a*******t
发帖数: 867 | 1 需要测试一些溶液的ORP值。但数据一直不稳定。
我用同一种化合物配溶液，浓度由低到高，ORP的读数先是上升，在更高浓度是反而下
降。测他们的PH值，随浓度上升而增加。
用DI W 来测试， 用NAOH 和HCL 调节PH，在PH 上升时，ORP值迅速下降。
是不是ORP的读数和PH密切相关？
原来以为ORP读数更大程度上取决于溶液中化合物的性质和浓度，现在看来PH更重要。
但是调节PH如何影响溶液的氧化还原能力？
以前没用过ORP。请高手指点我哪里弄错了。谢谢 |
c******n
发帖数: 16403 | 2 高手原来竟也是同行
【在 a*******t 的大作中提到】
: 需要测试一些溶液的ORP值。但数据一直不稳定。
: 我用同一种化合物配溶液，浓度由低到高，ORP的读数先是上升，在更高浓度是反而下
: 降。测他们的PH值，随浓度上升而增加。
: 用DI W 来测试， 用NAOH 和HCL 调节PH，在PH 上升时，ORP值迅速下降。
: 是不是ORP的读数和PH密切相关？
: 原来以为ORP读数更大程度上取决于溶液中化合物的性质和浓度，现在看来PH更重要。
: 但是调节PH如何影响溶液的氧化还原能力？
: 以前没用过ORP。请高手指点我哪里弄错了。谢谢
|
a***n
发帖数: 1500 | 3 wow!
【在 c******n 的大作中提到】
: 高手原来竟也是同行
|
a***n
发帖数: 1500 | 4 I assume O.R.P.= Oxidation Reduction Potential?
And yes, it is very much related to the pH of your solution.
Generally speaking, oxidation potential goes up when pH goes down (higher
concentration of H+), for most of the oxidizing reagents.
What are the compounds you tested?
【在 a*******t 的大作中提到】
: 需要测试一些溶液的ORP值。但数据一直不稳定。
: 我用同一种化合物配溶液，浓度由低到高，ORP的读数先是上升，在更高浓度是反而下
: 降。测他们的PH值，随浓度上升而增加。
: 用DI W 来测试， 用NAOH 和HCL 调节PH，在PH 上升时，ORP值迅速下降。
: 是不是ORP的读数和PH密切相关？
: 原来以为ORP读数更大程度上取决于溶液中化合物的性质和浓度，现在看来PH更重要。
: 但是调节PH如何影响溶液的氧化还原能力？
: 以前没用过ORP。请高手指点我哪里弄错了。谢谢
|
a*******t
发帖数: 867 | 5
Thank you very much.
Yes, I also noticed similar trend with different compounds. One is
hypochlorite solution and another one is a pesticide formulation.
I guess this correlation between ORP and pH (H+) should be guided by some
equations, like Nernst equation? But I do not see the [H+] item in the
equation.
So I guess we have to adjust pH to the same level in order to use the ORP
reading as an indicator of concentration of one compound?
To 疯哥:
高手不敢当。现在棋力下降了。
我作的是环境工程，跟化学有关。但是我的化学基础显然还不够....
【在 a***n 的大作中提到】
: I assume O.R.P.= Oxidation Reduction Potential?
: And yes, it is very much related to the pH of your solution.
: Generally speaking, oxidation potential goes up when pH goes down (higher
: concentration of H+), for most of the oxidizing reagents.
: What are the compounds you tested?
|
a***n
发帖数: 1500 | 6 H+ & OH- are part of many (not all) ox/red reactions.
Hypochlorite becomes a stronger oxidizing reagent with higher [H+].
See the half reaction below:
ClO- + 2H+ + 2e -> Cl- + H2O
O.R.P. is directly related to the concentration of your compound of interest
and very likely [H+]/[OH-]. So yeah, the pH should be the same in your test
, assuming your compound of interest is neutral or near neutral.
higher
【在 a*******t 的大作中提到】
:
: Thank you very much.
: Yes, I also noticed similar trend with different compounds. One is
: hypochlorite solution and another one is a pesticide formulation.
: I guess this correlation between ORP and pH (H+) should be guided by some
: equations, like Nernst equation? But I do not see the [H+] item in the
: equation.
: So I guess we have to adjust pH to the same level in order to use the ORP
: reading as an indicator of concentration of one compound?
: To 疯哥:
|
a*******t
发帖数: 867 | 7
interest
test
Thank you!
【在 a***n 的大作中提到】
: H+ & OH- are part of many (not all) ox/red reactions.
: Hypochlorite becomes a stronger oxidizing reagent with higher [H+].
: See the half reaction below:
: ClO- + 2H+ + 2e -> Cl- + H2O
: O.R.P. is directly related to the concentration of your compound of interest
: and very likely [H+]/[OH-]. So yeah, the pH should be the same in your test
: , assuming your compound of interest is neutral or near neutral.
:
: higher
|
