作者感谢基金会, 斯图加特的财政支持。我们还要感谢 Zschimmer & 施瓦茨 Mohsdorf 有限公司 & 公司的员工提供膦酸样品。

1. 为全 P 测定准备所有必需的解决办法
注意: 下面介绍的一些解决方案的准备工作在 ISO 687828中进行了说明。这些制备方法已略有适应这项工作的方法。所需的化学品纯度可在所附材料清单中找到。
<ol><li>编写 H2, 因此4解决方案 (13.5、9和 0.9 M2所以4) 注意: 在通风罩下工作。<ol>
<li>准备 13.5 M H2, 所以4<ol>
<li>用25毫升的水填充一个100毫升的油缸, 把它转移到一个100毫升的玻璃瓶里, 被放在烧杯中的冰块包围。</li>
			<li>用75毫升的浓硫酸填充相同的毕业圆筒, 并将其转移到瓶子里的水中搅拌。警告:热发展。</li>
			<li>在充分冷却 (最大40摄氏度) 的情况下, 将瓶子小心地从烧杯中取出。</li>
		</ol>
</li>
		<li>9米 H2的准备, 所以4 (为钼酸盐溶液的制备所需)<ol>
<li>用700毫升的水填满一个1升的圆筒, 把它转移到一个3升的玻璃烧杯里, 被放在水桶里的冰块包围。</li>
			<li>用700毫升浓硫酸填充相同的1升的气缸, 将其转移到3升烧杯中的水中。警告:热发展。</li>
			<li>当它足够冷却 (最大40°c), 并将其内容转换为2升玻璃瓶时, 请小心地从桶中取出3升烧杯。</li>
		</ol>
</li>
		<li>准备 0.9 M H2, 所以4<ol>
<li>用大约100毫升的水填充一个250毫升的容积烧瓶。</li>
			<li>将25毫升9米 H2, 所以4 (见 1.1.2) 到250毫升容积烧瓶使用25毫升容积吸管。警告:热发展。</li>
			<li>填充250毫升容积瓶与水高达250毫升环标记。</li>
			<li>用塞子关闭容积烧瓶, 摇动几次均匀, 将容积瓶的内容转换成250毫升玻璃瓶。</li>
		</ol>
</li>
	</ol></li>
	<li>盐酸漂洗液的制备 (约2米) 注意: 在通风罩下工作。<ol>
<li>用1升的水填满2升的圆筒。</li>
		<li>用400毫升 32% HCl (w/w) 溶液填充这个已毕业的气缸。</li>
		<li>现在添加600毫升的水, 以获得总容积2升在毕业气缸。</li>
		<li>用杆 (例如, 毕业的吸管) 将毕业圆筒的内容搅拌成2.5 升玻璃瓶。</li>
		<li>关闭瓶子, 并摇动它倒置几次, 以均匀化。</li>
		<li>只有在颜色更改变为可见时, 才可重用此解决方案。然后丢弃漂洗液并准备一个新的解决方案。</li>
	</ol></li>
	<li>盐酸溶液的制备 (10.2 和2米) 注意: 在通风罩下工作。<ol>
<li>使用 32% hcl (w/瓦) 作为10.2 米 hcl。</li>
		<li>2米盐酸盐的制备<ol>
<li>使用15毫升容积吸管填充100毫升容积烧瓶, 15 毫升 32% HCl (10.2 米)。</li>
			<li>使用微将另外4.67 毫升 32% HCl (10.2 米) 添加到容积烧瓶中。</li>
			<li>将容积瓶加水填满100毫升环标记。</li>
			<li>用塞子关闭容积烧瓶, 并将其翻转数次以均匀化, 将容积瓶的内容转换成100毫升玻璃瓶。</li>
		</ol>
</li>
	</ol></li>
	<li>氢氧化钠溶液的制备 (10, 2, 1.5 米氢氧化钠) 注意: 在通风罩下工作。<ol>
<li>将100.0 克 (10 米), 20 克 (2 米) 或15克 (1.5 米) 的氢氧化钠放入一个小烧杯中, 将烧杯的内容转化为250毫升容积烧瓶。</li>
		<li>将容积瓶加水填满250毫升环标记。用塞子关闭容积式烧瓶, 并将其翻转几次以均匀化 (警告:解决方案可能会变热)。如果水位的高度不再对应于圆环标记, 增加水 (总容量变动由于溶解过程)。</li>
		<li>将体积瓶的内容转移到一个250毫升的塑料瓶中 (注意:不要用玻璃瓶来处理氢氧化钠溶液)。</li>
	</ol></li>
	<li>准备 K2的2O8解决方案/悬浮 (8.33、41.67、50.00、58.33、66.66 克/升) 注: 磷测定需要不同浓度的 peroxodisulfate 混合物。因为其中一些是在 K2S2O8的饱和极限之上的大约. 50 克/升在20摄氏度, 建议将 K2S2O8直接称量为棕色玻璃瓶, 并将相应的水量倒在上面 (做不使用容积烧瓶作准备)。<ol>
<li>重2.08 克 (8.33 克/升), 10.42 克 (41.67 克/升), 12.50 (50.00 克/升), 14.58 克 (58.33 克/升) 或16.67 克 (66.66 克/升) 的固体 K2S2O8直接进入棕色250毫升玻璃瓶。</li>
		<li>用250毫升的水填充一个已毕业的圆筒, 然后将水倒入瓶子中的 K2S2O8 。</li>
		<li>搅拌瓶子的内容, 直到所有的成分被溶化或直到有轻微的浊度。</li>
		<li>在磁搅拌器的高湍流下进行 K2S2O8的提取, 以确保难溶 k 2 2 O 8 也可以尽可能均匀地提取。</li>
	</ol></li>
	<li>100克/升抗坏血酸溶液的制备
	<ol>
<li>将50克抗坏血酸重为500毫升容积烧瓶。</li>
		<li>将容积瓶加水填满500毫升环标记。</li>
		<li>在磁性搅拌器上搅拌容积烧瓶的内容, 直到抗坏血酸完全溶解为止。可能有必要纠正水面的水平, 使其与环标记一致, 增加一点水 (小心搅拌棒给出的体积以及)。然后将容积瓶的内容转移到棕500毫升玻璃瓶中。</li>
	</ol></li>
	<li>钼酸盐溶液的制备 (磷酸盐测定所需)
	<ol>
<li>重13.0 克固体 (NH4)6Mo7o24∙4H2o 直接进入100毫升玻璃瓶。用100毫升的水填满一个毕业的圆筒, 倒入瓶子里。将瓶子的内容搅拌在磁力搅拌器上, 直到完全溶解为止。</li>
		<li>重0.35 克固体 K (SbO) C4H4o6∙½H2o 直接进入一个新鲜的100毫升玻璃瓶。用100毫升的水填充一个已毕业的气缸并倒入瓶子中, K (SbO) C4H4O6∙½H2o 搅拌瓶子的内容, 直到完全溶解为止。</li>
		<li>填充300毫升9米 H2的毕业气缸,4 (见 1.1.2), 倒入棕色500毫升玻璃瓶。</li>
		<li>将(NH4)6Mo7o24∙4H2o 解决方案添加到300毫升 M 9, 所以2。然后将 K (SbO) C4H4o6∙½H2O 解决方案添加到此混合物中。关闭瓶子, 并摇几次倒置, 以均匀化。</li>
	</ol></li>
	<li>钼酸二溶液的制备 (全 P 测定所需)
	<ol>
<li>重13.0 克固体 (NH4)6Mo7o24∙4H2o 直接进入100毫升玻璃瓶。用100毫升的水填满一个毕业的圆筒, 倒入瓶子里。将瓶子的内容搅拌在磁力搅拌器上, 直到完全溶解为止。</li>
		<li>重0.35 克固体 K (SbO) C4H4o6∙½H2o 直接进入一个新鲜的100毫升玻璃瓶。用100毫升的水填充一个已毕业的气缸并倒入瓶子中, K (SbO) C4H4O6∙½H2o 搅拌瓶子的内容, 直到完全溶解为止。</li>
		<li>用70毫升的水填充一个已毕业的圆筒。添加230毫升9米 H2, 所以4 (见 1.1.2) 到的水在毕业的圆筒 (即, 填补多达300毫升)。用杆 (例如, 已毕业的吸管) 仔细融汇已毕业的气缸的内容。将毕业气缸的内容转换成棕500毫升玻璃瓶 (当前内容: 6.9 M H2, 因此4)。</li>
		<li>将(NH4)6Mo7o24∙4H2o 解决方案添加到300毫升 M 6.9, 所以2。然后将 K (SbO) C4H4o6∙½H2O 解决方案添加到此混合物中。关闭瓶子, 并摇几次倒置, 以均匀化。</li>
	</ol></li>
	<li>内部质量标准的编制 (智商: 1 毫克/升,2PO4P 在0.9 毫米 H2所以4)
	<ol>
<li>在干燥烤箱中, 在105摄氏度的小玻璃盘中干燥几克的干燥2PO4 , 直到达到质量恒常, 然后冷却了 2 PO 4 下至室温.</li>
		<li>将0.2197 克0.0002 克的干燥2PO4直接从 "从" 到 "1 L" 容量瓶中, 并将大约800毫升的水添加到容量烧瓶中。</li>
		<li>现在, 添加5毫升9米 H2, 所以4 (见 1.1.2) 到烧瓶使用5毫升容积吸管, 并填补瓶与水高达 1 L 环标记。</li>
		<li>在磁力搅拌器上搅拌容积烧瓶的内容, 将容积烧瓶的内容转移到1升玻璃瓶中 (当前内容:50 毫克/升,2PO4P 在45毫米 H2,4)。这个解决方案今后可以作为一个股票的解决方案, 为智商的准备。</li>
		<li>用10毫升容积吸管将这个溶液的10毫升转移到500毫升容积瓶中, 用水将容积烧瓶填满到500毫升环标记上, 并在磁力搅拌器上搅动容积瓶的含量。</li>
		<li>将容积瓶的内容转换成500毫升玻璃瓶 (当前内容: 1 毫克/升,2PO4P 在0.9 毫米 H2, 所以4)。这个解决方案就是智商。</li>
	</ol></li>
</ol>2. 制备含磷酸酯的缓冲溶液
<ol><li>将所需的缓冲器称量或吸管到容积式烧瓶中 (在 1 L 中的0.01 米缓冲器的目标浓度中,例如: 572 µL 100% AcOH, 2.1014 克 CitOH·H2O, MES 1.9520 克, 2.0926 克的拖把, 2.3831 克 HEPES, CAPSO 2.5233 克, 2.3732 克的, 2.2132 克, 5 毫升的2米氢氧化钠)。</li>
	<li>用水将容积烧瓶填满约三个季度, 并添加以前准备的1克/升膦磷溶液 (用于1毫克/升 p 的目标浓度为1升,例如, 1 毫升1克/升磷酸酯磷)。</li>
	<li>将烧瓶中的水填充到环形标记上, 在磁性搅拌器上搅拌瓶子的内容, 直到所有成分都溶解并将其转移到玻璃瓶中。</li>
	<li>搅拌时, 用 HCl (例如、2和 10.2 m) 或氢氧化钠 (例如、2和 10 m) 调整缓冲区解决方案中所需的 ph 值 (例如, MES 中的 ph 6) 或氢氧化钠 (即, 应避免添加酸性和基本溶液, 以防止不必要的增强离子强度)。</li>
	<li>为了确定膦酸磷浓度, 按照步骤4进行。</li>
</ol>3. 吸附试验的程序
<ol><li>用蒸馏水 (例如) 将过滤材料彻底冲洗干净, 然后用0.5 毫米的筛网将其干燥80摄氏度。 注意:协议可以在这里暂停。</li>
	<li>将过滤材料 (例如, 粒状氢氧化铁) 称量成50毫升离心管。 注意:协议可以在这里暂停。</li>
	<li>快速填充50毫升离心管与含膦酸溶液从步骤2到50毫升标记。</li>
	<li>快速关闭管并将其夹紧到运行的旋转体 (接触时间从现在开始)。</li>
	<li>在特定时间段 (例如、1 h), 每分钟旋转20次转管。</li>
	<li>用注射器过滤器 (0.45 µm 孔尺寸) 过滤出上清的大约10-20 毫升, 放入空玻璃瓶中。 注意:协议可以在这里暂停。</li>
	<li>确定滤液的 pH 值并确定磷酸酯磷的浓度, 并进行步骤4。在调查磷酸盐吸附的情况下, 继续步骤5。</li>
</ol>4. 根据 ISO迷你测定总磷 (膦酸磷)
注意: 下面的过程也显示在图 3中。
<ol><li>转移要分析的样品的整除 (V样品, 最大4毫升) 使用微入10毫升螺丝瓶盖瓶 (包括盖子的瓶子应该预先漂洗与 HCl (参见 1.2) 和 H2O 并且干燥在80-100 °c)。 注意: 协议可以在这里暂停。</li>
	<li>添加水与微, 以获得4毫升的总体积连同以前添加的样本 (V水= 4 毫升 V示例)。 注意: 协议可以在这里暂停。</li>
	<li>添加0.2 毫升0.9 米 H2, 因此4解决方案 (请参见 1.1.3) 使用微。如果在样品中有浓度为1米的氢氧化钠, 通常情况下再生解决方案, 增加0.2 毫升13.5 米 H2, 所以4解决方案 (见 1.1.1) (警告:这硫酸溶液高度集中)。 注意: 协议可以在这里暂停。</li>
	<li>添加4.8 毫升的 K2S2O8解决方案/悬浮 (见 1.5), 其浓度取决于样品中包含的缓冲区 (对应于0.01-1 米氢氧化钠的 ISO: 8.33 克/升 K2S2O8; 0.01 MCitOH, AcOH, MES: 41.67 克/升;0.01 M 拖把: 50.00 克/升;0.01 米 HEPES: 58.33 克/升;0.01 米无害, CAPSO, 帽: 66.66 克/升)。</li>
	<li>把瓶盖紧紧地关上, 摇动它。</li>
	<li>在恒温器中加热148-150 摄氏度的小瓶, 1 小时。</li>
	<li>把瓶子从恒温器里拿出来, 让它冷却到室温。 注意: 协议可以在这里暂停。</li>
	<li>打开瓶子, 加入0.4 毫升1.5 米氢氧化钠溶液 (见 1.4)。 注意: 协议可以在这里暂停。</li>
	<li>添加0.2 毫升100克/升抗坏血酸溶液 (见 1.6)。</li>
	<li>随后, 添加0.4 毫升钼酸二溶液 (见 1.8)。</li>
	<li>关闭瓶子, 并把它颠倒为均匀化。</li>
	<li>至少等待15分钟到最大值为4小时的颜色形成。</li>
	<li>用光度计测量 880 nm 波长的光谱吸光度 (A)。</li>
	<li>执行步骤 4.1-4.13 定期为4毫升的水 (为确定一个盲) 以及4毫升的智商 (见 1.9)。</li>
	<li>根据分析样品 (a) 的特定吸光度 (a)、盲样品的吸光度 (盲) 和样本体积 (V样本), 计算分析样品的总磷或膦磷浓度, 使用以下等式 (0.287 对应于定标线的斜率与 1 cm 小试管并且可能偏离取决于光度计): <img alt="Equation 2" src="/files/ftp_upload/57618/57618eq2v2.jpg">
</li>
</ol>5. 根据 ISO迷你确定 o PO43-P
注: 对无机邻磷酸盐在粒状滤料中的吸附作用进行研究, 可采用这种测定方法。在这种情况下, 要测试的样品不必被消化。
<ol><li>传输要分析的示例的整除 (V示例, 最大9.4 毫升) 通过微成一个10毫升螺丝瓶盖瓶 (包括瓶盖的瓶子应预先冲洗与 HCl (见 1.2) 和 H2O 和干燥在80-100 °c)。 注意: 协议可以在这里暂停。</li>
	<li>添加水与微, 以获得9.4 毫升的总体积连同以前添加的样本 (V水= 9.4 毫升 V示例)。 注意: 协议可以在这里暂停。</li>
	<li>添加0.2 毫升100克/升抗坏血酸溶液 (见 1.6)。</li>
	<li>随后, 添加0.4 毫升钼酸 I 溶液 (见 1.7)。</li>
	<li>关闭瓶子, 并把它颠倒为均匀化。</li>
	<li>至少等待15分钟到最大值为4小时的颜色形成。</li>
	<li>用光度计测量 880 nm 波长的光谱吸光度 (A)。</li>
	<li>执行步骤 5.1-5.7 定期为9.4 毫升的水 (为确定一个盲) 以及4毫升的智商 (见 1.9)。</li>
	<li>根据分析样本 (a)、盲样本 (盲) 和样本体积 (V样本) 的具体吸光度, 可以用4.15 中的方程计算分析样品的邻磷酸盐磷浓度。</li>
</ol>

