这项工作得到了中国农业科学与技术创新研究院 (grant CARS-19)、中国农业科技学院 (ASTIP-IBFC07)、创新基金 (赠款号) 等专项基金的支持。为东华大学研究生 (格兰特号 16D310107), "小萍科技创新团队" (产业化综合研究 & 开发的麻纤维生物脱胶), 中国奖学金委员会。

1. 苎麻的氧化脱胶
<ol><li>
氧化脱胶液的制备
	<ol>
<li>溶解 2 g H2O2, 1 克碱 (混合镁 (OH)2和氢氧化钠), 0.4 克 Na5P3O10, 0.1 克蒽醌和0.2 克 HEDP 在100毫升蒸馏水中做脱胶解决方案。</li>
	</ol>
</li>
	<li>
苎麻的氧化脱胶
	<ol>
<li>在脱胶液中浸泡10克生苎麻, 并在85° c 下冲刷60分钟。</li>
		<li>将温度提高到125° c (压力为0.6 公斤), 再冲刷60分钟。 注: 有关提高温度的说明, 请参阅讨论。</li>
	</ol>
</li>
	<li>
苎麻纤维的还原
	<ol>
<li>在100毫升蒸馏水中溶解0.4 克 NaHSO3 , 以制备还原溶液。然后, 在90° c 的还原液中对脱胶纤维进行60分钟的处理。 注: 在氧化反应中产生的纤维素中的羧基和醛类会导致氢键的还原, 从而损害纤维的性能。通过将羧基和醛基转化为羟基, 可以改善纤维的性能。</li>
	</ol>
</li>
	<li>
后续处理
	<ol>
<li>用去离子水彻底清洗脱胶苎麻纤维。</li>
		<li>将纤维浸泡在90° c 的脱胶油中15分钟, 然后将纤维在烤箱 (125 ° c) 中干燥4小时。</li>
	</ol>
</li>
</ol>2. 脱胶溶液性能的测试
<ol><li>
Mg (OH) 的溶解度测试2
	<ol>
<li>在100毫升蒸馏水中溶解2克毫克 (OH)2 。</li>
		<li>另外, 溶解2克毫克 (OH)2在100毫升溶液与完全可溶性脱胶添加剂, 包括 0.4 g Na5P3O10和 0.2 g HEDP。</li>
		<li>提高在步骤2.2.1 和2.2.2 中描述的溶液的温度到85° c。</li>
		<li>用烧结光盘提取溶毫克 (OH)2 。</li>
		<li>用以下公式计算 Mg (OH)2的溶解度: <img alt="Equation 2" src="/files/ftp_upload/56461/56461eq2.jpg"> 注意: 这里的m (g) 是溶 Mg (OH)2的重量。</li>
	</ol>
</li>
	<li>
Mg (OH)2替代率对脱胶液 pH 值、有向值和残余 H2O2含量的影响 注意:12,19是重要的水化学参数, 它为环境水的氧化或还原能力提供了一个测量工具。具有较强氧化性能的溶液具有较高的物性值。mg (oh)2替代率是指在总碱用量为 10% (织物重量) 下, 由 mg (oh)2取代的氢氧化钠的摩尔比例。<ol>
<li>根据步骤 60%, 分别准备0%、20%、40%、80%、100% 和1.1 的镁 (OH)2替代率的脱胶解决方案。</li>
		<li>将原苎麻浸泡在步骤2.2.1 中描述的脱胶溶液中。</li>
		<li>根据步骤1.2 开始脱胶过程。</li>
		<li>用蒸馏水冲洗混合的可处理电极, 并在空气中烘干。然后在脱胶解决方案中浸泡混合的可检测的电极仪表, 每10分钟读取一次可解的值. 将 ph 电极计浸在脱胶溶液中, 每10分钟读出 ph 值。</li>
		<li>根据中国标准 GB 22216-20087的高锰酸钾4滴定法, 测试脱胶解决方案的 H2O2内容, 每10分钟进行一次。</li>
	</ol>
</li>
</ol>3. 苎麻纤维性能测试
<ol><li>
脱胶产量
	<ol>
<li>用以下公式计算脱胶率: <img alt="Equation 3" src="/files/ftp_upload/56461/56461eq3.jpg"> 注: 在这里, w (g) 是纤维在脱胶后的干重;W (g) 是苎麻在脱胶前的干重。</li>
	</ol>
</li>
	<li>
纤维的残余牙龈 注: 根据中国标准 5889-86, 对纤维的残余牙龈进行了测试。<ol>
<li>测量称量瓶中纤维 (约5克) 的干重, 并将其浸泡在装有150毫升氢氧化钠溶液 (20 克/升) 的烧瓶中 (回流冷凝管)。</li>
		<li>将温度提高到100° c, 并保持在这个温度为1小时。</li>
		<li>刷新碱液溶液。</li>
		<li>将温度提高到100° c, 并保持2小时。</li>
		<li>在样品筛中清洗纤维。</li>
		<li>测量称量瓶中纤维的干重。</li>
