Preparation method of alkaline potassium persulfate:
稱取40g過硫酸鉀,15g氫氧化鈉,溶于無氨水中,稀釋1000mL。而HJ636—2012中則明確指出,2種溶液需分開配制,且要等到氫氧化鈉溶液冷卻到室溫后,再將2種溶液混勻。
Weigh 40g of potassium persulfate and 15g of sodium hydroxide, dissolve them in ammonia free water, and dilute to 1000mL. In HJ636-2012, it is explicitly stated that the two solutions need to be prepared separately and must wait until the sodium hydroxide solution cools to room temperature before mixing the two solutions evenly.
這是由于氫氧化鈉溶于水時會發(fā)熱,若將過硫酸鉀和氫氧化鈉同時放入燒杯中溶解,部分過硫酸鉀會因氫氧化鈉放熱導(dǎo)致局部溫度過高而失效,所以,在配制堿性過硫酸鉀溶液時,必須按HJ636—2012的規(guī)定進行。
This is because sodium hydroxide will generate heat when dissolved in water. If potassium persulfate and sodium hydroxide are dissolved in a beaker at the same time, some potassium persulfate will become ineffective due to excessive local temperature caused by the heat release of sodium hydroxide. Therefore, when preparing alkaline potassium persulfate solution, it is necessary to follow the regulations of HJ636-2012.
過硫酸鉀常溫下不易完全溶解,在配制時常常通過加熱促進溶解,但過硫酸鉀在60℃甚50℃就會分解,故加熱溫度應(yīng)控制在50℃以下為宜。
Potassium persulfate is not easily dissolved at room temperature and is often promoted by heating during preparation. However, potassium persulfate decomposes at 60 ℃ or even 50 ℃, so the heating temperature should be controlled below 50 ℃.
配制堿性過硫酸鉀溶液應(yīng)注意:
When preparing alkaline potassium persulfate solution, attention should be paid to:
①分別溶解過硫酸鉀和氫氧化鈉,待兩種試劑冷卻室溫再混合;
① Dissolve potassium persulfate and sodium hydroxide separately, wait for the two reagents to cool to room temperature before mixing;
②配制過硫酸鉀溶液需加熱溶解,但溫度一定要控制在60℃以下,防止過硫酸鉀分解失效;
② The preparation of potassium persulfate solution requires heating for dissolution, but the temperature must be controlled below 60 ℃ to prevent the decomposition and failure of potassium persulfate;
③溶液現(xiàn)用現(xiàn)配,長放置時間不超過3天,而且消解時加入堿性過硫酸鉀的量必須準(zhǔn)確。
③ The solution should be prepared immediately and stored for no more than 3 days. The amount of alkaline potassium persulfate added during digestion must be accurate.
過硫酸鉀作為氧化劑,應(yīng)避免與還原性物質(zhì)、硫、磷等混合存放,且要放在干燥的地方,不能存放太久。
Potassium persulfate, as an oxidant, should be stored in a dry place and should not be mixed with reducing substances, sulfur, phosphorus, etc. It should not be stored for too long.
堿性過硫酸鉀溶液更不能長期存放,標(biāo)準(zhǔn)中規(guī)定堿性過硫酸鉀溶液在聚乙烯瓶中存放不能超過7d。堿性過硫酸鉀在27~30℃環(huán)境下,存放超過3d,空白值就會大于0.030;建議實驗時盡量根據(jù)3d的需求量配制,存放盡量不要超過3d。您有什么疑惑或者需求,歡迎您隨時來我們網(wǎng)站
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Alkaline potassium persulfate solution cannot be stored for a long time. The standard stipulates that alkaline potassium persulfate solution cannot be stored in polyethylene bottles for more than 7 days. When alkaline potassium persulfate is stored in an environment of 27-30 ℃ for more than 3 days, the blank value will be greater than 0.030; It is recommended to prepare according to the demand for 3D as much as possible during the experiment, and store it as little as possible beyond 3D. If you have any doubts or needs, please feel free to come to our website at any time http://www.hkjzshop.com consulting service