<ol>
	<li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Directive+2000/60/EC+of+the+European+Parliament+and+of+the+Council+of+23+October+2000+establishing+a+framework+for+Community+action+in+the+field+of+water+policy.">Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy.</a> Official Journal of the European Communities. , 327 (2000).</li><li>Rott, E., Steinmetz, H., Metzger, J. 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没有宣布利益冲突。

膦酸的重要性越来越大, 需要研究如何将这些化合物从废水中去除, 以保护废水处理厂或接收水体。目前, 对从工业废水中去除膦酸的研究很少, 5, 11, 12, 13, 14, 16.这里提出的程序表明, 关于消除膦酸的研究, 通过吸附的极性氧化铁, 特别是粒状铁氢氧化铁, 可以进行快速和可靠的, 当按照给定的协议。
进行吸附研究的关键是 pH 值的维持。这不能在旋转离心管不使用缓冲器。在本文中, 它表明, 良好的缓冲只允许一个可接受的 pH 值调整, 只有在浓度为0.01 米, 甚至在这个浓度对膦酸吸附到海湾金融公司没有显著的影响。好的缓冲器的应用也是为什么这里提出的程序不能用于对非极性材料 (如活性炭) 吸附膦酸的研究。良好的缓冲器将与膦酸竞争, 免费的吸附网站。
由于用 HPLC 法直接分析了膦酸的22或 IC-ICP-MS 21 是非常复杂和昂贵的, 提出的方法表明, 与吸附剂接触后的膦酸酯应通过测定间接测量 的总 P。标准化方法 (ISO 687828) 通常用于总 P 测定, 通过 H2进行消化, 因此4和 K2S2O8在热板上, pH 值被设置为3-10 通过氢氧化钠和蓝色复合物 (与磷酸盐浓度呈线性比例的颜色强度) 是通过抗坏血酸和钼酸盐溶液形成的。这种标准化的方法非常耗费人力和时间, 这就是为什么开发了 iso 方法 (isomini) 的更快变体。ISOmini方法将总卷减少到1/5。消化在恒温器里发生, 并且消化后的氢氧化钠用量是固定的。这种方法能使大量的磷测定在很短的时间内进行, 并且与 ISO 方法相比, 不损害准确度。
每个缓冲区都有不同的 COD。此外, 相对较高的必要的缓冲浓度0.01 米意味着, 为了确保充分消化样品成分, 有相当高的数量的氧化剂必须剂量比它在 ISO 方法规定。如果 K2的2O8剂量过低或过高, 则会发生不正确的测量结果。在 ISOmini方法中, 此 K2S2O8的用量因此分别与每个缓冲区匹配。另一个关键点是氢氧化钠的用量。作为一个规则, 再生溶液有氢氧化钠浓度 > 0.1 m。为了避免 [h+]: 生成颜色复杂的25所需的 [Mo] 比率,26未被遵守, 因此在消化之前对 H2,所以4数量进行适当的调整是必要。当再生溶液多次重复使用, 从而改变其 pH 值和 COD 时, 问题就出现了。由于在螺钉盖瓶中无法进行可靠而简单的 ph 值测量, 并且未提供适当的 ph 值调整, 因此, 此处介绍的 ISO迷你方法, 达到了其对具有非常高酸碱度的样品的限制。因此, 对于再生解决方案, 建议使用 ISO 方法。

动机
在执行欧洲水框架指令1的情况下, 为减少地表水中的养分投入而作出的努力,除其他外, 必须对磷排放进行更详细的检查。膦酸的物质组 (图1) 用作纺织和造纸工业的漂白剂稳定剂, 作为饮用水处理的 antiscalants, 作为冷却水和洗涤剂和清洁剂的硬度稳定剂, 是在数量和环境相关性方面特别相关的2。膦酸被怀疑为水体的长期富营养化贡献 2, 3, 4.例如, 由于阳光的紫外线照射或在锰的II和溶解氧的存在下, 膦酸可以降级为微生物可用磷酸盐 5, 6.磷酸盐供过于求是生态不平衡水体的本质特征, 使磷成为水体生态环境持续改善的重要目标物质。
使用铁或铝盐7,8,9,10,膦酸可以通过沉淀/絮凝去除废水。在这个过程中, 金属被转化成难以溶解的金属氢氧化物。这些极地羊群与一个相对地大具体表面担当吸附剂为消极被充电的膦酸。然而, 絮凝过程可能有两个主要的缺点。根据废水的不同, 30% 的样品体积的污泥量可能会发生11。这种污泥必须在进一步沉淀或过滤阶段进行分离、处理和处理。此外, 膦酸可以使添加的絮凝剂复杂化, 从而防止羊群的形成, 特别是在低水硬度的废水中。这种效应可以通过增加的絮凝剂的数量来补偿。然而, 这导致β值 (β = 在废水中的絮凝剂与磷的摩尔比率) 的增加11,12。因此, 复杂的废水基质会使最佳絮凝剂用量的控制复杂化。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57618/57618fig1.jpg"> 图 1: 重要膦酸的结构公式 11.<a href="/files/ftp_upload/57618/57618fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
一种可能的替代方法是利用膦酸对含金属表面的高吸附亲和性, 而没有上述缺点的是基于铁 (氢) 氧化物的过滤材料。对于这种过滤材料, 文献主要介绍了消除磷酸盐的调查13,14,15,16。本文介绍了一种允许对选择性颗粒过滤材料的吸附能力进行调查的程序, 特别是用粒状氢氧化铁 (海湾金融公司) 对膦酸的研究, 其工作负荷小, 具有显著的节约成本。吸附能力的研究可分为以下几个步骤: 磷酸酯溶液的制备、吸附试验 (磷酸酯溶液与颗粒的接触) 和磷酸酯分析。所有步骤必须完全协调。
吸附试验的概念及适当缓冲器的使用 对于吸附能力的研究, 可以进行分批或柱试验。为了确定吸附剂的吸附等温线或 pH 依赖性, 该批处理方法是可取的, 因为许多结果可以得到在短时间内的可能性, 改变几个参数。pH 值是影响吸附的重要因素之一。对实验室技术员来说, 遵从或调整 ph 值是一个巨大的挑战, 因为在样品溶液中, 与吸附剂接触的 ph 值的简单调整通常是不够的。每个吸附剂材料通常力争接近 pH 值在它的零电荷点附近 (PZC)。因此, 当与吸附剂直接接触时, 水溶液,例如, 调整为 ph 值 3, 就可能改变为8的酸碱度。废水主要具有自然缓冲能力, 从而减弱了这种效应。但是, 如果只有清除某一特定的目标物质才能用某种吸附剂进行调查, 则必须使用合成废水,即, 纯净水, 特别是与目标物质混合, 或例如, 竞争性阴 离子。与粉状吸附剂不同的是, 在所需的范围内, 通过加入酸和碱, 可以很容易地维持 ph 值, 在颗粒的间歇处理方法中不能进行 ph 调整。为了保持颗粒均匀悬浮, 需要非常高的搅拌速度, 这将导致非常迅速的材料磨损。如果这种磨损是无意的, 最温和的方法是旋转封闭离心管, 使颗粒连续混合在溶液中。在这种情况下保持 pH 值常量的唯一方法是使用缓冲区。
为了能够研究磷酸盐和膦酸对含铁过滤材料的吸附, 必须满足以下要求: 无磷;无色;可溶性;最好没有络合剂;与膦酸在极性过滤材料上的吸附没有竞争;使用的不同缓冲器的相似结构;而缓冲剂或其降解产物对消化后的色络合物的光谱吸收量不能产生负面影响。为生物化学研究领域, 所谓的好缓冲器被开发了17,18,19, 有确切地这些属性。因此, 对于此工作的调查, 选择了表 1中的缓冲区。每个缓冲区的 pKa值指示缓冲区可以保持恒定的范围。但是, 对于 pH 值范围 < 5, 必须使用有机酸, 如柠檬酸 (CitOH) 和乙酸 (AcOH)。柠檬酸是一种络合剂, 但它在 pH 范围内缓冲, 而大多数含铁的过滤材料无论如何都变得不稳定。Nowack 和石7已经使用了醋酸和拖把来研究 NTMP 在 pH 值4.6 和7.2 上对浆料铁矿 (α-FeOOH) 的吸附。然而, 他们的 pH 依赖性的实验在吸附发生了, 不用缓冲。
<img alt="Table 1" src="/files/ftp_upload/57618/57618table1.jpg"> 表 1: pKa值20, 理论氧需求 (方法) 和分析的实际化学需氧量 (COD) 的缓冲区使用的研究.
总 P 确定 (ISO迷你) 适应缓冲区解决方案 在每次吸附试验后, 必须分析每个溶液中的膦酸残留浓度。仅在最近, 介绍了在0.1 µg 的范围内测定环境样品中膦酸的方法。它基于 IC-ICP-MS 方法和使用阳离子交换器 (用于将膦酸转化为 "游离" 膦酸) 和阴离子交换器 (用于预浓缩的膦酸)21。此外, 已经在 1997年, 介绍了从 Nowack22的方法, 以更高的检测范围的15-100 µg, 这是基于前络合的膦酸与 Fe III, 保留使用 HPLC 和光度检测这些配合 物。但是, 这些方法非常耗时且成本高昂。在含磷化合物为磷酸酯的合成废水的研究中, 通过测定总磷浓度来确定磷酸酯的浓度是足够的。无机磷酸盐的测定给出的实验者比总 P 的测定问题要少得多, 因为后者需要先前的消化。需要添加 priorly 的化学物质的数量必须与样品中存在的化合物精确匹配。
磷酸盐的测定目前主要采用墨菲和莱利23引入的方法进行。这种方法是基于分光光度法检测一个强烈有色磷钼蓝复合体 ([公安局 2 Mo 12 O 40] −与λ最大在 880 nm), 这是形成在存在磷酸盐和 以抗坏血酸和锑 (III.) 为还原剂的酸性钼酸盐为减水剂24。在其他研究中, [H+] 的最佳比率: [Mo] 被确定为 60-8025,26。为了确定总磷、消化、即, 在含磷化合物中对 p o p、c O p 和 c-P 键的断裂和磷对磷酸盐的氧化必须在磷钼蓝色形成之前进行 24.Eisenreich et 。27提供了一种基于在酸性环境中使用氧化剂 peroxodisulfate (K2S2O8) 的简化方法。其中许多研究结果已纳入 ISO 687828的开发, 系统地说明了测定水样中磷酸磷和总磷浓度的程序 (废水和海水)。
根据 ISO 6878 (图 2) 的总 P 测定要求, 样品要在锥形烧瓶中由 K2S2O8在酸性 pH 值 (使用硫酸) 中消化至少30分钟。消化后, pH 值设置为 3-10, 使用氢氧化钠和锥形瓶的内容转移到50毫升容积烧瓶。在这个烧瓶中, 抗坏血酸和含有钼酸盐和锑的酸性溶液加入到样品中, 然后装满水。10-30 分钟后, 这个蓝色着色的强度是以 880 nm 的波长来测量的。在磷酸盐测定的情况下, 消化被省略。这意味着, 样品混合在一个50毫升的体积瓶与抗坏血酸和溶液中含有钼酸盐和锑, 和蓝色的颜色的强度测量在光度计。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57618/57618fig2.jpg"> 图 2: 按 ISO 6878 进行的全 P 测定程序应用硫酸和 peroxodisulfate 钾进行消化, 随后用氢氧化钠和着色剂进行 pH 调整, 采用抗坏血酸和含钼酸盐溶液.<a href="/files/ftp_upload/57618/57618fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
总 P 决心的过程是非常复杂的, 因为在消化期间它必须总被照料样品不煮沸和样品的调整对 pH 值3-10 需要长时间。为了能够在很短的时间内分析尽可能多的样品, 在这个 ISO 方法的基础上, 开发了全 P 和邻磷酸盐测定的小型化形式。图 3总结了此方法的各个步骤。在这种小型化的测定方法 (iso迷你) 中, 颜色溶液的最终体积是10毫升 (在 iso 方法中, 这是50毫升)。因此, ISOmini方法可减少用于1/5 的解决方案的数量。在 iso迷你方法中, 消化是在恒温器中进行的 (与 ISO 方法相反), 在148-150 摄氏度时, 在锥形瓶中建议消化, 以获得尽可能高的氧化。与抗坏血酸和酸性钼酸盐溶液一起消化后加入氢氧化钠。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57618/57618fig3.jpg"> 图 3: 总 P 确定的过程根据 iso 6878 (iso迷你) 的修改和小型化形式,使用10毫升螺钉盖瓶, 与缓冲相关的钾 peroxodisulfate 浓度, 在恒温器中加热并添加颜色试剂直接到被消化的样品不转移它以前.<a href="/files/ftp_upload/57618/57618fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
与膦酸 (5-30 µM) 相比, 样品中含有的有机缓冲器必须相对高浓度 (10 毫米) 存在, 以有效维持 pH 值。在吸附试验后, 必须对这些缓冲器进行消化, 以便对总磷进行分析。因此, 必须将氧化剂的剂量量与每个缓冲器相匹配, 同时考虑到过多的氧化剂不应干扰消化后形成的颜色复合物的形成。为了能够估计 K2S2O8根据分析的化学需氧量 (COD) 在全 P 测定中消化每一个缓冲区所需的数量, 可以比较在需要还原 O2和 K2S2O8是必要的:
O2 + 4 h+ + 4 e- → 2 H2o
S2O82- + 2 e- →2所以42- 
因此, 一个特定分子的氧化需要两倍的 peroxodisulfate 分子作为 O2分子。因此, 在样品体积为20毫升的情况下, 样品的 COD 在使用 ISO 方法时不得超过500毫克/升。然而, 即使在 MES 的情况下, 从表 1中最小摩尔质量的良好缓冲区, 已经是2.4 克/升的 COD 存在于10毫米的浓度。本文除了吸附试验和 ISO迷你方法的分步协议外, 还研究了所需的缓冲浓度、缓冲剂对磷酸酯吸附的影响以及 K2S2O8在 ISO迷你方法中消化所需的数量和氢氧化钠用量。
弗雷德里奇吸附模型 吸附等温线,即, 加载 q (例如, 在镁磷/克吸附剂) 应用于溶解浓度 c (在镁/升 p) 的吸附后, 在吸收的特定接触时间, 可以用公式弗雷德里奇29建议:
<img alt="Equation 1" src="/files/ftp_upload/57618/57618eq1.jpg">
如果实验得到的值 q 和 c 以函数的形式绘制 (q) 在 ln (c) 中, 则由线性回归确定的此函数的斜率对应于 1/n, y 轴拦截到 KF值30。
过程概述 在膦酸中, 确定颗粒状氢氧化铁的吸附能力的整个过程分为几个步骤, 并在协议部分进行了说明。为了进行分析, 有必要准备足够数量的试剂解决方案 (议定书1节)。这些都是耐用的几个星期。然后制备含膦酸的溶液 (第2节), 其次是吸附试验 (磷酸酯溶液与粒状物质的接触) (3 节), 并根据小型化 ISO 方法对总 P 进行分析 (4 节)。