		<li>使用以下等式计算纤维的残余牙龈: <img alt="Equation 4" src="/files/ftp_upload/56461/56461eq4.jpg"> 注: 这里 m (g) 是纤维的干重;M (g) 是碱精练后苎麻的干重。</li>
	</ol>
</li>
	<li>
PD 试验 注: 根据国标 GB 5888-8615测试苎麻纤维的 PD 值。<ol>
<li>脱脂在 2:1 (v/五) 苯和乙醇混合物中浸入苎麻纤维。</li>
		<li>在室温下在空气中蒸发溶剂。</li>
		<li>使用剪刀将样品切成短片 (每样1-2 毫米, 约20-23 毫克)。</li>
		<li>在称量容器中, 将样品保持在控制湿度 (20 ±2° c, 相对湿度 = 65 ± 2%) 中, 直到它达到平衡含水量, 然后才能除去测试目的所需的材料。</li>
		<li>将一根铜线 (直径0.5 毫米) 浸在浓硝酸中, 其次为98% 无水乙二胺。然后, 用蒸馏水彻底冲洗铜颗粒。</li>
		<li>将纤维样品和铜颗粒放在塑料瓶中 (顶部)。</li>
		<li>在塑料瓶中加入10毫升蒸馏水和10毫升1摩尔/L cupriethylenediamine 溶液, 搅拌使用磁性搅拌棒, 准备 0.2 g/100 毫升 (约) 苎麻纤维 cupriethylenediamine 溶液。</li>
		<li>将6.5 毫升苎麻纤维 cupriethylenediamine 溶液转化为乌粘度计测定其内在粘度。用下列公式计算相对粘度: <img alt="Equation 5" src="/files/ftp_upload/56461/56461eq5.jpg"> 注: 这里ηr是相对粘度, t (s) 是苎麻纤维 cupriethylenediamine 溶液流经乌粘度计的平均时间, 而 t0 (s) 是0.5 摩尔/L cupriethylenediamine 溶液流经的平均时间乌粘度计。</li>
		<li>用以下公式计算苎麻纤维的 PD 值: <img alt="Equation 6" src="/files/ftp_upload/56461/56461eq6.jpg"> 注: 这里 [η] 是本征粘度, [η] ×C 值可从中国标准 GB 5888-86 的表中获得, C 是苎麻纤维 cupriethylenediamine 溶液的浓度。</li>
	</ol>
</li>
	<li>
纤维的线性密度
	<ol>
<li>使用以下等式计算纤维的线性密度: <img alt="Equation 7" src="/files/ftp_upload/56461/56461eq7.jpg"> 注: 这里 Lc是切割长度 (40 mm), n是纤维的数量, g (g) 是纤维的重量。纤维的线性密度是指在苎麻 (12%) 正式重拾的情况下, 1000 米长纤维的重量。</li>
	</ol>
</li>
	<li>
机械性能测试
	<ol>
<li>平衡在标准大气条件下的纤维样品 (T = 20 ±2° c, RH = 65% ± 2%) 为 24 h。</li>
		<li>在20° c、RH 65% 和 0.3 cN/dtex 的预张力下, 使用纤维强度仪测试纤维断裂的韧性、断裂伸长率和工作。将夹紧距离设置为 20 mm, 底部夹具的下降速度为 20 mm/分钟7,15。</li>
	</ol>
</li>
	<li>
脱胶废水的 COD 值
	<ol>
<li>根据国标/T 15456-2008 工业循环冷却水对脱胶废水 cod 的测定 cod-高锰酸钾法的检测方法 "7,15。</li>
	</ol>
</li>
	<li>
XRD 测试
	<ol>
<li>利用 x-射线衍射获得纤维的结晶度。记录 XRD 模式 2θ = 5-60 °的衍射仪配有石墨单色仪和 Cu Kα辐射在λ = 0.154 nm (40 伏, 200 毫安)。</li>
	</ol>
</li>
	<li>
FTIR 分析
	<ol>
<li>利用光谱仪获得了光纤的 FTIR 模式。将扫描时间设置为 30, 范围在 4,000-400 cm-1, 分辨率为8厘米-1。用红外光谱分析法测定处理纤维中的化学官能团。</li>
	</ol>
</li>
</ol>

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作者没有什么可透露的。

Mg (OH)2的设置取代率和反应温度是该协议的重点。Mg (OH)2取代率可以影响脱胶溶液的 pH 值和氧化能力。最好的 Mg (OH)2替代率苎麻脱胶是 20%, 因为纤维素不能得到足够的保护下的替代率低于 20%, 和过量的剩余牙龈 (低 DP 值和结晶度) 将保留在纤维低于 20% (图 4A) 的替代率。
反应温度会影响过氧化氢的反应途径。苎麻氧化脱胶过程中?...

