试程序还概述。

<table><tbody><tr><td>Acetic acid (CH&lt;sub&gt;3&lt;/sub&gt;COOH)</td><td>Caledon Laboratories</td><td>1000-1-29</td><td>Glacial (&amp;ge;99.7%).</td></tr><tr><td>Autoclave reactor</td><td>Parr</td><td>4525-T-HC-M(HC)</td><td>One liter volume, equipped with dual turbine impeller, baffle and electric heating jacket.</td></tr><tr><td>Blast Furnace (BF) slag</td><td>ArcelorMittal</td><td>-</td><td>Granulated BF Slag from Ghent (Belgium); Pelletized BF Slag from Hamilton (Canada).</td></tr><tr><td>Carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;)</td><td>Praxair</td><td>TBC</td><td>Industrial grade (99.5%).</td></tr><tr><td>Centrifugal Mill</td><td>Retsch</td><td>ZM100</td><td>0.50 mm sieve.</td></tr><tr><td>Centrifuge</td><td>Thermo Electron</td><td>IEC CL30</td><td>To separate solids from liquids.</td></tr><tr><td>Ecoclave reactor</td><td>B&amp;uuml;chi</td><td>Type 3E</td><td>One liter volume, equipped with turbine impeller, baffle and electric heating jacket.</td></tr><tr><td>Filter paper</td><td>Fisher Scientific</td><td>P8 (09-795F)</td><td>Porosity: coarse; flow rate: fast.</td></tr><tr><td>Hydrochloric acid (HCl)</td><td>Caledon Laboratories</td><td>6025-1-29</td><td>Reagent grade (36.5%-38.0%).</td></tr><tr><td>Incubator</td><td>New Brunswick Scientific</td><td>I 24</td><td>Orbital shaker with temperature control.</td></tr><tr><td>Inductively Coupled Plasma Mass Spectrometer (ICP-MS)</td><td>Thermo Electron</td><td>X Series</td><td>To determine the concentration of Al, Ca, Mg and Si in the post-extraction leachates and post-carbonation liquid medium.</td></tr><tr><td>Inductively Coupled Plasma Optical Emissions Spectrometer (ICP-OES)</td><td>PerkinElmer</td><td>Optima 8300</td><td>To determine the concentration of Ni in the post-centrifuged equilibrated adsorbent-adsorbated leachate.</td></tr><tr><td>Laser Diffraction Analysis (LDA)</td><td>Malvern</td><td>Mastersizer 3000</td><td>To measure the average particle size diameter and particle size distribution (PSD) of the solids.</td></tr><tr><td>Microbalance</td><td>Sartorius</td><td>Quintix224-S1</td><td>Four decimals.</td></tr><tr><td>Ni standard solution</td><td>Perkin Elmer</td><td>N9300136</td><td>Concentration of 1,000 mg/1,000 mL.</td></tr><tr><td>Nitric acid (HNO&lt;sub&gt;3&lt;/sub&gt;)</td><td>Caledon Laboratories</td><td>7525-1-29</td><td>Reagent grade (68.0%-70.0%).</td></tr><tr><td>Oven</td><td>Fisher Scientific</td><td>Isotemp oven</td><td>105&amp;deg;C.</td></tr><tr><td>pH meter</td><td>Fisher Scientific</td><td>AB15</td><td>Calibrated with standard solutions before each set of measurements; temperature corrected to 25 &amp;deg;C.</td></tr><tr><td>Sodium hydroxide (NaOH)</td><td>Caledon Laboratories</td><td>7871-6-42</td><td>Reagent grade (50% W/W).</td></tr><tr><td>X-ray Diffraction (XRD)</td><td>Rigaku</td><td>MiniFlex 600</td><td>To characterize mineralogical properties of adsorbant solids.</td></tr><tr><td>X-ray Fluorescence (XRF)</td><td>PANalytical</td><td>Zetium</td><td>To characterize chemical composition of solids.</td></tr><tr><td>Nitrogen Adsorption</td><td>Quantachrome</td><td>NOVAtouch&amp;nbsp;</td><td>To characterize specific surface area, pore volume and mean pore diameter of solids.</td></tr></tbody></table>

two-way valorization of blast furnace slag: synthesis of precipitated calcium carbonate and zeolitic heavy metal adsorbent

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (&lt;2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6&#8729;H2O). Based on its ability to adsorb Ni2+, as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications.