<table border="0" cellpadding="0" cellspacing="0" style="width:1359px;" width="1359">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:465px;">Sulfuric acid (H2SO4)</td>
			<td style="width:352px;">Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1120802510</td>
			<td style="width:423px;">98% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrochloric acid (HCl)</td>
			<td>VWR Chemicals (Fontenay-sous-Bois, France)</td>
			<td style="width:119px;">20254.401</td>
			<td>32% (AnalaR NORMAPUR, p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium hydroxide (NaOH)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1064981000</td>
			<td>&#8805;99% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Citric acid monohydrate (CitOH&#8729;OH)</td>
			<td>VWR Chemicals (Fontenay-sous-Bois, France)</td>
			<td style="width:119px;">20276.292</td>
			<td>99.9% (AnalaR NORMAPUR, p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acetic acid (AcOH)</td>
			<td>VWR Chemicals (Fontenay-sous-Bois, France)</td>
			<td style="width:119px;">20104.334</td>
			<td>100% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2-(N-morpholino)ethanesulfonic acid (MES)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">M3671-250G</td>
			<td>&#8805;99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">3-(N-morpholino)propanesulfonic acid (MOPS)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">M1254-250G</td>
			<td>&#8805;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">H3375-250G</td>
			<td>&#8805;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">4-(2-Hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">E9502-250G</td>
			<td>&#8805;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAPSO)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">C2278-100G</td>
			<td>&#8805;99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">N-cyclohexyl-3-aminopropanesulfonic acid (CAPS)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">C2632-250G</td>
			<td>&#8805;98%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2-Phosphonobutane-1,2,4-tricarboxylic acid (PBTC)</td>
			<td>Zschimmer &#38; Schwarz (Mohsdorf, Germany)</td>
			<td style="width:119px;">CUBLEN P 50</td>
			<td>50 % technical</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1-Hydroxyethane 1,1-diphosphonic acid monohydrate (HEDP&#183;H2O)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">54342-50G</td>
			<td>&#8805;95,0 %</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Nitrilotris(methylene phosphonic acid) (NTMP)</td>
			<td>SigmaAldrich (St. Louis, MO, USA)</td>
			<td style="width:119px;">72568-50G</td>
			<td>&#8805;97,0 %</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ethylenediamine tetra(methylene phosphonic acid) (EDTMP&#183;1.4H2O)</td>
			<td>Zschimmer &#38; Schwarz (Mohsdorf, Germany)</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Diethylenetriamine penta(methylene phosphonic acid) (DTPMP&#183;6H2O)</td>
			<td>Zschimmer &#38; Schwarz (Mohsdorf, Germany)</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium dihydrogen phosphate (KH2PO4)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1048731000</td>
			<td>&#8805;99.5% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium peroxodisulfate (K2S2O8)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1050920250</td>
			<td>&#8805;99.0% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">L(+)-Ascorbic acid (C6H8O6)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1004680500</td>
			<td>&#8805;99.7% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24&#183;4H2O)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1011800250</td>
			<td>&#8805;99.0% (p.a.)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Potassium antimony-(III) oxide tartrate hemihydrate (K(SbO)C4H4O6&#8729;&#189;H2O)</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1080920250</td>
			<td>&#8805;99.5% (p.a.)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Granular ferric hydroxide (GFH)</td>
			<td>Hego BioTec (Berlin, Germany)</td>
			<td style="width:119px;">-</td>
			<td>FerroSorp RW</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Syringe membrane filters</td>
			<td>Sartorius Stedim Biotech GmbH (G&#246;ttingen, Germany)</td>
			<td style="width:119px;">17765----------Q</td>
			<td>Minisart RC Hydrophilic 25 mm 0.45 &#956;m pore size</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Single-use syringes for membrane filtration</td>
			<td>Henke Sass Wolf (Tuttlingen, Germany)</td>
			<td style="width:119px;">5200.X00V0</td>
			<td>3-part Soft-Ject Luer 20 mL</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Rotator</td>
			<td>LLG Labware (Meckenheim, Germany)</td>
			<td style="width:119px;">6.263 660</td>
			<td>uniROTATOR2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Clamp for rotator</td>
			<td>LLG Labware (Meckenheim, Germany)</td>
			<td style="width:119px;">6.263 664</td>
			<td>Clamp for uniROTATOR2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Screw cap vial</td>
			<td>Glasger&#228;tebau Ochs (Bovenden, Germany)</td>
			<td style="width:119px;">135215</td>
			<td>Pr&#228;paratenglas Duran, 16x100 mm, thread GL18, cap with PTFE seal</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micropipette</td>
			<td>Eppendorf (Hamburg, Germany)</td>
			<td style="width:119px;">3123000047</td>
			<td>eppendorf Research plus 10&#8211;100 &#181;L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micropipette</td>
			<td>Eppendorf (Hamburg, Germany)</td>
			<td style="width:119px;">3123000063</td>
			<td>eppendorf Research plus 100&#8211;1000 &#181;L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Micropipette</td>
			<td>Eppendorf (Hamburg, Germany)</td>
			<td style="width:119px;">3123000071</td>
			<td>eppendorf Research plus 0.5&#8211;5 mL</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Precision balance</td>
			<td>Precisa Gravimetrics (Dietikon, Switzerland)</td>
			<td style="width:119px;">-</td>
			<td>Precisa LX 220 A SCS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Thermostat</td>
			<td>Hach (Berlin, Germany)</td>
			<td style="width:119px;">LTV077</td>
			<td>HT200S High Temperature Thermostat</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Thermostat</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td style="width:119px;">1712000001</td>
			<td>Spectroquant TR 320</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Spectrophotometer</td>
			<td>Jasco Labor- u. Datentechnik (Gro&#223;-Umstadt, Germany)</td>
			<td style="width:119px;">-</td>
			<td>UV/VIS Spectrophotometer Jasco V-550</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Centrifuge tube</td>
			<td>Sarstedt (N&#252;mbrecht, Germany)</td>
			<td style="width:119px;">62.559.001</td>
			<td>Tube 50 mL, 115x28 mm, flat/conical base PP, assembled cap</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">pH probe</td>
			<td>WTW (Weilheim, Germany)</td>
			<td style="width:119px;">103635</td>
			<td>WTW pH-Electrode SenTix 41</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">pH device</td>
			<td>WTW (Weilheim, Germany)</td>
			<td style="width:119px;">-</td>
			<td>WTW Multi 350i</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">COD determination</td>
			<td>Hach (Berlin, Germany)</td>
			<td style="width:119px;">LCK514</td>
			<td>100&#8211;2000 mg/L O2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sieve</td>
			<td>Retsch (Haan, Germany)</td>
			<td style="width:119px;">60.131.000500</td>
			<td>Test sieve 0.5 mm mesh (ISO 3310/1) stainless steel</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Drying cabinet</td>
			<td>Memmert (Schwabach, Germany)</td>
			<td style="width:119px;">-</td>
			<td>Modell 600</td>
		</tr>
	</tbody>
</table>