苎麻, 俗称 "中国草", 是一种多年生草本植物, 其纤维可作为纺织工业的优良材料1,2。它是中国原产的主要经济作物之一;中国苎麻产量占世界总产量的90% 以上1,2。苎麻纤维是最强和最长的植物纤维之一, 光泽与几乎柔滑的外观3,4。苎麻纤维长的长度使其适合于单纤维纺丝, 在麻纤维中很少见到。苎麻纤维织物具有冷却、抗菌、导热性能优异、透气性好等优点,等3,4
纤维素是苎麻纤维的主要成分, 苎麻中的其他成分如果胶、木质素、水溶性物质等, 被定义为牙龈5,6。苎麻纤维可通过溶于含有化学试剂的溶液中的牙龈来提取, 该过程定义为脱胶5,6。主要有两种苎麻纤维提取方法: 化学脱胶和生物脱胶。传统化学脱胶工艺中脱胶废水的能耗、时间消耗和 COD 值都比较高, 在高压下用浓碱液精练法提取纤维素纤维6至 8 h7,8.另外, 生物脱胶是苎麻纤维提取的一种环保选择。然而, 苛刻的反应条件和先进的设备抑制其进一步的工业应用9,10。因此, 用碱过氧化氢进行氧化脱胶, 提出了一种有价值的、可供选择的应用重点, 因为它需要较短的脱胶时间和较低的脱胶温度11,12。然而, 由于过氧化物的强氧化能力, 在脱胶过程中可能会发生大量的纤维素降解, 这会对纤维性能造成很大的损害13,14。这是苎麻碱氧化脱胶的最大缺点。
在以前的研究中, 苎麻纤维被提取的碱过氧化氢系统只支持氢氧化钠15。然而, 由于氢氧化钠的强碱性, 过氧化氢的氧化反应速度难以控制, 从而对处理后的纤维7造成很大的损害。为了改善苎麻纤维的性能, 本研究采用氢氧化钠和氢氧化镁组成的控释碱源, 为碱性过氧化氢系统的 pH 值提供了一个碱条件和缓冲剂16,17。
这项技术背后的基本原理可以描述如下。氢氧化镁在蒸馏水中略有溶解性, 它可以用 OH-的消耗逐渐溶入脱胶溶液, 并使脱胶液的 pH 值和氧化能力保持在适当的范围内18。氢氧化镁的取代率 (SR) 被定义为氢氧化镁在总碱用量为10% 时所取代的氢氧化钠的摩尔比例, 并可通过以下公式计算替代率。此外, Mg2 +可以防止过度氧化导致的纤维素降解,19,20。
<img alt="Equation 1" src="/files/ftp_upload/56461/56461eq1.jpg">
在这里, M2 (g) 是重量的 Mg (OH)2, M1 (g) 是氢氧化钠的重量, 40 是氢氧化钠的分子量, 58 是分子量的 mg (oh)2, 2 是在 mg (oh)2中的 "职业" 的数量, 而 SR 是替代率。
本协议的技术可以推广到碱式过氧化氢系统中的植物材料的提取、漂白和改性。然而, 必须指出的是, 碱性过氧化氢系统的 pH 值和反应温度的选择是这项技术的关键21。碱性过氧化氢系统的 pH 值可以通过改变置换率17来调整。碱过氧化氢体系的 pH 值和氧化能力随取代率的增加而降低。当反应温度设定在85° c 时, 自由基反应在系统中起主要作用, 系统的强氧化性适合于溶解物料;当反应温度设定在125° c 时, 自由基反应被抑制, 系统中存在大量的呼出, 使系统适合漂白19。