为了测试纯度和产率的碳酸盐沉淀物，几个仪器技术都可以应用。元素组成（包括主要和次要成分）可以通过感应耦合等离子体原子发射光谱（ICP-OES），由下列酸消化电感耦合等离子体质谱（ICP-MS）或原子吸收光谱法（AAS）来测定（在HCl中），或通过X射线荧光光谱（XRF）与粉末或颗粒形式的样品。 XRF为次要组分（&lt;1重量％）不敏感。更多细节和实施例是在德克罗姆等人发现。 6这些结果将证明，如果不希望的杂质存在，将有助于确定，由质量平衡，原炉渣中的钙含量转换成PCC的效率。矿物组合物最好通过X射线粉末衍射（XRD）测定的。由此产生的衍射图提供定性关于结晶矿物相的存在信息。的相对量的定量是由Rietveld精修技术制成（具有约±2-3％（重量）的准确度）。更多细节和例子可以在Santos 等中找到。 38这些结果将验证该工艺条件或杂质影响结晶过程中，除了产生额外的方解石阶段意外（ 碳酸钙 ）。粒度分布（PSD）和平均粒径最好通过湿法（DI水）的激光衍射来确定。更多细节和例子可以在德克罗姆等中找到。 6这些结果用于评估如果PCC满足其预定的应用程序（ 即，造纸）的要求，通常指定一个上限截止尺寸及分布的跨度。 提取后的渗滤液和碳化后的元素组成的产品，以及在X射线衍射图案和碳化后的沉淀物的基于体积的PSD中，在图1和2给出。用ICP-MS技术测量在渗滤液的钙提取阶段后的组合物和其碳化之前的某些金属（钙，镁，铝，和Si）的含量（重量％）。使用分析级乙酸（2M）作为浸出剂的导致了大约90％（ 图1a）一钙萃取。根据结果​​，对于镁（几乎100％），即可以有效地碳酸另一种金属，但更密集的条件下，检测到一个更高的提取效率。 二氧化硅和铝的在提取阶段的行为也进行了研究。要成功地生产过水热转化铝硅酸盐类矿物沸石，也避免与理解过程合成的PCC的污染sired元素，既二氧化硅和铝应在提取过程中保持在固相。根据结果，乙酸表现出二氧化硅和铝的令人满意的有限浸出，几乎92％的二氧化硅和期间浸出过程（ 图1b）其余不受影响铝62％。 纯化的渗滤液溶液的碳酸化导致产生的PCC的具有希望的特性，如在图2中所描绘。基于X射线衍射图上（ 图2b），这主要是合成的矿物相是方解石（88.2重量％），而nesquehonite少量（镁（HCO 3）（OH）·2H 2 O; 3.2％（重量））的和镁方解石（CA 1-0.85镁0-0.15 CO 3; 2.8％（重量））也出席了会议。从材料（ 图2c）的PSD分析，很明显的是，平均粒径SIZE组小，粒径分布窄。 在与碳酸平行，从提取阶段的固体残留物进行水热转化。水热转换材料的表征，以验证生产沸石矿物质和评估的形态，如下进行。的元素组成是最容易通过XRF获得。痕量元素确定需要酸溶解接着用ICP-OES，ICP-MS，或原子吸收，与使用顺序酸溶解进行的消化（HNO 3 -HF或HNO 3 -HClO 4 -HF）以溶解硅石相。虽然有针对性的为转换后的材料没有具体的元素组成，这个分析有助于澄清XRD确定的矿物成分。 X射线衍射分析，以确定矿物组合物，所述PSD和平均粒径进行类似确定为碳酸盐沉淀物，一Ş上述。比表面积，孔体积和平均孔径是由氮吸附法测定，通过使用根据布鲁诺尔 - 埃米特 - 特勒（BET）多点理论解释的等温线。样品应在真空下进行初始脱气在350℃保持4小时。更多细节和例子可以在Chiang 等中找到。 五 在水热转化材料的钙，镁，铝，和Si含量，通过使用ICP-OES技术测定，示于图3a中 ，而它们的矿物组合物，从X射线衍射图案确定的，在图3b中示出。平均粒度和粒度分布，从PSD分析得到，显示在图3c中 。钙方沸石（NaAlSi 2 O 6∙H 2 O）和雪硅钙石（:所得材料矿物学特征在于两个主要阶段的存在5（OH）2的Si 6 O 16∙4H 2 O）。后者的在转换提取残渣的存在证明在该材料的化学组成，检测到的，因为它是用X射线荧光分析的显着的钙含量（22.5重量％）。二氧化硅（37.​​2重量％）和铝（11.2重量％）分别为另一主要元件，而镁在约4重量％的量存在。基于该PSD分析，体积瞬间（德勃鲁克尔）意味着转换后的材料的粒径（D [4,3]）为86.6微米，而粒径分布从0.594微米至1.11毫米不等。