optimized procedure for determining the adsorption of phosphonates onto granular ferric hydroxide using a miniaturized phosphorus determination method

本文介绍了一种研究膦酸在含铁滤料上吸附的方法, 特别是颗粒状氢氧化铁 (海湾金融公司), 其工作性能极少, 可靠性高。磷酸酯,例如, nitrilotrimethylphosphonic 酸 (NTMP), 在一个由有机酸 (例如, 醋酸) 或良好的缓冲 (例如, 2--吗啉代) 缓冲的溶液中与转子中的海湾金融公司接触.磺酸) [MES] 和N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic 酸 [CAPSO]), 浓度为10毫米, 特定时间在50毫升离心管中。随后, 在膜过滤 (0.45 µm 孔径), 总磷 (总磷) 浓度的测量使用一个特别开发的测定方法 (ISO迷你)。此方法是对 ISO 6878 方法的修改和简化: 4 毫升的样本与 H2混合, 因此4和 K2S 2 O8在一个螺丝盖瓶, 加热到148-150 °c 为 1 H 然后混合与氢氧化钠, 抗坏血酸和酸性钼酸盐与锑 (III) (最终体积为10毫升) 产生蓝色复合物。spectrophotometrically (880 nm) 测量了与磷浓度成线性比例的颜色强度。结果表明, 使用的缓冲浓度对磷酸酯在 pH 值4和12之间的吸附没有显著影响。因此, 缓冲剂不与膦酸的吸附部位竞争。此外, 相对高浓度的缓冲需要更高剂量浓度的氧化剂 (K2S2O8) 的消化比在 ISO 6878, 这与氢氧化钠剂量, 配合到每个缓冲区。尽管进行了简化, 但与标准化方法相比, ISOmini方法并没有失去任何精度。