<table>
	<tbody>
		<tr>
			<td>Hydrogen peroxide, 30%</td>
			<td>Fisher Scientific</td>
			<td>H325-100</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Magnesium hydroxide, 99%</td>
			<td>Fisher Scientific</td>
			<td>AA1236722</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Fisher Scientific</td>
			<td>S318-1</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Sodium bisulfite</td>
			<td>Fisher Scientific</td>
			<td>S654-500</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Sodium tripolyphosphate</td>
			<td>Fisher Scientific</td>
			<td>AC218675000</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Anthraquinone, &#62;98%</td>
			<td>Fisher Scientific</td>
			<td>AC104930500</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>1-Hydroxy Ethylidene-1,1-Diphosphonic Acid</td>
			<td>Fisher Scientific</td>
			<td>50-901-10243</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Degumming oil</td>
			<td>Minglong auxiliaries limited liability company, Yiyang, Hunan,China</td>
			<td>&#8212;&#8212;</td>
			<td>Chemical for degumming</td>
		</tr>
		<tr>
			<td>Ethyl alcohol</td>
			<td>Fisher Scientific</td>
			<td>A962-4</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Benzene</td>
			<td>Fisher Scientific</td>
			<td>AA43817AE</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Copper wire,0.5mm (0.02in) dia</td>
			<td>Fisher Scientific</td>
			<td>AA10783H4</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Cupriethylenediamine solution 1mol/L</td>
			<td>Fisher Scientific</td>
			<td>24991</td>
			<td>Chemical for testing, caution toxic</td>
		</tr>
		<tr>
			<td>Nitric acid (65% ~68% )</td>
			<td>Fisher Scientific</td>
			<td>A200-612GAL</td>
			<td>Chemical for testing, caution</td>
		</tr>
		<tr>
			<td>Ethylenediamine</td>
			<td>Fisher Scientific</td>
			<td>AC118420100</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Potassium permanganate</td>
			<td>Fisher Scientific</td>
			<td>P279-500</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Sulphuric acid</td>
			<td>Fisher Scientific</td>
			<td>A300C-212</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Silver sulfate</td>
			<td>Fisher Scientific</td>
			<td>S190-25</td>
			<td>Chemical for testing</td>
		</tr>
		<tr>
			<td>Raw ramie</td>
			<td>Guangyuan limited liability company, Changde, Hunan,China</td>
			<td>&#8212;&#8212;</td>
			<td>Raw materials</td>
		</tr>
		<tr>
			<td>Electric-heated&#160;thermostatic&#160;water&#160;bath</td>
			<td>Senxin Experiment equipment limited liability company,Shanghai,China</td>
			<td>DK-S28</td>
			<td>Equipments for degumming</td>
		</tr>
		<tr>
			<td>High temperature lbaorator dyeing machine</td>
			<td>Shanghai Longda chemcials Crop.</td>
			<td>RY-1261</td>
			<td>Equipments for degumming</td>
		</tr>
		<tr>
			<td>Thermometer</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>100 &#176;C</td>
			<td>Equipments for degumming</td>
		</tr>
		<tr>
			<td>Vacuum suction machine</td>
			<td>Yukang KNET ,Shanghai,China</td>
			<td>SHB-IIIA</td>
			<td>Equipments for testing Mg(OH)2 solublity</td>
		</tr>
		<tr>
			<td>Suction flask</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>1000mL</td>
			<td>Equipments for testing Mg(OH)2 solublity</td>
		</tr>
		<tr>
			<td>Sand-core funnels</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>35mL</td>
			<td>Equipments for testing Mg(OH)2 solublity</td>
		</tr>
		<tr>
			<td>Oxidation reduction potential meter</td>
			<td>Dapu instrument, Shanghai, China</td>
			<td>MODEL 421</td>
			<td>Equipments for testing ORP value</td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Hanna instruments,Beijing,China</td>
			<td>HI 98129</td>
			<td>Equipments for testing pH value</td>
		</tr>
		<tr>
			<td>Acid burette</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>50mL</td>
			<td>Equipments for testing H2O2 content</td>
		</tr>
		<tr>
			<td>Flask</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>250mL/500mL</td>
			<td>Equipments for testing H2O2 content;&#160; residual gums content</td>
		</tr>
		<tr>
			<td>Electric furnace</td>
			<td>Jiangyi Experiment instruments limited liability company,Shanghai,China</td>
			<td>800-2000W</td>
			<td>Equipments for testing residual gums content</td>
		</tr>
		<tr>
			<td>Reflux condensing tube</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>250mL</td>
			<td>Equipments for testing residual gums content; COD value</td>
		</tr>
		<tr>
			<td>Fiber cutter (40mm)</td>
			<td>Changzhou No.2 Textile Machine Co.,Ltd</td>
			<td>Y171A</td>
			<td>Equipments for testing fiber density</td>
		</tr>
		<tr>
			<td>Ostwald viscometer</td>
			<td>Taizhou, jiaojiang, glass instruments company</td>
			<td>0.6mm</td>
			<td>Equipments for testing fiber PD value</td>
		</tr>
		<tr>
			<td>Spherical fat extractor</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>250mL</td>
			<td>Equipments for testing fiber PD value</td>
		</tr>
		<tr>
			<td>Soxhlet extractor</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>250mL</td>
			<td>Equipments for testing fiber PD value</td>
		</tr>
		<tr>
			<td>Torsion&#160;balance</td>
			<td>Liangping instrucments Co.,Ltd,Shanghai, China</td>
			<td>JN-B</td>
			<td>Equipments for testing fiber density</td>
		</tr>
		<tr>
			<td>Fiber strength instrument</td>
			<td>Xinxian instruments, shanghai,China</td>
			<td>XQ-2</td>
			<td>Equipments for testing fiber tensile property</td>
		</tr>
		<tr>
			<td>Tension clamp</td>
			<td>Depu textile technology Co.,Ltd, Changzhou, jiangsu, China</td>
			<td>0.3cN/dtex</td>
			<td>Equipments for testing fiber tensile property</td>
		</tr>
		<tr>
			<td>COD&#160;thermostatic&#160;heater</td>
			<td>Qiangdao Xuyu environment protection technology Lit company</td>
			<td>DL-801A</td>
			<td>Equipments for testing COD value</td>
		</tr>
		<tr>
			<td>FTIR</td>
			<td>Thermo Fisher, America</td>
			<td>Nicolet</td>
			<td>FTIR analysis</td>
		</tr>
		<tr>
			<td>XRD</td>
			<td>Rigaku, Japan</td>
			<td>D/max-2550 PC</td>
			<td>XRD analysis</td>
		</tr>
		<tr>
			<td>Electronic balance</td>
			<td>Shanghai jingtian Electronic instrument Co.,Ltd</td>
			<td>FA2004A</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Drying oven</td>
			<td>Tonglixinda&#160; instruments, Tianjin,China</td>
			<td>101-2AS</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Weighing bottle</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>50x30</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Beaker</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>500mL</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Sample sieve</td>
			<td>Xiaojin hardware instruments Co.,Ltd, Shangyu, Zhejiang</td>
			<td>120 mesh</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Glass rod</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>&#8212;&#8212;</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Cylinder</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>250mL, 50mL</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Pipette</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>5mL, 10mL</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Rubber&#160;suction&#160;bulb</td>
			<td>Sichuan Shubo (group)Co.,Ltd</td>
			<td>&#8212;&#8212;</td>
			<td>Generral equipments</td>
		</tr>
		<tr>
			<td>Orign</td>
			<td>OriginLab</td>
			<td>8.0</td>
			<td>Software for figure drawing</td>
		</tr>
	</tbody>
</table>

extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source

本协议演示了一种在受控释碱源支持的碱过氧化氢系统中, 在苎麻纤维上精练的方法。苎麻提取纤维是一种重要的纺织材料。在以前的研究中, 苎麻纤维被提取的碱过氧化氢系统只支持氢氧化钠。然而, 由于氢氧化钠的强碱性, 过氧化氢的氧化反应速度难以控制, 从而对处理后的纤维造成很大的损害。在本协议中, 一种由氢氧化钠和氢氧化镁组成的控释碱源, 用于提供碱性条件和缓冲碱氢 peroxidesystem 的 pH 值。氢氧化镁的取代率可以调节过氧化氢体系的 pH 值, 对纤维性能有很大的影响。ph 值和氧化还原电位值, 代表了碱过氧化氢系统的氧化能力, 分别采用 ph 计和检测仪进行监测。采用高锰酸钾4滴定法测定了萃取过程中碱过氧化氢体系中的剩余过氧化氢含量, 以及纤维萃取后废水的化学需氧量 (COD) 值。用精密电子天平测量纤维的收率, 用化学分析法测定纤维的残余牙龈。用乌粘度计测定了纤维的聚合度 (PD 值)。用纤维强度仪测定纤维的拉伸性能, 包括韧性、伸长率和断裂。利用傅里叶变换红外光谱和 X 射线衍射对纤维的官能团和晶体性质进行了表征。该方案证明, 控释碱源能改善碱性过氧化氢体系中提取的纤维的性能。

研究了在蒸馏水和脱胶溶液中 Mg (OH)2的溶解度 (图 1)。测试了镁 (OH)2取代率对脱胶溶液 pH 值和可解性值 (图 2) 的影响。用不同 Mg (OH)2替代率计算了纤维脱胶的脱胶率和残余牙龈 (图 3)。用 DP 值、结晶度、纤维拉伸性能 (图 4) 和废水 COD 值 (图 5<...

Watch this Scientific Journal Video about Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source at JoVE.com

Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source

缓释碱源负载碱性过氧化氢体系中苎麻纤维的提取

本文介绍了一种在受控释碱源支持的碱性过氧化氢体系中提取苎麻纤维的方案。

This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a ...

extraction-ramie-fiber-alkali-hydrogen-peroxide-system-supported

Research

JoVE Journal

Chemistry

11.3K 次观看.  Donghua University. 本文介绍了一种在受控释碱源支持的碱性过氧化氢体系中提取苎麻纤维的方案。

视频: Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source

Exfoliation of Egyptian Blue and Han Blue, Two Alkali Earth Copper Silicate-based Pigments