氮气吸附分析证实中孔材料的形成（46.0纳米平均孔径），具有比表面积和水热转换材料，分别的孔体积在4.89米2 /克增加到95.23米2 / g，且从0.014毫升/ g至0.610毫升/克比原炉渣。 r.within页="1"&gt;镍离子的平衡吸附等温线到水热转换材料，该平衡吸附剂吸附溶液的pH调整之前和之后，以及在实验数据的线性拟合朗缪尔，Freundlich吸附和特姆金吸附模型示于图4。 Langmuir模型是基于表征化学吸附过程的一些合理的假设。根据它们，吸附剂的表面仅提供固定数量的吸附位点的，具有相同的形状和大小，其特征在于用相同的吸附能力。吸附材料只形成一个层（一个分子的厚度）的吸附剂的表面上，并且在温度是恒定的。在数学上，Langmuir模型由下式表示: /files/ftp_upload/55062/55062eq2.jpg"/&gt; 其中C e是吸附物的溶液中的平衡浓度（微摩尔/ 100毫升）中，q e是金属的平衡（微摩尔/克）每克吸附剂的吸附量，D m是吸附剂的理论最大单层覆盖量（微摩尔/克），并且k是Langmuir等温恒定（100毫升/微摩尔）。 该Freundlich等温不是由Langmuir模型所需要的假设的限制。相反，它描述了可应用到吸附剂与异构表面的物理吸附过程。吸附位点，分布在整个吸附剂的表面，其特点是对于被吸附物不同的亲和力，而吸附材料构成的吸附剂的表面上的多于一个的层。符合Freundlich模型在数学上表示为: <img alt="方程" src="/files/ftp_upload/55062/55062eq3.jpg" />其中K f和n的Freundlich等温常数，对应于分别的吸附能力和吸附强度。 最后，的Temkin模型假定该层的所有分子的吸附热线性覆盖由于吸附剂的吸附物的相互作用减少，而结合能是均匀分布的。所述的Temkin模型由下式表示: <img alt="方程" src="/files/ftp_upload/55062/55062eq4.jpg" />其中，R是通用气体常数（8.314焦耳/摩尔/ K），T是第È温度（K），ΔQ是吸附能量（（焦耳/摩尔）∙（克/微摩尔））的变化，和K 0是的Temkin等温线平衡结合常数（100毫升/微摩尔）。 对于所有的应用的模型的系数的值进行计算的基础上绘制的吸附等温线（ 图4a）和朗缪尔，Freundlich吸附和的Temkin方程的线性形式（ 图4b-4d中 ）。的系数值，与线性方程一起列于表1中。最后，实验数据和Ni 2+的理论吸附等温线到用于三种不同的吸附模型活化材料之间的比较在图5中给出。基于图形的轮廓和实验结果的理论等温曲线的高接近上，已经证实，该新对MED吸附剂材料可以被有效地用作镍离子吸附剂。 通过比较图5a和5b，以及用于Langmuir和Freundlich模型（ 表1）的回归系数（R 2）提出的拟合结果，很清楚的是，Langmuir方程是更好地描述的实验数据之一。这意味着镍2+离子对转换的材料的吸附是一种单分子层吸附，并且其本质是一个化学过程。为了进一步分析研究了吸附的性质，我们还试图向的Temkin模型拟合到实验数据。从图5c和它的高，R 2（ 表1）所示的曲线图，它清楚的是，的Temkin模型还适合实验数据良好。基于所述变化的正值吸附能（ΔQ），可以得出结论，该吸附是放热的。 <img alt="图1" src="/files/ftp_upload/55062/55062fig1.jpg" /> 图1: 乙酸提取 。在渗滤液解铝，钙，镁，和硅的浓度（第一步骤，第二步骤，并且在总）从乙酸和地面，粒状高炉炉渣之间反应产生的在30℃下，以1000rpm和60分钟。 <a href="http://ecsource.jove.com/files/ftp_upload/55062/55062fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/55062/55062fig2.jpg" /> 图2: 碳酸钙沉淀。 （a）该碳酸酯沉淀的组成，在每个单元的重量百分数表示，归一化<html> d可100％的总。碳化后的沉淀物（b）的X射线衍射图。碳化后的沉淀物（ 三 ）粒度分布。从德克罗姆等转载。 6爱思唯尔（3879261230348）权限。 <a href="http://ecsource.jove.com/files/ftp_upload/55062/55062fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/55062/55062fig3.jpg" /> 图3: 水热转换材料。 （a）该水热转换材料的组成，表示每个元素的重量百分比，标准化为100％总。水热转化材料（b）的X射线衍射图。 （c）该水热转换材料的平均粒度分布。.COM /文件/ ftp_upload / 55062 / 55062fig3large.jpg"目标="_空白"&gt;点击此处查看该图的放大版本。 <img alt="图4" src="/files/ftp_upload/55062/55062fig4.jpg" /> 图4: 吸附等温线。 （ 一 ）前，将pH值调整后的沸石材料镍离子的吸附等温线的数据。 （ 二 - 四 ）拟合实验数据的线性朗缪尔，符合Freundlich和特姆金吸附模型。 <a href="http://ecsource.jove.com/files/ftp_upload/55062/55062fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/55062/55062fig5.jpg" /> 图5:实验和模拟数据接近。实验数据的比较（例如p）和根据（ 一个 ）朗缪尔镍离子的模拟吸附等温线（计算值），进入沸石材料，（B）符合Freundlich，和（c）的Temkin模型。 <a href="http://ecsource.jove.com/files/ftp_upload/55062/55062fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td></td><td colspan="2"> 线性方程组 </td><td> 系数 </td><td> 未调整 </td><td> 调整 </td></tr><tr><td rowspan="3"> Langmuir方程 </td><td colspan="2" rowspan="3"><img alt="方程" src="/files/ftp_upload/55062/55062tableeq1.jpg" /></td><td> Dμm时 </td><td> 196.08 </td><td> 196.08 </td></tr><tr><td> ķ </td><td> 0.174 </td><td> 0.0851 </tD&gt; </tr><tr><td> R 2 </td><td> 0.997 </td><td> 0.993 </td></tr><tr><td rowspan="3"> Freundlich方程 </td><td colspan="2" rowspan="3"><img alt="方程" src="/files/ftp_upload/55062/55062tableeq2.jpg" /></td><td> ñ </td><td> 2.50 </td><td> 2.13 </td></tr><tr><td> ķ˚F </td><td> 26.50 </td><td> 17.64 </td></tr><tr><td> R 2 </td><td> 0.840 </td><td> 0.893 </td></tr><tr><td rowspan="3"> 特姆金公式 </td><td colspan="2" rowspan="3"><img alt="方程" src="/files/ftp_upload/55062/55062tableeq3.jpg" /></td><td> ΔQ </td><td> 102.30 </td><td> 93.99 </td></tr><tr><td> ķ0 </td><td> 9.97 </td><td> 3.58 </td></tr><tr><td> R 2 </td><td> 0.998 </td><td> 0.978 </td></tr></tbody></table>表1:吸附等温线参数为镍 离子 吸附到沸石材料。的方程，并从线性朗缪尔，Freundlich吸附和特姆金吸附模型拟合参数。