用所提出的程序获得的等温线示例 图 4显示了在应用该协议时所获得的结果的一个示例, 其中对海湾金融公司在不同 pH 值下对 NTMP 的吸附进行了研究。NTMP 的选择是因为, 与三个膦酸组, 它是最具代表性的膦酸酯的广泛的可能膦酸, 其中膦酸组的数量不同 (PBTC) 和五 (DTPMP)。此外, 摩尔质量的 NTMP (299.05 克/摩尔) 也位于膦酸的中间范围 (HEDP: 206.03 克/摩尔, DTPMP: 573.20 克/摩尔)。在图 4中, 在接触时间为1小时后, 在不同的缓冲和 pH 值上描述了吸附等温线,即, 磷酸酯在残留磷酸酯浓度以上的负载. 接触次数越长可能导致不良由于颗粒间接触太长, 材料磨损。对于每一个等温线, 一个解决方案与1毫克/升 NTMP, 并根据所需的 ph 值范围, 在0.01 米浓度的缓冲制备和调整到一个初步的酸碱度, 通过盐酸或氢氧化钠。这是 4.0 (AcOH), 6.0 (MES), 8.0 (无害), 10.0 (cap) 和 12.0 (氢氧化钠)。根据海湾金融公司浓度的不同, 由于1小时的接触时间, 溶液中的 pH 值改变了最多 2.0: 4.0-6.0 (AcOH), 6.0-7.3 (MES), 8.0-8.2 (无害化), 9.4-10.0 (cap), 10.9-12.0 (氢氧化钠)。海湾金融公司的 PZC 约为 8.6, 因此, 由于与海湾金融公司的接触和 ph 值 < 8.6 的增加, ph 值 > 8.6 的浓度下降是相应的。进一步离开这个被调整的 ph 值是从 8.6, 更强 ph 变化是。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57618/57618fig4.jpg"> 图 4: 将 NTMP (1 毫克/升 NTMP 的初始浓度) 加载到浓度为 0.7-的粒状氢氧化铁上室温下1 小时接触时间后的14克/升.在图中所提到的 pH 值中使用了下列0.01 摩尔/L 浓度的缓冲器: AcOH (ph 值 4.0-6.0), MES (ph 6.0-7.3), 无害 (ph 8.0-8.2), 瓶盖 (ph 9.4-10.0) 和氢氧化钠 (ph 10.9-12.0)。绘制的曲线为弗雷德里奇等温线。<a href="/files/ftp_upload/57618/57618fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
图 4中的所有等温线都是使用弗雷德里奇方程 (从左到右的 R²值和增加的酸碱度来建模的: 0.875、0.905、0.890、0.986、0.952; 对应的 n 值: 2.488、3.067、4.440、2.824、1.942; 相应的 KF值: 0.619, 0.384, 0.260, 0.245, 0.141)。在 pH 值 4-6, 装载0.55 毫克 NTMP-P/g 达到, 对应于1.8 毫克 NTMP/g。pH 值越高, 吸附水平越低。铁氧化物在其表面上有大量的铁-OH 基团, 这可能是质子或 deprotonated 取决于 pH 值。与 ph 值的深度, 表面主要地是质子,即, 正面地被充电, 意味着多齿膦酸, 在几乎整个 pH 范围被消极地被充电, 被吸引。较高的 pH 值将氢氧化铁表面的电荷转移到负方向, 进而导致增加的静电斥力7。有趣的是, 即使在 pH 值 12, 它对应于 OH-集中 0.01 M, 吸附发生了。因此, 对于成功的解吸, 必须使用更高浓度的氢氧化钠溶液。
与其他研究人员的研究结果相比, 在这项工作中, 最高可达0.55 毫克 NTMP/克海湾金融公司的最大负荷量似乎相当低。Boels et 。14发现最大负载71毫克 NTMP/克海湾金融公司, 这相当于21.7 毫克的 NTMP-磷/克海湾金融公司在他们的实验中, 合成反渗透浓缩与30毫克/升 NTMP (9.3 毫克/升 NTMP P) 在 pH 值7.85。他们使用粉末海湾金融公司和搅拌的合成解决方案, 其中包含HCO3, 也作为一个缓冲区, 24 h.因此, 他们的结果不能直接与这项工作的结果相比, 因为他们使用了更高的初始浓度和粉末海湾金融公司, 这可能会导致更高的表面面积, 因此, 从而导致更好的吸附性能。此外, 接触时间明显长于这项工作。Nowack 和石头7在0.42 克/升铁矿浆中进行了40µM NTMP 溶液 (3.72 毫克 NTMP P/升) 的实验, pH 为7.2。该溶液被搅拌 2 h, 导致最大负荷约30µM NTMP/克铁矿 (2.79 毫克 NTMP P/克)。1毫米拖把被用作缓冲器。同样, 由于磷酸酯的初始浓度较高, 结果不能直接与这项工作的结果进行比较。此外, 由铁矿群组成的泥浆具有较高的表面积。但是, 来自 Boels et 等的等温线的形状。14和 Nowack 和斯通7同意这项工作, 所有这些都可以由弗雷德里奇模型很好地安装。
缓冲液对磷酸酯吸附和所需缓冲浓度的影响 以往的实验, 以确定的吸附动力学已经表明, 也与使用缓冲器, 平衡 pH 值是在很短的时间内达到。ph 值可能与先前在含磷酸酯溶液中所设定的酸碱度 (调整后的酸碱度) 有显著的背离。这个平衡 pH 值倾向于过滤材料的 PZC, 是8.6 为颗粒状的氢氧化铁这里谈论 (根据自己的调查)。因此, 可以假定, 在接触时间后的 ph 值 (最终 ph) 对于磷酸酯的吸附程度是决定性的。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57618/57618fig5.jpg"> 图 5: 左: NTMP (1 毫克/升 NTMP 的初始浓度) 到2.5 克/升颗粒状氢氧化铁作为 pH 值在不同缓冲浓度的作用后, 接触时间为1小时。右: 1 小时接触时间后 ph 值与库存溶液中 ph 值的比较, 在不同浓度的缓冲器 AcOH、MES、拖把、无害化、CAPSO 和瓶盖接触之前, 与颗粒状的氢氧化铁进行了对比。<a href="/files/ftp_upload/57618/57618fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
在图 5的右图中, 在不同缓冲浓度的 NTMP 溶液中设置的 ph 值与1毫克/升 NTMP 和2.5 克/升海湾金融公司之间 1 h 接触后的最终 ph 值进行比较。很明显, 在溶液中的 ph 值与最终 ph 值之间的特定相关性是唯一可达到的, 因此只有当使用10毫米浓度的缓冲器时, 才可能进行相对可靠的 ph 调整。这反映在相关函数中, 用多项式回归方法确定, 并在右图中再现。事实是, 在缓冲浓度低于 10 mM pH 值2-4 必须预设, 以获得最终 ph 值6-7 显示, 预测最终 ph 值, 这是决定性的吸附, 从而安全执行的吸附试验 f或者这样的缓冲浓度是有挑战性的。
在图 5的左侧图中, 1 毫克/升 NTMP 在2.5 克/升海湾金融公司上的吸附程度被描述为不同缓冲浓度的最终 pH 值的函数。假设负荷的线性依赖性在 ph 值范围4-12 根据等式 y = ax + b, 被调查的所有缓冲集中的线性回归计算的价值是非常相似的 (10 毫米: a = −0.0673, b = 1.0914, R² = 0.9837; 6.6 毫米: a = −0.0689, b = 1.1047, R² = 0.9512;3.3 毫米: a = −0.0672, b =-0.0672, R² = 0.9570;0毫米: a = −0.0708, b = 1.157, R² = 0.8933)。确定系数是最高的为10毫米缓冲器, 清楚地表明, 以这个缓冲集中不仅最后的 pH 值是容易调整的, 而且最可靠的结果在吸附被实现了。仅路线没有缓冲器表明吸附程度的可能的偏差在 pH 值5和7之间。然而, 为了实现这些最终的 ph 值没有缓冲, 非常低的 ph 值必须设置在股票的解决方案, 其中一些只是略高于2。由于 ph 值和最终酸碱度之间的极强差异, 因此, 在没有缓冲的情况下, 最终酸碱度对吸附的程度没有决定性作用。因此可以假定, 在表 1中提到的良好缓冲区的使用对膦酸对海湾金融公司的吸附没有显著影响, 即, 膦酸酯与缓冲液之间的吸附点没有竞争。这种选择性是普遍存在的, 因为 NTMP 在海湾金融公司上的吸附主要是由于形成了单二齿配合物15。另一方面, 好的缓冲区几乎没有形成金属络合物的倾向17,19, 这就是为什么 NTMP 最好受海湾金融公司约束的原因。在具有极少极性表面的吸附剂 (如活性炭) 的情况下, 可以假定良好的缓冲器也占据游离的吸附点, 从而影响磷酸酯的吸附。因此, 不建议使用这些缓冲器研究膦酸在活性炭上的吸附。
