钠的测定翻译（PNa电极法）-中英对照
1、概述：用PNa电极和甘汞参比电极浸入被测水样中，组成电极对，PNa电极的电位随液中钠离子的活度而变化，用DWS—51型钠度计即可测出钠离子的含量。
PNa=-lg[Na+]
2、测定方法
（1）接通电源，仪器预热半小时。
（2）调零：温度补偿和刻度“校正”。
（3）定位：定位和复定位误差不超过±0.02至±0.03PNa（定位液PH要调至10以上）。
（4）水样测定：用二异丙胺调PH为10以上的好水清洗电极，洗至PNa值大于6.5以上然后用调过PH的水样进行测定，取稳定值。
五． 磷酸根的测定
1、概述：
在0.6N酸度下,磷酸盐与钼酸铵生成磷钼黄,用氯化亚锡还原成磷钼兰后，与同时配制的标准色进行比色测定，反应如下。
PO43-+12Mo2-+27H+→H3[P（Mo3O10）4]+12H2O
（磷钼黄）
[P（Mo3O10）4]3-+11H++4Sn2+→H3[P（Mo3O9）4]+4Sn4+4H2O
2、测定方法：
（1）量取0.2、0.5、0.7、0.9、1.1、1.3毫升磷酸盐工作液（1ml=0.025mgPO43-）及水样2.5ml，分别注入一组比色管中，用好水稀释约20ml，摇匀。
（2）于上述比色管中加入3.5ml硫酸—钼酸铵混合液，用好水稀释至刻度，摇匀。
（3）于每支比色管中加入5滴氯化亚锡溶液摇匀，待3分钟后进行比色。PO43-按下式计算：
PO43-
a：与水样颜色相当的标准中加入PO43-工作液体积，毫升；
V：水样体积。
六． 溶解氧的测定（靛蓝二磺酸钠葡萄糖比色法）
概要
（1）在PH为12.5左右时，靛蓝二磺酸钠葡萄糖还原成浅黄色的还原物。当其与水中溶解氧相遇时，即与溶解氧反应产生红色半靛醌中间产物。此中间产物在有溶解氧的情况下，还会继续被氧化成为蓝色的靛蓝二磺酸钠。
（2）在高碱性的情况下，还原型靛蓝二磺酸钠在氧化过程中会出现红色半靛醌中间产物，因此就大大提高了在溶解氧测定过程中各色阶的变化范围，更有利于目视比色的测定。其色泽的变化范围为浅绿黄色、黄色、桔红色、红色、绛红色、紫色、蓝色，最后为蓝绿色。
（3）由于有副反应，因此在中间阶段的变色范围内，根据在测试中条件的不同（例如试剂批号、分析时水温以及水样中杂质等因素），会出现所发生的色泽与标准色阶不甚匹配的现象。本法的测定范围为0~100ug/L，假色标准还可扩大至160ug/L。其中以0~20以及50~100ug/L区间为最灵敏。
试剂
（1）靛蓝二磺酸钠贮备液。
（2）葡萄糖贮备溶液。
（3）氢氧化钾溶液。
（4）靛蓝二磺酸钠葡萄糖溶液：量取上述靛蓝二磺酸钠和葡萄糖贮备溶液各5ml，氢氧化钾溶液5ml，加水10ml，充分混合后，立即注入25ml滴定管内，并用矿物油作油封。使其充分变成柠檬黄色后使用，时间通常为1 ~2小时。
3、测定方法
（1）标准色的配制。
瓶号 溶解氧含量 溶液颜色
1 0.000 黄带绿色
2 0.005 微绿黄色
3 0.010 橙黄色
4 0.015 橙黄带红色
5 0.020 粉红色
6 0.025 桔红色
7 0.030 红色
8 0.035 绛红色
9
0.040 绛红色
10 0.050 绛红微紫
11 0.060 红紫色
12 0.070 浅红紫色
13 0.080 紫色
14 0.100 深紫色
（2）水样的测定：用1只125mL的专用溶氧瓶取样，然后迅速加入1.0mL还原型靛蓝二磺酸钠葡萄糖工作溶液，立即塞紧瓶盖，放置1~2min，立即在自然光或白色日光灯下，以白色作背景，同标准色进行比较。
注：①按规定的加药量，最后水样的PH值为12.0～12.5的规定。
②由于本方法是在较高的PH条件下测定的，因此如水样中含有较多的钙、镁、铁等金属离子时，由于会产生沉淀，均不宜采用此方法。
③由于所配试剂碱性较大，当用碱式滴定管情况下，如较长时间不用或出现活塞有渗漏时，应将管内剩余试剂放掉，并用蒸馏水冲洗干净。必要时再擦上润滑脂，以防活塞固死。
④显色后水样碱性很大，应尽量避免同皮肤接触，每次测试完毕后，应立即用清水将手冲洗干净，以免侵蚀皮肤。
⑤靛蓝二磺酸钠葡萄糖工作溶液配好后，如室温较高，放置时间可以短些。但最好是隔夜配好，并放置于阴冷处。否则，如还原反应未完全，工作溶液尚未完全变成浅黄色，则所测结果会大大偏高。
VI．Acid Rinsing:
On electrolyzing seawater, it is unavoidable to generate precipitates as calcium and magnesium besides sodium hypochlorite and hydrogen gas, which accumulate on the cathode of the electrolytic cell, resulting in the increase of cell voltage, the decrease of current efficiency and the growth of power consumption as well. Therefore, it is necessary to do some acid rinsing to the electrolytic cell regularly so as to remove the precipitates on the surface of cathode. At this moment, PLC is used to analyze the running time and the abnormality of cell voltage in order to judge if acid rinsing is required. Giving alarming signal during acid rinsing and light warning on the panel of control cabinet is necessary for acid rinsing. During the course of acid rinsing, the generator will be locked till the acid rinsing is completed, which shall be unlocked automatically for standby after it.