Watch this Scientific Journal Video about Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent at JoVE.com

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

A protocol for the parallel production of precipitated calcium carbonate and zeolitic material from blast furnace slag via mineral carbonation and alkaline hydrothermal conversion, respectively, is presented. The performance of the zeolitic material towards nickel adsorption is tested.

高炉矿渣的双向稳定物价:沉淀碳酸钙和沸石重金属吸附剂的合成

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with ...

two-way-valorization-blast-furnace-slag-synthesis-precipitated

Nanyang Technological University

Research

JoVE Journal

Engineering

12.3K 次观看.  Cranfield University. A protocol for the parallel production of precipitated calcium carbonate and zeolitic material from blast furnace slag via mineral carbonation and alkaline hydrothermal conversion, respectively, is presented. The performance of the zeolitic material towards nickel adsorption is tested. 

视频: Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing

This paper discusses fluorescent core microcavity-based sensors that can operate in a microfluidic analysis setup. These structures are based on the formation of a fluorescent quantum-dot (QD) coating on the channel surface of a conventional microcapillary. Silicon QDs are especially attractive for this application, owing in part to their negligible toxicity compared to the II-VI and II-VI compound QDs, which are legislatively controlled substances in many countries. While the ensemble emission spectrum is broad and featureless, an Si-QD film on the channel wall of a capillary features a set of sharp, narrow peaks in the fluorescence spectrum, corresponding to the electromagnetic resonances for light trapped within the film. The peak wavelength of these resonances is sensitive to the external medium, thus permitting the device to function as a refractometric sensor in which the QDs never come into physical contact with the analyte. The experimental methods associated with the fabrication of the fluorescent-core microcapillaries are discussed in detail, as well as the analysis methods. Finally, a comparison is made between these structures and the more widely investigated liquid-core optical ring resonators, in terms of microfluidic sensing capabilities.

Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.

折光传感荧光芯微腔的合成和操作

This paper discusses  fluorescent core microcavity-based sensors that can operate in a microfluidic  analysis setup. These structures are based on the ...

科研

工程学

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

在极端的压力和温度的合成和Microdiffraction

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Picoinjection of Microfluidic Drops Without Metal Electrodes

Existing methods for picoinjecting reagents into microfluidic drops require metal electrodes integrated into the microfluidic chip. The integration of these electrodes adds cumbersome and error-prone steps to the device fabrication process. We have developed a technique that obviates the needs for metal electrodes during picoinjection. Instead, it uses the injection fluid itself as an electrode, since most biological reagents contain dissolved electrolytes and are conductive. By eliminating the electrodes, we reduce device fabrication time and complexity, and make the devices more robust. In addition, with our approach, the injection volume depends on the voltage applied to the picoinjection solution; this allows us to rapidly adjust the volume injected by modulating the applied voltage. We demonstrate that our technique is compatible with reagents incorporating common biological compounds, including buffers, enzymes, and nucleic acids.

We have developed a technique for picoinjecting microfluidic drops that does not require metal electrodes. As such, devices incorporating our technique are simpler to fabricate and to use.

微流控的Picoinjection滴无金属电极

Existing methods for picoinjecting reagents into microfluidic drops require metal electrodes integrated into the microfluidic chip. The integration of ...

Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route

Zeolites are an important class of materials that have wide ranging applications such as heterogeneous catalysts and adsorbents which are dependent on their framework topology. For new applications or improvements to existing ones, new zeolites with novel pore systems are desirable. We demonstrate a method for the synthesis of novel zeolites using the ADOR route. ADOR is an acronym for Assembly, Disassembly, Organization and Reassembly. This synthetic route takes advantage of the assembly of a relatively poorly stable that which can be selectively disassembled into a layered material. The resulting layered intermediate can then be organized in different manners by careful chemical manipulation and then reassembled into zeolites with new topologies. By carefully controlling the organization step of the synthetic pathway, new zeolites with never before seen topologies are capable of being synthesized. The structures of these new zeolites are confirmed using powder X-ray diffraction and further characterized by nitrogen adsorption and scanning electron microscopy. This new synthetic pathway for zeolites demonstrates its capability to produce novel frameworks that have never been prepared by traditional zeolite synthesis techniques.

Synthesis of Zeolites Using the ADOR Assembly-Disassembly-Organization-Reassembly Route

A protocol for the preparation of novel zeolites by the ADOR (Assembly-Disassembly-Organization-Reassembly) synthetic route is presented.

沸石使用ADOR（汇编拆卸组织-重组）路线的合成

Zeolites are an important class of materials that have wide ranging applications such as heterogeneous catalysts and adsorbents which are dependent on ...