ISO 的校准迷你方法和对 ISO 的遵从性 图 6显示了使用内部质量标准的校准行 (iq: 1 毫克/升,2PO4P 在0.9 毫米 H2所以4) 根据 iso 6878 以及修改后的 iso迷你方法为总 P 和 o PO43-P 确定。基于线性回归, 相当于 ISO 6878 的校准函数是 y = 0.0033 + 0.2833x (R² = 0.99978)。线性回归用于磷酸盐测定的小型化变体导致校准函数 y = 0.0058 + 0.2864x (R² = 0.99999)。与 y = 0.0020 + 0.2890x (R² = 0.99985) 根据 ISO迷你方法的总 P 测定的校准函数非常相似, 也非常精确。所有变体都有一个非常高的确定系数, 这意味着 ISO迷你方法不会通过将样本体积的减少到1/5 来损害准确性。在步骤4.15 中的协议中给出了由测量的光谱 absorbances 确定分析样本中 P 浓度的校准函数确定的转换方程。经验表明, 盲样品的吸光度通常可以忽略, 因为在 880 nm 的信号发出的光度计可以跳非常强烈的非常小的测量范围。因此, 测量值0.287 在 4 mL 样品量 (ISO迷你) 对应于磷浓度1毫克/升 P。
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57618/57618fig6.jpg"> 图 6: 根据 iso 6878 和 iso迷你确定总磷和邻磷酸盐 p 的校准线。根据协议的 2, iq (1 毫克/升的2PO4P 在0.9 毫米 H4,1.9) 中使用。对于 iso 方法, iq 用于整除数4、8、12、16和 20 ml, 以及在0.8、1.6、2.4、3.2 和 4.0 ml 整除数中修改的iso迷你方法。<a href="/files/ftp_upload/57618/57618fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
ISO 的可信性和与缓冲区相关的剂量数量迷你方法 如已经提及, 一个可靠的 pH 值调整在吸附试验仅是可能的以缓冲集中 0.01 m。但是, 这样的缓冲区集中需要比 ISO 6878 中为大多数缓冲区指定的更高的 K2S2O8剂量。此外, ISO 规定, ph 值必须设置为3-10 使用 ph 探针后消化。由于这种 pH 调整不能在一个小的螺帽瓶中进行, 所以必须确定不同缓冲液的匹配的氢氧化钠用量。图 7显示了与1毫克/升 NTMP 不同的包含缓冲区的解决方案的吸光度, 当这些溶液被不同的 K2S2O8数量根据 ISO迷你进行消化并以不同数量的氢氧化钠消化后。因此, 每个矩阵都基于以下步骤: 4 毫升的溶液与0.2 毫升0.9 米 H2, 所以4, 提供不同的 K22O8数量, 并填写与 H2o 到相同的总体积为9毫升。现在按照《议定书》 (1 小时148-150 摄氏度) 消化这一情况。冷却后, 添加了不同的氢氧化钠数量, 并填充了9.4 毫升的总体积与 H2O。随后, 添加了0.2 毫升抗坏血酸溶液和0.4 毫升钼酸二溶液。在添加这些色试剂后, 对吸光度 (880 nm) 的测定进行了4小时。这次选择是为了确保特定的吸光度是稳定的。本文还研究了1毫克/升 NTMP 和1米氢氧化钠的溶液。然而, 而不是 K2S2O8和氢氧化钠数量, H2因此4数量是不同的, 以确保 pH 值足够低, 以消化。目标吸光度值为 0.287 (请参阅图 6中的校准行)。因此, 在图 7中, 这些值以淡绿色显示, 此目标值偏离了最多5%。每个矩阵中的一个值用深绿色高亮显示。这将标记 K2S2O8和用于此类缓冲区解决方案的常规 ISO迷你方法的氢氧化钠剂量数量。
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/57618/57618fig7.jpg"> 图 7: 在880厘米小试管中, 用不同的 K 2 S 2 O 8 和氢氧化钠剂量数量的不同膦酸和缓冲溶液的光谱吸光度 (×1000).步骤: 4 毫升解决方案 (如图所示, 并调整为从热力学 pka值改编的缓冲区的 pKa值等。20到浓度为0.01 米和25°c31) 被放置在10毫升螺丝瓶盖瓶, 混合了0.2 毫升的0.9 米 H2, 所以4和不同数量的 K2S2O8 (如图所示)。然后加入水, 在消化前为所有样品获得9毫升的总容积。现在瓶在恒温器加热在148-150 °c 为 1 h (消化)。冷却到室温后, 添加了不同数量的氢氧化钠 (如图所示), 加上水的增加, 确保所有瓶子中都有9.4 毫升的总容积。4 h 在添加0.2 毫升抗坏血酸溶液和0.4 毫升钼酸二溶液后, 测定了 880 nm 的吸光度。在溶液 l (1 毫克/升 NTMP 在1米氢氧化钠) 的情况下, H2所以4的数量是不同的, 而不是 K2S2O8。在这里, 所有样品中的氢氧化钠的剂量对应于0.4 毫升1.5 米氢氧化钠,即, 0.60 毫摩尔的氢氧化钠。浅绿色: 最大5% 偏离目标值: 287。深绿色: 此缓冲和含磷酸酯解决方案的推荐设置。虚线: 鳕鱼, 直线: 方法。<a href="/files/ftp_upload/57618/57618fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
虽然在颜色形成过程中必须以还原条件为准, 而且过量的 k22O8可能会干扰此问题, 但解决方案 a 和 b (图 7) 的结果, 没有 (iq) 或只有很少数量的 k2S2O8 (只有无缓冲区的 NTMP) 是必需的, 显示 K2S2O8的较高数量不会自动导致吸光度的突然减少。这里还应该提到, 其他膦酸的解决方案类似的解决方案 b 与1毫克/升 PBTC (吸光度: 0.3005), 1 毫克/升 HEDP (0.3035), 1 毫克/升 EDTMP P (0.2952) 或1毫克/升 DTPMP-p (0.2936) 完全使用 ISO迷你方法根据协议与 0.04 g K2S2O8和0.6 毫摩尔氢氧化钠。因此, 该方法也可用于膦酸以外的 NTMP。
表 1显示了理论氧需求 (方法), 用于在0.01 米缓冲液中通过 Hach LCK 514 试管快速试验测定每个缓冲器的氧化量和化学需氧量 (COD)。众所周知, 重铬酸钾, 用于 COD 测定的氧化剂, 不氧化有机束缚氮32。对于良好的缓冲器, 测定的 COD 总是介于 c 和 h 氧化和 c、h 和 S 氧化的理论量之间。仅对于具有 c OH 组的缓冲区 (HEPES、无害化、CAPSO), 测量值与 c、H 和 S 氧化的理论值相对应。在不包含 C OH 组 (MES、拖把、cap) 的缓冲器中, 磺组明显没有完全降解到硫酸盐。
对于解决方案7c到7j, 可以很清楚地看到, K2S2O8数量显著低于根据缓冲区 COD 所需的氧化剂用量, 独立于氢氧化钠量, 没有有助于实现目标价值。在10毫米, 这些溶液中的缓冲液浓度约为1000倍, 高于 NTMP。如果不消化缓冲液, 就不能保证磷酸酯可以完全氧化。仅在 COD 之外的 K2S2O8数量导致了目标值的可靠实现。因此, 所有的缓冲器都不需要对缓冲 (方法) 的完全氧化所需的理论氧化剂进行应用, 因为氮和某些缓冲器的磺基团没有完全分解。除 COD 以外的任何氧化剂都没有与缓冲反应, 因此, 有足够的过量的 K2S2O8来氧化膦酸。NTMP 也含有氮。虽然这可能不会完全氧化为硝酸盐, 所有磷酸酯组明显氧化为磷酸盐。否则, 你将找不到1毫克/升 p 的吸收量丰富过量的 K2S2O8当然也有助于磷酸酯的完全氧化, 但消化后一些 K2S2O8仍然存在并且可能与抗坏血酸发生反应, 这对于还原蓝钼酸盐-磷酸盐复合体是必要的。结果是吸光度低于目标值。
在每一行中, 吸光度随氢氧化钠的用量从一定量的氢氧化钠开始增加。因此, 它也发生了低于所需的氧化剂的数量, 根据 COD 的缓冲, 测量的吸光度值可以按照目标值, 虽然 NTMP 显然没有完全消化 (见解决方案7c,7f和7h)。在这种情况下, 吸光度的增加是由于钼酸盐离子的自还原由于过低 [H+]: [Mo] 比率26, 并且任何通信因此是仅随机的。因此, 使用较高的 K2S2O8数量, 消化后可以使用更多的氢氧化钠, 因为 k2S2O8降低了 pH 值。
在大多数溶液中, 即使没有使用碱液剂量, 吸光度也与目标值一致。然而, 偶尔地, 从这个价值的偏差发生了, 可能是因为缺乏氢氧化钠导致事实最佳的 [H+]: [Mo] 比率没有被维护和因而颜色复合体变得不稳定。因此, 无论分析的解决方法, 建议的剂量0.6 毫摩尔氢氧化钠, 因为, 从而, 颜色复合物被证明是最稳定的。再生溶液通常有1米氢氧化钠的浓度。其中一个案例由矩阵 l 所覆盖。在这里, 它表明, 只有一个非常窄的频谱 H2, 所以4剂量是允许的, 证明使用 ph 探针来调整 ph 值后消化可能是一个更安全的程序在这里。
图 7 (n=12) 中的所有暗绿色吸光度值, 根据图 6中的校准行转换为 P 总浓度, 平均值为1.013 毫克/升。标准偏差为0.014 毫克/升。典型的偏差从目标价值 (1.000 毫克/升) 因此仅 0.11-2. 67% (1.013-0.014-1.000)/1.000 x 100% = 0.11%;(1.013 + 0.014-1.000)/1.000 x 100% = 2.67%)。这显示了 ISOmini方法的高精度。