In a visualized example of the ancient past connecting with modern times, we describe the preparation and exfoliation of CaCuSi4O10 and BaCuSi4O10, the colored components of the historic Egyptian blue and Han blue pigments. The bulk forms of these materials are synthesized by both melt flux and solid-state routes, which provide some control over the crystallite size of the product. The melt flux process is time intensive, but it produces relatively large crystals at lower reaction temperatures. In comparison, the solid-state method is quicker yet requires higher reaction temperatures and yields smaller crystallites. Upon stirring in hot water, CaCuSi4O10 spontaneously exfoliates into monolayer nanosheets, which are characterized by TEM and PXRD. BaCuSi4O10 on the other hand requires ultrasonication in organic solvents to achieve exfoliation. Near infrared imaging illustrates that both the bulk and nanosheet forms of CaCuSi4O10 and BaCuSi4O10 are strong near infrared emitters. Aqueous CaCuSi4O10 and BaCuSi4O10 nanosheet dispersions are useful because they provide a new way to handle, characterize, and process these materials in colloidal form.

The preparation and exfoliation of CaCuSi4O10&#160;and BaCuSi4O10 are described. Upon stirring in hot water, CaCuSi4O10 spontaneously exfoliates into monolayers, whereas BaCuSi4O10&#160;requires ultrasonication in organic solvents. Near infrared (NIR) imaging illustrates the NIR emission properties of these materials, and aqueous dispersions of these nanomaterials are useful for solution processing.

埃及蓝色和汉蓝，两碱地球铜硅酸盐类颜料剥落

In a visualized example of the ancient past connecting with modern times, we describe the preparation and exfoliation of CaCuSi4O10 and BaCuSi4O10, the ...

科研

化学

Preparing Adherent Cells for X-ray Fluorescence Imaging by Chemical Fixation

X-ray fluorescence imaging allows us to non-destructively measure the spatial distribution and concentration of multiple elements simultaneously over large or small sample areas. It has been applied in many areas of science, including materials science, geoscience, studying works of cultural heritage, and in chemical biology. In the case of chemical biology, for example, visualizing the metal distributions within cells allows us to study both naturally-occurring metal ions in the cells, as well as exogenously-introduced metals such as drugs and nanoparticles. Due to the fully hydrated nature of nearly all biological samples, cryo-fixation followed by imaging under cryogenic temperature represents the ideal imaging modality currently available. However, under the circumstances that such a combination is not easily accessible or practical, aldehyde based chemical fixation remains useful and sometimes inevitable. This article describes in as much detail as possible in the preparation of adherent mammalian cells by chemical fixation for X-ray fluorescent imaging.

Here, we present a protocol on how to determine the quantity and distribution of metals in a sample using synchrotron X-ray fluorescence. We focus on adherent cells, and describe the chemical fixation method to prepare this sample. We then describe how to mount and image the sample using synchrotron X-rays.

化学固定准备贴壁细胞的X射线荧光成像

X-ray fluorescence imaging allows us to non-destructively measure the spatial distribution and concentration of multiple elements simultaneously over ...

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

Nitrogen is an effective supercritical fluid for extraction or drying processes due to its small molecular size, high density in the near-liquid supercritical regime, and chemical inertness. We present a supercritical nitrogen drying protocol for the purification treatment of reactive, porous materials.

超临界氮处理的活性多孔材料的净化

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) hydrogen fuel cells. Researchers seeking to develop such systems require a method of measuring the generated hydrogen. Herein, we describe a simple, low-cost, and robust method to measure the hydrogen generated from the reaction of solids with aqueous solutions. The reactions are conducted in a conventional one-necked round-bottomed flask placed in a temperature controlled water bath. The hydrogen generated from the reaction in the flask is channeled through tubing into a water-filled inverted measuring cylinder. The water displaced from the measuring cylinder by the incoming gas is diverted into a beaker on a balance. The balance is connected to a computer, and the change in the mass reading of the balance over time is recorded using data collection and spreadsheet software programs. The data can then be approximately corrected for water vapor using the method described herein, and parameters such as the total hydrogen yield, the hydrogen generation rate, and the induction period can also be deduced. The size of the measuring cylinder and the resolution of the balance can be changed to adapt the setup to different hydrogen volumes and flow rates.

The study of methods to generate on-demand hydrogen for fuel cells continues to grow in importance. However, systems to measure hydrogen evolution from the reaction of chemicals with water can be complicated and expensive. This article details a simple, low-cost, and robust method to measure the evolution of hydrogen gas.

一种简单，低成本和强大的系统来测量氢气与水溶液化学反应放出的音量

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) ...

Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental exposure in a non-invasive manner. In this work, we present a protocol to characterize the exhaled VOCs in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry (Sec-nanoESI-HRMS). The homemade Sec-nanoESI source was readily set up based on a commercial nanoESI source. Hundreds of peaks were observed in the background-subtracted mass spectra of exhaled breath, and the mass accuracy values are -4.0-13.5 ppm and -20.3-1.3 ppm in the positive and negative ion detection modes, respectively. The peaks were assigned with accurate elemental composition according to the accurate mass and isotopic pattern. Less than 30 s is used for one exhalation measurement, and it takes approximately 7 min for six replicated measurements.