Operation mentioned above does not need disassemble any equipment or pipeline and do no harm to operators.
Section two Working Principle and Technical Specification of Main Equipment
I. Seawater Booster Pump:
The seawater booster pump selects Dalian Acid-resistant Pump, LH vertical type single-stage and single-suction submergible pump, 3 sets. The model: LH50—400; the flow rate: 34m3/h; the pressure: 0.35 MPa; the axial length: 4.5m; the axle, axle sleeve and impeller of the seawater booster pump are all made of 316L stainless steel form abroad. The bearing of vertical long-axle submerged pump is an inlet one; the motor speed is 1450r/min.
II．Automatic Backwashing Filter:
1．Working Principle:
Automatic backwashing filter utilizes the pressure difference of system to implement backwashing without any influence on flowing of seawater and no special cleaning fluid is required during the cleaning process. In the normal operation, crude seawater runs into sieve through the inlet of filter, all impurities with diameter larger than 0.5mm will be retained on the sieve. This process carries on until the impurities accumulate to a certain degree, which causes the increase of pressure difference, when the pressure differential controller achieves the preset value（0.035Mpa）, automatic backwashing starts up. Sliding seal plate connected to the backwashing outlet will clean each part of sieve effectively. The internal pressure in the filter shell is higher than that of backwashing outlet pipe, thus some seawater flows in an opposite direction through sieve and cleans all accumulated impurities effectively, discharging them into trench through the blowdown valve.
The whole process is carried out by the differential pressure controller automatically. After all sieves of filters were cleaned, the automatic backwash cycle stops, and filters restore to the normal mode till next action of the pressure controller takes place, washing repeatedly.
2．Characteristics of Equipment:
- It is unnecessary to shut down during backwashing and the water consumption for backwashing is quite low.
Backwashing adopts small and light motor with low power for convenience of maintenance.
● The lid of filter shall be easily disassembled for maintenance of the sieve,
● Unique structure of sieve prevents from being blocked by impurities with strong anti-mechanical wear and anti-scour abilities.
● The possibility of damage is eliminated due to the separation of sieve and backwashing components.
● The import 316L stainless steel has strong anti-corrosion ability to seawater and longer service life.
● The low inertia of backwashing components ensures the minimum power consumption.
● The blowdown valve adopts an electric ball valve, which opens automatically during backwashing and closes after it.
3．Equipment Specification:
ZHG56-LA Automatic Backwashing Filter, water treatment capacity is 68m3/h.
III．Sodium Hypochlorite Generator:
1．Working Principle:
The seawater that passes through the electrolytic cell shall be electrolyzed at both anode and cathode with chemical reactions as below:
Anodic reaction： 2Cl—2e→Cl2 （1）
Cathodic reaction： 2H2O+2e→2OH-+H2↑ （2）
Reaction between electrodes of electrolytic cell: Cl2+ 2NaOH→2NaClO+H2↑ （3）
Hypochlorous acid and hypochlorous acid ion are all called effective chlorine, and prevention of sea biological defile is realized by using effective chlorine which is generated from electrolyzing seawater.
2．Characteristics of Equipment:
Lid of electrolytic cell: the lid is made of UV-resistant organic glass which is transparent so that the operator is able to directly observe chemical reactions in the cell through the lit during operation which is helpful for operators to judge and master maintenance of electrolytic cell and time of acid rinsing well.
Shell of electrolytic cell: the shell is made of PVC with perfect corrosion resistance to the sodium hypochlorite. This material possesses features of high strength, anti-aging and corrosion resistance compared with other materials with higher safety and stability, eliminating the leakage of liquid.
武汉翻译公司
2013.7.11