Watch this Scientific Journal Video about Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method at JoVE

Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

本文介绍了一种研究膦酸在含铁滤料上吸附的方法, 特别是颗粒状氢氧化铁, 其工作性能极少, 可靠性高。在缓冲溶液中, 磷酸酯通过转子与吸附剂接触, 然后通过小型化的磷测定方法进行分析。

用小型化磷测定法测定膦酸在粒状氢氧化铁上吸附的优化方法

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric ...

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Research

JoVE Journal

Environment

14.5K 次观看.  University of Stuttgart. 本文介绍了一种研究膦酸在含铁滤料上吸附的方法, 特别是颗粒状氢氧化铁, 其工作性能极少, 可靠性高。在缓冲溶液中, 磷酸酯通过转子与吸附剂接触, 然后通过小型化的磷测定方法进行分析。

视频: Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

在使用高通量微孔板测定水，土壤，沉积物和微生物测定胞外酶活性的

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

科研

环境科学

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American lobsters. Recent work in exploited crustacean populations (crabs and lobsters) suggests that there are circumstances where mature females are unable to achieve their full reproductive potential due to sperm limitation. To examine this possibility in different regions of the American lobster fishery, a reliable and noninvasive method was developed for sampling large numbers of female lobsters at sea. This method involves inserting a blunt-tipped needle into the female&#39;s seminal receptacle to determine the presence or absence of a sperm plug and to withdraw a sample that can be examined for the presence of sperm. A series of control studies were conducted at the dock and in the laboratory to test the reliability of this technique. These efforts entailed sampling 294 female lobsters to confirm that the presence of a sperm plug was a reliable indicator of sperm within the receptacle and thus, mating. This paper details the methodology and the results obtained from a subset of the total females sampled. Of the 230 female lobsters sampled from George&#39;s Bank and Cape Ann, MA (size range = 71-145 mm in carapace length), 90.3% were positive for sperm. Potential explanations for the absence of sperm in some females include: immaturity (lack of physiological maturity), breakdown of the sperm plug after being used to fertilize a clutch of eggs, and lack of mating activity. The surveys indicate that this technique for examining the mating success of female lobsters is a reliable proxy that can be used in the field to document reproductive activity in natural populations.

A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters Homarus americanus

Fishery-induced changes to exploited crustacean fisheries, such as the American lobster fishery, could potentially influence their reproductive dynamics, leading to a reduction in mating success. This study&#39;s goal was to develop a noninvasive method for ascertaining the mating success of female lobsters that may be physiologically or functionally mature.

一种非侵入性的方法<em&gt;原位</em&gt;交配成功的女美国龙虾​​（测定<em&gt;美洲螯龙虾</em&gt;）

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American ...

Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy

Structural determination of proteins is rather challenging for proteins with molecular masses between 40 - 200 kDa. Considering that more than half of natural proteins have a molecular mass between 40 - 200 kDa1,2, a robust and high-throughput method with a nanometer resolution capability is needed. Negative staining (NS) electron microscopy (EM) is an easy, rapid, and qualitative approach which has frequently been used in research laboratories to examine protein structure and protein-protein interactions. Unfortunately, conventional NS protocols often generate structural artifacts on proteins, especially with lipoproteins that usually form presenting rouleaux artifacts. By using images of lipoproteins from cryo-electron microscopy (cryo-EM) as a standard, the key parameters in NS specimen preparation conditions were recently screened and reported as the optimized NS protocol (OpNS), a modified conventional NS protocol 3 . Artifacts like rouleaux can be greatly limited by OpNS, additionally providing high contrast along with reasonably high&#8208;resolution (near 1 nm) images of small and asymmetric proteins. These high-resolution and high contrast images are even favorable for an individual protein (a single object, no average) 3D reconstruction, such as a 160 kDa antibody, through the method of electron tomography4,5. Moreover, OpNS can be a high&#8208;throughput tool to examine hundreds of samples of small proteins. For example, the previously published mechanism of 53 kDa cholesteryl ester transfer protein (CETP) involved the screening and imaging of hundreds of samples 6. Considering cryo-EM rarely successfully images proteins less than 200 kDa has yet to publish any study involving screening over one hundred sample conditions, it is fair to call OpNS a high-throughput method for studying small proteins. Hopefully the OpNS protocol presented here can be a useful tool to push the boundaries of EM and accelerate EM studies into small protein structure, dynamics and mechanisms.