A protocol for characterizing chemical composition of exhaled breath in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry is demonstrated.

利用二次 Nanoelectrospray 电离耦合高分辨质谱的实时呼吸分析

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental ...

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound electrons with neutral molecules/atoms. State-of-the-art in vacuo anion generation techniques allow application to a broad range of atomic, molecular, and cluster anion systems. These are separated and selected using time-of-flight mass spectrometry. Electrons are removed by linearly polarized photons (photo detachment) using table-top laser sources which provide ready access to excitation energies from the infra-red to the near ultraviolet. Detecting the photoelectrons with a velocity mapped imaging lens and position sensitive detector means that, in principle, every photoelectron reaches the detector and the detection efficiency is uniform for all kinetic energies. Photoelectron spectra extracted from the images via mathematical reconstruction using an inverse Abel transformation reveal details of the anion internal energy state distribution and the resultant neutral energy states. At low electron kinetic energy, typical resolution is sufficient to reveal energy level differences on the order of a few millielectron-volts, i.e., different vibrational levels for molecular species or spin-orbit splitting in atoms. Photoelectron angular distributions extracted from the inverse Abel transformation represent the signatures of the bound electron orbital, allowing more detailed probing of electronic structure. The spectra and angular distributions also encode details of the interactions between the outgoing electron and the residual neutral species subsequent to excitation. The technique is illustrated by the application to an atomic anion (F&#8722;), but it can also be applied to the measurement of molecular anion spectroscopy, the study of low lying anion resonances (as an alternative to scattering experiments) and femtosecond (fs) time resolved studies of the dynamic evolution of anions.

Here, we present a protocol for photoelectron imaging of anionic species. Anions generated in vacuo and separated by mass spectrometry are probed using velocity mapped photoelectron imaging, providing details of anion and neutral energy levels, anion and neutral structure and the nature of the anion electronic state.

由 F− 310 Nm 支队所示的阴离子光电子成像

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound ...

Extraction of Lignin with High &#946;-O-4 Content by Mild Ethanol Extraction and Its Effect on the Depolymerization Yield

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the emerging elegant procedures to obtain specific aromatic products rely on the lignin substrate having a high content of the readily cleavable &#946;-O-4 linkage as present in the native lignin structure. This provides a miss-match with typical technical lignins that are highly degraded and therefore are low in &#946;-O-4 linkages. Therefore, the extraction yields, and the quality of the obtained lignin are of utmost importance to access new lignin valorization pathways. In this manuscript, a simple protocol is presented to obtain lignins with high &#946;-O-4 content by relatively mild ethanol extraction that can be applied to different lignocellulose sources. Furthermore, analysis procedures to determine the quality of the lignins are presented together with a depolymerization protocol that yields specific phenolic 2-arylmethyl-1,3-dioxolanes, which can be used to evaluate the obtained lignins. The presented results demonstrate the link between lignin quality and potential for the lignins to be depolymerized into specific monomeric aromatic chemicals. Overall, the extraction and depolymerization demonstrates a trade-off between the lignin extraction yield and the retention of the native aryl-ether structure and thus the potential of the lignin to be used as the substrate for the production of chemicals for higher-value applications.

Here, we present a protocol to perform ethanol extraction of lignin from several biomass sources. The effect of the extraction conditions on the lignin yield and &#946;-O-4 content are presented. Selective depolymerization is performed on the obtained lignins to obtain high aromatic monomer products.

轻度乙醇萃取高β-o-4 的木质素及其对解聚产率的影响

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the ...

U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen

We describe a method to produce U2O5 films in situ using the Labstation, a modular machine developed at JRC Karlsruhe. The Labstation, an essential part of the Properties of Actinides under Extreme Conditions laboratory (PAMEC), allows the preparation of films and studies of sample surfaces using surface analytical techniques such as X-ray and ultra-violet photoemission spectroscopy (XPS and UPS, respectively). All studies are made in situ, and the films, transferred under ultra-high vacuum from their preparation to an analyses chamber, are never in contact with the atmosphere. Initially, a film of UO2 is prepared by direct current (DC) sputter deposition on a gold (Au) foil then oxidized by atomic oxygen to produce a UO3 film. This latter is then reduced with atomic hydrogen to U2O5. Analyses are performed after each step involving oxidation and reduction, using high-resolution photoelectron spectroscopy to examine the oxidation state of uranium. Indeed, the oxidation and reduction times and corresponding temperature of the substrate during this process have severe effects on the resulting oxidation state of the uranium. Stopping the reduction of UO3 to U2O5 with single U(V) is quite challenging; first, uranium-oxygen systems exist in numerous intermediate phases. Second, differentiation of the oxidation states of uranium is mainly based on satellite peaks, whose intensity peaks are weak. Also, experimenters should be aware that X-ray spectroscopy (XPS) is a technique with an atomic sensitivity of 1% to 5%. Thus, it is important to obtain a complete picture of the uranium oxidation state with the entire spectra obtained on U4f, O1s, and the valence band (VB). Programs used in the Labstation include a linear transfer program developed by an outside company (see Table of Materials) as well as data acquisition and sputter source programs, both developed in-house.