化学

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone as a cheap and readily available CO2 sorbent. While the technology has been widely studied, there are a few available options that could be applied to make it more economically viable. One of these is to increase the oxygen concentration in the calciner to reduce or eliminate the amount of recycled gas (CO2, H2O and impurities); therefore, decreasing or removing the energy necessary to heat the recycled gas stream. Moreover, there is a resulting increase in the energy input due to the change in the combustion intensity; this energy is used to enable the endothermic calcination reaction to occur in the absence of recycled flue gases. This paper presents the operation and first results of a CaL pilot plant with 100% oxygen combustion of natural gas in the calciner. The gas coming into the carbonator was a simulated flue gas from a coal-fired power plant or cement industry. Several limestone particle size distributions are also tested to further explore the effect of this parameter on the overall performance of this operating mode. The configuration of the reactor system, the operating procedures, and the results are described in detail in this paper. The reactor showed good hydrodynamic stability and stable CO2 capture, with capture efficiencies of up to 70% with a gas mixture simulating the flue gas of a coal-fired power plant.

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner

This manuscript describes a procedure for operating a calcium looping pilot-plant for post-combustion carbon capture with high oxygen concentrations in the calciner in order to reduce or eliminate the flue gas recycle.

在煅烧炉中使用高氧浓度的 25 KWth钙循环试验装置的操作

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone ...

环境科学

Blast Quantification Using Hopkinson Pressure Bars

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

This protocol details the use of Hopkinson pressure bars to measure reflected blast loading from near-field explosive events. It is capable of interpolating a pressure-time history at any point on a reflective boundary and as such can be used to fully characterize the spatial and temporal variations in loading produced.

高炉利用定量霍普金森杆

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures ...

Adsorption Device Based on a Langatate Crystal Microbalance for High Temperature High Pressure Gas Adsorption in Zeolite H-ZSM-5

We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate crystal microbalance, LCM) and its use for gas adsorption measurements in zeolite H-ZSM-5. Prior to the adsorption measurements, zeolite H-ZSM-5 crystals were synthesized on the gold electrode in the center of the LCM, without covering the connection points of the gold electrodes to the oscillator, by the steam-assisted crystallization (SAC) method, so that the zeolite crystals remain attached to the oscillating microbalance while keeping good electroconductivity of the LCM during the adsorption measurements. Compared to a conventional quartz crystal microbalance (QCM) which is limited to temperatures below 80 &#176;C, the LCM can realize the adsorption measurements in principle at temperatures as high as 200-300 &#176;C (i.e., at or close to the reaction temperature of the target application of one-stage DME synthesis from the synthesis gas), owing to the absence of crystalline-phase transitions up to its melting point (1,470 &#176;C). The system was applied to investigate the adsorption of CO2, H2O, methanol and dimethyl ether (DME), each in the gas phase, on zeolite H-ZSM-5 in the temperature and pressure range of 50-150 &#176;C and 0-18 bar, respectively. The results showed that the adsorption isotherms of these gases in H-ZSM-5 can be well fitted by Langmuir-type adsorption isotherms. Furthermore, the determined adsorption parameters, i.e., adsorption capacities, adsorption enthalpies, and adsorption entropies, compare well to literature data. In this work, the results for CO2 are shown as an example.

A protocol for high-temperature and high-pressure gas adsorption measurements on zeolite H-ZSM-5 using an adsorption measurement device based on a langatate crystal microbalance is presented. Prior to the adsorption measurements, the synthesis of zeolite H-ZSM-5 on the langatate crystal microbalance sensor by the steam-assisted crystallization (SAC) method is demonstrated.

基于一个Langatate体微天平的高温高压气体吸附在分子筛吸附器H-ZSM-5

We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate ...

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is proposed. Bagasse impregnated with phosphoric acid is utilized as the precursor. To pyrolyze the precursor, two separate heating modes are used: microwave pyrolysis and conventional electric-heating pyrolysis. The resulting bagasse-derived carbon samples are modified with nitrification and reduction modification. Nitrogen (N)/oxygen (O) functional groups are simultaneously introduced to the surface of activated carbon, enhancing its adsorption of Cu(II) by complexing and ion-exchange. Characterization and copper adsorption experiments are performed to investigate the physicochemical properties of four prepared carbon samples and determine which heating method favors the subsequent modification for doping of N/O functional groups. In this technique, based on analyzing data of nitrogen adsorption, Fourier transform infrared spectroscopy, and batch adsorption experiments, it is proven that microwave-pyrolyzed carbon has more defect sites and, therefore, time-saving effective microwave pyrolysis contributes more N/O species to the carbon, although it leads to a lower specific surface area. This technique offers a promising route to synthesis adsorbents with higher nitrogen and oxygen content and a higher adsorption capacity of heavy-metal ions in wastewater remediation applications.