More than half of proteins are small proteins (molecular mass &#60;200 kDa) that are challenging for both electron microscope imaging and three-dimensional reconstructions. Optimized negative staining is a robust and high-throughput protocol to obtain high contrast and relatively high resolution (~1 nm) images of small asymmetric proteins or complexes under different physiological conditions.

优化负染:通过电子显微镜检查小和不对称蛋白结构的高通量协议

Structural determination of proteins is rather challenging for proteins with molecular masses between 40 - 200 kDa. Considering that more than half of ...

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

实验室确定的磷通量湖泊沉积物作为内部磷载入一个测量

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

An Optimized Enrichment Technique for the Isolation of Arthrobacter Bacteriophage Species from Soil Sample Isolates

Bacteriophage isolation from environmental samples has been performed for decades using principles set forth by pioneers in microbiology. The isolation of phages infecting Arthrobacter hosts has been limited, perhaps due to the low success rate of many previous isolation techniques, resulting in an underrepresented group of Arthrobacter phages available for study. The enrichment technique described here, unlike many others, uses a filtered extract free of contaminating bacteria as the base for indicator bacteria growth, Arthrobactersp. KY3901, specifically. By first removing soil bacteria the target phages are not hindered by competition with native soil bacteria present in initial soil samples. This enrichment method has resulted in dozens of unique phages from several different soil types and even produced different types of phages from the same enriched soil sample isolate. The use of this procedure can be expanded to most nutrient rich aerobic media for the isolation of phages in a vast diversity of interesting host bacteria.

An Optimized Enrichment Technique for the Isolation of Arthrobacter Bacteriophage Species from Soil Sample Isolates

We present an enrichment protocol for the isolation of bacteriophages infecting bacteria in the Arthrobacter genus. This enrichment protocol produces fast and reproducible results for the isolation and amplification of Arthrobacter phages from soil isolates.

一种优化富集技术的隔离<em&gt;节杆菌</em&gt;噬菌体种从土壤样品隔离

Bacteriophage isolation from environmental samples has been performed for decades using principles set forth by pioneers in microbiology. The isolation of ...

A Bending Test for Determining the Atterberg Plastic Limit in Soils

The thread rolling test is the most commonly used method to determine the plastic limit (PL) in soils. It has been widely criticized, because a considerable subjective judgment from the operator that carries out the test is involved during its performance, which may affect the final result significantly. Different alternative methods have been put forward, but they cannot compete with the standard rolling test in speed, simplicity and cost.
In an earlier study by the authors, a simple method with a simple device to determine the PL was presented (the &#34;thread bending test&#34; or simply &#34;bending test&#34;); this method allowed the PL to be obtained with minimal operator interference. In the present paper a version of the original bending test is shown. The experimental basis is the same as the original bending test: soil threads which are 3 mm in diameter and 52 mm long are bent until they start to crack, so that both the bending produced and its related moisture content are determined. However, this new version enables the calculation of PL from an equation, so it is not necessary to plot any curve or straight line to obtain this parameter and, in fact, the PL can be achieved with only one experimental point (but two experimental points are recommended).
The PL results obtained with this new version are very similar to those obtained through the original bending test and the standard rolling test by a highly experienced operator. Only in particular cases of high plasticity cohesive soils, there is a greater difference in the result. Despite this, the bending test works very well for all types of soil, both cohesive and very low plasticity soils, where the latter are the most difficult to test via the standard thread rolling method.

The traditional standardized test for determining the plastic limit in soils is performed by hand, and the result varies depending on the operator. An alternative method based on bending measurements is presented in this study. This allows the plastic limit to be obtained with a clear and objective criterion.

弯曲试验在土壤确定阿太堡限塑

The thread rolling test is the most commonly used method to determine the plastic limit (PL) in soils. It has been widely criticized, because a ...

Experimental System of Solar Adsorption Refrigeration with Concentrated Collector

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The main components of the system were the adsorbent bed, the condenser, the evaporator, the cooling sub-system, and the solar collector. In the first step of the experiment, the vapor-saturated bed was heated by the solar radiation under closed conditions, which caused the bed temperature and pressure to increase. When the bed pressure became high enough, the bed was switched to connect to the condenser, thus water vapor flowed continually from the bed to the condenser to be liquefied. Next, the bed needed to cool down after the desorption. In the solar-shielded condition, achieved by aluminum foil, the circulating water loop was opened to the bed. With the water continually circulating in the bed, the stored heat in the bed was took out and the bed pressure decreased accordingly. When the bed pressure dropped below the saturation pressure at the evaporation temperature, the valve to the evaporator was opened. A mass of water vapor rushed into the bed and was adsorbed by the zeolite material. With the massive vaporization of the water in the evaporator, the refrigeration effect was generated finally. The experimental result has revealed that both the COP (coefficient of the performance of the system) and the SCP (specific cooling power of the system) of the SAPO-34 zeolite was greater than that of the ZSM-5 zeolite, no matter whether the adsorption time was longer or shorter. The system of the SAPO-34 zeolite generated a maximum COP of 0.169.

With solar energy as the driving force, a novel adsorption refrigeration system has been developed and experimentally investigated. Water vapor and zeolite formed the working pair of the adsorption system. This manuscript describes the setup of the experimental rig, the operation procedure, and the important results.

聚光集热器太阳能吸附制冷实验系统

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The ...

Determination of the Settling Rate of Clay/Cyanobacterial Floccules

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.

The interaction and sedimentation of the clay and bacterial cells within the marine realm, observed in natural environments, can be best investigated in a controlled lab environment. Here, we describe a detailed protocol, which outlines a novel method for measuring the sedimentation rate of clay and cyanobacterial floccules.

粘土/蓝藻 Floccules 沉降速率的测定

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction ...

A Novel Method for the Pentosan Analysis Present in Jute Biomass and Its Conversion into Sugar Monomers Using Acidic Ionic Liquid

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, lower vapor pressure, non-flammability, higher heat capacity, and tunable solubility and acidity. Here, we demonstrate a method for the synthesis of C5 sugars (xylose and arabinose) from the pentosan present in jute biomass in a one-pot process by utilizing a catalytic amount of Br&#248;nsted acidic 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate IL. The acidic IL is synthesized in the lab and characterized using NMR spectroscopic techniques for understanding its purity. The various properties of BAIL are measured such as acid strength, thermal and hydrothermal stability, which showed that the catalyst is stable at a higher temperature (250 &#176;C) and possesses very high acid strength (Ho 1.57). The acidic IL converts over 90% of pentosan into sugars and furfural. Hence, the presenting method in this study can also be employed for the evaluation of pentosan concentration in other kinds of lignocellulosic biomass.

We present a protocol for the synthesis of C5 sugars (xylose and arabinose) from a renewable non-edible lignocellulosic biomass (i.e., jute) with the presence of Br&#248;nsted acidic ionic liquids (BAILs) as the catalyst in water. The BAILs catalyst exhibited better catalytic performance than conventional mineral acid catalysts (H2SO4 and HCl).

利用酸性离子液体戊聚糖分析黄麻生物量及其转化为糖单体的新方法

Recently, ionic liquids (ILs) are used for biomass valorization into valuable chemicals because of their remarkable properties such as thermal stability, ...

A Loop-mediated Isothermal Amplification (LAMP) Assay for Rapid Identification of Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many countries around the world. Severe yield losses are caused by direct feeding, and even more importantly, also by the transmission of more than 100 harmful plant pathogenic viruses. As for other invasive pests, increased international trade facilitates the dispersal of B. tabaci to areas beyond its native range. Inspections of plant import products at points of entry such as seaports and airports are, therefore, seen as an important prevention measure. However, this last line of defense against pest invasions is only effective if rapid identification methods for suspicious insect specimens are readily available. Because the morphological differentiation between the regulated B. tabaci and close relatives without quarantine status is difficult for non-taxonomists, a rapid molecular identification assay based on the loop-mediated isothermal amplification (LAMP) technology has been developed. This publication reports the detailed protocol of the novel assay describing rapid DNA extraction, set-up of the LAMP reaction, as well as interpretation of its read-out, which allows identifying B. tabaci specimens within one hour. Compared to existing protocols for the detection of specific B. tabaci biotypes, the developed method targets the whole B. tabaci species complex in one assay. Moreover the assay is designed to be applied on-site by plant health inspectors with minimal laboratory training directly at points of entry. Thorough validation performed under laboratory and on-site conditions demonstrates that the reported LAMP assay is a rapid and reliable identification tool, improving the management of B. tabaci.

A Loop-mediated Isothermal Amplification LAMP Assay for Rapid Identification of Bemisia tabaci

This paper reports the protocol for a rapid identification assay for Bemisia tabaci based on loop-mediated isothermal amplification (LAMP) technology. The protocol requires minimal laboratory training and can, therefore, be implemented on-site at points of entry for plant imports such as seaports and airports.

循环介导等温扩增 (灯管) 法快速识别烟粉虱

The whitefly Bemisia tabaci (Gennadius) is an invasive pest of considerable importance, affecting the production of vegetable and ornamental crops in many ...