U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen

This protocol presents the preparation of U2O5 thin films obtained in situ under ultra-high vacuum. The process involves oxidation and reduction of UO2 films with atomic oxygen and atomic hydrogen, respectively.

利用uo2沉积制备 u2o5 薄膜, 利用原子氧和原子氢连续氧化还原

We describe a method to produce U2O5 films in situ using the Labstation, a modular machine developed at JRC Karlsruhe. The Labstation, an essential part ...

Experimental Methods for Efficient Solar Hydrogen Production in Microgravity Environment

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the Earth's atmosphere. So-called 'solar fuel' devices, currently developed for terrestrial applications in the quest for realizing a sustainable energy economy on Earth, provide promising alternative systems to existing air-revitalization units employed on the International Space Station (ISS) through photoelectrochemical water-splitting and hydrogen production. One obstacle for water (photo-) electrolysis in reduced gravity environments is the absence of buoyancy and the consequential, hindered gas bubble release from the electrode surface. This causes the formation of gas bubble froth layers in proximity to the electrode surface, leading to an increase in ohmic resistance and cell-efficiency loss due to reduced mass transfer of substrates and products to and from the electrode. Recently, we have demonstrated efficient solar hydrogen production in microgravity environment, using an integrated semiconductor-electrocatalyst system with p-type indium phosphide as the light-absorber and a rhodium electrocatalyst. By nanostructuring the electrocatalyst using shadow nanosphere lithography and thereby creating catalytic 'hot spots' on the photoelectrode surface, we could overcome gas bubble coalescence and mass transfer limitations and demonstrated efficient hydrogen production at high current densities in reduced gravitation. Here, the experimental details are described for the preparations of these nanostructured devices and further on, the procedure for their testing in microgravity environment, realized at the Bremen Drop Tower during 9.3 s of free fall.

Efficient solar-hydrogen production has recently been realized on functionalized semiconductor-electrocatalyst systems in a photoelectrochemical half-cell in microgravity environment at the Bremen Drop Tower. Here, we report the experimental procedures for manufacturing the semiconductor-electrocatalyst device, details of the experimental set-up in the drop capsule and the experimental sequence during free fall.

微重力环境下高效太阳能氢气生产的实验方法

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the ...

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, &#60;10-5 mbar). The preparation of SiO2-700 (silica dehydroxylated at 700 &#176;C) and subsequent applications (the grafting of complexes and catalytic runs) requires the use of HVLs and double-Schlenk techniques. Several well-known characterization methods are used, such as Fourier-transform infrared spectroscopy (FTIR), elemental microanalysis, solid-state nuclear magnetic resonance spectroscopy (SSNMR), and state-of-the-art dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS). FTIR and elemental microanalysis permit scientists to establish the grafting and its stoichiometry. 1H and 13C SSNMR allows the structural determination of the hydrocarbon ligands coordination sphere. DNP SENS is an emerging powerful technique in solid characterization for the detection of poorly sensitive nuclei (15N, in our case). SiO2-700 is treated with about one equivalent of the metal precursor compared to the amount of surface silanol (0.30 mmol&#183;g-1) in pentane at room temperature. Then, volatiles are removed, and the powder samples are dried under dynamic high vacuum to afford the desired materials [(&#8801;Si-O-)Hf(&#951;2&#960;-MeNCH2)(&#951;1-NMe2)(&#951;1-HNMe2)]. After a thermal treatment under high vacuum, the grafted complex is converted into metal imido silica complex [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)]. [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] effectively promotes the metathesis of imines, using the combination of two imine substrates, N-(4-phenylbenzylidene)benzylamine, or N-(4-fluorobenzylidene)-4-fluoroaniline, with N-benzylidenetert-butylamine as substrates. A significantly lower conversion is observed with the blank runs; thus, the presence of the imido group in [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is correlated to the catalytic performance.

A new group IV metal catalyst for imine metathesis is prepared by grafting amine metal complex onto dehydroxylated silica. Surface metal fragments are characterized using FT-IR, elemental microanalysis, and solid-state NMR spectroscopy. Further dynamic nuclear polarization surface enhanced NMR spectroscopy experiments complement the determination of the coordination sphere.

利用表面有机金属化学方法，利用硅支持的催化剂进行Imine金属分析

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared ...

缓释碱源负载碱性过氧化氢体系中苎麻纤维的提取

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