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis

Here, we present a protocol to synthesize nitrogen/oxygen dual-doped mesoporous carbon from biomass by chemical activation in different pyrolysis modes followed by modification. We demonstrate that the microwave pyrolysis benefits the subsequent modification process to simultaneously introduce more nitrogen and oxygen functional groups on the carbon.

微波热解法制备了更高氮素/氧螯合吸附的生物物质基介孔碳对 cu (ii) 的研究

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is ...

Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal

Heavy metal-polluted water is of great concern to human health and the eco-environment. In situ water remediation techniques enabled by highly efficient adsorption materials are of great importance in these circumstances. Among all the materials used in water remediation, iron-based nanomaterials and porous materials are of great interest, benefiting from their rich redox reactivity and adsorption function. Here, we developed a facile protocol to directly convert the widely spread red soil in south China to fabricate the Fe2O3/faujasite (FAU)-type zeolite composite material. 
The detailed synthesis procedure and synthesis parameters, such as reaction temperature, reaction time, and the Si/Al ratio in the raw materials, have been carefully tuned. The as-synthesized composite materials show good adsorption capacity for typical heavy metal(loid) ions. With 0.001 g/mL Fe2O3/FAU-type zeolite composite material added to different heavy metal(loid)-polluted aqueous solutions (single type of heavy metal(loid) concentration: 1,000 mg/L [ppm]), the adsorption capacity was shown to be 172, 45, 170, 40, 429, 693, 94, and 133 mg/g for Cu (II), Cr (III), Cr (VI), As (III), Cd (II), Pb (II), Zn (II), and Ni (II) removal, respectively, which can be further expanded for heavy metal-polluted water and soil remediation.

Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal

This article presents a novel and convenient route to synthesize Fe2O3/faujasite (FAU)-type zeolite composite material from red soil. The detailed synthesis parameters have been finely tuned. The obtained composite material can be used for efficient heavy metal-contaminated water remediation, indicating its potential applications in environmental engineering.

红壤资源化循环利用合成Fe2O3/FAU型重金属去除用分子筛复合材料

Heavy metal-polluted water is of great concern to human health and the eco-environment. In situ water remediation techniques enabled by highly efficient ...

胺化化合物的浸渍和接枝到二氧化硅基材上

A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture

Recently, there has been a significant effort towards reducing or mitigating CO2 emissions through the use of carbon capture materials for point source or direct air capture (DAC) methods. This work focuses on amine-functionalized CO2 adsorbents for DAC. These materials show promise for CO2 removal because they have low regeneration energy consumption and high adsorption capacity. The incorporation of amine species into a porous substrate combines the advantages of the amine species&#39; affinity to CO2 with the large pore volumes and surface areas of the porous substrate. There are three methods commonly used to prepare amine-based CO2 sorbents, depending on the selection of the amine species, material support, and preparation method. These methods are impregnation, grafting, or chemical synthesis. Silica is a prevalent choice of substrate material because of its adjustable pore size, moisture tolerance, temperature stability, and ability to adsorb CO2 in low concentrations for DAC applications. Typical synthetic procedures and primary attributes of both impregnated and grafted amine-silica composites are described herein.

作者聚焦:胺基二氧化硅复合材料作为直接空气捕获的 CO2 吸附剂的标准化开发 

This work aims to facilitate the development of standardized techniques for impregnating or grafting aminated compounds onto silica substrates, which are often broadly described in the literature. Specific amounts of solvent, substrate, amines, and the values of other important experimental parameters will be discussed in detail.

一种制备浸渍接枝胺基二氧化硅复合材料的合成方法

Recently, there has been a significant effort towards reducing or mitigating CO2 emissions through the use of carbon capture materials for point source or ...

高炉矿渣的双向稳定物价:沉淀碳酸钙和沸石重金属吸附剂的合成

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